Objective: To investigate whether rheumatoid factor isotypes and anti-cyclic citrullinated peptide (anti-CCP) antibodies are related to clinical response in patients with rheumatoid arthritis treated with tumour necrosis factor α (TNFα) inhibitors.
Methods: The study was carried out on 132 patients with advanced rheumatoid arthritis refractory to disease-modifying antirheumatic drugs. Patients were treated with infliximab (n = 63), etanercept (n = 35) or adalimumab (n = 34). All patients completed 1 year of follow-up, and 126 were evaluable for clinical response according to the disease activity score (DAS) criteria. IgM, IgA and IgG rheumatoid factors and anti-CCP antibodies were assessed by ELISA both before anti-TNFα treatment and 1 year later.
Results: The DAS response was reached in 66% of evaluable patients (61% infliximab, 65% etanercept and 76% adalimumab; p = 0.354). A significant reduction in the rheumatoid factor level was reported by all treatment groups after 1 year. The frequency of positive tests for the different antibodies did not differ between responders and non-responders at baseline; however, significantly higher IgA rheumatoid factor levels were reported by the non-responder group (130.4 U/ml (interquartile range 13.8–276.7) v 24.8 U/ml (10.2–90.8); p = 0.003). A significant decrease (p<0.001) in the levels of all rheumatoid factor isotypes in the responder group was reported after 1 year of treatment, whereas anti-CCP antibody levels were not significantly affected.
Conclusions: According to the clinical response, anti-TNFα agents seem to reduce IgM, IgG and IgA rheumatoid factor levels. More interestingly, high pretreatment levels of IgA rheumatoid factor are associated with a poor clinical response to TNFα inhibitors.
- CCP, cyclic citrullinated peptide
- CRP, C reactive protein
- DAS, disease activity score
- DMARD, disease-modifying antirheumatic drug
- HAQ, Health Assessment Questionnaire
- TNF, tumour necrosis factor
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.
Published Online First 1 November 2006
Funding: This work was supported by a grant of IRCCS Policlinico S Matteo Foundation of Pavia, Italy.
Competing interests: None declared.