Interleukin 10 Responses Are Associated With Sustained CD4 T-Cell Counts in Treated HIV Infection

Background. Inflammation persists in treated human immunodeficiency virus (HIV) infection and may contribute to an increased risk for non-AIDS-related pathologies. We investigated the correlation of cytokine responses with changes in CD4 T-cell levels and coinfection with hepatitis C virus (HCV) during highly active antiretroviral treatment (HAART). Methods.A total of 383 participants in the Women's Interagency HIV Study (212 with HIV monoinfection, 56 with HCV monoinfection, and 115 with HIV/HCV coinfection) were studied. HIV-infected women had < 1000 HIV RNA copies/mL, 99.7% had > 200 CD4 T cells/mu L; 98% were receiving HAART at baseline. Changes in CD4 T-cell count between baseline and 2-4 years later were calculated. Peripheral blood mononuclear cells (PBMCs) obtained at baseline were used to measure interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6), interleukin 10 (IL-10), interleukin 12 (IL-12), and tumor necrosis factor alpha (TNF-alpha) responses to Toll-like receptor (TLR) 3 and TLR4 stimulation. Results.Undetectable HIV RNA (< 80 copies/mL) at baseline and secretion of IL-10 by PBMCs were positively associated with gains in CD4 T-cell counts at follow-up. Inflammatory cytokines (IL-1 beta, IL-6, IL-12, and TNF-alpha) were also produced in TLR-stimulated cultures, but only IL-10 was significantly associated with sustained increases in CD4 T-cell levels. This association was significant only in women with HIV monoinfection, indicating that HCV coinfection is an important factor limiting gains in CD4 T-cell counts, possibly by contributing to unbalanced persistent inflammation. Conclusions.Secreted IL-10 from PBMCs may balance the inflammatory environment of HIV, resulting in CD4 T-cell stability.