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1.  Disparate Associations of HLA Class I Markers with HIV-1 Acquisition and Control of Viremia in an African Population 
PLoS ONE  2011;6(8):e23469.
Background
Acquisition of human immunodeficiency virus type 1 (HIV-1) infection is mediated by a combination of characteristics of the infectious and the susceptible member of a transmission pair, including human behavioral and genetic factors, as well as viral fitness and tropism. Here we report on the impact of established and potential new HLA class I determinants of heterosexual HIV-1 acquisition in the HIV-1-exposed seronegative (HESN) partners of serodiscordant Zambian couples.
Methodology/Principal Findings
We assessed the relationships of behavioral and clinically documented risk factors, index partner viral load, and host genetic markers to HIV-1 transmission among 568 cohabiting couples followed for at least nine months. We genotyped subjects for three classical HLA class I genes known to influence immune control of HIV-1 infection. From 1995 to December 2006, 240 HESNs seroconverted and 328 remained seronegative. In Cox proportional hazards models, HLA-A*68:02 and the B*42-C*17 haplotype in HESN partners were significantly and independently associated with faster HIV-1 acquisition (relative hazards = 1.57 and 1.55; p = 0.007 and 0.013, respectively) after controlling for other previously established contributing factors in the index partner (viral load and specific class I alleles), in the HESN partner (age, gender), or in the couple (behavioral and clinical risk score). Few if any previously implicated class I markers were associated here with the rate of acquiring infection.
Conclusions/Significance
A few HLA class I markers showed modest effects on acquisition of HIV-1 subtype C infection in HESN partners of discordant Zambian couples. However, the striking disparity between those few markers and the more numerous, different markers found to determine HIV-1 disease course makes it highly unlikely that, whatever the influence of class I variation on the rate of infection, the mechanism mediating that phenomenon is identical to that involved in disease control.
doi:10.1371/journal.pone.0023469
PMCID: PMC3157381  PMID: 21858133
2.  Bacterial Vaginosis Associated with Increased Risk of Female-to-Male HIV-1 Transmission: A Prospective Cohort Analysis among African Couples 
PLoS Medicine  2012;9(6):e1001251.
In a prospective study, Craig Cohen and colleagues investigate the association between bacterial vaginosis and the risk of female-to-male HIV-1 transmission.
Background
Bacterial vaginosis (BV), a disruption of the normal vaginal flora, has been associated with a 60% increased risk of HIV-1 acquisition in women and higher concentration of HIV-1 RNA in the genital tract of HIV-1–infected women. However, whether BV, which is present in up to half of African HIV-1–infected women, is associated with an increase in HIV-1 transmission to male partners has not been assessed in previous studies.
Methods and Findings
We assessed the association between BV on female-to-male HIV-1 transmission risk in a prospective study of 2,236 HIV-1–seropositive women and their HIV-1 uninfected male partners from seven African countries from a randomized placebo-controlled trial that enrolled heterosexual African adults who were seropositive for both HIV-1 and herpes simplex virus (HSV)-2, and their HIV-1–seronegative partners. Participants were followed for up to 24 months; every three months, vaginal swabs were obtained from female partners for Gram stain and male partners were tested for HIV-1. BV and normal vaginal flora were defined as a Nugent score of 7–10 and 0–3, respectively. To reduce misclassification, HIV-1 sequence analysis of viruses from seroconverters and their partners was performed to determine linkage of HIV-1 transmissions. Overall, 50 incident HIV-1 infections occurred in men in which the HIV-1–infected female partner had an evaluable vaginal Gram stain. HIV-1 incidence in men whose HIV-1–infected female partners had BV was 2.91 versus 0.76 per 100 person-years in men whose female partners had normal vaginal flora (hazard ratio 3.62, 95% CI 1.74–7.52). After controlling for sociodemographic factors, sexual behavior, male circumcision, sexually transmitted infections, pregnancy, and plasma HIV-1 RNA levels in female partners, BV was associated with a greater than 3-fold increased risk of female-to-male HIV-1 transmission (adjusted hazard ratio 3.17, 95% CI 1.37–7.33).
Conclusions
This study identified an association between BV and increased risk of HIV-1 transmission to male partners. Several limitations may affect the generalizability of our results including: all participants underwent couples HIV counseling and testing and enrolled in an HIV-1 prevention trial, and index participants had a baseline CD4 count ≥250 cells/mm3 and were HSV-2 seropositive. Given the high prevalence of BV and the association of BV with increased risk of both female HIV-1 acquisition and transmission found in our study, if this association proves to be causal, BV could be responsible for a substantial proportion of new HIV-1 infections in Africa. Normalization of vaginal flora in HIV-1–infected women could mitigate female-to-male HIV-1 transmission.
Trial Registration: ClinicalTrials.com NCT00194519
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Since the first reported case of AIDS in 1981, the number of people infected with HIV, the virus that causes AIDS, has risen steadily. By the end of 2010, 34 million people were living with HIV/AIDS. At the beginning of the epidemic more men than women were infected with HIV. Now, however, 50% of all adults infected with HIV are women and in sub-Saharan Africa, where two-thirds of HIV-positive people live, women account for 59% of people living with HIV. Moreover, among 15–24 year-olds, women are eight times more likely than men to be HIV-positive. This pattern of infection has developed because most people in sub-Saharan Africa contract HIV through unprotected heterosexual sex. The risk of HIV transmission for both men and women in Africa and elsewhere can be reduced by abstaining from sex, by only having one or a few partners, by always using condoms, and by male circumcision. In addition, several studies suggest that antiretroviral therapy (ART) greatly reduces HIV transmission.
Why Was This Study Done?
Unfortunately, in sub-Saharan Africa, only about a fifth of HIV-positive people are currently receiving ART, which means that there is an urgent need to find other effective ways to reduce HIV transmission in this region. In this prospective cohort study (a type of study that follows a group of people for some time to see which personal characteristics are associated with disease development), the researchers investigate whether bacterial vaginosis—a condition in which harmful bacteria disrupt the normal vaginal flora—increases the risk of female-to-male HIV transmission among African couples. Bacterial vaginosis, which is extremely common in sub-Saharan Africa, has been associated with an increased risk of HIV acquisition in women and induces viral replication and shedding in the vagina in HIV-positive women, which may mean that HIV-positive women with bacterial vaginosis are more likely to transmit HIV to their male partners than women without this condition. If this is the case, then interventions that reduce the incidence of bacterial vaginosis might be valuable HIV prevention strategies.
What Did the Researchers Do and Find?
The researchers analyzed data collected from 2,236 heterosexual African couples enrolled in a clinical trial (the Partners in Prevention HSV/HIV Transmission Study) whose primary aim was to investigate whether suppression of herpes simplex virus infection could prevent HIV transmission. In all the couples, the woman was HIV-positive and the man was initially HIV-negative. The female partners were examined every three months for the presence of bacterial vaginosis and the male partners were tested regularly for HIV infection. The researchers also determined whether the men who became HIV-positive were infected with the same HIV strain as their partner to check that their infection had been acquired from this partner. The HIV incidence in men whose partners had bacterial vaginosis was 2.9 per 100 person-years (that is, 2.9 out of every 100 men became HIV-positive per year) whereas the HIV incidence in men whose partners had a normal vaginal flora was 0.76 per 100 person-years. After controlling for factors that might affect the risk of HIV transmission such as male circumcision and viral levels in female partner's blood, the researchers estimated that bacterial vaginosis was associated with a 3.17-fold increased risk of female-to-male HIV transmission in their study population.
What Do These Findings Mean?
These findings suggest that HIV-positive African women with bacterial vaginosis are more than three times as likely to transmit HIV to their male partners as those with a normal vaginal flora. It is possible that some unknown characteristic of the men in this study might have increased both their own risk of HIV infection and their partner's risk of bacterial vaginosis. Nevertheless, because bacterial vaginosis is so common in Africa (half of the women in this study had bacterial vaginosis at least once during follow-up) and because this condition is associated with both female HIV acquisition and transmission, these findings suggest that bacterial vaginosis could be responsible for a substantial proportion of new HIV infections in Africa. Normalization of vaginal flora in HIV-infected women by frequent presumptive treatment with antimicrobials (treatment with a curative dose of antibiotics without testing for bacterial vaginosis) or possibly by treatment with probiotics (live “good” bacteria) might, therefore, reduce female-to-male HIV transmission in sub-Saharan Africa.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001251.
Information is available from the US National Institute of Allergy and infectious diseases on all aspects of HIV infection and AIDS and on bacterial vaginosis
The US Centers for Disease Control and Prevention has information on all aspects of HIV/AIDS, including specific information about HIV/AIDS and women; it also has information on bacterial vaginosis (in English and Spanish)
NAM/aidsmap provides basic information about HIV/AIDS, and summaries of recent research findings on HIV care and treatment, and information on bacterial vaginosis and HIV transmission (in several languages)
Information is available from Avert, an international AIDS nonprofit group on many aspects of HIV/AIDS, including detailed information on HIV and AIDS prevention, on women, HIV and AIDS and on HIV/AIDS in Africa (in English and Spanish); personal stories of women living with HIV are available; the website Healthtalkonline also provides personal stories about living with HIV
More information about the Partners in Prevention HSV/HIV Transmission Study is available
doi:10.1371/journal.pmed.1001251
PMCID: PMC3383741  PMID: 22745608
3.  Influence of CCR5 and CCR2 Genetic Variants in the Resistance/Susceptibility to HIV in Serodiscordant Couples from Colombia 
AIDS Research and Human Retroviruses  2013;29(12):1594-1603.
