Human immunodeficiency virus type-2 (HIV-2) is a close relative of the prototype acquired immunodeficiency syndrome (AIDS) virus, HIV-1. HIV-2 is biologically similar to HIV-1, but information is lacking concerning clinical outcomes of HIV-2-infected individuals. From 1985 to 1993, a prospective clinical study was conducted in women with HIV-2 and HIV-1 infection to determine and compare rates of disease development. HIV-1-infected women had a 67% probability of AIDS-free survival 5 years after seroconversion in contrast with 100% for HIV-2-infected women. In addition to having significantly less HIV-related disease outcome in HIV-2 enrollees compared to HIV-1 enrollees, the rate of developing abnormal CD4+ lymphocyte counts with HIV-2 infection was also significantly reduced. This natural history study demonstrates that HIV-2 has a reduced virulence compared to HIV-1.

Background As HAART is introduced into areas of the world with high hepatitis B virus (HBV) endemicity, it is important to determine the influence of HBV on HIV-HBV co-infected persons receiving antiretroviral therapy (ART). Methods We studied 1,564 HIV-infected subjects in Jos, Nigeria who initiated ART. HIV-HBV co-infected participants had HBeAg and HBV DNA status determined. CD4+ T-cell count and HIV viral load at ART initiation were compared between HIV mono-infected and HIV-HBV co-infected subjects using univariate methods. Regression analyses were used to determine if HBeAg status or HBV DNA at ART initiation were associated with baseline HIV parameters or ART response. Results The CD4+ T-cell counts of the 262 (16.7%) HIV-HBV co-infected participants was 107 cells/mL compared to 130 cells/mL in HIV monoinfected participants (p <0.001) at ART initiation. HIV-HBV co-infected participants also had higher HIV viral loads than HIV monoinfected subjects (4.96 vs. 4.75 log10 copies/mL; p = 0.02). Higher HBV DNA and detectable HBeAg were independently associated with lower CD4+ T-cell counts at ART initiation but not with higher HIV viral load. In a multivariable model, HBeAg-positive subjects were less likely to suppress HIV replication to ≤400 copies/ml (OR 0.54, p=0.03) at 24 weeks, but they had similar CD4+ T cell increases. At 48 weeks, there was no significant effect of HBeAg status on ART response. Conclusions In HIV-infected Nigerian individuals, HBV co-infection, especially in those with high levels of HBV replication, was associated with lower CD4+ T-cell counts at ART initiation independent of HIV RNA level. Subjects with HBeAg positive status had a slower virological response to ART. Further work is needed to understand the effects of HBV on CD4+ T-cells.

A diverse array of non-subtype B HIV-1 viruses circulates in Africa and dominates the global pandemic. It is important to understand how drug resistance mutations in non-B subtypes may develop differently from the patterns described in subtype B. HIV-1 reverse transcriptase and protease sequences from 338 patients with treatment failure to first-line ART regimens were evaluated. Multivariate logistic regression was used to examine the effect of subtype on each mutation controlling for regimen, time on therapy, and total mutations. The distribution of HIV-1 subtypes included CRF02_AG (45.0%), G (37.9%), CRF06_cpx (4.4%), A (3.6%), and other subtypes or recombinant sequences (9.2%). The most common NRTI mutations were M184V (89.1%) and thymidine analog mutations (TAMs). The most common NNRTI mutations were Y181C (49.7%), K103N (36.4%), G190A (26.3%), and A98G (19.5%). Multivariate analysis showed that CRF02_AG was less likely to have the M41L mutation compared to other subtypes [adjusted odds ratio (AOR) ¼ 0.35; p ¼ 0.022]. Subtype A patients showed a 42.5-fold increased risk (AOR ¼ 42.5, p ¼ 0.001) for the L210W mutation. Among NNRTI mutations, subtype G patients had an increased risk for A98G (AOR ¼ 2.40, p ¼ 0.036) and V106I (AOR ¼ 6.15, p ¼ 0.010), whereas subtype CRF02_AG patients had an increased risk for V90I (AOR ¼ 3.16; p ¼ 0.003) and a decreased risk for A98G (AOR ¼ 0.48, p ¼ 0.019). Five RT mutations were found to vary significantly between different non-B West African subtypes. Further study to understand the clinical impact of subtype-specific diversity on drug resistance will be critically important to the continued success of ART scale-up in resource-limited settings.

The human immunodeficiency virus type 1 (HIV-1) viral setpoint during the disease-free interval has been strongly associated with future risk of disease progression. An awareness of the correlation between viral setpoint and HIV-1 genetic evolution over time is important in the understanding of viral dynamics and infection. We examined genetic diversity in HIV-1 CRF02_A/G-IbNG-infected seroincident women in Dakar, Senegal; determined whether a viral setpoint kinetic pattern existed for CRF02_A/G-IbNG during the diseasefree interval; and correlated viral load level and diversity. Samples were drawn during the disease-free interval from consenting CRF02_A/G-IbNG-infected, antiretroviral therapy-naïve female commercial sex workers in Dakar, Senegal. Based on sequential plasma RNA values, low and high viral setpoint groups were established. Intrapatient diversity and divergence over time was determined from earlier and later time point DNA samples from each person. Most individuals followed the viral setpoint paradigm. For each 1|؊|log 10 copy/ml of plasma increase in viral load, intrapatient diversity increased by 1.4% (P ‫؍‬ 0.028). A greater diversification rate was observed in the high viral setpoint group than in the low viral setpoint group (P ‫؍‬ 0.01). Greater nucleotide (P ‫؍‬ 0.015) and amino acid (P ‫؍‬ 0.048) divergences and a greater nucleotide divergence rate (P ‫؍‬ 0.03) were found in the high viral setpoint group. There was no difference between the groups in the ratio of the number of nonsynonymous substitutions per nonsynonymous site to the number of synonymous substitutions per synonymous site. The greater intrapatient diversity, divergence, and diversification rates observed in the high viral setpoint group supports the notion that diversity is driven by cycles of viral replication resulting in accumulated mutations. Recognizing diversity potential based on viral load levels in individuals may inform the design of vaccines and therapies.

In July 2009, the Center for Mental Health Research on AIDS at the National Institute of Mental Health organized and supported the meeting “NeuroAIDS in Africa.” This meeting was held in Cape Town, South Africa, and was affiliated with the 5th IAS Conference on HIV Pathogenesis, Treatment and Prevention. Presentations began with an overview of the epidemiology of HIV in sub-Saharan Africa, the molecular epidemiology of HIV, HIV-associated neurocognitive disorders (HANDs), and HAND treatment. These introductory talks were followed by presentations on HAND research and clinical care in Botswana, Cameroon, Ethiopia, The Gambia, Kenya, Malawi, Nigeria, Senegal, South Africa, Uganda, and Zambia. Topics discussed included best practices for assessing neurocognitive disorders, patterns of central nervous system (CNS) involvement in the region, subtype-associated risk for HAND, pediatric HIV assessments and neurodevelopment, HIV-associated CNS opportunistic infections and immune reconstitution syndrome, the evolving changes in treatment implementation, and various opportunities and strategies for NeuroAIDS research and capacity building in the region.