High IgA rheumatoid factor levels are associated with poor clinical response to tumour necrosis factor α inhibitors in rheumatoid arthritis
- Francesca Bobbio-Pallavicini1,
- Roberto Caporali1,
- Claudia Alpini2,
- Stefano Avalle2,
- Oscar M Epis1,
- Catherine Klersy3,
- Carlomaurizio Montecucco4
- 1Cattedra di Reumatologia, IRCCS Policlinico S Matteo, Pavia, Italy
- 2Laboratori Analisi Chimico-Cliniche, IRCCS Policlinico S.Matteo, Pavia, Italy
- 3Servizio di Biometria ed Epidemiologia Clinica, IRCCS Policlinico S Matteo, Pavia, Italy
- 4Cattedra di Reumatologia, Policlinico S Matteo, Pavia, Italy
- Correspondence to:
Prof C Montecucco
Cattedra di Reumatologia, Policlinico S Matteo, 27100 Pavia, Italy;
- Accepted 22 October 2006
- Published Online First 1 November 2006
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
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.