Reactive lesions of the pleura. Immunohistochemical characterization.

The visceral pleura of 8 lung tissue specimens with non-tumorous pleural lesions and of 10 specimens with secondary pleural infiltration of different primary tumours were tested by avidin-biotin-method with the following antibodies: anti-keratin KL1, anti-vimentin V9, anti-CEA (BMA 130c), HEA 125, Leu M1, HMFG 2 and anti-collagen type IV. In all cases anti-keratin positive subserosal cells could be proved. Activated mesothelial cells expressed vimentin additionally to keratin. The antibodies Leu M1, HEA 125 and BMA 130c (against CEA) showed no reaction in subserosal and mesothelial cells. With the antibody HMFG 2, however, a weak reaction could be observed. A distinction between reactive and neoplastic pleural lesions is not possible by using these antibodies. The antibodies LeuM1, HEA 125 and BMA 130c can be helpful for differential diagnosis in single cases with pleural carcinosis. The antibody against collagen type IV demonstrates newly developed basal membrane structures in areas with proliferating subserosal cells. Considering our results the entity of mesothelium and submesothelium is discussed with regard to the histogenetical aspect of mesothelioma.