REPEATED TREATMENT WITH CHIMERIC ANTI-CD4 ANTIBODY IN MULTIPLE-SCLEROSIS

We treated 21 multiple sclerosis patients with two to four doses of cM -T412, a chimeric monoclonal antibody against the CD4 antigen found on helper/inducer T lymphocytes. The mean number (a standard error) of c irculating CD4 lymphocytes decreased from 888 (+/- 81) cells/mm(3) at baseline to 246 (+/- 18) after treatment. At 1 year after the last tre atment, the CD4 count had recovered to only 335 (+/- 32). The antibody had no effect on CD8 lymphocytes, B lymphocytes, or other leukocytes. Side effects were minimal. Despite the prolonged depletion of CD4 lym phocytes, no opportunistic infections occurred. Only 1 patient had a p ossible allergic reaction. Most patients were clinically stable, but a few progressed. We conclude that repeated treatment with cM-T412 is e ffective in reducing the number of circulating CD4 lymphocytes and has no limiting side effects.