The helper T type 1 (Th1) function of CD4(+) T lymphocytes is presumed to be of key importance in host defense against HIV-1. As the production of different antibody isotypes is dependent on this helper T function, we investigated whether HIV-1-specific responses of a particular IgG isotype could be a reliable marker of long-term HIV-1 control. Assessment of the IgG subclass distribution in the plasma of HIV-1-infected patients enrolled in the French prospective Asymptomatic Long-Term (ALT) cohort showed that IgG2 directed against HIV-1 Env gp41 and Gag proteins was associated with low viral load, high CD4(+) lymphocyte count, and weak neutralizing activity. By contrast, levels of anti-Env and anti-Pol IgG1 as well as the magnitude of neutralizing activity were correlated with the viral load and thus merely reflect the level of HIV replication. Furthermore, IgG2 directed against Gag proteins was significantly associated with HIV-1 p24-specific Th1 cell production of interferon gamma and interleukin 2. In multivariate analysis, only two variables, anti-gp41 IgG2 and plasma HIV-1 RNA, were found to be independent prognostic factors of remaining long-term nonprogressive over time. By providing new insight into the nature of an HIV-specific antibody response associated with the control of virus replication, these findings have implications for the design of HIV vaccines.

ObjectivesData on the extent of drug use and associated HIV, hepatitis C and hepatitis B infection in West Africa are lacking. The objectives of ANRS12244 UDSEN study were to estimate the size of the heroin and/or cocaine drug user (DU) population living in the Dakar area (Senegal), and assess the prevalence and risk factors of HIV, hepatitis C virus (HCV) and hepatitis B virus (HBV), including behavioural determinants in this population, in order to set up an integrated prevention and treatment programme for DUs.Design and methodsA capture-recapture method was applied for population size estimation, whereas the respondent-driven sampling (RDS) method was used to recruit a sample of DUs living in the Dakar area and determine HIV, HBV and HCV prevalence. Behavioural data were gathered during face-to-face interviews, and blood samples were collected on dried blood spots for analysis in a central laboratory. Data analysis was performed using the RDS analysis tool, and risk factors were determined by logistic regression. Access to laboratory results was organized for the participants.ResultsThe size of the DU population in the Dakar area was estimated to reach 1324 (95% confidence interval (95% CI: 1281–1367)). Based on the 506 DUs included in the study, the HIV, HCV and HBV prevalence were 5.2% (95% CI: 3.8–6.3), 23.3% (95% CI: 21.2–25.2) and 7.9% (95% CI: 5.2–11.1), respectively. In people who inject drugs (PWID), prevalence levels increased to 9.4% for HIV and 38.9% for HCV (p=0.001 when compared to those who never injected). Women were more at risk of being HIV infected (prevalence: 13.04% versus 2.97% in males, p=0.001). Being PWID was a risk factor for HCV and HIV infection (odds ratio, OR: 2.7, 95% CI: 1.7–4.3, and OR: 4.3, 95% CI: 1.7–10.7, respectively), whereas older age and female sex were additional risk factors for HIV infection (10% increase per year of age, p=0.03 and OR: 4.9, 95% CI: 1.6–156, respectively). No specific determinant was associated with the risk of HBV infection.ConclusionsHigh HIV and HCV prevalence were estimated in this population of DUs (including non-injectors) living in the Dakar area, Senegal, whereas HBV prevalence was close to that of the global Senegalese population, reflecting a risk of infection independent of drug use. Women seem to be highly vulnerable and deserve targeted interventions for decreasing exposure to HIV, while behavioural risk factors for HIV and HCV include the use of unsafe injections, reflecting the urgent need for developing harm reduction interventions and access to opioid substitution therapy services.

Our study does not show a beneficial effect of chemoprophylaxis with low-dose cotrimoxazole on survival or occurrence of opportunistic or nonopportunistic infections for HIV-1-infected patients in Dakar, Senegal.

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