Anti-myelin-associated glycoprotein antibody in sera from patients with demyelinating diseases

An enzyme-linked immunosorbent assay (ELISA) was developed for quantitating anti-myelin-associated glycoprotein (MAG) IgM antibody in human sera. Absorbance values of anti-MAG antibody were higher than 0.2 at 1:80 of serum dilution in sera from some patients with demyelinating diseases of the central or peripheral nervous systems including multiple sclerosis, subacute sclerosing panencephalitis, Guillain-Barré syndrome, chronic relapsing polyradiculoneuritis and carcinomatous polyneuropathy and also some patients with autoimmune diseases such as collagen diseases and myasthenia gravis. However, absorbance values of anti-MAG antibody in sera from control individuals and patients with some other neurological diseases were less than 0.2 and considered as negative. Because of the reported existence of a cross antigenicity between MAG and lymphocyte, and especially natural killer cells, the possibility of the functional importance of anti-MAG antibody on cellular immunity is discussed with particular reference to the demyelinating diseases.