LYMPHOCYTE STUDIES IN ASYMPTOMATIC CIGARETTE SMOKERS - COMPARISON BETWEEN LUNG AND PERIPHERAL-BLOOD

Abstract

Lung and peripheral blood lymphocyte populations were compared in asymptomatic human subjects, 21-31 yr of age, who smoked 1.5-2 packs of cigarettes daily for 3 or more years. The T[thymus derived]- and B[bone marrow derived]-lymphocyte populations in peripheral blood were quantified, B cells by the complement receptor (EAC [erythrocyte, antibody complement] rosettes), and T cells by the E rosette technique. Proliferative response of peripheral blood lymphocytes to the mitogens, phytohemagglutinin [PHA] and concanavalin A were measured. In 10 smokers, mean .+-. SD proportion of T cells in peripheral blood was 75 .+-. 7%; of B cells, 18 .+-. 4%. These values, as well as the absolute number of T and B cells, did not differ significantly from those in 17 nonsmokers of comparable age. There was no significant difference between smokers and nonsmokers in the proliferative response of peripheral blood lymphocytes to PHA and concanavalin A. In 5 of the smokers in whom cells were recovered by segmental bronchial lavage, lung lymphocytes consisted at 55% (range, 27-72%) T cells and 13% (range 7-22%) B cells and did not differ significantly from lung lymphocyte subpopulations recovered from 8 nonsmoking control subjects. The response to PHA and concanavalin A of lung lymphocytes from smokers was markedly decreased (P < 0.01 for PHA and P < 0.005 for concanavalin A) compared to lung lymphocytes from nonsmokers. The diminished response of lung lymphocytes in smokers could not be explained by impaired cell survival, a decreased number of T cells in mitogen cultures or to inhibitory effects of smoker macrophages. Decreased mitogen responsiveness in lymphocytes obtained from lungs of smokers lends some support to the hypothesis that cigarette smoke may impair local immune defenses.