Aim: To investigate the clinical response and to evaluate by magnetic resonance imaging the inflammatory tissue changes in refractory rheumatoid arthritis patients treated with infliximab.
Methods: Sixteen refractory rheumatoid arthritis patients who were treated with intravenous infliximab (3 mg/kg) at weeks 0, 2, 6 and every 8 weeks thereafter were examined with magnetic resonance imaging of the dominant affected wrist and hand before treatment and 1 year after therapy. The volume of the enhancing inflammatory tissue was evaluated in fat suppressed contrast enhanced T1-weighted images by using the Analyse 4.0 software. Disease activity was evaluated by assessing the disease activity score for 28 joint indices. The clinical improvement was evaluated according to the American College of Rheumatology 20% response criteria.
Results: There were 13 females and 3 males with mean age 49.5 (17.0) years and mean disease duration 10.5 (8.0) years. Ten patients had positive IgM rheumatoid factor. One year after treatment, a significant reduction of the erythrocyte sedimentation rate, the C-reactive protein, the disease activity score for 28 joint indices and the volume of the enhancing inflammatory tissue was observed. All but two of the rheumatoid arthritis patients achieved the American College of Rheumatology 20% response criteria, while 9 (56.25%) and 5 (31.25%) patients achieved the 50% and 70% American College of Rheumatology response criteria, respectively. A positive correlation among the volume of the enhancing inflammatory tissue, swollen joint count, tender joint count, as well as disease activity score for 28 joint indices (r=0.66, r=0.79, r=0.57 respectively) was found before treatment.
Conclusions: In refractory rheumatoid arthritis patients, the addition of infliximab therapy may result in clinical, laboratory and magnetic resonance imaging improvement. Magnetic resonance imaging assessment of the volume of the enhancing inflammatory tissue may represent an additional tool for the investigation of joint disease activity and responsiveness to treatment.