Immunocompetent Cells in Bronchoalveolar Lavage Reflect the Cell Populations in Transbronchial Biopsies in Pulmonary Sarcoidosis1–3

The purpose of this study was to examine the relationship between the inflammatory cells seen in transbronchial lung biopsy samples (TBB) and the bronchoalveolar lavage fluid (BAL) taken from patients with pulmonary sarcoidosis. Monoclonal antibodies and histochemical methods were used to identify mononuclear inflammatory cells in cryostat tissue sections and to compare these with cell populations in BAL-derived cytospin preparations. The subsets of lymphocytes identified in BAL accurately reflected the type and proportion of subsets present in the TBB. Although the ratio of T4+:T8+ lymphocytes was variable from patient to patient, concordance between BAL and TBB specimens was found in each subject. In the BAL, a high proportion of T lymphocytes expressed class II MHC antigen (HLADR+). Monoclonal antibodies were also used to identify sub-populations of macrophages and dendritic cells in the BAL and tissue samples. Macrophage subsets defined by phenotypic differences were found in both cases. Although no c...