Stavudine is no longer recommended for use in first-line antiretroviral therapy (ART), but it remains in high demand worldwide because it is affordable. We report the clinical presentation and incidence of severe hyperlactatemia (SL) in HIV-infected adults who initiated ART between April 2005 and May 2009 in Côte d'Ivoire, West Africa. In a prospective cohort study at the HIV care center affiliated with the National Centre for Blood Transfusion, we used standardized forms to record baseline and follow-up data. We measured serum lactate levels for all adults on ART who showed signs of hyperlactatemia. SL was defined as serum lactate >2.5 mmol/liter. Overall, 806 adults initiated ART. Among the 591 patients (73%) on stavudine-containing regimens, 394 were women (67%); the median pre-ART CD4 count was 150 /mm3 and the median body mass index was 20.9 kg/m2. These patients were followed for a median of 28 months. We detected SL only among patients taking stavudine. The incidence of SL was 0.55/100 person-years (PY) (95% CI 0.47–0.63) overall and 0.85/100 PY among women (95% CI 0.75–0.95). Among the eight patients with SL, 100% lost >9% of body weight before diagnosis, 100% had serum lactate >4 mmol/liter (range 4.2–12.1), 50% had pre-ART BMI >25 kg/m2, and three patients died (38%), accounting for 6.4% of deaths among patients taking stavudine. As long as HIV clinicians continue to use stavudine in sub-Saharan Africa, they should watch out for acute unexplained weight loss in patients taking ART, particularly among women and patients with high pre-ART BMI.
The HLA-B*27 allele is overrepresented in patients who control HIV-1 replication without antiretroviral therapy. CD8+ T cell responses that target the immunodominant KK10 epitope in Gag are thought to play a major role in this control, and escape at R264 of KK10 is often associated with dramatic virologic breakthrough. We present a case in which an HLA-B*27-positive chronic progressor transmitted HIV-1 to an HLA-B*27-positive viremic controller who was temporarily on HAART, but who has since controlled viremia for over 4 years. We hypothesized that differences in the KK10 epitope of these patients would affect pathogenesis and viral fitness, but found no correlation between autologous KK10 mutations and disease progression or between the predicted fitness impact of autologous HLA-B*27-associated mutations and the actual fitness of autologous virus. This case of viral transmission between two HLA-B*27-positive individuals provides further evidence that prolonged control of fully pathogenic HIV-1 is possible.
Several new antiretroviral (ARV) agents for treatment experienced HIV-infected patients have been approved since June 2006, including darunavir (DRV) and raltegravir (RAL). While efficacious in clinical trials, the effectiveness, durability, and tolerability of these new ARVs remains understudied in the context of routine clinical care. The Darunavir Outcomes Study is a prospective cohort study of three-class ARV-experienced patients changing regimens at the 1917 Clinic after 1/7/2006. All treatment decisions were at the discretion of primary providers. Multivariate (MV) logistic regression for 48 week VL <400c/ml and Cox models for regimen durability were completed. Propensity score methods controlled for sociodemographics. Among 108 patients, mean age of 46, 48% were white, 80% male, with prior exposure to a mean 10.5 ARVs. Overall, 64% of patients achieved 48-week VL <400 c/ml. In MV modeling DRV/rll (OR = 5.77;95%CI = 1.62–20.58) and RAL (OR = 3.84;95%CI = 1.23–11.95) use increased odds of 48-week suppression. Use of these agents exhibited a trend towards prolonged regimen durability in Cox models. Among those highly ARV-experienced, regimens containing DRV/r and/or RAL were more likely to achieve 48-week VL <400 c/ml and exhibited a trend towards prolonged durability. New agents have transformed the treatment landscape for ARV-experienced patients, with effectiveness in routine clinical care mirroring efficacy in clinical trials.
Current methods to detect intraclade HIV dual infection are poorly suited for determining its prevalence in large cohorts. To investigate the potential of ultra-deep sequencing to screen for dual infection, we compared it to bulk sequence-based synonymous mixture index and the current standard of single genome sequencing. The synonymous mixture index identified samples likely to harbor dual infection, while ultra-deep sequencing captured more intra-host viral diversity than single genome sequencing at approximately 40% of the cost and 20% of the laboratory and analysis time. The synonymous mixture index and ultra-deep sequencing are promising methods for rapid and cost-effective systematic identification of HIV dual infection.
