Sistema complementare e artrite reumatoide: Correlazioni con autoanticorpi, caratteristiche cliniche e di laboratorio e farmaci anti-TNF α

Objectives. Rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA) and complement system are involved in rheumatoid arthritis (RA) pathogenesis. Aim of this study is to investigate whether ACPA can activate the Complement system in vivo in patients with Rheumatoid Arthritis who are treated by means of traditional and/or biologic DMARDs. Methods. One-hundred fourteen RA patients (89 F/25 M) 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. Seventy-six patients started anti-TNF α treatments and were studied also after 22 weeks. Disease activity was measured with DAS28 and response to therapy with EULAR criteria. Results. At baseline, C3, C4 and CH50 levels in RA patients were significantly higher than in controls. No demographic or clinical differences were observed between ACPA+ (n = 76) and ACPA- (n = 38) patients, nor in C3, C4 and CH50 levels. In patients undergoing anti-TNF α therapy, C3, C4 and RF were significantly reduced after 22 weeks. RF changes showed positive correlation with CH50 after 22 weeks. DAS28 significantly ameliorated after 22 weeks. Conclusions. C3, C4, CH50 levels that we studied in serum of RA patients seem to correlate with RF levels rather than ACPA, independently from the therapy administered.