Multiple sclerosis: demyelination and myelination inhibition of organotypic tissue cultures of the spinal cord by sera of patients with multiple sclerosis and other neurological diseases.

Sera from 44 patients with Multiple Sclerosis, of three patients with neurological syndromes compatible with Multiple Sclerosis, of 34 patients suffering from other neurological diseases and of 25 pregnant healthy young women were tested for their demyelinating activity in myelinated tissue cultures. In order to leave the investigators unprejudiced, all sera were coded and intermixed with controls of rabbit EAE serum which had a potent demyelinating capacity. Demyelination was graded (from 0--4), heat lability at 56 degrees C (complement dependency?) was also tested with each serum. Only demyelination of a degree of 2 and more, which was abolished by heating to 56 degrees C, was counted as positive. Six of the 44 sera from MS patients (13.6%), 19 of 37 sera from neurological patients and none of the healthy young women demyelinated. Thus, serum demyelination of tissue cultures seems to be a nonspecific indicator of chronic disease of the nervous system and is of considerable general neurological interest, but does not indicate a demyelinating disease. Myelination inhibition was not observed with any of the human sera tested for it.