HIV-1 RNA Levels in an African Population-Based Cohort and Their Relation to CD4 Lymphocyte Counts and World Health Organization Clinical Staging:

Predicting CD4 lymphocyte count <200 cells/mm(3) in an HIV type 1-infected African population

Clinical criteria are recommended to select HIV-infected patients for initiation of antiretroviral therapy when CD4 lymphocyte testing is unavailable. We evaluated the performance characteristics of WHO staging criteria, anthropometrics, and simple laboratory measurements for predicting CD4 lymphocyte count (CD4 count) <200 cells/mm(3) among HIV-infected patients in Tanzania. A total of 202 adults, diagnosed with HIV infection through community-based testing, underwent a detailed evaluation including staging history and examination, anthropometry, complete blood count, erythrocyte sedimentation rate (ESR), and CD4 count. Univariable analysis and recursive partitioning were used to identify characteristics associated with CD4 count 200 cells/mm(3). Of 202 participants 109 (54%) had a CD4 count <200 cells/mm(3). Characteristics most strongly associated with CD4 count <200 cells/mm(3) (p-value <0.0001) were the presence of mucocutaneous manifestations (72% vs. 28%), lower total lymphocyte count (TLC) (median 1,450 vs. 2,200 cells/mm(3)), lower total white blood cell count (median 4,200 vs. 5,500 cells/mm(3)), and higher ESR (median 95 vs. 53 mm/h). In a partition tree model, TLC <1,200 cells/mm(3), ESR >or=120 mm/h, or the presence of mucocutaneous manifestations yielded a sensitivity of 0.85 and specificity of 0.63 for predicting CD4 count <200 cells/mm(3). The sensitivity of the 2006 WHO Staging system improved from 0.75 to 0.93 with inclusion of these parameters, at the expense of specificity (0.36 to 0.26). The presence of mucocutaneous manifestations, TLC <1,200 cells/mm(3), or ESR >or=120 mm/h was a strong predictor of CD4 count <200 cells/mm(3) and enhanced the sensitivity of the 2006 WHO staging criteria for identifying patients likely to benefit from antiretrovirals.

Genotypic variation in the pol gene of HIV type 1 in an antiretroviral treatment-naive population in rural southwestern Uganda

The majority of studies of HIV-1 drug resistance have involved subtype B viruses. Here we have characterized subtype distribution and determined the levels of polymorphism at protease (PR) and reverse transcriptase (RT) drug resistance positions, in antiretroviral treatment-naive HIV-positive Ugandan patients. We have also investigated codon usage variability at these positions and assessed intersubtype recombination within the pol gene. The study population consisted of 187 patients, from a cohort established by the UK Medical Research Council Programme on AIDS in Uganda in 1990. Results indicate that 28.3% of patients were infected with subtype A (n = 53), 64.2% subtype D (n = 120), 6.4% A/D recombinant (n = 12), and 1.1% subtype C (n = 2). Variation in amino acid usage at drug resistance-associated positions was minimal between the two main subtypes (A and D) in RT, but there was appreciable variation in PR. Codon usage, however, was considerably more variable between subtypes A and D in both PR and RT. Thus, while no natural high-level resistance to antiretroviral therapy was detected in this cohort, subtypes A and D may possess different genetic barriers to be overcome in order to achieve resistance. With the increasing introduction of antiretroviral therapy into Africa, such information will be vital in our understanding and evaluation of the development of drug resistance as it occurs, and how to interpret resistance data the type of which has rarely previously been seen. This analysis also significantly increases the number of Ugandan PR and RT sequences characterized to date.

Plasma HIV-1 RNA to Guide Patient Selection for Antiretroviral Therapy in Resource-Poor Settings

Scaling up access to highly active antiretroviral therapy (HAART) requires eligibility criteria that safeguard treatment efficiency in resource-poor settings. We determined whether supply of HAART on the basis of plasma viral load testing could result in a stronger reduction of AIDS incidence as compared with CD4 count-driven strategies. Expected AIDS incidence rates corresponding to distinct HAART eligibility criteria were calculated by relying on risk parameters obtained through the Amsterdam cohort studies on HIV infection and AIDS. We modeled 2 different treatment settings derived from sub-Saharan African surveys. In a hospital-based setting, the reduction in the 1-year AIDS incidence is the same for any HAART administration rate if patients are selected on a single CD4 cell count criterion or on (additional) criteria for plasma HIV-1 RNA. In a community-based setting, where patients are identified at less advanced stages of infection, the reduction in the 1-year AIDS incidence is higher at particular HAART administration rates if patients are selected on criteria for plasma HIV-1 RNA rather than CD4 cell count. Plasma viral load testing can ensure a more efficient allocation of antiretroviral therapy but only when applied to a strategy of active case finding in the community.

Mortality During the First 24 Months After Delivery in Relation to CD4 T-Lymphocyte Levels and Viral Load in a Cohort of Breast-Feeding HIV-1-Infected Women in Dar es Salaam, Tanzania

