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Human immunology  2011;72(4):312-318.
Populations of African ancestry continue to account for a disproportionate burden of human immunodeficiency virus type 1 (HIV-1) epidemic in the US. We investigated the effects of human leukocyte antigen (HLA) class I markers in association with virologic and immunologic control of HIV-1 infection among 338 HIV-1 subtype B-infected African Americans in two cohorts: REACH (Reaching for Excellence in Adolescent Care and Health) and HERS (HIV Epidemiology Research Study). One-year treatment-free interval measurements of HIV-1 RNA viral loads and CD4+ T-cells were examined both separately and combined to represent three categories of HIV-1 disease control (76 “controllers,” 169 “intermediates,” and 93 “non-controllers”). Certain previously or newly implicated HLA class I alleles (A*32, A*36, A*74, B*14, B*1510, B*3501, B*45, B*53, B*57, Cw*04, Cw*08, Cw*12, and Cw*18) were associated with one or more of the endpoints in univariate analyses. After multivariable adjustments for other genetic and non-genetic risk factors of HIV-1 progression, the subset of alleles more strongly or consistently associated with HIV-1 disease control included A*32, A*74, B*14, B*45, B*53, B*57, and Cw*08. Carriage of infrequent HLA-B but not HLA-A alleles was associated with more favorable disease outcomes. Certain HLA class I associations with control of HIV-1 infection span the boundaries of race and viral subtype; while others appear confined within one or the other of those boundaries.
PMCID: PMC3778654  PMID: 21262311
HLA class I; Allele frequency; HIV-1 control; African American
2.  Incidence, Prevalence and Epidemiology of Herpes Simplex Virus-2 in HIV-1-positive and HIV-1-negative Adolescents 
Sexually Transmitted Diseases  2012;39(4):300-305.
Several studies have assessed risk factors associated with herpes simplex virus-2 (HSV-2) prevalence in adults; however, few have focused on HSV-2 incidence, particularly in adolescents. The objective of this study was to determine HSV-2 prevalence and incidence and associated risk factors in a HIV-1-positive and at risk HIV-1-negative adolescent population.
Sera were tested for HSV-2 antibodies in 518 adolescents in the Reaching for Excellence in Adolescent Care and Health (REACH) cohort at baseline and again at the final follow-up visit. Prevalence at baseline and incidence (per person years) of HSV-2 infection were calculated. Furthermore, among HIV-1-positive individuals, a subgroup analysis was performed to assess risk factors for HSV-2 infection. Conditional logistic regression was used to estimate odds ratios (OR) and p-values (p) for associations between CD4+ T-cell (CD4+) count, HIV-1 viral load (VL), and HSV-2 acquisition, adjusting for antiretroviral therapy use, other sexually transmitted infections, gender, race, and number of sexual partners.
At baseline, 179 (35%) subjects were HSV-2 positive, with an additional 47 (16%) new cases being identified during a median follow-up time of 1.95 years and an incidence rate of 7.35 cases per 100 person years (py). Several risk factors were associated with HSV-2 prevalence (being female, non-Hispanic, uncertainty of sexual preference, and HIV-1 positive) and incidence (using drugs, alcohol, and number of new sexual partners). Among HIV-1 positives, an increase in CD4+ count by 50 cell/mm3 (OR, 1.17; 95% CI 1.04–1.31, p=0.008) was associated with HSV-2 acquisition.
The high prevalence and incidence of HSV-2 infection among adolescents, compared to the general population at this age group suggests a critical need for screening and preventive programs among this targeted group.
PMCID: PMC3306602  PMID: 22421698
HIV-1; HSV-2; CD4+ count; adolescents
3.  Transitional Probability-Based Model for HPV Clearance in HIV-1-Positive Adolescent Females 
PLoS ONE  2012;7(1):e30736.
HIV-1-positive patients clear the human papillomavirus (HPV) infection less frequently than HIV-1-negative. Datasets for estimating HPV clearance probability often have irregular measurements of HPV status and risk factors. A new transitional probability-based model for estimation of probability of HPV clearance was developed to fully incorporate information on HIV-1-related clinical data, such as CD4 counts, HIV-1 viral load (VL), highly active antiretroviral therapy (HAART), and risk factors (measured quarterly), and HPV infection status (measured at 6-month intervals).
