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 log10 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 log10 per 106 peripheral blood mononuclear cell. In recent infections, viral RNA set point was 4.00 ± 0.97 log10 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.