BASEMENT-MEMBRANE PROTEINS IN SYNOVIAL-MEMBRANE - DISTRIBUTION IN RHEUMATOID-ARTHRITIS AND SYNTHESIS BY FIBROBLAST-LIKE CELLS

Rheumatoid arthritis is a complex disease of unknown origin. In conseq uence of some immunological reactions, proliferative invading synovial tissue leads to destruction of normal joint architecture. The aim of this study was to investigate qualitative changes in extracellular mat rix distribution of proliferating rheumatoid synovium and their cellul ar origin. Synovial tissues from 57 clinically indicated arthrotomies were investigated with immunofluorescence, using specific antibodies a gainst extracellular matrix proteins in tissue slides and cultured cel ls, which were also studied for collagen biosynthesis. Results indicat ed that synovial fibroblast-like cells synthesize and secrete basement membrane proteins laminin and collagen type IV as e.g. endothelial ce lls or organogenic fibroblasts. Laminin and collagen type IV were spec ifically demonstrated pericellularly in the hyperplastic lining layer of active rheumatoid synovitis. These findings are discussed with resp ect to the possible implication of altered cell-matrix interactions in rheumatoid synovial proliferation.