MATRIX METALLOPROTEINASE MMP-19 (RASI-1) IS EXPRESSED ON THE SURFACE OF ACTIVATED PERIPHERAL-BLOOD MONONUCLEAR-CELLS AND IS DETECTED AS AN AUTOANTIGEN IN RHEUMATOID-ARTHRITIS

In order to characterize the autoimmune response participating in the pathogenesis of rheumatoid arthritis (RA) a cDNA expression library co nstructed from mRNAs which had been isolated from the inflamed synoviu m of an RA patient was screened with autologous IgG autoantibodies. Th is led to the identification of gene rasi-1 which encodes a protein sh owing sequence identity with the zinc-binding matrix metalloprotoinase MMP-19. MMP-19 is detected on the surface of activated PBMCs, T(H)1 l ymphocytes, and Jurkat T lymphoma cells. It exhibits gelatinolytic act ivity and is recognized by autoantibodies in 26% and, respectively, 33 % of sera collected from Rk patients and systemic lupus erythematosus (SLE) patients. The novel autoantigen MMP-19 thus could play a role in the pathological processes participating in RA-associated joint tissu e destruction.