Lymphocytotoxic and monocytotoxic antibodies in the serum and cerebrospinal fluid of multiple sclerosis patients

Serum cold cytotoxic antibodies (CA), detected at 15°C using a microcytotoxicity technique, were present in 12 of 21 multiple sclerosis (MS) patients, weak or absent in 6 neurological patients without MS and present but weak in 5 out of 32 healthy controls. In MS, these cold CA were directed against 3 distinct cellular populations: total lymphocytes, B lymphocytes and monocytes; certain antibody tests were positive at 37°C; no correlation between CA and clinical disease was observed. Cerebrospinal fluid (CSF) antibody levels were high in both MS and non-MS patients and at 37°C produced lysis of monocytes in the absence of complement. These antibodies may be normal CSF constituents. Our results suggest that there may be 3 different antibodies and that they may play a role in immunomodulation, especially in MS.