Phylogeography can improve the understanding of local and worldwide HIV epidemics, including the migration of subepidemics across national borders. We analyzed HIV-1 sequences sampled from Mexico and San Diego, California to determine the relatedness of these epidemics. We sampled the HIV epidemics in (1) Mexico by downloading all publicly available HIV-1 pol sequences from antiretroviral-naive individuals in GenBank (n = 100) and generating similar sequences from cohorts of injection drug users and female sex workers in Tijuana, Mexico (n = 27) and (2) in San Diego, California by pol sequencing well-characterized primary (n = 395) and chronic (n = 267) HIV infection cohorts. Estimates of population structure (FST), genetic distance cluster analysis, and a cladistic measure of migration events (Slatkin–Maddison test) were used to assess the relatedness of the epidemics. Both a test of population differentiation (FST = 0.06; p < 0.01) and a cladistic estimate of migration events (84 migrations, p < 0.01) indicated that the Tijuana and San Diego epidemics were not freely mixing. A conservative cluster analysis identified 72 clusters (two or more sequences), with two clusters containing both Mexican and San Diego sequences (permutation p < 0.01). Analysis of this very large dataset of HIV-1 sequences suggested that the HIV-1 epidemics in San Diego, California and Tijuana, Mexico are distinct. Larger epidemiological studies are needed to quantify the magnitude and associations of cross-border mixing.
The crucial role of recombination in HIV-1 biology is being increasingly recognized. In vitro studies have shown that up to 30 strand-transfer events may occur per viral replication cycle. Thus, recombination may surpass mutation as a major mechanism driving HIV-1 evolution. Currently, recombinant strains comprise 37% of the full-genome HIV-1 sequence database, including sequences representing 47 Circulating Recombinant Forms (CRFs) and more than 250 different Unique Recombinant Forms (URFs). Mapping of recombination breakpoints helps establish relationships among strains that are related by descent, such as CRF07_BC and CRF08_BC in China, and sheds light on their origin and epidemic spread. Additionally, unrelated recombinants sharing common breakpoints may reflect recombination hotspots within the viral genome. Here we present a software tool, RecDraw, for the graphical representation and efficient comparison of recombinant HIV-1 structures and breakpoints. RecDraw is a platform-flexible, Java stand-alone application available through http://www.hivresearch.org/research.php?ServiceID = 5&SubServiceID = 6.
The purpose of this study is to evaluate whether the choice of a PI- or an efavirenz (EFV)-based HAART initial regimen impacts on the viral diversity after failure from a second, class-switch salvage regimen. Sequential HAART failures after a class switch were identified for which the genotypes showed evidence of signature mutations at each failure. Each second failure was required to be from a viral burden <400 RNA c/ml. Thirteen cases of sequential failure from an initial EFV-containing to a PI-containing regimen (EP), and 19 sequential failures from an initial PI-containing to an EFV-containing regimen (PE) were identified. The persistence of signature mutations from the first failure were evaluated at second failure and compared between the EP and PE groups. Phylogenetic trees were constructed for a subgroup of cases from existing genetic sequence information and branch length analysis was used to determine evidence of viral diversity between groups. For EP sequential therapy, 10 of 12 cases carried forward a key non-nucleoside reverse transcriptase inhibitor (NNRTI) mutation in the second failure compared to 5 of 13 cases for PE sequential therapy (p = 0.041). Phylogenetic analysis demonstrated that there was more viral diversity in the PE group as compared to the EP group, consistent with the interpretation that mutations at the second failure added to an ancestral virus closer to baseline rather than to the dominant virus at first failure. The development of HIV viral diversity after multiple HAART failures is determined by the sequence in which the regimens are ordered.
