DEMONSTRATION OF GRANZYME-A AND PERFORIN MESSENGER-RNA IN THE SYNOVIUM OF PATIENTS WITH RHEUMATOID-ARTHRITIS

Objective. To examine the gene expression of 2 highly specific markers of cytotoxic T lymphocyte (CTL) activation, the serine protease granzyme A and the pore-forming protein perforin, in synovial tissue of patients with rheumatoid arthritis (RA), and to compare the findings with those in osteoarthritis (OA) synovial tissue, Methods, Snap-frozen synovial tissue Specimens from 9 patients with RA and 5 patients with OA were examined, The number of CTL that expressed granzyme A or perforin messenger RWA was determined by in situ hybridization using nonradioactive riboprobes for granzyme A and perforin, and by a novel in situ reverse transcriptase technique, The signals were visualized by an immunogold-silver immunohistochemistry technique and compared with immunohistochemical labeling of T and B cells, Additional double-labeling was achieved using anti-type IV collagen, anti-macrophage (anti-CD68), anti-T lymphocyte; (anti-CD45RO), anti-B lymphocyte (anti-CD20), and anti-natural killer cell (anti-CD56) antibodies in an alkaline phosphatase-anti-alkaline phosphatase assay, Results, Granzyme A and perforin messenger RNA (mRNA) was observed In CTL in synovial specimens froth all of the RA patients, whereas in specimens from OA patients only a few, single cells with a positive mRNA signal for these molecules could be detected, In the RA specimens, the number of lymphocytes showing a positive mRNA signal for granzyme A or perforin varied from 10% to 50%, reflecting the recent findings of other investigators studying synovial fluid, Conclusion. Our results demonstrate that gene expression of at least 2 CTL products, granzyme A aid perforin, is up-regulated in the synovium of patients with RA compared with that in the synovium of patients with OA, These molecules presumably play an important role not only in lymphocyte-mediated cytotoxicity, but also in facilitating the migration of blood-borne mononuclear cells through the vascular basement membrane into the rheumatoid synovium.