Immunoglobulin G immunosuppression of multiple sclerosis. Suppression of all three major lymphocyte subsets.

Six patients with relapsing chronic progressive multiple sclerosis were treated on 2 consecutive days with large amounts of IgG to induce immunosuppression. Peripheral blood lymphocyte subsets were monitored for 5 weeks after IgG treatment to determine immunosuppression. Decreased numbers of B, T, and natural killer lymphocytes were detected after treatment. Lymphocyte numbers were at a nadir 1 week after treatment, but an immunosuppressive effect continued to be present after 5 weeks. Although clinical efficacy was not evident in this brief open trial, the decrease of peripheral lymphocyte numbers and the apparent safety of the procedure warrant further study.