Th1 CD4 T cells are less functional than Th17 CD4 T cells in HIV-infected patients. PB lymphocytes from cohorts of HIV-uninfected and -infected patients were stimulated with anti-CD3 overnight in the presence of brefeldin A and stained as in “Intracellular cytokine assay.” The ability of IL-17–producing or IFN-γ–producing CD27⁺ (A,B) and CD27⁻ (C,D) memory CD4 T cells to coproduce IL-2 and TNF was analyzed using SPICE as described in “Flow cytometric analysis.” Statistical significance was determined by the Mann-Whitney test.