Alcohol decreases T-lymphocyte migration into lung tissue in response to Pneumocystis carinii and depletes T-lymphocyte numbers in the spleens of mice.

Previous work from our laboratory has shown that chronic alcohol consumption in mice creates immunosuppression sufficient to permit infection with the opportunistic pathogen Pneumocystis carinii. Host defense against P. carinii is critically dependent upon host T lymphocytes. In these experiments, we address the effect of chronic alcohol consumption on recruitment of T lymphocytes into infected lung tissue and on lymphocytes in host lymphoid tissue. We find that mice administered alcohol in drinking water and then inoculated with P. carinii show significantly decreased recruitment of CD4+ and CD8+ T lymphocytes into lung tissue in comparison with control mice. Additional experiments show significant depletion of CD4+ lymphocytes in spleens from alcohol mice and decreased numbers of activated T lymphocytes. Analysis of surface expression of the adhesion molecules LFA-1, VLA-4, and ICAM-1 show no significant differences in lymphocytes from alcohol-consuming mice, and lymphocyte chemotaxis in vitro is also unaltered. We conclude that chronic consumption of alcohol impairs lung recruitment of lymphocytes in response to an infectious challenge. This impaired lymphocyte recruitment may be a consequence of depletion of T lymphocytes in host lymphoid tissue. Impaired recruitment of lymphocytes may explain the increased morbidity and mortality of pulmonary infections in alcoholic subjects.