ANALYSIS OF BRONCHOALVEOLAR LAVAGE FROM HUMAN LUNG-TRANSPLANT RECIPIENTS BY FLOW-CYTOMETRY

Bronchoalveolar lavage (BAL) cells and peripheral blood leucocytes (PB L) from 24 lung transplant recipients were analysed for leucocyte subs ets and expression of cell surface antigens. Total and differential wh ite cell counts were performed on BAL, and lymphocyte subsets were eva luated in both BAL and peripheral blood. Measurement of immunofluoresc ence by flow cytometry was used to assess the percentage of: T cells ( CD3+); T-helper cells (CD4+); T-cytotoxic/suppressor cells (CD8+); and activated lymphocytes (HLA-DR+). Lymphocyte subsets in BAL demonstrat ed marked differences to those in blood. A lower percentage of CD3+ an d CD4+ lymphocytes were found in BAL, whereas CD8+ cells were more pre valent in BAL than in PBL. The mean CD4:CD8 ratio was significantly lo wer in BAL (1:1) than in blood (2.1:1). In the absence of pulmonary in fection, there was a trend for a lower CD4:CD8 ratio in BAL associated with acute rejection (1.1:1) and obliterative bronchiolitis (1:1), wh en compared to the group with no evidence of rejection (1.4:1). In the absence of pulmonary rejection, pulmonary infection was associated wi th a marginally lower CD4:CD8 ratio in BAL (0.7:1), than when infectio n was absent (1.4:1). This difference was more evident in cases of cyt omegalovirus (CMV) infection with a mean CD4:CD8 ratio of 0.3:1, compa red to 1.5:1 in the absence of CMV disease (P < 0.05).