Immune profile of HIV–1 discordant couples attending AMPATH clinics and MTRH in Western Kenya.

Background: The basis of apparent resistance to HIV-1 infection by some HIV-1 exposed heterosexual couples is unclear. The nature and functional characteristics of their immune cells could offer insight. Objective: To characterise immune profile in terms of CD8+ CD4+ CD56+/16+ and CD19+ cell number and Th1/Th2 cytokine expression in heterosexual HIV–1 discordant couples. Methods: Thirty-three (33) untreated HIV-1 discordant (index with CD4³250 cells/µL) concordant positive and negative control couples were recruited at MTRH/USAID-AMPATH partnership clinics in Western Kenya. Lymphocyte phenotypes complete blood count viral load (VL) and Th1/Th2 cytokine levels were determined and compared between the study groups. Results: Differences were observed between: HIV-1 discordant index females and concordant positive females CD8+ 711.0 cells/ml vs 1070.8 cells/ml (p = 0.005); %CD8+ 43.0% vs 56.3%;( p = 0.017); CD4+ 28.0% vs 18.3% (p = 0.02); CD56+/16+ 208.0 cells/ml vs 447.5 cells/ml (p = .011); discordant index males and concordant negative males CD4+ 700.7cell/ml vs 1000.4 cells/ml (p = 0.003); CD8+ 554.7 cells/ml vs 1062.4 cells/ml (p = 0.002); CD56+/16+ 290.5 cells/ml vs 450.7 cells/ml (p = 0.027). Uninfected female partners had higher mean cells/µL and percentage CD19+ than index females. In discordant index log10 viral load as negatively correlated with CD4+ (rho = -0.274) and CD56+/16+ (rho = -0.319). No Th1 to Th2 cytokine shift occurred in both index and partners of discordant couples. Conclusion: Lymphocyte subsets counts and cytokine levels correlate with HIV-1 resistance among the studied heterosexual HIV-1 discordant couples. Studies using HIV-1 specific antigens and lymphocytes from similar cohorts are necessary to improve understanding the role of immune response in HIV-1 discordance.