ENHANCED PROLIFERATION AND IL-2 SECRETION BY LUNG LYMPHOCYTES FROM HIV-INFECTED SUBJECTS

Human immunodeficiency virus (HIV)-positive patients frequently develo p a CD3(+)/CD8(+) cytotoxic T cell lymphocytic alveolitis. This could occur through in situ expansion of lung lymphocytes. We evaluated lung and blood lymphocyte proliferation in asymptomatic HIV-infected indiv iduals by measuring spontaneous and cytokine-induced tritiated thymidi ne incorporation. Interleukin (IL)-2 and IL-4 secretion was determined with the use of enzyme-linked immunosorbent assay. Western blotting, and immunoprecipitation techniques. Spontaneous proliferation by lung lymphocytes from HIV-positive patients was significantly greater than that of normal volunteers. Proliferation was confined to the CD8(+) ly mphocyte subset. Over time, spontaneous proliferation declined unless autologous alveolar macrophages (AM) were added, suggesting AM were pr oviding additional stimulatory signals to lung lymphocytes. Lung and b lood lymphocytes proliferated in response to IL-2 but not IL-4. Lympho cytes in HIV-infected lung spontaneously produced and secreted more IL -2 than either normal lung lymphocytes or autologous blood lymphocytes . IL-4 production was not detectable in either group. These findings s upport the hypothesis that lymphocytic alveolitis in asymptomatic HIV- positive patients results from IL-2-dependent in situ proliferation of CD3(+)/CD8(+) cytotoxic T cells.