Impaired alveolar macrophage accessory cell function and reduced incidence of lymphocytic alveolitis in HIV-infected patients who smoke.

OBJECTIVE: To determine the effects of smoking on alveolar macrophage (AM) accessory cell (AC) function and the incidence of lymphocytic alveolitis in asymptomatic HIV-infected individuals.
METHODS: AM AC function in smoking and nonsmoking HIV-positive volunteers was measured in concanavalin A and pokeweed mitogen assays. Mitogen-induced AM-T-cell adherence was determined. AM cytokine secretion was analyzed by interleukin (IL)-6 bioassay and IL-1 enzyme-linked immunosorbent assay (ELISA). The incidence of lymphocytic alveolitis in both groups was determined.
RESULTS: AM from smokers were significantly poorer AC than AM from nonsmokers. Though AM-T-cell adherence was unaffected by smoking, IL-1 and IL-6 secretion was significantly impaired. Lymphocytic alveolitis was significantly less common in HIV-infected smokers.
CONCLUSION: Smoking reduces AM AC function in HIV-infected individuals, probably by impairing secretion of cytokines important in T-cell proliferation. This may explain the decreased incidence of lymphocytic alveolitis in HIV-infected people who smoke.