[Cytoenzymological, immunological and scanning electron microscopic studies on 49 cases (author's transl)].

Light cytology, enzymology, immunofluorescence and scanning electron microscopy have been performed on 49 bronchoalveolar fluids recovered by bronchoscopic lavage. The patients had the following lung diseases: infectious pneumonitis (19 cases), pulmonary fibrosis (13 cases) including 5 sarcoïdosis, 3 idiopathic pulmonary fibrosis and 5 silicosis, hypersensitivity pneumonitis (5 cases) and miscellaneous lung tumors (12 cases). Cytologic studies in comparison with clinical aspects show 4 groups: Group I (chronic bronchopneumopathy and inactive fibrosis) presents numerous cells but few lymphocytes (less than 5%); in Group II (evolutive fibrosis) have an increase percentage of lymphocytes (20%); in Group III (hypersensitivity pneumonitis) is observed a very high percentage of lymphocytes (45%); and in Group IV (cancerous lung diseases) values are not far from normal percentage except for lymphomas. Small macrophages (diameter: 10 microns) with a central monocytoïde nucleus and few cytoplasma, are abundant in groups II and III where lymphocytosis is higher. Scanning electron microscopy shows irregular and rough surface, and numerous spontaneous adherences with erythrocytes, lymphocytes, or bacterias. Enzymatic activity (acid hydrolase, esterase, oxydase) increases in these cells. Lymphocytes have a smooth surface ovocative of T origin which is confirmed by granular acid phosphatase positivity and rosette forming test. Immunofluorescence shows positive granules with IgG, C1Q and C3 in macrophages only for Groups II and III while free immunoglobulins were present in the recovered lavage fluid.