Viral Load and CD4(+) T-Cell Dynamics in Primary HIV-1 Subtype C Infection

Background: Most knowledge of primary HIV-1 infection is based on subtype B studies, whereas the evolution of viral parameters in the early phase of HIV-1 subtype C infection is not well characterized. Methods: The kinetics of viral RNA, proviral DNA, CD4(+) T-cell Count, and subsets of CD4(+) T cells expressing CCR5 or CXCR4 were characterized in 8 acute and 62 recent subtype C infections over the first year postseroconversion. Results: The viral RNA peak was 6.25 +/- 0.92 log (10) copies per milliliter. After seroconversion, heterogeneity among acute cases was evident by patterns of change in viral load and CD4(+) T-cell count over time. The patterns were supported by the rate of viral RNA decline from peak (P = 0.022), viral RNA means (P = 0.005), CD4 levels (P < 0.001). and CD4 decline to 350 (P = 0.011) or 200 (P = 0.046). Proviral DNA had no apparent peak and its mean was 2.59 +/- 0.69 log(10) per 106 peripheral blood mononuclear cell. In recent infections, vital RNA set point was 4.00 +/- 0.97 log(10) and viral RNA correlated inversely with CD4(+) T cells (P < 0.001) and directly with proviral DNA (P < 0.001). Conclusions: Distinct patterns of viral RNA evolution may exist shortly after seroconversion in HIV-1 subtype C infection. The study provides better understanding of the early phase of subtype C infection.