Flow Cytometric Analysis of Lymphocyte Phenotypes in Bronchoalveolar Lavage Fluid: Comparison of a Two-Color Technique with a Standard Immunoperoxidase Assay

Characterization of lymphocytes in bronchoalveolar fluid has provided insight into the pathogenesis of many pulmonary diseases. Identification of lymphocyte phenotypes has become highly successful due to development of specific monoclonal antibodies and reliable methods for detecting labeled cells such as flow cytometry (FCM) and immunocytochemistry. FCM permits rapid screening of many cells, but this analysis may be confounded by heterogeneity in the size and granularity of the cells being evaluated. Such heterogeneity may lead to exclusion of cells of interest and inclusion of unwanted cells. Often peripheral blood leukocytes are used to define the gate for lung lymphocytes, but this gate may be inappropriate due to considerable variation in size and granularity of cells in bronchoalveolar lavage (BAL) fluid. Here we report an alternative method for generating a gate which employed fluorescence and side scatter signals to analyze lymphocyte subsets in BAL fluid by FCM. This gating technique avoids the p...