Prevalence- and gender-specific immune response to opportunistic infections in HIV-infected patients in Lesotho.

Background: The objective of this study was to assess the seroprevalence of coinfecting viruses and Treponema pallidum (T. pallidum) in a cohort of 205 antiretrovirally treated HIV-infected individuals (152 females and 53 males, aged: 19-71 years) in rural Lesotho. Furthermore agent-specific immune responses were investigated by analyzing antibody titers against herpes simplex virus type 2 (HSV-2) and against T. pallidum.

Methods: Serum samples were tested by enzyme-linked immunosorbent assay for antibodies against HSV-2, cytomegalovirus, hepatitis A, B, and C viruses, and T. pallidum.

Results: Seroprevalences (95% confidence intervals) were found to be 100% (98.5%-100%) for anti-cytomegalovirus, 98.5% (95.7%-99.7%) for anti-hepatitis A virus, 35.5% (28.9%-42.6%) for anti-HBc, 5.5% (2.8%-9.6%) for hepatitis B surface antigen, and 0.5% (0.0%-2.8%) for anti-hepatitis C virus. Only 78.5% (72.2%-84.0%) were anti-HSV-2 positive and 29.0% (22.8%-35.8%) had antibodies against T. pallidum. Only anti-HSV-2 titers showed gender- and CD4 cell-count dependent differences: females with >500 CD4 cells/microL had an average anti-HSV-2 titer of 446 compared with males of 398 AU/mL (not significant), but in those with 250 to 500 CD4 cells/microL, there was a significant difference with a mean titer of 467 compared to 302 AU/mL in males (P = 0.001).

Conclusions: A high seroprevalence of CMV, HAV, and HBV was found in both genders. One-third of the patients had been exposed to HBV and T. pallidum. The generally high HSV-2 prevalence showed gender- and CD4 cell count-dependent differences in HSV-2 antibody titer.