Changes in lung lymphocyte populations reflect those seen in peripheral blood in HIV-1 positive individuals.

We have investigated the level of lymphocytosis present in the lung of human immunodeficiency virus (HIV)-1+ infected patients with and without pulmonary disease and how changes in natural killer (NK), B and T-cells seen in peripheral blood (PB) compare with those seen in bronchoalveolar lavage fluid (BALF). Lymphocyte subpopulations and their expression of activation, cytotoxic markers and memory status were characterized by triple immunofluorescence. Macrophages accounted for over 80% of the BAL cells. Only three out of 72 patients had a lymphocyte percentage >30%. No statistically significant differences in the relative proportions of NK, CD4 and CD8 populations were seen in BALF when compared to PB, except for a twofold increase in the percentage of activated CD8 cells in BALF. The only differences in BALF populations between the HIV-1+ groups were a lower percentage of CD4+ cells, and a higher percentage of activated CD8+ cells in the patients with pneumonitis. In the present cohort of patients there was little evidence for an overall lymphocytosis in bronchoalveolar lavage fluid of HIV-1+ subjects. Changes observed in lymphocyte subsets of bronchoalveolar lavage fluid populations reflected those in peripheral blood, and were similar for patients with and without pneumonitis. Evidence of increased CD8 subset activity in bronchoalveolar lavage fluid did, however, emerge.