To investigate the impact of infliximab treatment on anticyclic citrullinated peptide (anti-CCP) antibody and rheumatoid factor (RF) levels in patients with rheumatoid arthritis (RA).
Sera from 33 RA patients receiving infliximab and disease modifying antirheumatic drugs were tested for anti-CCP antibody, IgA-, IgG- and IgM-RF using a commercially available semiquantitative ELISA at baseline, 30 and 54 weeks after treatment.
The serum levels of anti-CCP antibody and IgA-RF decreased significantly after 30 weeks (P = 0.002 and 0.024); however, the decrease was not significant at week 54 (P = 0.147 and 0.207). The decrease in IgG-RF level was not significant at 30 and 54 weeks (P = 0.059 and 0.097). IgM-RF levels, however decreased significantly at 30 and 54 weeks (P = 0.002 and 0.004). A strong correlation between anti-CCP and IgA-, IgG- and IgM-RF was observed at baseline (r(s) = 0.48, 0.43, 0.65, P = < 0.05) and after infliximab treatment at 30 (r(s) = 0.45, 0.46, 0.62, P = < 0.05) and 54 (r(s) = 0.49, 0.45, 0.60, P = < 0.05) weeks.
Treatment with infliximab results in decreased anti-CCP antibody and IgA-RF early in the course of therapy that is not sustained. IgM-RF declines and remains decreased for at least 54 weeks. Investigations in larger cohorts of RA patients (especially early RA) with longer follow-up are needed to assess the impact of specific therapeutic interventions on anti-CCP antibody and RF levels and the relationship of their levels to disease activity.