HIGH PROPORTION OF GAMMA-DELTA T-CELL RECEPTOR-POSITIVE T-CELLS IN BRONCHOALVEOLAR LAVAGE AND PERIPHERAL-BLOOD OF HIV-INFECTED PATIENTS WITH PNEUMOCYSTIS-CARINII PNEUMONIAS

To investigate the local immunological situation in the lung of HIV-in fected patients with Pneumocystis carinii pneumonias (HIV-PCP), we ana lyzed the proportion and the distribution of lymphocyte subpopulations and their state of activation in bronchoalveolar lavage (BAL) and per ipheral blood of 21 HIV-PCP patients (CDC classification group IV) com pared to 24 HIV-negative patients with interstitial lung diseases (ILD ). Peripheral blood lymphocytes (PBL) and BAL cells were stained with monoclonal antibodies. Two-color cytofluorometric analysis (flow cytom etry) was performed with a cytofluorograph (Epics Profile, Coulter Cor p., Hialeah, Fla., USA). In BAL from HIV-PCP patients the number of CD 3-positive lymphocytes was significantly increased, yet there was no d ifference in the number of macrophages and neutrophils when compared t o patients with ILD. Quantification of lymphocyte subpopulations showe d that the increased number of BAL CD3-positive lymphocytes in HIV-PCP patients was mainly due to a significantly increased number of CD8-po sitive T cells, while the pulmonary CD4-positive T cells were decrease d both in relative and absolute numbers. As a consequence, an inverted pulmonary CD4/CD8 ratio resulted for HIV-infected patients with PCP. Analysis of in-vivo-activated T cells in BAL and peripheral blood when measured by the expression of IL-2R, HLA-DR and VLA-1 revealed increa sed numbers of II-2R and HLA-DR bearing CD8-positive T cells but signi ficantly decreased numbers of IL-2R and HLA-DR bearing CD4-positive T cells as well as a higher number of CD8/CD57 double positive T cells i n HIV-infected individuals when compared to patients with ILD. Moreove r, a significantly higher proportion of gamma delta T cell receptor po sitive T cells (TCR-gammadelta-positive T cells) was found both in BAL and peripheral blood of HIV-infected patients with PCP (p < 0.05 resp . p < 0.001). Our study extends knowledge about the distribution of ly mphocyte subsets and their state of activation in HIV-PCP patients whe n compared to patients with ILD and supports the view that TCR-gammade lta-positive T cells may play an important role in the pulmonary immun e defense of HIV-infected patients.