COMPLEMENT SYSTEM AND RHEUMATOID ARTHRITIS: RELATIONSHIPS WITH AUTO ANTIBODIES, SEROLOGICAL, CLINICAL FEATURES, AND ANTI-TNF TREATMENT

• Published in: International journal of immunopathology and pharmacology 2011-06, Vol.24 (2), p.357-366
• Main Authors: Di Muzio, G, Perricone, C, Ballanti, E, Kroegler, B, Greco, E, Novelli, L, Conigliaro, P, Cipriani, P, Giacomelli, R, Perricone, R
• Format: Article
• Language: English
• ISSN: 0394-6320

Autoantibodies (rheumatoid factor, RF; anti-citrullinated-protein antibodies, ACPA) and complement system are involved in rheumatoid arthritis (RA). ACPA and anti-TNF agents are capable of in vitro modulating complement activity. We investigated the relationships between complement, autoantibodies, and anti-TNF treatment in vivo. One-hundred fourteen RA patients (89F/25M), diagnosed according to 1987 ACR criteria, and 30 healthy controls were enrolled. Serological analysis included ESR, CRP, complement C3, C4 and CH50, RF and ACPA (ELISA, cut-off>20U/ml). Split-products (SP) of C3 and B were studied by immunoelectrophoresis/counterimmunoelectrophoresis. Seventy-six patients started anti-TNF treatment and were studied at baseline and after 22 weeks. Disease activity was measured with DAS28 and response to therapy with EULAR criteria. At baseline, RA patients showed significantly higher levels of C3 and C4 than controls (C3127.9 plus or minus 26.5 vs 110 plus or minus 25mg/dl, P=0.0012; C429.7 plus or minus 10.2 vs 22.7 plus or minus 8.3mg/dl, P=0.0003). No differences in C3, C4 and CH50 levels were observed between ACPA+ (n=76) and ACPA- (n=38) patients. After 22 weeks of anti-TNF, C3, C4 and RF were significantly reduced (P