HIV-specific T-cell responses and generalized activation in HIV-1 infected long-term non-progressors and progressors from South India.

Background: Anti-viral cytokine expressions by cytotoxic T-cells and lower activation rates have been reported to correlate with suppressed HIV replication in long-term non-progressors (LTNP) Immune mechanisms underlying disease non-progression in LTNP might vary with HIV-1 subtype and geographical locations. Objective: This study evaluates cytokine expression and T-cells activation in relation to disease non-progression in LTNP. Methods: HIV-1 Subtype C infected LTNP (n=20) and progressors (n=15) were enrolled and flowcytometry assays were performed to study HIV-specific CD8 T-cells expressing IL-2, IFN-gamma, TNF-alpha and MIP-1 beta against gag and env peptides. CD4+ T-cell activation was evaluated by surface expression of HLADR and CD38. Results: Proportions of cytokines studied did not differ significantly between LTNP and progressors, while contrasting correlations with disease progression markers were observed in LTNP. CD4+ T-cell activation rates were significantly lower in LTNP compared to progressors which indicate the potential role of T-cell activation rates in disease non-progression in LTNP. Conclusion: LTNP and progressors showed similar CD8+ T-cell responses, but final conclusions can be drawn only by comparing multiple immune factors in larger LTNP cohort with HIV-1 infected individuals at various levels of disease progression. A possible role of HIV-1 subtype variation and ethnic differences in addition to host-genetic and viral factors cannot be ruled out.