Enhanced IFN-γ production in vitro by CD8⁺ T cells in hemophiliacs with AIDS as demonstrated on the single-cell level

We examined T cells from HIV-infected hemophiliacs under antiviral therapy, on the single-cell level, for cytokine production in vitro in response to stimulation. The percentage of IL-2-producing cells was markedly decreased among both CD3⁺CD8^- and CD3⁺CD8⁺ cells, while the proportion of IFN-γ-producing cells was preserved among CD3⁺CD8^- cells and increased among CD3⁺CD8⁺ cells in HIV⁺ subjects, compared with HIV-uninfected controls. The increase in IFN-γ-producing CD8⁺ cells was accounted for by the expansion of CD8⁺CD28^- cells among total CD8⁺ T cells and by the higher percentage of IFN-γ-expressing cells among both CD8⁺CD28⁺ and CD8⁺CD28^- cells in HIV⁺ individuals, compared with controls. The enhanced IFN-γ production in CD8⁺ cells from individuals in the advanced phase of HIV infection might implicate the host's response to chronic viral infection or senescence of host CD8⁺ cells.