C3 come indicatore di efficacia terapeutica in pazienti con artrite reumatoide in terapia con inibitori del TNFα

Objectives. Complement system is involved in rheumatoid arthritis (RA) pathogenesis. Anti-TNF agents are capable in vitro of modulating complement activity, but there is a paucity of in vivo data. Thus, we investigated the complement system in RA patients and the possible use of C3 as marker of efficacy in patients treated with anti-TNF agents. Methods. One-hundred fourteen RA patients and thirty healthy controls were enrolled. Serological analysis included ESR, CRP, complement C3, C4 and CH50, RF, split-products of C3 and B. Seventy-six patients started anti-TNF treatments and were studied also after 14 and 22 weeks. Disease activity was measured with DAS28 and response to therapy with EULAR criteria. Results. At baseline C3, C4 and CH50 levels were significantly higher in rheumatoid arthritis patients than in controls. In patients undergoing anti-TNF therapy, C3, C4 and RF were significantly reduced after 22 weeks. Patients with higher baseline C3 levels or with a lower reduction of C3 after 22 weeks of therapy with anti-TNF had a worse EULAR outcome. Conclusions. The presence of high levels of C3 in RA patients might be a negative prognostic factor ascribed to a pro-inflammatory status reverted by anti-TNF.