Th17 cells are not preferentially lost from the BAL of HIV-infected patients. (A-F) GI tract, PB, and BAL lymphocytes from HIV-uninfected persons (○) and HIV-infected patients (●) were stimulated with anti-CD3 in the presence of brefeldin A and stained as in “Intracellular cytokine assay.” Frequencies of memory CD4 T cells that produce either IL-17 (A,C,E) or IFN-γ (B,D,F) were then measured by flow cytometry. (G) BAL lymphocytes from 4 HIV-infected patients were stimulated with CA antigen in the presence of brefeldin A and stained as in “Intracellular cytokine assay.” Production of either IL-17 or IFN-γ by memory CD4 T cells is shown.