HIV-1 subtype D (HIV-1D) progresses to disease faster and has lower transmissibility than subtype A (HIV-1A). We examined whether these differences could lead to a population level change in the distribution of these subtypes over time. HIV-1 viral RNA was extracted from stored serum samples from HIV-positive subjects participating in a population-based cohort study in Rakai, Uganda in 1994 and 2002. Portions of the viral proteins gag and gp41 were sequenced and subtyped. HIV-1 subtype assignments were generated for 773 subjects in 1994 and 812 subjects in 2002. The change in subtype distribution of the population as a whole as well as quartile age groups were examined for significant changes using a linear model. There was a significant decrease in the proportion of subjects infected with HIV-1D from 70.2% to 62.4% and a significant increase in subjects infected with HIV-1A from 16.7% to 23.3% over the 8-year period (p = 0.005). The most marked changes in proportion of HIV-1D and A were seen in the younger individuals (<25 and 25–30 years; p < 0.05). The percentages of subjects infected with HIV-1C and recombinant subtypes did not change significantly. Over this 8-year period, the overall viral population in this region evolved toward the less virulent HIV-1A strain, most likely as a consequence of the faster disease progression and lower transmissibility of HIV-1D.
The evolution of hematological parameters in HIV-1-exposed uninfected infants according to various durations of perinatal zidovudine exposure was studied. We used data prospectively collected among 1122 HIV-uninfected formula-fed infants born to HIV-infected mothers who participated in a clinical trial to prevent perinatal transmission in Thailand (PHPT-1). Infants were exposed to different durations of zidovudine both in utero and after birth. Hemoglobin level and leukocyte, absolute neutrophil, and lymphocyte counts were measured at birth and at 6 weeks of age. The association between hematological parameters at birth and the duration of zidovudine exposure in utero was studied using a linear regression model, and changes between birth and 6 weeks of age and the duration of postnatal zidovudine exposure using mixed effects models. At birth, the hemoglobin level was lower in newborns exposed to zidovudine for more than 7.5 weeks in utero (adjusted regression coefficient: −0.6 g/dl; 95% confidence interval: −1.1 to −0.1). Six weeks after birth, the hemoglobin level had decreased faster in infants administered zidovudine for more than 4 weeks (adjusted regression coefficient: −0.1 g/dl; 95% confidence interval: −0.2 to −0.1). The duration of perinatal zidovudine exposure was not associated with the evolution of leukocyte, neutrophil, and lymphocyte counts. Despite the differences in hemoglobin levels, grade 3 or 4 anemia did not significantly differ by maternal or infant zidovudine duration. The clinical impact appeared modest, but longer exposure may warrant close monitoring.
Events that occur during acute HIV infection likely contribute to the immune dysfunction common in HIV-infected individuals. During this early stage, there is high-level viral replication, loss in CD4+ T cell number and function, and an up-regulation of proinflammatory and immunoregulatory cytokines. The mechanisms responsible for this are not completely understood. We hypothesize that the HIV envelope glycoprotein, gp120, contributes to immune dysfunction during early HIV infection. Using a cohort of subjects enrolled during acute and early HIV infection, we determined the amount of gp120, TNF-α, IL-6, IL-10, IFN-α, and IFN-γ in plasma at baseline and 6 months. At matched time points, we also measured CD4+ T cell proliferation, T cell activation, and apoptosis. Plasma from 109 subjects was screened for gp120. Thirty-six subjects (33%) had detectable gp120 (0.5–15.6 ng/ml). Subjects with greater than 1 ng/ml of gp120 at baseline had similar levels at all time points tested, even when viral replication was undetectable due to therapy. Subjects with detectable gp120 had higher levels of plasma IL-6, IL-10, and TNF-α. There was no difference in the level of T cell activation, proliferation, or apoptosis in subjects with gp120 compared to those without. We conclude that persistent expression of gp120 occurs in a subset of individuals. Furthermore, the presence of gp120 is associated with higher levels of plasma IL-6, IL-10, and TNF-α, which may contribute to immune dysfunction during early HIV infection.