Abstract
The main genetic factor related to HIV-1 resistance is the CCR5-Δ32 mutation; however, the homozygous genotype is uncommon. The CCR5-Δ32 mutation along with single nucleotide polymorphisms (SNPs) in the CCR5 promoter and the CCR2-V64I mutation have been included in seven human haplogroups (HH) previously associated with resistance/susceptibility to HIV-1 infection and different rates of AIDS progression. Here, we determined the association of the CCR5 promoter SNPs, the CCR5-Δ32 mutation, CCR2-V64I SNP, and HH frequencies with resistance/susceptibility to HIV-1 infection in a cohort of HIV-1-serodiscordant couples from Colombia. Seventy HIV-1-exposed, but seronegative (HESN) individuals, 57 seropositives (SP), and 112 healthy controls (HC) were included. The CCR5-Δ32 mutation and CCR2-V64I SNP were identified by PCR, and the CCR5 promoter SNPs were evaluated by sequencing. None of the individuals exhibited a homozygous Δ32 genotype; the CCR2-I allele was more frequent in HESN (34%) than HC (23%) (p=0.039, OR=1.672). The frequency of the 29G allele was higher in SP than HC (p=0.003, OR=3). HHF2 showed a higher frequency in HC (19%) than SP (9%) (p=0.027), while HHG1 was more frequent in SP (11.1%) than in HC (4.2%) (p=0.019). The AGACCAC-CCR2-I-CCR5 wild-type haplotype showed a higher frequency in SP (14.2%) than in HC (3.7%) (p=0.001). In conclusion, the CCR5-Δ32 allele is not responsible for HIV-1 resistance in this HESN group; however, the CCR2-I allele could be protective, while the 29G allele might increase the likelihood of acquiring HIV-1 infection. HHG1 and the AGACCAC-CCR2-I-CCR5 wild-type haplotype might promote HIV-1 infection while HHF2 might be related to resistance. However, additional studies are required to evaluate the implications of these findings.
doi:10.1089/aid.2012.0299
PMCID: PMC3848445  PMID: 24098976
4.  Comparison of Sexual Behavior and HIV Risk between Two HIV-1 Serodiscordant Couple Cohorts: The CHAVI 002 Study 
PLoS ONE  2012;7(5):e37727.
Background
The CHAVI002 study was designed to characterize immune responses, particularly HIV-specific T-cell responses, amongst 2 cohorts of HIV-exposed seronegative (HESN) individuals. The absence of a clear definition of HESNs has impaired comparison of research within and between such cohorts. This report describes two distinct HESN cohorts and attempts to quantify HIV exposure using a ‘HIV risk index’ (RI) model.
Methods
HIV serodiscordant couples (UK; 24, Uganda; 72) and HIV unexposed seronegative (HUSN) controls (UK; 14, Uganda; 26 couples, 3 individuals) completed sexual behavior questionnaires every 3 months over a 9 month period. The two cohorts were heterogeneous, with most HESNs in the UK men who have sex with men (MSM), while all HESNs in Uganda were in heterosexual relationships. Concordance of responses between partners was determined. Each participant’s sexual behavior score (SBS) was estimated based on the number and type of unprotected sex acts carried out in defined time periods. Independent HIV acquisition risk factors (partner plasma viral load, STIs, male circumcision, pregnancy) were integrated with the SBS, generating a RI for each HESN.
Results
96 HIV serodiscordant couples completed 929 SBQs. SBSs remained relatively stable amongst the UK cohort, whilst decreasing from Visit 1 to 2 in the Ugandan cohort. Compared to the Ugandan cohort, SBSs and RIs in the UK cohort were lower at visit 1, and generally higher at later visits. Differences between the cohorts, with lower rates of ART use in Uganda and higher risk per-act sex in the UK, had major impacts on the SBSs and RIs of each cohort. There was one HIV transmission event in the UK cohort.
Conclusions
Employment of a risk quantification model facilitated quantification and comparison of HIV acquisition risk across two disparate HIV serodiscordant couple cohorts.
doi:10.1371/journal.pone.0037727
PMCID: PMC3358272  PMID: 22629447
5.  Human Leukocyte Antigen Class I Genotypes in Relation to Heterosexual HIV Type 1 Transmission within Discordant Couples1 
Differences in immune control of HIV-1 infection are often attributable to the highly variable HLA class I molecules that present viral epitopes to cytotoxic T-lymphocytes. In our immunogenetic analyses of 429 HIV-1 discordant Zambian couples (infected index partners paired with cohabiting seronegative partners), several HLA class I variants in index partners were associated with contrasting rates and incidence of HIV-1 transmission within a 12-year study period. In particular, A*3601 on the A*36-Cw*04-B*53 haplotype was the most unfavorable marker of HIV-1 transmission by index partners, while Cw*1801 (primarily on the A*30-Cw*18-B*57 haplotype) was the most favorable, irrespective of the direction of transmission (male to female or female to male) and other commonly recognized co-factors of infection, including age and genital ulcer/inflammation. The same HLA markers were further associated with contrasting viral load levels in index partners, but they had no clear impact on HIV-1 acquisition by the seronegative partners. Thus, HLA class I gene products not only mediate HIV-1 pathogenesis and evolution but also influence heterosexual HIV-1 transmission. {This is an author-produced version of a manuscript accepted for publication in The Journal of Immunology (The JI). The American Association of Immunologists, Inc. (AAI), publishers of The JI, holds the copyright to this manuscript. This manuscript has not been copyedited or subjected to editorial proofreading by The JI; hence it may differ from the final version published in The JI (online and in print). AAI (The JI) is not liable for errors or omissions in this author-produced version of the manuscript or in any version derived from it by the United States National Institutes of Health or any other third party. The final, citable version of record can be found at www.jimmunol.org}.
PMCID: PMC2570252  PMID: 18684953
AIDS; Comparative Immunology; Human; MHC
6.  Partner Characteristics Predicting HIV-1 Set Point in Sexually Acquired HIV-1 Among African Seroconverters 
Abstract
Plasma HIV-1 RNA set point is an important predictor of HIV-1 disease progression. We hypothesized that inoculum size and HIV-1 exposure prior to HIV-1 transmission may modulate set point. We evaluated predictors of set point among 141 African HIV-1 seroconverters and their HIV-1-infected study partners. We compared characteristics of seroconverters and their HIV-1-infected partners and HIV-1 set point. Data were from a clinical trial of genital HSV-2 suppression with acyclovir to reduce HIV-1 transmission in HIV-1 serodiscordant couples with HIV-1 transmission linkage assigned through virus sequencing. Our analysis includes data from all transmissions including those with transmission linkage to the HIV-1-infected “source partner” and those that were not linked to their HIV-1-infected study partner. In multivariable analysis, higher plasma HIV-1 in source partners was associated with higher seroconverter set point (+0.44 log10 copies/ml per log10 source partner plasma HIV-1, p<0.001). In addition, bacterial vaginosis (BV) among female source partners near the time of infection was associated with higher set point in their male seroconverters (+0.49 log10, p=0.04). Source partner characteristics associated with lower set point included male circumcision (−0.63 log10, p=0.03) and assignment to acyclovir (−0.44 log10, p=0.02). The proportion of variation in set point explained by plasma HIV-1 RNA of the source partner, after controlling for other factors, was 0.06. Source partner plasma HIV-1 level is the most significant predictor of seroconverter set point, possibly reflecting characteristics of the transmitted virus. Acyclovir use, BV among women source partners, and circumcision among male source partners may alter the set point by affecting transmitted virus inoculum in the source partners' genital compartment.
doi:10.1089/aid.2012.0206
PMCID: PMC3537302  PMID: 23061422
7.  Quantifying Ongoing HIV-1 Exposure in HIV-1–Serodiscordant Couples to Identify Individuals With Potential Host Resistance to HIV-1 
The Journal of Infectious Diseases  2012;206(8):1299-1308.
Background. Immunogenetic correlates of resistance to HIV-1 in HIV-1–exposed seronegative (HESN) individuals with consistently high exposure may inform HIV-1 prevention strategies. We developed a novel approach for quantifying HIV-1 exposure to identify individuals remaining HIV-1 uninfected despite persistent high exposure.
Methods. We used longitudinal predictors of HIV-1 transmission in HIV-1 serodiscordant couples to score HIV-1 exposure and define HESN clusters with persistently high, low, and decreasing risk trajectories. The model was validated in an independent cohort of serodiscordant couples. We describe a statistical tool that can be applied to other HESN cohorts to identify individuals with high exposure to HIV-1.
Results. HIV-1 exposure was best quantified by frequency of unprotected sex with, plasma HIV-1 RNA levels among, and presence of genital ulcer disease among HIV-1–infected partners and by age, pregnancy status, herpes simplex virus 2 serostatus, and male circumcision status among HESN participants. Overall, 14% of HESN individuals persistently had high HIV-1 exposure and exhibited a declining incidence of HIV-1 infection over time.
Conclusions. A minority of HESN individuals from HIV-1–discordant couples had persistent high HIV-1 exposure over time. Decreasing incidence of infection in this group suggests these individuals were selected for resistance to HIV-1 and may be most appropriate for identifying biological correlates of natural host resistance to HIV-1 infection.
doi:10.1093/infdis/jis480
PMCID: PMC3448964  PMID: 22926009
8.  CCR5 Haplotypes Influence HCV Serostatus in Caucasian Intravenous Drug Users 
PLoS ONE  2013;8(7):e70561.