Methodology and Findings
Data from 266 HIV-1-positive and 134 at-risk HIV-1-negative adolescent females from the Reaching for Excellence in Adolescent Care and Health (REACH) cohort were used in this study. First, the associations were evaluated using the Cox proportional hazard model, and the variables that demonstrated significant effects on HPV clearance were included in transitional probability models. The new model established the efficacy of CD4 cell counts as a main clearance predictor for all type-specific HPV phylogenetic groups. The 3-month probability of HPV clearance in HIV-1-infected patients significantly increased with increasing CD4 counts for HPV16/16-like (p<0.001), HPV18/18-like (p<0.001), HPV56/56-like (p = 0.05), and low-risk HPV (p<0.001) phylogenetic groups, with the lowest probability found for HPV16/16-like infections (21.60±1.81% at CD4 level 200 cells/mm3, p<0.05; and 28.03±1.47% at CD4 level 500 cells/mm3). HIV-1 VL was a significant predictor for clearance of low-risk HPV infections (p<0.05). HAART (with protease inhibitor) was significant predictor of probability of HPV16 clearance (p<0.05). HPV16/16-like and HPV18/18-like groups showed heterogeneity (p<0.05) in terms of how CD4 counts, HIV VL, and HAART affected probability of clearance of each HPV infection.
This new model predicts the 3-month probability of HPV infection clearance based on CD4 cell counts and other HIV-1-related clinical measurements.
PMCID: PMC3265500  PMID: 22292027
4.  Interleukin-10 (IL-10) Pathway: Genetic Variants and Outcomes of HIV-1 Infection in African American Adolescents 
PLoS ONE  2010;5(10):e13384.
Immunological and clinical outcomes can vary considerably at the individual and population levels during both treated and untreated HIV-1 infection. Cytokines encoded by the interleukin-10 gene (IL10) family have broad immunomodulatory function in viral persistence, and several SNPs in the IL10 promoter sequence have been reported to influence pathogenesis or acquisition of HIV-1 infection.
Methodology/Principal Findings
We examined 104 informative SNPs in IL10, IL19, IL20, IL24, IL10RA and IL10RB among 250 HIV-1 seropositive and 106 high-risk seronegative African American adolescents in the REACH cohort. In subsequent evaluation of five different immunological and virological outcomes related to HIV-1 infection, 25 SNPs were associated with a single outcome and three were associated with two different outcomes. One SNP, rs2243191 in the IL19 open reading frame (Ser to Phe substitution) was associated with CD4+ T-cell increase during treatment. Another SNP rs2244305 in IL10RB (in strong linkage disequilibrium with rs443498) was associated with an initial decrease in CD4+ T-cell by 23±9% and 29±9% every 3 months (for AA and AG genotypes, respectively, compared with GG) during ART-free period. These associations were reversed during treatment, as CD4+ T-cell increased by 31±0.9% and 17±8% every 3 months for AA and AG genotype, respectively.
In African Americans, variants in IL10 and related genes might influence multiple outcomes of HIV-1 infection, especially immunological response to HAART. Fine mapping coupled with analysis of gene expression and function should help reveal the immunological importance of the IL10 gene family to HIV-1/AIDS.
PMCID: PMC2954785  PMID: 20976276
5.  Human Leukocyte Antigen Class I Supertypes and HIV-1 Control in African Americans▿  
Journal of Virology  2009;84(5):2610-2617.
The role of human leukocyte antigen (HLA) class I supertypes in controlling human immunodeficiency virus type 1 (HIV-1) infection in African Americans has not been established. We examined the effects of the HLA-A and HLA-B alleles and supertypes on the outcomes of HIV-1 clade B infection among 338 African American women and adolescents. HLA-B58 and -B62 supertypes (B58s and B62s) were associated with favorable HIV-1 disease control (proportional odds ratio [POR] of 0.33 and 95% confidence interval [95% CI] of 0.21 to 0.52 for the former and POR of 0.26 and 95% CI of 0.09 to 0.73 for the latter); B7s and B44s were associated with unfavorable disease control (POR of 2.39 and 95% CI of 1.54 to 3.73 for the former and POR of 1.63 and 95% CI of 1.08 to 2.47 for the latter). In general, individual alleles within specific B supertypes exerted relatively homogeneous effects. A notable exception was B27s, whose protective influence (POR, 0.58; 95% CI, 0.35 to 0.94) was masked by the opposing effect of its member allele B*1510. The associations of most B supertypes (e.g., B58s and B7s) were largely explained either by well-known effects of constituent B alleles or by effects of previously unimplicated B alleles aggregated into a particular supertype (e.g., B44s and B62s). A higher frequency of HLA-B genotypic supertypes correlated with a higher mean viral load (VL) and lower mean CD4 count (Pearson's r = 0.63 and 0.62, respectively; P = 0.03). Among the genotypic supertypes, B58s and its member allele B*57 contributed disproportionately to the explainable VL variation. The study demonstrated the dominant role of HLA-B supertypes in HIV-1 clade B-infected African Americans and further dissected the contributions of individual class I alleles and their population frequencies to the supertype effects.
