Autoantibodies against a novel citrullinated fibrinogen peptide related to smoking status, disease activity and therapeutic response to methotrexate in cuban patients with early rheumatoid arthritis

Treatment recommendations of early rheumatoid arthritis (RA) suggest differential management of patients on the basis of prognostic factors. In this study we aimed to investigate the relationship between autoantibodies against a novel citrullinated fibrinogen peptide (anti-CFP), smoking status, clinical activity and therapeutic response in Cuban patients with early RA, receiving treatment with methotrexate in comparison to rheumatoid factor (RF), anti-cyclic citrullinated peptide of second generation (anti-CCP2) and anti-mutated citrullinated vimentin (anti-MCV). A 6-month prospective observational study was performed in 60 early RA patients at baseline and 6 months after receiving methotrexate. Baseline and outcome measures included disease activity score of 28 joints (DAS 28), simplified disease activity index (SDAI), anti-CFP antibodies, RF, anti-CCP2 and anti-MCV. Therapeutic response was determined using 20/50/70 American College of Rheumatology (ACR) response rates. DAS28 (p < 0.0001), SDAI (p < 0.0001) as well as titres of anti-CFP (p = 0.0481), anti-CCP2 (p = 0.0082), RF IgM (p = 0.0187) and RF IgA (p = 0.0252) decreased under therapy. Multivariate analyses showed association of final anti-CFP values with sex and smoking status (p = 0.0296). It is of note that anti-CFP antibodies were one of predictors for DAS 28 (p = 0.0072) SDAI (p < 0.0001) and ACR response (p = 0.0003) in multivariate models. Anti-CFP antibodies decrease in correspondence with clinical improvement after 6-month therapy and are associated with sex and smoking status. Moreover, baseline anti-CFP antibodies, using in combination with sex, smoking status and autoantibodies (anti-CCP2, anti-MCV or RF) seems to have clinical relevance for predicting clinical activity and therapeutic response.