A study of immune responses to myelin and cardiolipin in patients with systemic lupus erythematosus (SLE).

Sera from 39 patients with SLE, 20 patients with cerebrovascular disease with no evidence of SLE, and 20 normal controls were tested for antibodies to cardiolipin (CL), brain total upper (UPG) and lower phase (LPG) glycolipids, myelin basic protein (MBP), myelin, and single strand DNA (ssDNA) by ELISA. Binding to the glycolipids and MBP was negative or negligible in all the groups, but significant binding was observed against CL, myelin and ssDNA in some of the SLE patients. Many sera from SLE patients with cerebral disorders and high CL binding also demonstrated high binding to myelin. These sera also labelled cell surface antigens on neonatal mouse neurons and astrocytes by immunofluorescence in tissue culture. A correlation was found to exist between anti-CL and antimyelin antibodies in SLE patients with cerebral lesions, but not between anti-ssDNA and anti-CL antibodies. As much as 80-90% of the specific activity of these antibodies could be absorbed out by the relevant antigens but only partially by the other antigens. In the control groups binding was low and no specific absorption could be demonstrated.