Background
Up to 90% HIV-1 positive intravenous drug users (IDUs) are co-infected with HCV. Although best recognized for its function as a major co-receptor for cell entry of HIV, CC chemokine receptor 5 (CCR5) has also been implicated in the pathogenesis of HCV infection. Here, we investigated whether CCR5 haplotypes influence HIV-1 and HCV seropositivity among 373 Caucasian IDUs from Estonia.
Methods
Of these IDUs, 56% and 44% were HIV and HCV seropositive, respectively, and 47% were coinfected. 500 blood donors seronegative for HIV and HCV were also evaluated. CCR5 haplotypes (HHA to HHG*2) were derived after genotyping nine CCR2–CCR5 polymorphisms. The association between CCR5 haplotypes with HIV and/or HCV seropositivity was determined using logistic regression analysis. Co-variates included in the models were length of intravenous drug use, HBV serostatus and copy number of CCL3L1, the gene encoding the most potent HIV-suppressive chemokine and ligand for CCR5.
Results
Compared to IDUs seronegative for both HCV and HIV (HCV−/HIV-), IDUs who were HCV+/HIV- and HCV+/HIV+were 92% and 82%, respectively, less likely to possess the CCR5-HHG*1 haplotype, after controlling for co-variates (Padjusted = 1.89×10−4 and 0.003, respectively). This association was mostly due to subjects bearing the CCR5 HHE and HHG*1 haplotype pairs. Approximately 25% and<10% of HCV−/HIV- IDUs and HCV−/HIV- blood donors, respectively, possessed the HHE/HHG*1 genotype.
Conclusions
Our findings suggest that HHG*1-bearing CCR5 genotypes influence HCV seropositivity in a group of Caucasian IDUs.
doi:10.1371/journal.pone.0070561
PMCID: PMC3723663  PMID: 23936229
9.  Genetic Variations and Heterosexual HIV-1 Infection: Analysis of Clustered Genes Encoding CC-motif Chemokine Ligands 
Genes and immunity  2011;13(2):202-205.
Several CC-motif chemokine ligands (CCLs) can block HIV-1 binding sites on CC-motif chemokine receptor 5 (CCR5) and inhibit viral entry. We studied single nucleotide polymorphisms (SNPs) in genes encoding three CCR5 ligands [CCL3 (MIP-1α), CCL4 (MIP-1β), and CCL5 (RANTES)] along with an adjacent gene encoding a CCR2 ligand [CCL2 (MCP-1)] to identify candidate markers for HIV-1 infection and pathogenesis. Analyses of 567 HIV-1 serodiscordant Zambian couples revealed that rs5029410C (in CCL3 intron 2) was associated with lower viral load (VL) in seroconverters, adjusted for gender and age (regression β=−0.57 log10, P=4×10−6). In addition, rs34171309A in CCL3 exon 3 was associated with increased risk of HIV-1 acquisition in exposed seronegatives (hazard ratio=1.52, P=0.006 when adjusted for donor VL and genital ulcer/inflammation). The CCL3 exon 3 SNP, encoding a conservative Glu-to-Asp substitution, and five neighboring SNPs in tight linkage disequilibrium all showed similar associations with HIV-1 acquisition. How these multiple CCL3 SNPs may alter the occurrence or course of HIV-1 infection remains to be determined.
doi:10.1038/gene.2011.70
PMCID: PMC3559129  PMID: 21975429
HIV-1 transmission; CCL2; CCL3; CCL4; CCL5; SNP
10.  HIV-1-Specific Enzyme-Linked Immunosorbent Spot Assay Responses in HIV-1-Exposed Uninfected Partners in Discordant Relationships Compared to Those in Low-Risk Controls 
Clinical and Vaccine Immunology : CVI  2012;19(11):1798-1805.
A number of studies of highly exposed HIV-1-seronegative individuals (HESN) have found HIV-1-specific cellular responses. However, there is limited evidence that responses prevent infection or are linked to HIV-1 exposure. Peripheral blood mononuclear cells (PBMC) were isolated from HESN in HIV-1-discordant relationships and low-risk controls in Nairobi, Kenya. HIV-1-specific responses were detected using gamma interferon (IFN-γ) enzyme-linked immunosorbent spot (ELISpot) assays stimulated by peptide pools spanning the subtype A HIV-1 genome. The HIV-1 incidence in this HESN cohort was 1.5 per 100 person years. Positive ELISpot responses were found in 34 (10%) of 331 HESN and 14 (13%) of 107 low-risk controls (odds ratio [OR] = 0.76; P = 0.476). The median immunodominant response was 18.9 spot-forming units (SFU)/106 peripheral blood mononuclear cells (PBMC). Among HESN, increasing age (OR = 1.24 per 5 years; P = 0.026) and longer cohabitation with the HIV-1-infected partner (OR = 5.88 per 5 years; P = 0.003) were associated with responses. These factors were not associated with responses in controls. Other exposure indicators, including the partner's HIV-1 load (OR = 0.99 per log10 copy/ml; P = 0.974) and CD4 count (OR = 1.09 per 100 cells/μl; P = 0.238), were not associated with responses in HESN. HIV-1-specific cellular responses may be less relevant to resistance to infection among HESN who are using risk reduction strategies that decrease their direct viral exposure.
doi:10.1128/CVI.00179-12
PMCID: PMC3491560  PMID: 22971780
11.  Cervicovaginal HIV-1 Neutralizing IgA Detected among HIV-1-Exposed Seronegative Female Partners in HIV-1-Discordant Kenyan Couples 
AIDS (London, England)  2012;26(17):2155-2163.
Objective
Cervicovaginal HIV-1-neutralizing IgA was associated with reduced HIV-1 acquisition in a cohort of commercial sex workers. We aimed to define the prevalence and correlates of HIV-1-neutralizing IgA from HIV-1-exposed seronegative (HESN) women in HIV-1-serodiscordant relationships.
Methods
HIV-1-serodiscordant couples in Nairobi were enrolled and followed quarterly up to two years, and women in concordant HIV-1-negative relationships were enrolled as controls. Cervicovaginal, seminal, and blood samples were collected at enrollment and follow-up. Cervicovaginal IgA was assessed for HIV-1-neutralizing activity by a peripheral blood mononuclear cell-based assay using an HIV-1 clade A primary isolate.
Results
HESN women in discordant relationships had significantly more HIV-1-neutralizing IgA detected in genital secretions compared to control women (36 of 155 [23%] vs. 4 of 70 [6%], respectively; odds ratio [OR] 5.0; 95% confidence interval [CI] 1.70–14.64; P=0.003). These responses persisted over time in all available follow-up cervicovaginal samples from women with detectable HIV-1-neutralizing IgA at baseline. Partner median HIV-1 plasma viral load was lower among women who had HIV-1-neutralizing IgA compared to women without detectable activity (4.3 vs. 4.8 log10 copies/ml, respectively; OR 0.70; 95% CI 0.51–0.94; P=0.02). A similar trend was found with partner seminal viral load (OR 0.57; 95% CI 0.32–1.02; P=0.06).
Conclusion
HESN women were 5-times more likely to have neutralizing IgA in cervicovaginal secretions than low-risk control women, and these responses were inversely associated with partner viral load. These observations support the existence of antiviral activity in the mucosal IgA fraction following sexual HIV-1 exposure.
doi:10.1097/QAD.0b013e328359b99b
PMCID: PMC3799883  PMID: 22948273
HIV; immunoglobulin A; discordant couple; exposed uninfected; Africa; neutralization; viral load
12.  Distribution of Chemokine Receptor CCR2 and CCR5 Genotypes and Their Relative Contribution to Human Immunodeficiency Virus Type 1 (HIV-1) Seroconversion, Early HIV-1 RNA Concentration in Plasma, and Later Disease Progression 
Journal of Virology  2002;76(2):662-672.
At the CC (β) chemokine receptor 2 (CCR2) and CCR5 loci, combinations of common single-nucleotide polymorphisms (SNPs) and a 32-bp deletion (Δ32) form nine stable haplotypes (designated A through G*2). The distribution of these CCR2-CCR5 haplotypes was examined among 703 participants in the Multicenter AIDS Cohort Study (MACS), the District of Columbia Gay (DCG) Study, and the San Francisco Men’s Health Study (SFMHS). Highly exposed and persistently seronegative (HEPS; n = 90) Caucasian men from MACS more frequently carried heterozygous G*2 (Δ32) genotypes (especially A/G*2) and less frequently carried the homozygous E/E genotype compared with 469 Caucasian seroconverters (SCs) from the same cohort (P = 0.004 to 0.042). Among 341 MACS Caucasian SCs with 6- to 12-month human immunodeficiency virus type 1 (HIV-1) seroconversion intervals and no potent antiretroviral therapy, mean plasma HIV-1 RNA level during the initial 42 months after seroconversion was higher in carriers of the E/E genotype and lower in those with the 64I-bearing haplotype F*2 or the Δ32-bearing haplotype G*2 (and especially genotypes A/G*2 and F*2/G*2). A multivariable model containing these CCR markers showed significant composite effects on HIV-1 RNA at each of four postconversion intervals (P = 0.0004 to 0.050). In other models using time to AIDS as the endpoint, the same markers showed more modest contributions (P = 0.08 to 0.24) to differential outcome during 11.5 years of follow-up. Broadly consistent findings in the larger MACS Caucasian SCs and the smaller groups of MACS African-American SCs and the DCG and SFMHS Caucasian SCs indicate that specific CCR2-CCR5 haplotypes or genotypes mediate initial acquisition of HIV-1 infection, early host-virus equilibration, and subsequent pathogenesis.
doi:10.1128/JVI.76.2.662-672.2002
PMCID: PMC136835  PMID: 11752157
13.  Optimal Uses of Antiretrovirals for Prevention in HIV-1 Serodiscordant Heterosexual Couples in South Africa: A Modelling Study 
PLoS Medicine  2011;8(11):e1001123.
