LOCAL PROLIFERATION OF FIBROBLAST-LIKE SYNOVIOCYTES CONTRIBUTES TO SYNOVIAL HYPERPLASIA - RESULTS OF PROLIFERATION CELL NUCLEAR ANTIGEN CYCLIN, C-MYC, AND NUCLEOLAR ORGANIZER REGION STAINING/

Objective. To test the hypothesis that local proliferation contributes significantly to the hyperplasia of rheumatoid synovium. Methods. Imm unohistologic and chemical staining was used to identify 3 markers of cell proliferation: proliferating cell nuclear antigen, c-mye proto-on cogene, and nucleolar organizer regions. Synovium from 21 patients wit h rheumatoid arthritis, 34 with degenerative joint disease, and 7 with joint trauma was examined. Results. All 3 markers indicated substanti al, active proliferation of synovial lining cells in synovium with hyp erplasia. Proliferating cells showed type I procollagen immunoreactivi ty but were negative for CD68, a monocyte/macrophage marker. Prolifera tion was greater in rheumatoid arthritis than in the other conditions evaluated. Conclusion. In situ proliferation of fibroblast-like synovi ocytes in the synovium lining contributes considerably to the increase in cell numbers in rheumatoid synovium.