Leukocyte Iso- and Autoantibodies in Multiple Sclerosis (MS) with Special Regard to Complement-Dependent Cold-Reacting Auto-Lymphocytotoxins (CoCoCy)

Studies on leukocyte antibodies in multiple sclerosis (MS) yielded positive results in 34% of 462 MS patients who were in the chronic stage of the disease, when the sera were tested at 15 °C against homologous lymphocytes of 10 cell donors bearing different HL-A antigens. The corresponding value in healthy controls was 7%. When autologous cells were used for demonstration of complement-dependant cold-reacting cytotoxins (auto-CoCoCy) the percentage of positive reactions rose up to 75%. No correlation of iso-CoCoCy with the HL-A antigens could be demonstrated. CoCoCy-positive sera did not react either with homologous or autologous lymphocytes at 37 °C. CoCoCy activity in sera was destroyed by means of 2-mercaptoethanol. The biological significance of CoCoCy in MS remains unclear.