Hallett et al use a mathematical model to examine the long-term impact and cost-effectiveness of different pre-exposure prophylaxis (PrEP) strategies for HIV prevention in serodiscordant couples.
Background
Antiretrovirals have substantial promise for HIV-1 prevention, either as antiretroviral treatment (ART) for HIV-1–infected persons to reduce infectiousness, or as pre-exposure prophylaxis (PrEP) for HIV-1–uninfected persons to reduce the possibility of infection with HIV-1. HIV-1 serodiscordant couples in long-term partnerships (one member is infected and the other is uninfected) are a priority for prevention interventions. Earlier ART and PrEP might both reduce HIV-1 transmission in this group, but the merits and synergies of these different approaches have not been analyzed.
Methods and Findings
We constructed a mathematical model to examine the impact and cost-effectiveness of different strategies, including earlier initiation of ART and/or PrEP, for HIV-1 prevention for serodiscordant couples. Although the cost of PrEP is high, the cost per infection averted is significantly offset by future savings in lifelong treatment, especially among couples with multiple partners, low condom use, and a high risk of transmission. In some situations, highly effective PrEP could be cost-saving overall. To keep couples alive and without a new infection, providing PrEP to the uninfected partner could be at least as cost-effective as initiating ART earlier in the infected partner, if the annual cost of PrEP is <40% of the annual cost of ART and PrEP is >70% effective.
Conclusions
Strategic use of PrEP and ART could substantially and cost-effectively reduce HIV-1 transmission in HIV-1 serodiscordant couples. New and forthcoming data on the efficacy of PrEP, the cost of delivery of ART and PrEP, and couples behaviours and preferences will be critical for optimizing the use of antiretrovirals for HIV-1 prevention.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Every year, about 2.5 million people become infected with HIV, the virus that causes AIDS. HIV is usually transmitted through unprotected sex with an HIV-infected partner. It destroys immune system cells (including CD4 cells, a type of lymphocyte), leaving infected individuals susceptible to other infections. There is no cure for AIDS, although HIV can be held in check with antiretroviral therapy (ART), and there is no vaccine that protects against HIV infection. So, to halt the AIDS epidemic, other ways of preventing the spread of HIV are needed. Antiretroviral drugs could potentially be used in two ways to reduce HIV transmission. First, ART could be given to HIV-infected people before they need it for their own health to reduce their infectiousness; the World Health Organization currently recommends that HIV-positive people initiate ART when their CD4 count drops below 350 cells/µl blood but in many African countries ART is only initiated when CD4 counts fall below 200 cells/µl. Second, ART could be given to HIV-uninfected people to reduce acquisition of the virus. This approach—preexposure prophylaxis (PrEP)—has provided protection against HIV transmission in some but not all clinical trials.
Why Was This Study Done?
Couples in long-term relationships where one partner is HIV-positive and the other is HIV-negative (HIV serodiscordant couples) are a priority group for prevention interventions. In sub-Saharan Africa, where most new HIV infections occur, 10%–20% of stable partnerships are serodiscordant and condom use is often low, not least because such couples may want children. Earlier ART or PrEP might reduce HIV transmission in this group but the merits of different approaches have not been analyzed. In this study, the researchers use a mathematical model to examine the long-term impact and cost-effectiveness of different PrEP and ART strategies for HIV prevention in serodiscordant couples.
What Did the Researchers Do and Find?
The researchers constructed a model to simulate HIV infection and disease progression among hypothetical HIV serodiscordant stable heterosexual couples. The model incorporated data from South Africa on couple characteristics, disease progression, ART use, pregnancies, frequency of sex, and contact with other sexual partners, as well as estimates of the effectiveness of PrEP from clinical trials. The researchers used the model to compare the impact on HIV transmission, survival and quality of life, and the cost-effectiveness of no PrEP with four PrEP strategies—always use PrEP after diagnosis of HIV serodiscordancy, use PrEP up to and for a year after ART initiation by the HIV-infected partner (at a CD4 count of ≤200 cells/µl or ≤350 cells/µl), use PrEP only up to ART initiation by the infected partner, and use PrEP only while trying for a baby and during pregnancy. The model predicts, for example, that the cost per infection averted of PrEP used before ART initiation will be offset by future savings in lifelong treatment, particularly among couples with multiple partners, low condom use, and a high risk of transmission. To keep couples alive without the HIV-uninfected partner becoming infected, it could be more cost-effective to provide PrEP to the uninfected partner than to initiate ART earlier in the infected partner, provided the annual cost of PrEP is less than 40% of the annual cost of ART and PrEP is more than 70% effective. Finally, if PREP is 30%–60% effective, the most cost-effective strategy for couples could be to use PrEP in the uninfected partner prior to ART initiation in the infected partner at a CD4 count ≤350 cells/µl.
What Do These Findings Mean?
These findings suggest that the strategic use of PrEP and ART could cost-effectively reduce HIV transmission in HIV serodiscordant stable heterosexual couples in sub-Saharan Africa. The accuracy of these findings depends on the assumptions included in the mathematical model and on the data fed into it. In particular, the interpretation of these results is complicated by uncertainties in the likely cost of PrEP and the “real-world” effectiveness of PrEP. Nevertheless, these findings suggest that PrEP may become a valuable addition in some settings to existing approaches for HIV prevention such as condom promotion and male circumcision programs. Moreover, additional simulations with this mathematical model using more accurate information on the costs and effectiveness of PrEP could assist in future policy making decisions.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001123.
Information is available from the US National Institute of Allergy and infectious diseases on HIV infection and AIDS
NAM/aidsmap provides basic information about HIV/AIDS, summaries of recent research findings on HIV care and treatment, and a section on PrEP
Information is available from Avert, an international AIDS charity on many aspects of HIV/AIDS, including information on all aspects of HIV prevention, and on HIV/AIDS in Africa (in English and Spanish)
AVAC Global Advocacy for HIV Prevention provides up-to-date information on all aspects of HIV prevention, including PrEP
The US Centers for Disease Control and Prevention also has information on PrEP
WHO provides information about antiretroviral therapy
Patient stories about living with HIV/AIDS are available through Avert and through the charity website Healthtalkonline
doi:10.1371/journal.pmed.1001123
PMCID: PMC3217021  PMID: 22110407
14.  Risk Factors for HSV-2 Infection among Sexual Partners of HSV-2/HIV-1 Co-Infected Persons 
BMC Research Notes  2011;4:64.
Background
Herpes simplex virus type 2 (HSV-2) is the most frequent cause of genital ulcer disease worldwide and has been associated with increased risk for HIV-1 acquisition and transmission. We conducted a cross-sectional analysis of risk factors for HSV-2 infection among HIV-1 uninfected partners, whose partners were co-infected with HIV-1 and HSV-2.
Methods
Between November 2004 and April 2007, 3408 HIV-discordant couples, in which the HIV-1 infected partners were HSV-2 seropositive with CD4 250 cells/mm3 or greater, were enrolled in an HSV-2 suppression trial to prevent HIV-1 transmission at 14 sites in 7 African countries. Clinical & behavioral data, HSV-2 and HIV-1 testing were conducted at enrolment. Univariate and multivariate Poisson regression analyses were performed separately, by gender of the HIV-1 infected partner.
Results
Among 3354 HIV-1 uninfected participants, 32% were female and overall 71% were HSV-2 seropositive. Among couples with female HIV-1 infected partners, HIV-1 plasma RNA [aPR 1.03; 95% CI: 0.99 to 1.06; p = 0.11] and CD4 count [aPR 1.00; 95% CI: 0.98 to 1.01; p = 0.48] in the HSV-2/HIV-1 dually infected female and circumcision in the HIV-1 uninfected male partner [aPR 0.94; 95% CI: 0.88 to 1.00; p = 0.06] were not associated with reduced risk of HSV-2 seropositivity, after adjusting for other factors.
Conclusions
In this cross-sectional analysis of African HIV-1 serodiscordant heterosexual couples with prevalent HSV-2 infection in the HIV-1 infected partner, HIV-1 plasma RNA and CD4 count in the dually-infected partner and male circumcision in the HIV-1 uninfected partner were not associated with HSV-2 concordance.
Trial Registration
ClinicalTrials.gov NCT00194519
doi:10.1186/1756-0500-4-64
PMCID: PMC3064615  PMID: 21406077
15.  Effect of serotesting with counselling on condom use and seroconversion among HIV discordant couples in Africa. 
BMJ : British Medical Journal  1992;304(6842):1605-1609.
