Studies on bronchoalveolar cells in human diseases. II General morphology and ultrastructure of pulmonary macrophages and small mononuclear cells in sarcoidosis

Data are presented from light and electron microscopic studies on bronchoalveolar lavage (BAC) in sarcoidosis, with particular emphasis on the ultrastructural morphology and functional characteristics of pulmonary macrophages (PM) and small mononuclear cells (SMC). Light microscopy showed an average of over 77% of the BAC to be PM, range 99-51%. SMC populations were also extremely variable. These variations may relate directly to the degree of disease activity. Electron microscopy demonstrated a wide range of morphological and implied functional (biosynthetic and phagocytic) characteristics of PM. Some of these are morphologically comparable to cells found in tissue granulomata. Our ultrastructural study has shown that the SMC population is made up of lymphocytes, monocytes and cells with intermediate characteristics (precursors). [PubMed - indexed for MEDLINE]