AIDS vaccine and pathogenesis research will benefit from a more diverse array of cloned SIV challenge stocks from which to choose. Toward this end, 20 envelope genes were cloned from an extensively used, primary stock of uncloned SIVmac251. Each of the 20 clones had a unique sequence. Their translated sequences differed by as many as 26 amino acids from one another and by as many as 45 amino acids from the commonly used clone SIVmac239. Envelope sequences up to and including the membrane-spanning domain were exchanged into the infectious pathogenic SIVmac239 clone and virus stocks were produced by HEK293T cell transfection. Seventeen of the 20 recombinants were replication competent. The infectivities per ng p27 of the 17 new replication-competent recombinants in C8166-SEAP cells and in TZM-bl cells ranged from minus 32-fold to plus 7.6-fold relative to SIVmac239. A range of sensitivities to neutralization by sCD4 and by sera from SIV-infected macaques was observed but none was as sensitive to these neutralizing agents as SIVmac316, the highly macrophage-competent derivative of SIVmac239. Four strains that were most sensitive to sCD4 inhibition were also among the most sensitive to antibody-mediated neutralization. None of the new recombinant viruses replicated as well as SIVmac316 in primary alveolar macrophage cultures from rhesus monkeys but three of the strains did exhibit significant levels of delayed replication in these primary macrophages, reaching peak levels of virus production of ≥50 ng/ml p27 compared to 600–800 ng/ml p27 with SIVmac316. These new SIV clones are being contributed to the NIH AIDS Reagent Repository and are available to the scientific community.
In this study, HIV strains circulating among military personnel were characterized, in Malabo, the capital city of Equatorial Guinea. One sample was found to be HIV-2 group A while a high degree of genetic diversity was recorded in the pol region of 41 HIV-1-positive samples. CRF02_AG accounted for 53.7% of the strains, and 11 different variants were obtained in the remaining 19 samples: subtype G (n = 3), A3 (n = 2), C (n = 2), CRF26_A5U (n = 2), F2 (n = 1), CRF06 (n = 1), CRF09 (n = 1), CRF11 (n = 1), CRF22 (n = 1), and divergent subtype A (n = 1) and F (n = 1). One strain could not be classified and three were unique recombinants. Analysis of antiretroviral drug resistance mutations revealed two patients each harboring one major mutation, M46I in protease and D67N in reverse transcriptase sequences, respectively. The high genetic diversity and emerging ARV resistance mutations call for frequent surveys and appropriate monitoring of ARV considering the increasing access to ARV in the country.
Adherence to medications is critical to optimizing HIV care and is a major challenge in youth. The utility of directly observed therapy (DOT) to improve adherence in youth with HIV remains undefined and prompted this pilot study. Four U.S. sites were selected for this 24-week cooperative group study to assess feasibility and to identify the logistics of providing DOT to HIV-infected youth with demonstrated adherence problems. Once-a-day DOT was provided by DOT facilitators at the participant's choice of a community-based location and DOT tapered over 12 weeks to self-administered therapy based on ongoing adherence assessments. Twenty participants, median age 21 years and median CD4 227 cells/μl, were enrolled. Participants chose their homes for 82% of DOT visits. Compliance with recommended DOT visits was (median) 91%, 91%, and 83% at weeks 4, 8, and 12, respectively. Six participants completed >90% of the study-specified DOT visits and successfully progressed to self-administered therapy (DOT success); only half sustained >90% medication adherence 12 weeks after discontinuing DOT. Participants considered DOT successes were more likely to have higher baseline depression scores (p = 0.046). Via exit surveys participants reported that meeting with the facilitator was easy, DOT increased their motivation to take medications, they felt sad when DOT ended, and 100% would recommend DOT to a friend. In conclusion, this study shows that while community-based DOT is safe, feasible, and as per participant feedback, acceptable to youth, DOT is not for all and the benefits appear short-lived. Depressed youth appear to be one subgroup that would benefit from this intervention. Study findings should help inform the design of larger community-based DOT intervention studies in youth.
HIV viruses are usually genetically homogeneous shortly after infection, and become more heterogeneous over time. We developed a high-resolution melting (HRM) assay to analyze HIV diversity without sequencing. Plasma samples from the HIVNET 012 trial were obtained from nine Ugandan mother–infant pairs. DNA amplified from the HIV gag region was analyzed to determine the number of degrees over which the DNA melted (HRM score). HRM gag DNA was also cloned and sequenced (50 clones/mother; 20 clones/infant). The median HRM score for infants (4.3, range 4.2–5.3) was higher than that for control plasmids (3.4, range 3.2–3.8, p < 0.001) and lower than that for mothers (5.7, range 4.4–7.7, p = 0.005, exact Wilcoxon rank sum test). The intraclass correlation coefficient reflecting assay reproducibility was 94% (95% CI: 89–98%). HRM scores were also compared to sequenced-based measures of HIV diversity; higher HRM scores were associated with higher genetic diversity (p < 0.001), complexity (p = 0.009), and Shannon entropy (p = 0.022), but not with length variation (p = 0.111). The HRM assay provides a novel, rapid method for assessing HIV diversity without sequencing. This assay could be applied to any region of the HIV genome or to other genetic systems that exhibit DNA diversity.