OBJECTIVE--To determine whether HIV testing and counselling increased condom use and decreased heterosexual transmission of HIV in discordant couples. DESIGN--Prospective study. SETTING--Kigali, the capital of Rwanda. SUBJECTS--Cohabiting couples with discordant HIV serology results. MAIN OUTCOME MEASURES--Condom use in the couple and HIV seroconversion in the negative partners. RESULTS--60 HIV discordant couples were identified, of whom 53 were followed for an average of 2.2 years. The proportion of discordant couples using condoms increased from 4% to 57% after one year of follow up. During follow up two of the 23 HIV negative men and six of the 30 HIV negative women seroconverted (seroconversion rates of 4 and 9 per 100 person years). The rate among women was less than half that estimated for similar women in discordant couples whose partners had not been serotested. Condom use was less common among those who seroconverted (100% v 5%, p = 0.01 in men; 67% v 25%, p = 0.14 in women). CONCLUSIONS--Roughly one in seven cohabiting couples in Kigali have discordant HIV serological results. Confidential HIV serotesting with counselling caused a large increase in condom use and was associated with a lower rate of new HIV infections. HIV testing is a promising intervention for preventing the spread of HIV in African cities.
PMCID: PMC1881972  PMID: 1628088
16.  Variants in Host Viral Replication Cycle Genes Are Associated With Heterosexual HIV-1 Acquisition in Africans 
Supplemental Digital Content is Available in the Text.
Objective:
We evaluated genetic variants in 51 candidate genes encoding proteins that interact with HIV-1 during the virus life cycle for association with HIV-1 outcomes in an African cohort.
Methods:
Using a nested case–control study within a cohort of heterosexual HIV-1–serodiscordant couples, we genotyped 475 haplotype-tagging single-nucleotide polymorphisms (tagSNPs) and 18 SNPs previously associated with HIV-1 transmission and/or progression (candidate SNPs) in 51 host genes. We used logistic and Cox proportional hazard regression with adjustment for sex, age, and population stratification to detect SNP associations with HIV-1 acquisition, plasma HIV-1 set point, and a composite measure of HIV-1 disease progression. Significant thresholds for tagSNP, but not candidate SNP, associations were subjected to Bonferroni correction for multiple testing.
Results:
We evaluated 491 HIV-1–infected and 335 HIV-1–uninfected individuals for 493 SNPs, 459 of which passed quality control filters. Candidate SNP PPIA rs8177826 and tagSNP SMARCB1 rs6003904 were significantly associated with HIV-1 acquisition risk (odds ratio = 0.14, P = 0.03, and odds ratio = 2.11, Pcorr = 0.01, respectively). Furthermore, the TT genotype for CCR5 rs1799988 was associated with a mean 0.2 log10 copies per milliliter lower plasma HIV-1 RNA set point (P = 0.04). We also identified significant associations with HIV-1 disease progression for variants in FUT2 and MBL2.
Conclusions:
Using a targeted gene approach, we identified variants in host genes whose protein products interact with HIV-1 during the virus replication cycle and were associated with HIV-1 outcomes in this African cohort.
doi:10.1097/QAI.0000000000000113
PMCID: PMC4025588  PMID: 24463784
HIV; cell cycle genes; genotype–phenotype association; HIV genetics; Africa
17.  CCR5 promoter haplotype transcription complex characterization 
CC chemokine receptor 5 (CCR5) is a major coreceptor for cell entry of human immunodeficiency virus (HIV); its expression is highly associated with virus replication and susceptibility. Single nucleotide polymorphisms (SNPs) in the CCR5 promoter play a critical role in CCR5 transcriptional regulation. HHA and HHE represent two contrasting haplotypes of CCR5 with two base pair difference in the promoter. Identifying the transcription factors (TFs) that differentially bind to the polymorphic sites (SNPs) in CCR5 haplotypes helps elucidate HIV transmission/pathogenesis. Promoter binding and two-dimensional southwestern blot analysis are coupled with HPLC-ESI-MS/MS to purify transcription complex and identify the differential TFs binding profile, including proteins bound to one haplotype in different amounts than the other and proteins specificly bound to one haplotype. This strategy has great promise for investigating how differential TF binding to CCR5 haplotypes may impact HIV-AIDS (acquired immune deficiency syndrome) susceptibility or disease progression.
doi:10.1353/hpu.2011.0169
PMCID: PMC3326658  PMID: 22102307
CCR5; haplotype; SNPs; HHA; HHE; promoter trapping; two-dimensional southwestern blot; transcription factors
18.  HIV Incidence and Risk Factors for Acquisition in HIV Discordant Couples in Masaka, Uganda: An HIV Vaccine Preparedness Study 
PLoS ONE  2011;6(8):e24037.
Objectives
To determine the incidence of and risk factors for HIV acquisition in a cohort of HIV-uninfected partners from HIV discordant couples in Masaka, Uganda, and to establish its suitability for HIV vaccine trials.
Methods
HIV-uninfected adults living in HIV discordant couple relationships were enrolled and followed for 2 years. Interviews, medical investigations, HIV counseling and testing, syphilis and urine pregnancy (women) tests were performed at quarterly visits. Sexual risk behaviour data were collected every 6 months.
Results
495 participants were enrolled, of whom 34 seroconverted during 786.6 person-years of observation (PYO). The overall HIV incidence rate [95% confidence interval (CI)] was 4.3 [3.1–6]; and 4.3 [2.8–6.4] and 4.4 [2.5–8] per 100 PYO in men and women respectively. Independent baseline predictors for HIV acquisition were young age [18–24 (aRR = 4.1, 95% CI 1.6–10.8) and 25–34 (aRR = 2.7, 95% CI 1.2–5.8) years]; alcohol use (aRR = 2.6, 95% CI 1.1–6); and reported genital discharge (aRR = 3.4, 95% CI 1.6–7.2) in the past year. Condom use frequency in the year preceding enrolment was predictive of a reduced risk of HIV acquisition [sometimes (aRR = 0.4, 95% CI 0.2–0.8); always (aRR = 0.1, 95% CI 0.02–0.9)]. In the follow-up risk analysis, young age [18–24 (aRR = 6.2, 95% CI 2.2–17.3) and 25-34 (aRR = 2.3, 95% CI 1.1–5.0) years], reported genital discharge (aRR = 2.5, 95% CI 1.1–5.5), serological syphilis (aRR 3.2, 95% CI 1.3–7.7) and the partner being ART naïve (aRR = 4.8, 95% CI 1.4–16.0) were independently associated with HIV acquisition. There were no seroconversions among participants who reported consistent condom use during the study.
Conclusions
The study has identified important risk factors for HIV acquisition among HIV discordant couples. HIV-uninfected partners in discordant couples may be a suitable population for HIV vaccine efficacy trials. However, recent confirmation that ART reduces heterosexual HIV transmission may make it unfeasible to conduct HIV prevention trials in this population.
doi:10.1371/journal.pone.0024037
PMCID: PMC3166075  PMID: 21909379
19.  Association of the ANRS-12126 Male Circumcision Project with HIV Levels among Men in a South African Township: Evaluation of Effectiveness using Cross-sectional Surveys 
PLoS Medicine  2013;10(9):e1001509.
Betran Auvert and colleagues report findings from the Bophelo Pele project, a community-based HIV prevention intervention offering free voluntary medical male circumcision (VMMC), that demonstrate an association between VMMC roll-out and a reduction in the incidence and prevalence of HIV in the community.
Please see later in the article for the Editors' Summary
Background
Randomized controlled trials have shown that voluntary medical male circumcision (VMMC) reduces HIV infection by 50% to 60% in sub-Saharan African populations; however, little is known about the population-level effect of adult male circumcision (MC) as an HIV prevention method. We assessed the effectiveness of VMMC roll-out on the levels of HIV in the South African township of Orange Farm where the first randomized controlled trial (RCT) to test the effect of VMMC on HIV acquisition was conducted in 2002–2005.
Methods and Findings
The Bophelo Pele project is a community-based campaign against HIV, which includes the roll-out of free VMMC. A baseline cross-sectional biomedical survey was conducted in 2007–2008 among a random sample of 1,998 men aged 15 to 49 (survey response rate 80.7%). In 2010–2011, we conducted a follow-up random survey among 3,338 men aged 15 to 49 (survey response rate 79.6%) to evaluate the project. Participants were interviewed, blood samples were collected and tested for HIV and recent HIV infection (using the BED HIV incidence assay), and MC status was assessed through a clinical examination. Data were analyzed using multivariate and propensity statistical methods.
Owing to the VMMCs performed in the context of the RCT and the Bophelo Pele project, the prevalence rate of adult MC increased from 0.12 (95% CI 0.10–0.14) to 0.53 (95% CI 0.51–0.55). Without these VMMCs, the HIV prevalence rate in 2010–2011 would have been 19% (95% CI 12%–26%) higher (0.147 instead of 0.123).
When comparing circumcised and uncircumcised men, no association of MC status with sexual behavior was detected. Among circumcised and uncircumcised men, the proportion consistently using condoms with non-spousal partners in the past 12 months was 44.0% (95% CI 41.7%–46.5%) versus 45.4% (95% CI 42.2%–48.6%) with weighted prevalence rate ratio (wPRR) = 0.94 (95% CI 0.85–1.03). The proportion having two or more non-spousal partners was 50.4% (95% CI 47.9%–52.9%) versus 44.2% (95% CI 41.3%–46.9%) with wPRR = 1.03 (95% CI 0.95–1.10).
We found a reduction of BED-estimated HIV incidence rate ranging from 57% (95% CI 29%–76%) to 61% (95% CI 14%–83%) among circumcised men in comparison with uncircumcised men.
