Immunolocalization of Adhesion Molecules in Rheumatoid and Osteoarthritic Synovial Tissues

To elucidate the potential role of adhesion molecules in the pathogenesis of rheumatoid arthritis (RA), we stained specimens of synovial tissue from patients with RA and osteoarthritis (OA) with monoclonal antibodies against adhesion molecules using an immunohistochemical method. Positive staining with anti-ICAM-1 monoclonal antibody was detected on the synovial lining cells, the sublining cells and the capillary endothelial cells in the synovium from patients with RA, and, to a lesser degree, in that from patients with OA. The capillary endothelial cells from patients with RA intensively expressed both ELAM-1 and VLA-5α molecules, in contrast to that from OA patients. The intensity of both ICAM-1 and ELAM-1 on the capillary endothelial cells in RA synovium was comparable to disease activity and to the degree of synovial proliferation. A high density of expression of LFA-1α , VLA-4α and VLA-5α was observed on the mononuclear cells that infiltrated the RA synovium, especially in the lesions with aggregated mononuclear cells. The findings clearly demonstrated an up-regulation of the expression of adhesion molecules on synovial cells, capillary endothelial cells and infiltrated mononuclear cells in the synovial tissues of patients with RA. This enhanced expression of adhesion molecules may play an important role in the migration of mononuclear cells into the synovial tissues and thus perpetuate the inflammatory response in these tissues

Different expression levels of TNF receptors on the rheumatoid synovial macrophages derived from surgery and a synovectomy as detected by a new flow cytometric analysis

TNFα plays a crucial role in the pathogenesis of rheumatoid arthritis. It is very important to examine the expression of the TNF receptors, the ligand of TNFα. In this study, we developed a triple-color flow cytometric analysis using CD45 and CD14 monoclonal antibodies to simply detect the expression of the TNF receptors on the heterogeneous rheumatoid synovial cells. Using this system, we detected a higher population of macrophages and a greater TNF receptor expression on the synovial macrophages derived from a synovectomy in comparison to the findings obtained from knee joint replacement surgery