IL-10-Rα blockade enhances cytokine secretion by HIV-specific CD4⁺ T cells. (A-C) Cytokine secretion by HIV-specific CD4 T-cell proliferation was measured by multiplex immunoassay in supernatants of CD8 T cell–depleted PBMCs incubated with no antigen or an HIV Gag peptide pool, plus isotype control antibody or IL-10Rα antibody. Blockade of the IL-10 pathway increased IFN-γ and IL-2 cytokine secretion by HIV-specific CD4 T cells, as shown in these 3 representative subjects. (D-E) Statistical analysis of data on 14 untreated subjects indicated a significant increase of both IFN-γ (P = .004; D) and IL-2 (P = .026; E) in the presence of IL-10Rα blockade (Wilcoxon matched pairs test).