PT  - JOURNAL ARTICLE
AU  - L De Rycke
AU  - X Verhelst
AU  - E Kruithof
AU  - F Van den Bosch
AU  - I E A Hoffman
AU  - E M Veys
AU  - F De Keyser
TI  - Rheumatoid factor, but not anti-cyclic citrullinated peptide antibodies, is modulated by infliximab treatment in rheumatoid arthritis
AID  - 10.1136/ard.2004.023523
DP  - 2005 Feb 01
TA  - Annals of the Rheumatic Diseases
PG  - 299--302
VI  - 64
IP  - 2
4099  - http://ard.bmj.com/content/64/2/299.short
4100  - http://ard.bmj.com/content/64/2/299.full
SO  - Ann Rheum Dis2005 Feb 01; 64
AB  - Objectives: To analyse the effect of infliximab on IgM rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibodies, and determine whether baseline autoantibody titres (IgM RF and anti-CCP antibodies) are associated with changes in acute phase reactants. Patients and methods: 62 patients with refractory RA were treated with infliximab combined with methotrexate. At baseline and week 30, serum samples were tested for IgM RF by two agglutination assays, and for anti-CCP antibodies by an ELISA. Percentage change in C reactive protein (CRP) and erythrocyte sedimentation rate (ESR) was calculated. Results: At baseline and week 30 RF titres were reduced significantly during infliximab treatment (p<0.001 and p = 0.038, respectively), whereas anti-CCP antibodies were unchanged (p = 0.240). Baseline IgM RF titres, but not anti-CCP antibodies, correlated inversely with changes in CRP and ESR during treatment. Patients with a marked decrease in acute phase reactants had lower IgM RF titres than those with a smaller decrease in CRP and ESR; no significant differences were found for anti-CCP antibodies. Conclusion: The differential effect of infliximab treatment on IgM RF and anti-CCP antibodies, and the different predictive value on changes in acute phase reactants during infliximab treatment support the existing evidence that RF and anti-CCP antibodies are independent autoantibody systems in RA.