Therapeutic use of monoclonal anti-CD4 antibody in rheumatoid arthritis.

Ten patients with severe rheumatoid arthritis were treated with a murine monoclonal anti-CD4 (B-F5) antibody in an open study (one with 10 mg/day, 2 with 15 mg/day, 7 with 20 mg/day) for 10 consecutive days. Tolerance was excellent. All patients improved during treatment clinically (Ritchie's index, morning stiffness, pain scale) (p = 0.005), as well as biologically C-reactive protein (p = 0.008) with an average 60% reduction of each of these variables at Day 15, and clinical benefit lasted over 6 months in some patients. No significative depletion was noted in total lymphocyte or CD3, CD4, CD8, CD20, positive cells after treatment. Evidence of murine immunization was found in only 2 patients.