Our previous studies have shown two distinct disease patterns (rapid and normal onset of clinical symptoms) in morphine-dependent SHIV/SIV-inoculated rhesus macaques. We have also shown that control as well as 50% of morphine-dependent macaques (normal progressor) developed humoral and cellular immune responses whereas the other half of the morphine-dependent macaques (rapid progressor) did not develop antiviral immune responses after infection with SIV/SHIV. In the present study, we analyzed the association between cytokine production, immune response, and disease progression. To study the immunological effects of morphine at cytokine levels in the context of a lentiviral infection, we inoculated rhesus macaques with a mixture of SHIVKU−18, SHIV89.6P, and SIV/17E-Fr. These animals were followed for a period of 56 weeks for cytokine level production in plasma. Drug-dependent rapid disease progressors exhibited an increase in IL-18 and IL-1Ra and a decrease in IL-12 levels in the plasma. Morphine-dependent normal progressors and control macaques exhibited an increase in both IL-18 and IL-12, whereas IL-Ra levels remained constant throughout the observation period. These results suggest that rapid disease progression in relation to morphine dependency may be the result of an altered cytokine profile.
Parathyroid hormone (PTH) elevations are associated with reduced bone mineral density and adverse health outcomes and have been reported in patients with HIV infection. We aimed to examine the impact of vitamin D status and tenofovir (TDF) use on PTH levels among HIV-infected patients receiving combination antiretroviral therapy (cART). Demographics, medication and supplement use, and clinical data, including 25-hydroxyvitamin D [25(OH)D] and PTH, were collected on 45 HIV-infected men on ART. Suboptimal vitamin D status was defined as 25(OH)D < 30 ng/ml. The relationship between antiretroviral agents, suboptimal 25(OH)D, and PTH levels was examined. Among subjects with suboptimal vitamin D status, PTH values greater than or equal to the ULN (87 pg/ml) were more common among TDF users than nonusers: 41% versus 0% (p = 0.018); and median PTH was higher in TDF users: 80 pg/ml versus 55 pg/ml (p = 0.02). Among TDF users, PTH was higher in the group with suboptimal 25(OH)D (p = 0.045). Multivariable linear regression showed that PTH was independently and directly related to TDF use (p = 0.017) and inversely related to 25(OH)D (p = 0.017). PTH was not related to the estimated glomerular filtration rate (p = 0.9). In this cross-sectional study of HIV-infected men on ART, the use of TDF and the level of 25(OH)D were independently associated with PTH levels. Because TDF is a potent and widely used antiretroviral drug, information about cofactors that may exacerbate its side effects is of significant clinical value.
Vascular endothelial dysfunction may contribute to the increase in cardiovascular events during HIV-1 infection and its treatment. Antiretroviral therapy (ART), metabolic factors, lipodystrophy, and HIV infection itself may be involved. Ninety-six HIV-infected subjects were evaluated for endothelial function by measurement of brachial artery flow-mediated dilation (FMD) by ultrasound, single-slice CT of the abdomen and mid-thigh, whole-body dual x-ray absorptiomety (DXA) scans, and metabolic evaluations in a cross-sectional study. The median age was 40 years; 28% were female, 38% black, 3% Hispanic, and 59% white. Forty-nine (51%) were receiving ART, which included a PI in 28 (57%) and was non-PI based in 21 (43%). FMD (±SD) in subjects not on ART was 5.5 ± 4.3%, PI-ART 5.3 ± 3.6%, and non-PI-ART 5.5 ± 4.1% (p = 0.9). Age, race, CD4 cell count, and HIV RNA did not correlate significantly with FMD. Among ART-treated subjects in the lowest tertile of thigh subcutaneous fat area (range 3–31 cm2), FMD was 4.4 ± 3.5% and in the highest tertile (range 67–237 cm2) FMD was 6.8 ± 3.6% (p = 0.07, t-test). However, in multivariate analyses, no body composition measure showed a significant association with FMD for either the group as a whole or in ART-treated subjects. ART use, PI use, CD4 cell count, and HIV RNA levels were not associated with endothelial dysfunction by brachial FMD. A definitive association with measures of adiposity was not detected in multivariate analysis, suggesting that lipoatrophy may not be an important contributor to endothelial dysfunction in HIV-infected individuals on ART.
