Immunologic responses of progressive multiple sclerosis patients treated with an anti-T-cell monoclonal antibody, anti-T12.

Twelve patients with progressive MS were treated with a murine IgM pan-T-cell monoclonal antibody reactive against T12, a determinant present on most post-thymic T-cells. Circulating T12+ cells could not be detected from days 1 to 7, although T3+T11+T12- cells appeared by day 3. Human anti-mouse antibodies were detected in 78% of patients by day 7 and correlated with a decrease in anti-T12 MAb blood levels and the reappearance of T12+ cells in the blood. Although there were high levels of anti-T12 MAb in the serum, there were only barely detectable levels in the CSF and no decrease in the proportion of T12+ cells in the CSF with treatment. Immunologic studies demonstrated a decrease of in vitro pokeweed mitogen-driven Ig synthesis on day 3 with an increase on day 10 that consisted in part of human anti-mouse antibodies. Eleven of 12 patients completed therapy. Prednisone was administered with the treatment after mild allergic reactions occurred in the first two patients. Because this was an open phase one study and patients were treated with prednisone, the effect of treatment on the progression of disease is difficult to assess, and no definitive conclusions concerning clinical effects can be made.