Conclusions
Findings suggest that the roll-out of VMMC in Orange Farm is associated with a significant reduction of HIV levels in the community. The main limitation of the study is that it was not randomized and cannot prove a causal association. The roll-out of VMMC among adults in sub-Saharan Africa should be an international priority and needs to be accelerated to effectively combat the spread of HIV.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Every year about 2.2 million people (mostly in sub-Saharan Africa) become infected with HIV, the virus that causes AIDS. There is no cure for HIV/AIDS. Consequently, prevention of HIV transmission is extremely important. Because HIV is most often spread through unprotected sex with an infected partner, individuals can reduce their risk of HIV infection by abstaining from sex, by having only one or a few sexual partners, and by always using a male or female condom. The results of three randomized controlled trials conducted in sub-Saharan Africa also suggest that voluntary medical male circumcision (VMMC)—the removal of the foreskin, a loose fold of skin that covers the head of the penis—can reduce the heterosexual acquisition of HIV in men by 50%–60%. In 2007, the World Health Organization (WHO) and the Joint United Nations Programme on HIV/AIDS (UNAIDS) recommended that VMMC should be offered as part of comprehensive HIV risk reduction programs in settings with generalized HIV epidemics and low levels of male circumcision and prioritized 14 east and southern African countries for VMMC roll-out.
Why Was This Study Done?
To date, about 3 million VMMCs have been performed for HIV prevention but it is not known whether “real world” VMMC roll-out programs will replicate the promising results obtained in the earlier trials. Indeed, there are fears that “risk compensation” (an increase in risky sexual behaviors after VMMC) might lead to increased HIV transmission in regions where VMMC is rolled out. In this study, the researchers use sequential cross-sectional surveys (studies that collect data from a group of people at a single time point) to investigate HIV infection levels in men in Orange Farm, a township in South Africa where one of the randomized controlled trials of VMMC was undertaken. The surveys were conducted before and after implementation of the Bophelo Pele project, a community-based campaign against HIV that was initiated in 2008 and that includes free VMMC.
What Did the Researchers Do and Find?
The researchers asked a random sample of nearly 2,000 men aged 15–49 years about their sexual behavior (for example, how many non-spousal partners they had had over the past year), and their intention to become circumcised if uncircumcised in a baseline survey in 2007–2008. The study participants were also offered HIV counseling and testing (including a test that indicated whether the participant had recently become HIV positive) and were examined to see whether they were already circumcised. A similar follow-up survey was conducted in 2010–2011 in which more than 3,000 men were invited to take part. At baseline, 12% of the men surveyed had been circumcised (a prevalence of circumcision of 12%) whereas in the follow-up survey, the overall prevalence of circumcision and the prevalence of circumcision among 15–29 year-olds (an important target group for VMMC roll-out) were 53% and 58%, respectively. The overall HIV prevalence at follow-up was 12% and the researchers estimated that without the VMMCs performed during the Bophelo Pele project and the preceding randomized control trial the prevalence of HIV among men living in Orange Farm would have been 15% in 2011. Using various cut-off values and corrections for a laboratory-based test to measure recent HIV infections, the researchers reported a reduction in the rate of new HIV infections (incidence rate) ranging from 57% to 61% among circumcised men in comparison with uncircumcised men. Importantly, there was no evidence of an association between circumcision status and risky sexual behavior but circumcision was associated with a reduction in the number of men who had recently become HIV positive.
What Do These Findings Mean?
These findings suggest that VMMC roll out in Orange Farm is associated with a reduction in HIV infection levels in the community and that circumcision is not associated with changes in sexual behavior that might affect HIV infection rates. They also suggest that VMMC roll-out is associated with a rapid uptake of VMMC, especially among young men, in an African community where male circumcision is not a social norm. Because this study is not a randomized controlled trial, it cannot establish cause and effect. Thus, although the observed reduction in HIV prevalence among circumcised men compared to uncircumcised men suggests that circumcision provided protection against HIV acquisition within the study population, the results do not conclusively prove this. The findings of this study nevertheless support the continuation and acceleration of the roll-out of adult VMMC in Africa although further studies are needed to show whether VMMC roll-out is also associated with a reduction in HIV acquisition among women and among uncircumcised men.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001509.
Information and resources on male circumcision for HIV prevention are available
Information is available from the US National Institute of Allergy and infectious diseases on HIV infection and AIDS
NAM/aidsmap provides basic information about HIV/AIDS, summaries of recent research findings on HIV care and treatment, and information on male circumcision for the prevention of HIV transmission
Information is available from WHO and UNAIDS on all aspects of HIV/AIDS; the Clearinghouse on Male Circumcision, a resource provided by WHO, UNAIDS and other international bodies, provides information and tools for VMMC policy development and program implementation; a report entitled Progress in scaling up voluntary medical male circumcision for HIV prevention in East and Southern Africa, January-December 2011 is available
Information is available from Avert, an international AIDS charity on many aspects of HIV/AIDS, including information on HIV and AIDS in South Africa, on HIV prevention, and on circumcision and HIV (in English and Spanish)
A 2010 PLOS Medicine Research Article by Pascale Lissouba et al. provides more information about the Bophelo Pele project
Personal stories about living with HIV/AIDS are available through Avert, through Nam/aidsmap, and through the charity website Healthtalkonline; a personal story about circumcision in Zimbabwe is available
doi:10.1371/journal.pmed.1001509
PMCID: PMC3760784  PMID: 24019763
20.  Modified Kigali Combined Staging Predicts Risk of Mortality in HIV-Infected Adults in Lusaka, Zambia 
Abstract
We assessed the utility of the modified Kigali combined (MKC) staging system for predicting survival in HIV-infected Zambian adults in a prospective, longitudinal, open cohort. From 1995 to 2004, HIV-discordant couples (one HIV-infected partner and one HIV-negative partner) were recruited from couples' voluntary counseling and testing centers in Lusaka, Zambia and followed at 3-month intervals. MKC stage, which incorporates clinical stage with erythrocyte sedimentation rate (ESR), hematocrit, and body mass index (BMI), was determined at enrollment. Kaplan–Meier survival and Cox proportional hazard methods were used to calculate median survival and relative hazards. We enrolled 1479 HIV-discordant couples with a combined 7305 person-years of follow-up. Among HIV-infected participants over the 9-year study period, there were 333 confirmed deaths. The time to 50% mortality was 8.5 years with MKC stage 1 and 2 disease compared to 3.7 years with MKC stage 4 disease at enrollment. Survival rates at 3 years were 85% with MKC stage 1 and 2 disease, 74% with MKC stage 3 disease, and 51% with MKC stage 4 disease. A total of 275 HIV-negative partners seroconverted during follow-up. In comparison, survival rates at 3 years were 94% for HIV-negative participants and 92% for participants who seroconverted during follow-up. In multivariate analysis, MKC stage 4 disease (HR = 3.7, 95% CI = 2.7–5.0) remained a strong predictor of mortality. Incorporating ESR, hematocrit, and BMI with clinical staging is a powerful, low-cost tool to identify HIV-infected adults at high risk for mortality.
doi:10.1089/aid.2007.0297
PMCID: PMC2928550  PMID: 18593343
21.  Adherence to Antiretroviral Prophylaxis for HIV Prevention: A Substudy Cohort within a Clinical Trial of Serodiscordant Couples in East Africa 
PLoS Medicine  2013;10(9):e1001511.
Jessica Haberer and colleagues investigate the association between high adherence to antiretroviral pre-exposure prophylaxis and HIV transmission in a substudy of serodiscordant couples participating in a clinical trial.
Please see later in the article for the Editors' Summary
Background
Randomized clinical trials of oral antiretroviral pre-exposure prophylaxis (PrEP) for HIV prevention have widely divergent efficacy estimates, ranging from 0% to 75%. These discrepancies are likely due to differences in adherence. To our knowledge, no studies to date have examined the impact of improving adherence through monitoring and/or intervention, which may increase PrEP efficacy, or reported on objective behavioral measures of adherence, which can inform PrEP effectiveness and implementation.
Methods and Findings
Within the Partners PrEP Study (a randomized placebo-controlled trial of oral tenofovir and emtricitabine/tenofovir among HIV-uninfected members of serodiscordant couples in Kenya and Uganda), we collected objective measures of PrEP adherence using unannounced home-based pill counts and electronic pill bottle monitoring. Participants received individual and couples-based adherence counseling at PrEP initiation and throughout the study; counseling was intensified if unannounced pill count adherence fell to <80%. Participants were followed monthly to provide study medication, adherence counseling, and HIV testing. A total of 1,147 HIV-uninfected participants were enrolled: 53% were male, median age was 34 years, and median partnership duration was 8.5 years. Fourteen HIV infections occurred among adherence study participants—all of whom were assigned to placebo (PrEP efficacy = 100%, 95% confidence interval 83.7%–100%, p<0.001). Median adherence was 99.1% (interquartile range [IQR] 96.9%–100%) by unannounced pill counts and 97.2% (90.6%–100%) by electronic monitoring over 807 person-years. Report of no sex or sex with another person besides the study partner, younger age, and heavy alcohol use were associated with <80% adherence; the first 6 months of PrEP use and polygamous marriage were associated with >80% adherence. Study limitations include potential shortcomings of the adherence measures and use of a convenience sample within the substudy cohort.
