A CD8+ lymphocytic alveolitis occurs in up to 60% of asymptomatic human immunodeficiency virus (HIV)-infected individuals. Early in HIV infection, lymphocytes consist predominantly of cytotoxic T lymphocytes directed against HIV-infected targets. As HIV disease progresses, they are replaced by CD8+CD57+suppressor cells. Virus-specific cytotoxic T lymphocytes secrete interferon-γ (IFN-γ), an important cytokine in upregulating immune responses, primarily through macrophage activation. We examined the ability of lung and blood lymphocytes from HIV-positive patients at various stages of HIV infection to secrete IFN-γ spontaneously and in response to phytohemagglutinin A. IFN-γ production and secretion were determined with ELISA, Western blot, immunoprecipitation, and Northern blot techniques. Lung lymphocytes from HIV-infected individuals secreted large amounts of IFN-γ. However, this ability was lost in patients with late-stage disease. Correlation between blood and lung lymphocyte IFN-γ secretion was poor, suggesting regional differences in lymphocyte function. These data suggest that lung levels of IFN-γ are high until late in HIV disease. These findings support the concept of administering exogenous IFN-γ to patients with late-stage HIV disease and opportunistic infections.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.