PMCID: PMC2820922  PMID: 20032191
6.  Host Genetics and HIV-1 Viral Load Set-point in African-Americans 
AIDS (London, England)  2009;23(6):673-677.
In a recent genome-wide association study of HIV-1-infected individuals in the Euro-CHAVI cohort, viral load set-point was strongly associated with genotypes defined by two SNPs (rs9264942 and rs2395029) within the human MHC region on chromosome 6. We attempted to confirm this finding in African-Americans and assess if these SNPs are in linkage disequilibrium (LD) with HLA class I alleles that mediate innate and adaptive immunity.
Our analyses relied on 121 African American adolescents with chronic HIV-1 infection and quarterly immunological and virological outcome measures in the absence of therapy.
PCR-based techniques were used to genotype two SNPs along with HLA class I alleles. Their associations with HIV-1 viral load set-point and longitudinal CD4+ and CD8+CD38+ T-cell counts were tested in univariate and multivariate models.
The CC genotype at rs9264942 was associated with reduced viral load but not with immunological outcomes or category of disease control. Consistent associations of HLA-B*57 (mostly B*5703) with favorable virological and immunological outcomes were observed, but not rs2395029G allele at the HCP5 locus, which is in absolute linkage disequilibrium with B*5701 (in individuals of European descent), and not B*5703.
While rs9264942 and B*57 (but not rs2395029G) are clearly associated with control of viral load set-point among African-Americans, fine-mapping of MHC SNPs in populations of African and European descent should help reveal the true variants and the underlying functional mechanisms.
PMCID: PMC2663898  PMID: 19276793
HIV-1; genetics; viral load; African American
7.  Clear and independent associations of several HLA-DRB1 alleles with differential antibody responses to hepatitis B vaccination in youth 
Human Genetics  2009;126(5):685-696.
To confirm and refine associations of human leukocyte antigen (HLA) genotypes with variable antibody (Ab) responses to hepatitis B vaccination, we have analyzed 255 HIV-1 seropositive (HIV+) youth and 80 HIV-1 seronegatives (HIV−) enrolled into prospective studies. In univariate analyses that focused on HLA-DRB1, -DQA1, and -DQB1 alleles and haplotypes, the DRB1*03 allele group and DRB1*0701 were negatively associated with the responder phenotype (serum Ab concentration ≥ 10 mIU/mL) (P = 0.026 and 0.043, respectively). Collectively, DRB1*03 and DRB1*0701 were found in 42 (53.8%) out of 78 non-responders (serum Ab <10 mIU/mL), 65 (40.6%) out of 160 medium responders (serum Ab 10–1,000 mIU/mL), and 27 (27.8%) out of 97 high responders (serum Ab >1,000 mIU/mL) (P < 0.001 for trend). Meanwhile, DRB1*08 was positively associated with the responder phenotype (P = 0.010), mostly due to DRB1*0804 (P = 0.008). These immunogenetic relationships were all independent of non-genetic factors, including HIV-1 infection status and immunodeficiency. Alternative analyses confined to HIV+ youth or Hispanic youth led to similar findings. In contrast, analyses of more than 80 non-coding, single nucleotide polymorphisms within and beyond the three HLA class II genes revealed no clear associations. Overall, several HLA-DRB1 alleles were major predictors of differential Ab responses to hepatitis B vaccination in youth, suggesting that T-helper cell-dependent pathways mediated through HLA class II antigen presentation are critical to effective immune response to recombinant vaccines.
Electronic supplementary material
The online version of this article (doi:10.1007/s00439-009-0720-z) contains supplementary material, which is available to authorized users.
PMCID: PMC2771141  PMID: 19597844

Results 1-7 (7)