Conclusions
The high PrEP adherence achieved in the setting of active adherence monitoring and counseling support was associated with a high degree of protection from HIV acquisition by the HIV-uninfected partner in heterosexual serodiscordant couples. Low PrEP adherence was associated with sexual behavior, alcohol use, younger age, and length of PrEP use.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Every year, about 2.5 million people (mostly living in sub-Saharan Africa) become infected with HIV, the virus that causes AIDS. HIV, which is usually transmitted through unprotected sex with an HIV-infected partner, destroys immune system cells, leaving infected individuals susceptible to other infections. There is no cure for AIDS, although antiretroviral drugs can hold HIV in check, and there is no vaccine against HIV infection. Individuals can reduce their risk of HIV infection by abstaining from sex, by having only one or a few low risk sexual partners, and by always using a condom. In addition, antiretroviral drugs can potentially be used in two ways to reduce HIV transmission. First, these drugs could be given to HIV-positive individuals to reduce their infectiousness. Second, antiretroviral drugs could be given to HIV-uninfected people to reduce acquisition of the virus. This approach—pre-exposure prophylaxis (PrEP)—has provided varying levels of protection against HIV infection in randomized controlled trials (RCT; studies that monitor the outcomes of groups of patients randomly assigned to receive different test drugs or a placebo/dummy drug).
Why Was This Study Done?
One hypothesis for the varying efficacy of PrEP in RCTs is differential adherence—differences in whether trial participants took the antiretroviral drugs correctly. Antiretroviral drugs only control HIV infections effectively when they are taken regularly and adherence to antiretroviral PrEP is probably also important for HIV prevention. Here, the researchers investigate adherence to antiretroviral prophylaxis in a substudy within the Partners PrEP Study, a placebo-controlled RCT of oral antiretroviral drugs among nearly 5,000 HIV-uninfected members of serodiscordant couples in East Africa. In serodiscordant couples, only one partner is HIV-positive; 20% of couples in Africa who know their HIV status are serodiscordant. In the Partner PrEP Study, the efficacy of HIV protection with oral antiretroviral drugs was 67%–75%.
What Did the Researchers Do and Find?
The researchers selected a “convenience” sample—a sample is taken non-randomly from a population that is close at hand—of 1,147 HIV-uninfected partners enrolled in Uganda. They used unannounced home-based pill counts (an approach that reduced the chance of participants dumping unused pills to appear more adherent than they actually were) and electronic pill bottle monitoring (a microchip in the medication bottle cap recorded whenever the bottle was opened) to measure PrEP adherence in this cohort. All the participants received adherence counseling at PrEP initiation and throughout the study; counseling was intensified if unannounced pill count adherence fell below 80%. Fourteen participants, all of whom had been assigned to placebo, became HIV-positive during the adherence substudy. The average adherence to PrEP was 99.1% and 97.2% as measured by unannounced pill counts and by electronic monitoring, respectively. About 7% and 26% of participants had less than 80% adherence as measured by unannounced pill count and electronic monitoring, respectively, during at least one 3-month period of the substudy. Greater than 80% adherence was associated with the first 6 months of PrEP use and polygamous marriage. Adherence less than 80% was associated with report of no sex or sex with another person besides the study partner, younger age, and heavy alcohol use. Finally, the adherence intervention (intensified counseling) was well received and in the first unannounced pill count after the intervention, adherence increased to above 80% in 92% of participants.
What Do These Findings Mean?
These findings indicate that the high level of PrEP adherence achieved in the setting of active adherence monitoring and counseling support was associated with a high level of protection from HIV acquisition by the HIV-uninfected partner in heterosexual serodiscordant couples. The findings also suggest that low PrEP adherence is associated with sexual behavior, alcohol use, younger age, and length of PrEP use. Several aspects of the study design may limit the accuracy of these findings. For example, although the adherence measures used here are probably more accurate than participant reports of missed doses and clinic-based pill counts (adherence measures that are often used in RCTs), they are not perfect. Nevertheless, these findings provide further support for the ability of PrEP to prevent HIV acquisition when taken regularly; they suggest that adherence interventions in the implementation setting should address sexual behavior, risk perception, and heavy alcohol use; and they provide data to guide ethical decisions about resource allocation for prevention and treatment of HIV infection.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001511.
The 2012 UNAIDS World AIDS Day Report provides up-to-date information about the AIDS epidemic and efforts to halt it
Information is available from the US National Institute of Allergy and infectious diseases on HIV infection and AIDS
NAM/aidsmap provides basic information about HIV/AIDS, summaries of recent research findings on HIV care and treatment, and information on HIV transmission and prevention and on PrEP
Information is available from Avert, an international AIDS charity, on many aspects of HIV/AIDS, including information on HIV and AIDS in Uganda, on HIV prevention, and on PrEP (in English and Spanish)
PrEP Watch provides detailed information about PrEP and links to other resources; it includes personal stories from people who have chosen to use PrEP
More information about the Partners PrEP Study is available
Personal stories about living with HIV/AIDS are available through Avert, through Nam/aidsmap, and through the charity website Healthtalkonline
doi:10.1371/journal.pmed.1001511
PMCID: PMC3769210  PMID: 24058300
22.  Concordance of CCR5 Genotypes that Influence Cell-Mediated Immunity and HIV-1 Disease Progression Rates 
The Journal of Infectious Diseases  2011;203(2):263-272.
We used cutaneous delayed-type hypersensitivity responses, a powerful in vivo measure of cell-mediated immunity, to evaluate the relationships among cell-mediated immunity, AIDS, and polymorphisms in CCR5, the HIV-1 coreceptor. There was high concordance between CCR5 polymorphisms and haplotype pairs that influenced delayed-type hypersensitivity responses in healthy persons and HIV disease progression. In the cohorts examined, CCR5 genotypes containing -2459G/G (HHA/HHA, HHA/HHC, HHC/HHC) or -2459A/A (HHE/HHE) associated with salutary or detrimental delayed-type hypersensitivity and AIDS phenotypes, respectively. Accordingly, the CCR5-Δ32 allele, when paired with non-Δ32-bearing haplotypes that correlate with low (HHA, HHC) versus high (HHE) CCR5 transcriptional activity, associates with disease retardation or acceleration, respectively. Thus, the associations of CCR5-Δ32 heterozygosity partly reflect the effect of the non-▵32 haplotype in a background of CCR5 haploinsufficiency. The correlations of increased delayed-type hypersensitivity with -2459G/G-containing CCR5 genotypes, reduced CCR5 expression, decreased viral replication, and disease retardation suggest that CCR5 may influence HIV infection and AIDS, at least in part, through effects on cell-mediated immunity.
doi:10.1093/infdis/jiq023
PMCID: PMC3071050  PMID: 21288827
23.  When Do HIV-Infected Women Disclose Their HIV Status to Their Male Partner and Why? A Study in a PMTCT Programme, Abidjan 
PLoS Medicine  2007;4(12):e342.
Background
In Africa, women tested for HIV during antenatal care are counselled to share with their partner their HIV test result and to encourage partners to undertake HIV testing. We investigate, among women tested for HIV within a prevention of mother-to-child transmission of HIV (PMTCT) programme, the key moments for disclosure of their own HIV status to their partner and the impact on partner HIV testing.
Methods and Findings
Within the Ditrame Plus PMTCT project in Abidjan, 546 HIV-positive and 393 HIV-negative women were tested during pregnancy and followed-up for two years after delivery. Circumstances, frequency, and determinants of disclosure to the male partner were estimated according to HIV status. The determinants of partner HIV testing were identified according to women's HIV status. During the two-year follow-up, disclosure to the partner was reported by 96.7% of the HIV-negative women, compared to 46.2% of HIV-positive women (χ2 = 265.2, degrees of freedom [df] = 1, p < 0.001). Among HIV-infected women, privileged circumstances for disclosure were just before delivery, during early weaning (at 4 mo to prevent HIV postnatal transmission), or upon resumption of sexual activity. Formula feeding by HIV-infected women increased the probability of disclosure (adjusted odds ratio 1.54, 95% confidence interval 1.04–2.27, Wald test = 4.649, df = 1, p = 0.031), whereas household factors such as having a co-spouse or living with family reduced the probability of disclosure. The proportion of male partners tested for HIV was 23.1% among HIV-positive women and 14.8% among HIV-negative women (χ2 = 10.04, df = 1, p = 0.002). Partners of HIV-positive women who were informed of their wife's HIV status were more likely to undertake HIV testing than those not informed (37.7% versus 10.5%, χ2 = 56.36, df = 1, p < 0.001).
Conclusions
In PMTCT programmes, specific psychosocial counselling and support should be provided to women during the key moments of disclosure of HIV status to their partners (end of pregnancy, weaning, and resumption of sexual activity). This support could contribute to improving women's adherence to the advice given to prevent postnatal and sexual HIV transmission.
In a mother-to-child HIV prevention program in Côte d'Ivoire, Annabel Desgrées-du-Loû and colleagues identify three junctures at which women tend to disclose their HIV status to partners.
Editors' Summary
Background.
Since the first reported case of AIDS (acquired immunodeficiency syndrome) in 1981, the number of people infected with the human immunodeficiency virus (HIV), which causes AIDS, has risen steadily. By the end of 2006, nearly 40 million people were infected, 25 million of them in sub-Saharan Africa. HIV is most often spread by having unprotected sex with an infected partner. In Africa, most sexual transmission of HIV is between partners in stable relationships—many such couples do not adopt measures that prevent viral transmission, such as knowing the HIV status of both partners and using condoms if one partner is HIV-positive. HIV can also pass from a mother to her baby during pregnancy, labor, or delivery, or through breastfeeding. Mother-to-child transmission (MTCT) of HIV can be reduced by giving anti-HIV drugs to the mother during pregnancy and labor and to her newborn baby, and by avoiding breastfeeding or weaning the baby early.
