Canadian Institutes of Health Research.

The immune-enhancing effects of selenium (Se) supplementation make it a promising complementary and alternative medicine modality for boosting immunity, although mechanisms by which Se influences immunity are unclear. Mice fed low (0.08 mg/kg), medium (0.25 mg/kg), or high (1.0 mg/kg) Se diets for 8 wk were challenged with peptide/adjuvant. Antigen-specific CD4(+) T cell responses were increased in the high Se group compared with the low and medium Se groups. T cell receptor signaling in ex vivo CD4(+) T cells increased with increasing dietary Se, with all 3 groups differing from one another in terms of calcium mobilization, oxidative burst, translocation of nuclear factor of activated T cells, and proliferation. The high Se diet increased expression of interleukin (IL)-2 and the high affinity chain of the IL-2 receptor compared with the low and medium Se diets. The high Se diet skewed the T helper (Th)1/Th2 balance toward a Th1 phenotype, leading to higher interferon-gamma and CD40 ligand levels compared with the low and medium Se diets. Prior to CD4(+) T cell activation, levels of reactive oxygen species did not differ among the groups, but the low Se diet decreased free thiols compared with the medium and high Se diets. Addition of exogenous free thiols eliminated differences in CD4(+) T cell activation among the dietary groups. Overall, these data suggest that dietary Se levels modulate free thiol levels and specific signaling events during CD4(+) T cell activation, which influence their proliferation and differentiation.

These subtype differences in coreceptor use may partially explain the faster progression rates we have previously reported in individuals infected with subtype D compared with subtype A. Our observations may have implications for the future use of coreceptor inhibitors in this population.

HIV-1 prevalence is rising in this cohort. Incidence is stabilizing, and shows signs of increasing among some subgroups. The extent to which changing sexual behaviour has played a role in these epidemiological trends is unclear, but it is likely to have contributed. To solidify the success that Uganda had throughout the 1990s in controlling the HIV epidemic, the efforts in HIV prevention need to be re-strengthened, using all strategies known.

We examined whether use of antiretroviral (ARV) therapy is associated with increased sexual risk behavior in a cross-sectional study of patients undergoing ARV therapy (ARV experienced) compared to patients not undergoing ARV therapy (ARV-naïve) attending an urban HIV clinic in Kampala, Uganda. Sexual behavior during the prior 6 months and sexually transmitted disease (STD) treatment was determined by face-to-face structured interviews. Multiple logistic regression was used to identify independent correlates of sexual activity, multiple sexual partners, inconsistent condom use, and STD treatment during the prior 6 months. Three hundred forty-seven (48%) of the 723 respondents reported a history of sexual intercourse in the 6 months prior to the interview (sexually active). Receipt of ARV therapy was not associated with a significantly higher likelihood of being sexually active (adjusted odds ratio [AOR], 2.0 95% confidence interval [CI], 0.3-9.9). Among both ARV-experienced and ARV-naïve persons who were sexually active, 35% (120) reported one or more casual sexual partners in addition to a main partner (no difference by ARV status). Consistent condom use with spouse, regular, casual, and commercial partners was reported by 57%, 65%, 85%, and 85% of the sexually active respondents, respectively. The ARV-experienced respondents were more likely to report consistent condom use with their spouses than were ARV-naïve respondents (OR 2.82 95% CI 1.74-4.6). ARV-experienced respondents were more likely than ARV-naïve respondents to have disclosed their HIV status to their spouses (OR 1.57 95% CI 1.07-2.30).The ARV-experienced group was more likely to report STD treatment in the prior 6 months (AOR 2.62 95% CI 1.8-3.83) than the ARV-naïve group. The findings suggest that in this population, use of ARV therapy was not associated with risky sexual behavior in the prior 6 months. Still, recall and social desirability biases remain important limitations in interpreting these conclusions.