Analysis of the cell infiltrate and expression of matrix metalloproteinases and granzyme B in paired synovial biopsy specimens from the cartilage-pannus junction in patients with RA

Objectives-Examination of synovial tissue (ST) obtained at surgery because of end stage destructive rheumatoid arthritis (RA) showed that macrophages and fibroblasts are the major cell types at the cartilage-pannus junction ( CPJ). This study aimed at defining the cell infiltrate and mediators of joi nt destruction in ST selected at arthroscopy from the CPJ in patients with RA who did not require joint surgery. Methods-Paired synovial biopsy specimens were obtained at arthroscopy from ST adjacent to the CPJ and the suprapatellar pouch from the knee joints of 17 patients with RA. Immunohistological analysis was performed using monocl onal antibodies to detect T cells, B cells, plasma cells, macrophages, fibr oblastlike synoviocytes, mast cells, and granzyme B+ cytotoxic cells as wel l as the expression of metalloproteinase (MMP)-1, MMP-3, and MMP-13. The se ctions were evaluated by computer assisted image analysis and semiquantitat ive analysis. Results-The cell infiltrate comprised mainly T cells, macrophages, and plas ma cells. The ST was also infiltrated by the other cell types, but at lower numbers. Expression of MMPs was abundant, especially MMP-3. The features o f ST at the CPJ were generally similar to those at the suprapatellar pouch. Conclusions-The synovium at the CPJ in patients with RA who did not require joint surgery exhibits, in general, the same type of cell infiltrate and e xpression of MMPs and granzymes as ST from the suprapatellar pouch. The pat hological changes that have been described at the CPJ in patients with RA w ith end stage, destructive disease may well reflect the transition to a pro cess in which macrophages, fibroblast-like synoviocytes, and other cell typ es become increasingly important.