SUBSTANCE-P LEVELS IN THE SYNOVIUM AND SYNOVIAL-FLUID FROM PATIENTS WITH RHEUMATOID-ARTHRITIS AND OSTEOARTHRITIS

Experimental results suggest that substance P (SP) may play an importa nt role in pain and inflammation in rheumatic diseases. Measurements o f SP-like immunoreactivity (SPLI) were performed in synovial fluid (SF ) and synovial tissue from 40 patients with rheumatoid arthritis (RA) or osteoarthritis (OA). High levels of SPLI were found in the SF of pa tients with RA compared with OA. Conversely, SPLI content in synovial tissue was higher in OA than in RA, suggesting that there is an active secretory process of SPLI into the SF in RA, thus depleting SPLI stor es in the synovium. Our data support the involvement of SP in the perp etuation and exacerbation of inflammation in RA, and may also explain some clinical features of this disease.