Human immunodeficiency virus (HIV) infections are rarely acquired via an oral route in adults. Previous studies have shown that human whole saliva inhibits HIV infection in vitro, and multiple factors present in human saliva have been shown to contribute to this antiviral activity. Despite the widespread use of simian immunodeficiency virus (SIV)-infected rhesus macaques as models for HIV pathogenesis and transmission, few studies have monitored SIV in the oral cavity of infected rhesus macaques and evaluated the viral inhibitory capacity of macaque saliva. Utilizing a cohort of rhesus macaques infected with SIVMac251, we monitored virus levels and genotypic diversity in the saliva throughout the course of the disease; findings were similar to previous observations in HIV-infected humans. An in vitro infectivity assay was utilized to measure inhibition of HIV/SIV infection by normal human and rhesus macaque whole saliva. Both human and macaque saliva were capable of inhibiting HIV and SIV infection. The inhibitory capacity of saliva samples collected from a cohort of animals postinfection with SIV increased over the course of disease, coincident with the development of SIV-specific antibodies in the saliva. These findings suggest that both innate and adaptive factors contribute to inhibition of SIV by whole macaque saliva. This work also demonstrates that SIV-infected rhesus macaques provide a relevant model to examine the innate and adaptive immune responses that inhibit HIV/SIV in the oral cavity.
Predictors of study retention and scheduled visit attendance in the University of North Carolina Center for AIDS Research (UNC CFAR) prospective clinical cohort of HIV-infected patients enrolled between 1 January 2001 and 1 January 2008 are reported. At study entry, 1636 participants were 32% female, 58% were African-American, 49% had not received HIV care elsewhere, 71% were receiving or initiated combination antiretroviral therapy, and 26% were diagnosed with AIDS, with median (quartiles) age of 40 (34; 47) years, distance to clinic of 45 (21; 70) miles, HIV-1 RNA of 1396 (200; 26,750) copies/ml, and CD4 of 374 (182; 602) cells/mm3. Participants contributed a median of 7 (4; 13) scheduled visits and 2.25 (1.0; 3.9) years alive under follow-up. During 6134 person-years of follow-up, 414 participants dropped out and 145 died. Accounting for differences in death by participant characteristics, the 6-year cumulative probability of retention was 67% [95% confidence limits (CL): 65, 70%], with 6.75 (95% CL: 6.13, 7.43) drop outs per 100 person-years. In a multivariable Cox proportional hazards model, retention was higher among participants who were insured, had not received HIV care elsewhere, had controlled HIV viremia, and were living in nonurban areas or proximate to the clinic. In a multivariable modified Poisson regression model that accounted for differences in drop out and death by participant characteristics, visit attendance was higher among older, AIDS-diagnosed, immune compromised, and cART-initiated participants. The UNC CFAR clinical cohort has ample enrollment with retention and visit attendance modestly influenced by factors such as disease severity.
We determined the incidence of and risk factors for distal sensory polyneuropathy (DSP) in individuals on HAART. Sixty-one HIV-positive subjects on HAART for at least 6 months and neuropathy free were retrospectively selected. The study included subjects who had previously tolerated d-drugs without developing DSP. Neuropathy incidence over 4 years was calculated. Cox proportional hazards models were used to determine risk factors associated with incident DSP. Nineteen subjects developed DSP over a mean follow-up of 2.4 years. Subjects never treated with a d-drug developed DSP at a rate of 21 cases per 100 person-years (95% CI, 8.9–33.7). Subjects with a history of d-drug treatment but not on a d-drug at enrollment developed DSP at a rate of 17 cases per 100 person-years (95% CI, 2.1–31.8). Those on d-drug treatment developed DSP at a rate of 25 cases per 100 person-years (95% CI, 8.7–41.6). Multivariable analysis identified age [hazard ratio (HR) = 1.09; p < 0.01] and low CD4+ nadir [hazard ratio (HR) = 0.79; p = 0.03] as significant risk factors. Current or prior history of treatment with d-drug was not a significant risk factor for incident DSP in subjects who had previously tolerated d-drug treatment without developing a toxic DSP. Age and low CD4+ are risk factors for incident DSP. However, current or prior history of d-drug treatment is not a significant risk factor for incident DSP in subjects who had previously tolerated d-drug treatment without developing a toxic DSP.