Why Was This Study Done?
Many African countries have programs for prevention of MTCT (PMTCT) that offer pregnant women prenatal HIV counseling and testing. As a result, women are often the first member of a stable relationship to know their HIV status. PMTCT programs advise women to disclose their HIV test result to their partner and to encourage him to have an HIV test. But for many women, particularly those who are HIV-positive, talking to their partner about HIV/AIDS is hard because of fears of rejection (which could mean loss of housing and food) or accusations of infidelity. Knowing more about when women disclose their HIV status and what makes them decide to do so would help the people running PMTCT programs to support women during the difficult process of disclosure. In this study, the researchers have investigated when and why women participating in a PMTCT research project in Abidjan (Côte d'Ivoire) told their partner about their HIV status and the impact this disclosure had on their partner's uptake of HIV testing.
What Did the Researchers Do and Find?
At regular follow-up visits, the researchers asked women in the Abidjan PMTCT project whether they had told their partners their HIV status and whether they were breast-feeding or had resumed sexual activity. Nearly all the women who tested negative for HIV, but slightly fewer than half of the HIV-positive (infected) women had told their partner about their HIV status by two years after childbirth. Two-thirds of the HIV-positive women who disclosed their status did so before delivery. Other key times for disclosure were at early weaning (4 months after birth) for women who breast-fed their babies, and when sexual activity resumed. HIV-positive women who bottle fed their babies from birth were more likely to tell their partners of their status than women who breast-fed. Factors that prevented women disclosing their HIV status included living in a polygamous relationship or living separately from their partners. Finally, the researchers report that the partners of HIV-positive women who disclosed their HIV status were about three times more likely to take an HIV test than the partners of HIV-positive women who did not disclose.
What Do These Findings Mean?
These findings identify three key times when women who have had an HIV test during pregnancy are likely to disclose their HIV status to their partner. The main one is before delivery and relates, in part, to how the mother plans to feed her baby. To bottle feed in Abidjan, women need considerable support from their partners and this may be the impetus for disclosing their HIV status. Disclosure at early weaning may reflect the woman's need to enlist her partner's support for this unusual decision—the normal time for weaning in Abidjan is 17 months. Finally, disclosure when sexual activity resumes may be necessary so that the woman can explain why she wants to use condoms. Although these findings need confirmation in other settings, targeting counseling and support within PMTCT programs to these key moments might help HIV-positive women to tell their partners about their status. This, hopefully, would help to reduce sexual transmission of HIV within stable relationships in sub-Saharan Africa.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040342.
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS and on HIV infection in women
HIV InSite has comprehensive information on all aspects of HIV/AIDS
Women Children and HIV provides extensive information on prevention of mother-to-child transmission of HIV in developing countries
Information is available from Avert, an international AIDS charity, on HIV and AIDS in Africa and on HIV and AIDS prevention
AIDSinfo, a service of the US Department of Health and Human Services provideshealth information for HIV-positive pregnant women (in English and Spanish)
doi:10.1371/journal.pmed.0040342
PMCID: PMC2100145  PMID: 18052603
24.  Polymorphisms in the CCR5 genes of African green monkeys and mice implicate specific amino acids in infections by simian and human immunodeficiency viruses. 
Journal of Virology  1997;71(11):8642-8656.
CCR5, a receptor for the CC chemokines RANTES, Mip1alpha, and Mip1beta, has been identified as a coreceptor for infections by macrophage-tropic isolates of human immunodeficiency virus type 1 (HIV-1). To study its structure and function, we isolated cDNA clones of human, African green monkey (AGM), and NIH/Swiss mouse CCR5s, and we quantitatively analyzed infections by macrophage-tropic HIV-1 and SIVmac251 after transfecting human HeLa-CD4 cells with the CCR5 expression vectors. The AGM and NIH/Swiss mouse CCR5 proteins are 97.7 to 98.3% and 79.8% identical to the human protein, respectively. In addition, we analyzed site-directed mutants and chimeras of these CCR5s. Cell surface expression of CCR5 proteins was monitored by using a specific rabbit antiserum and by binding the chemokine [125I]Mip1beta. Our major results were as follows. (i) Two distinct AGM CCR5 sequences were reproducibly found in DNA from CV-1 cells. The AGM clone 1 CCR5 protein differs from that of clone 2 by two substitutions, Y14N in the amino-terminal extracellular region and L352F at the carboxyl terminus. Interestingly, AGM clone 1 CCR5 was inactive as a coreceptor for all tested macrophage-tropic isolates of HIV-1, whereas AGM clone 2 CCR5 was active. As shown by chimera studies and site-directed mutagenesis, the Y14N substitution in AGM clone 1 CCR5 was solely responsible for blocking HIV-1 infections. In contrast, both AGM CCR5 clones were active coreceptors for SIVmac251. Studies of DNA samples from other AGMs indicated frequent additional CCR5 polymorphisms, and we cloned an AGM clone 2 variant with a Q93R substitution in the extracellular loop 1 from one heterozygote. This variant CCR5 was active as a coreceptor for SIVmac251 but was only weakly active for macrophage-tropic isolates of HIV-1. In addition, SIVmac251 appeared to be dependent on the extracellular amino terminus and loop 2 regions of human CCR5 for maximal infection. Our results suggest major differences in the interactions of SIVmac251 and macrophage-tropic HIV-1 isolates with 19, N13, and Y14 in the amino terminus; with Q93 in extracellular loop 1; and with extracellular loop 2 of human CCR5. (ii) The NIH/Swiss mouse CCR5 protein differs at multiple positions from sequences recently reported for other inbred strains of mice. This CCR5 was inactive as a coreceptor for HIV-1 and SIVmac251. Studies of chimeras that contained different portions of NIH/Swiss mouse CCR5 substituted into human CCR5, as well as the reciprocal chimeras, indicated that the amino-terminal region and extracellular loops 1 and 2 of human CCR5 contribute to its coreceptor activity for macrophage-tropic isolates of HIV-1. Specific differences with previous CCR5 chimera results occurred because the NIH/Swiss mouse CCR5 contains a unique substitution corresponding to P183L in extracellular loop 2 that is nonpermissive for coreceptor activity. We conclude that diverse CCR5 sequences occur in AGMs and mice, that SIVmac251 and macrophage-tropic HIV-1 isolates interact differently with specific CCR5 amino acids, and that multiple regions of human CCR5 contribute to its coreceptor functions. In addition, we have identified naturally occurring amino acid polymorphisms in three extracellular regions of CCR5 (Y14N, Q93R, and P183L) that do not interfere with cell surface expression or Mip1beta binding but prevent infections by macrophage-tropic isolates of HIV-1. In contrast to previous evidence, these results suggest that CCR5 contains critical sites that are essential for HIV-1 infections.
PMCID: PMC192328  PMID: 9343222
25.  Host Genetic Factors Associated with Symptomatic Primary HIV Infection and Disease Progression among Argentinean Seroconverters 
PLoS ONE  2014;9(11):e113146.
Background
Variants in HIV-coreceptor C-C chemokine receptor type 5 (CCR5) and Human leukocyte antigen (HLA) genes are the most important host genetic factors associated with HIV infection and disease progression. Our aim was to analyze the association of these genetic factors in the presence of clinical symptoms during Primary HIV Infection (PHI) and disease progression within the first year.
Methods
Seventy subjects diagnosed during PHI were studied (55 symptomatic and 15 asymptomatic). Viral load (VL) and CD4 T-cell count were evaluated. HIV progression was defined by presence of B or C events and/or CD4 T-cell counts <350 cell/mm3. CCR5 haplotypes were characterized by polymerase chain reaction and SDM-PCR-RFLP. HLA-I characterization was performed by Sequencing.
Results
Symptoms during PHI were significantly associated with lower frequency of CCR5-CF1 (1.8% vs. 26.7%, p = 0.006). Rapid progression was significantly associated with higher frequency of CCR5-CF2 (16.7% vs. 0%, p = 0.024) and HLA-A*11 (16.7% vs. 1.2%, p = 0.003) and lower frequency of HLA-C*3 (2.8% vs. 17.5%, p = 0.035). Higher baseline VL was significantly associated with presence of HLA-A*11, HLA-A*24, and absence of HLA-A*31 and HLA-B*57. Higher 6-month VL was significantly associated with presence of CCR5-HHE, HLA-A*24, HLA-B*53, and absence of HLA-A*31 and CCR5-CF1. Lower baseline CD4 T-cell count was significantly associated with presence of HLA-A*24/*33, HLA-B*53, CCR5-CF2 and absence of HLA-A*01/*23 and CCR5-HHA. Lower 6-month CD4 T-cell count was associated with presence of HLA-A*24 and HLA-B*53, and absence of HLA-A*01 and HLA-B*07/*39. Moreover, lower 12-month CD4 T-cell count was significantly associated with presence of HLA-A*33, HLA-B*14, HLA-C*08, CCR5-CF2, and absence of HLA-B*07 and HLA-C*07.
Conclusion
Several host factors were significantly associated with disease progression in PHI subjects. Most results agree with previous studies performed in other groups. However, some genetic factor associations are being described for the first time, highlighting the importance of genetic studies at a local level.
doi:10.1371/journal.pone.0113146
PMCID: PMC4236131  PMID: 25406087

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