The objective of this study was to analyze the mortality during the first 24 months after delivery in relation to CD4 T-lymphocyte levels and viral load at enrollment (36 weeks of gestation) in a cohort of HIV-1-seropositive breast-feeding women at the Dar es Salaam site of the multicenter Petra trial (a mother-to-child HIV-1 transmission intervention trial using antiretroviral therapy). Antiretroviral treatment was not available in this setting apart from the short treatment given within the trial around delivery to prevent mother-to-child transmission of HIV. T-lymphocyte subsets were determined by flow cytometry. Plasma HIV-1 RNA was quantified by the Amplicor HIV-1 RNA Monitor v 1.5 assay. Mortality after delivery was analyzed using the life-table technique and Cox regression. The analysis included 266 mothers. The CD4 cell counts at enrollment were <200 cells/mm in 14.5% of the mothers. The viral load at enrollment was >100,000 RNA copies/mL in 33.6% of the mothers. The mortality 24 months after delivery was 6.7% (95% CI = 3.1-10.1%). The mortality 24 months after delivery was 29.9% (95% CI = 13.1-46.9%) for mothers with <200 CD4 cells/mm at enrollment, 3.3% (95% CI = 0-6.6%) for mothers with 200-499 CD4 cells/mm, 2.9% (95% CI = 0-7.1%) for mothers with >500 CD4 cells/mm (P = 0.0000), 15.0% (95% CI = 6.6-23.4%) for mothers with viral load >100,000 copies/mL at enrollment, and 2.8% (95% CI = 0-5.6%) for mothers with viral load <100,000 copies/mL (P = 0.0000). In the multivariate analysis CD4 cell counts and viral load were both independent risk factors for mortality (P < 0.001 and P = 0.004, respectively). In conclusion, the mortality was high among women with severe immunosuppression or high viral load at enrollment, but not in the rest of the women. CD4 lymphocyte count in late pregnancy was a better predictor of death within 2 years than was viral load. The results support the World Health Organization recommendation to initiate antiretroviral treatment in resource-limited settings in HIV-1-infected adults with CD4 cell counts <200/mm and show that this is appropriate also among perinatal women.

Sex and the course of HIV infection in the pre- and highly active antiretroviral therapy eras

We reviewed the available literature on the potential effects of sex on the course of HIV infection and found that there is little evidence for sex differences in the rate of disease progression in the pre-highly active antiretroviral therapy (HAART) and HAART era. Compared to men, women appeared to have lower HIV RNA levels and higher CD4 cell counts shortly after infection with HIV, but studies were inconclusive regarding whether these differences diminish over time. Differences in viral load or CD4+ cell count might cause women to delay initiation of HAART. Nonetheless, we found no substantial sex difference in the benefit of antiretroviral therapy. The studies we reviewed failed to find any harmful effect of pregnancy on HIV disease progression. With the availability of effective antiretroviral agents, HIV-infected women have increasingly decided to have children. Conflicting results exist on the effect of HAART on regression of cervical intra-epithelial neoplasia (CIN). Unlike CIN, invasive cervical cancer has not been found to be much higher in HIV-infected women than in HIV-uninfected women. Although publication bias cannot be ruled out, published studies suggest higher rates of adverse events among HIV-infected women on therapy as compared to men. As more pharmacological agents are developed, it is especially important that potential sex differences in pharmacodynamics are assessed. The relationship between metabolic abnormalities, changes in body habitus, and endocrine perturbations has not been extensively studied. Whether sex differences are due to unalterable genetic factors or social and environmental conditions, it is imperative that all HIV-infected individuals have equal access to interventions that can slow disease progression.

Rapid disease progression in human immunodeficiency virus type 1-infected seroconverters in India

To determine if the early immunological and virological events of HIV infection are unique in a setting with limited access to health care and HIV-1 subtype C infection, we undertook a prospective cohort study to characterize the early natural history of HIV viral load and CD4(+) T lymphocyte counts in individuals with recent HIV seroconversion in India. CD4(+) T lymphocyte counts were prospectively measured for up to 720 days in 46 antiviral drug-naive persons with very early HIV infection, documented by HIV antibody seroconversion. HIV viral RNA levels were measured subsequently on reposited plasma samples from these same time points. The median viral load "set point" for Indian seroconverters was 28,729 RNA copies/ml. The median CD4(+) cell count following acute primary HIV infection was 644 cells/mm(3). Over the first 2 years since primary infection, the annual rate of increase in HIV viral load was +8274 RNA copies/ml/year and the annual decline in CD4 cell count was -120 cells/year. Although the viral "set point" was similar, the median trajectory of increasing viral load in Indian seroconverters was greater than what has been reported in untreated HIV seroconverters in the United States. These data suggest that the more rapid HIV disease progression described in resource-poor settings may be due to very early virological and host events following primary HIV infection. A rapid increase in viral load within the first 2 years after primary infection may have to be considered when applying treatment guidelines for antiretroviral therapy and opportunistic infection prophylaxis.

Correlates of plasma HIV-1 RNA viral load among HIV-1-seropositive women in Dar es Salaam, Tanzania

This study was conducted to determine the predictors of plasma HIV-1 RNA viral load in HIV-1-positive pregnant women (N = 151) participating in a clinical trial in Tanzania. Viral load was measured at randomization, delivery, and approximately 7 months after delivery. The median viral load was 20,400 copies/mL at baseline, 20,216 copies/mL at delivery, and 19,100 copies/mL 7 months after delivery. The absolute CD4+ lymphocyte count had a strong negative correlation with HIV-1 RNA viral load at baseline (r = -.38), time of delivery (r = -.36), and 7 months after delivery (r = -.53). The association between CD4+ lymphocyte count and HIV-1 RNA viral load was modified by the per capita daily food expenditure in the household, although the difference in viral load became small as the food expenditure in the household increased and was marginally significant at the 75th percentile of the per capita food expenditure. The presence of malaria parasites at baseline was associated with an approximate 116% higher viral load at the three evaluation points (p =.007). Although the long-term effects of malaria on viral load are unknown, prevention of malaria among people living with HIV-1 should be given the highest priority.

Rapid disease progression and the rate of spread of the HIV epidemic

Traditional HIV epidemic models suggest that rapid disease progression may lead to reduced transmission because of a decreased time for the spread of the virus. We present a transmission model structured by age and duration of infection, and propose that rapid disease progression may lead to higher viraemia at a younger age, when individuals are more sexually active. We suggest that rapid disease progression should be considered as a factor in the scale of the HIV epidemic in Africa.