T cell-mediated viral clearance is classically attributed to the CD8+ T cell subset, but CD4+ T cells can sometimes assume this role. One such instance was illustrated by the immunization of C57BL/6 mice with HIV-1 envelope, followed by challenge with a recombinant Sendai virus (rSeV-env) carrying a gene for secreted HIV-1 envelope protein. Vaccinated mice that lacked both B cells (μMT) and CD8+ T cells controlled virus, but control was lost when CD4+ T cells were depleted. To explain this activity, we questioned whether CD4+ T cells might utilize perforin for killing of MHC class II-positive targets. We also asked if the process might depend on IFN-γ, which can upregulate MHC expression and enhance T cell recruitment to sites of virus challenge. To address these possibilities, we vaccinated perforin-KO mice with HIV-1 envelope and challenged them with rSeV-env. We found that perforin was not required for (1) CD4+ T cell homing to the site of virus challenge, (2) expression of Th1 and Th2 cytokines (including IFN-γ), or (3) virus clearance. To determine if IFN-γ was required for protection, we repeated experiments in IFN-γ-KO animals. In this case, significant protection was lost, although the CD4+ T cells trafficked readily to the site of infection. In fact, local CD4+ T cell numbers in vaccinated IFN-γ- KO mice exceeded those in wild type animals. In both cases, cells were αß TCR+, NK-1.1–, and CD44+, typifying an activated CD4+ T cell subset. Taken together, our results showed that HIV-1 envelope recombinant virus clearance was dependent on CD4+ T cells and IFN-γ, but occurred in the absence of B cells, CD8+ T cells, or perforin.
Humanized Rag2-/-γc-/- mice (Hu-DKO mice) become populated with functional human T cells, B cells, and dendritic cells following transplantation with human hematopoietic stem cells (HSC) and represent an improved model for studying HIV infection in vivo. In the current study we demonstrated that intrasplenic inoculation of hu-DKO mice with HIV-1 initiated a higher level of HIV infection than intravenous or intraperitoneal inoculation, associated with a reciprocal decrease in peripheral CD4+ T cells and increase in peripheral CD8+ T cells. HIV infection by intrasplenic injection increased serum levels of human IgG and IgM including human IgM and IgG specific for HIV-1 gp120. There was a significant inverse correlation between the level of HIV-1 infection and the extent of CD4+ T cell depletion. Highly active antiretroviral therapy (HAART) initiated 1 week after HIV-1 inoculation markedly suppressed HIV-1 infection and prevented CD4+ T cell depletion. Taken together, these findings demonstrate that intrasplenic injection of hu-DKO mice with HIV is a more efficient route of HIV infection than intravenous or intraperitoneal injection and generates increased infection associated with an increased anti-HIV humoral response. This animal model can serve as a valuable in vivo model to study the efficacy of anti-HIV therapies.
The prevalence of antiretroviral therapy (ART) resistance mutations present in HIV-1 subtype C pol and env regions of the proviral DNA was analyzed and compared from therapy-naive individuals before (Cohort A) and after (Cohort B) the availability of free ART in Zambia. Mutations present in sequences published in a previous study from Zambian ART-naive individuals infected with subtype C were analyzed using current parameters for the classification of ART drug resistance and compared with Cohorts A and B. No statistically significant differences were observed when comparing mutations present in the pol and env of these cohorts. However, an increase in the number of minor, borderline, or partial resistance mutations as well as the presence of major resistance mutations were observed in Cohort B. These results suggest there is an increasing trend of drug resistance-associated mutations that could be a result of the availability of free ART in Zambia. Moreover, the high prevalence of resistance mutations observed for maraviroc and vicriviroc in both cohorts may suggest a limited efficacy of entry inhibitors on HIV-1 subtype C.