Chimeric CD7 monoclonal antibody therapy in rheumatoid arthritis

Murine monoclonal antibody (Mab) therapy in patients with rheumatoid arthritis (RA) produces an antimouse immunoglobulin response by the recipient. We studied a chimeric (human/mouse) CD7 Mab, in a dose ranging tolerability study in 10 patients with RA. Modest improvements in disease activity occurred with frequent acute adverse effects of malaise, fever and nausea. After treatment, peripheral blood T lymphocyte numbers fell by 50% and CD7 expression fell by 97% for less than 7 days. Our study demonstrates chimeric Mab function in vivo and illustrates the influence of antibody isotype and patient characteristics on adverse effects.