Expression of intercellular adhesion molecule-1 (ICAM-1) by reactive mesothelial cells in pleural effusions.

Reactive mesothelial cells in serous effusions have been assessed for their capacity to express intercellular adhesion molecule-1 (ICAM-1), when pleural cavities are involved in inflammatory and immune reactions. Cytospin smears prepared from 10 benign and 10 malignant effusion specimens were used in an immunocytochemical procedure. Mesothelial cells were positively immunolabeled by a monoclonal antibody to human ICAM-1, whereas lymphocytes clustered around them reacted positively with a monoclonal antibody to human Lymphocyte Function-associated antigen-1 alpha chain (LFA-1-alpha). The ICAM-1/LFA-1 interaction enables mesothelial cells to regulate leukocyte transmigration to and accumulation in serous cavities and therefore they are actively involved in the development of serous effusions.