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-infected patients with Pneumocystis carinii pneumonias (HIV-PCP), we analyzed the proportion and the distribution of lymphocyte subpopulations and their state of activation in bronchoalveolar lavage (BAL) and peripheral blood of 21 HIV-PCP patients (CDC classification group IV) compared 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 cytometry) was performed with a cytofluorograph (Epics Profile, Coulter Corp., Hialeah, Fla., USA). In BAL from HIV-PCP patients the number of CD3-positive lymphocytes was significantly increased, yet there was no difference in the number of macrophages and neutrophils when compared to patients with ILD. Quantification of lymphocyte subpopulations showed that the increased number of BAL CD3-positive lymphocytes in HIV-PCP patients was mainly due to a significantly increased number of CD8-positive T cells, while the pulmonary CD4-positive T cells were decreased 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 increased numbers of IL-2R and HLA-DR bearing CD8-positive T cells but significantly 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 in HIV-infected individuals when compared to patients with ILD.(ABSTRACT TRUNCATED AT 250 WORDS)