Serum demyelinating factors in multiple sclerosis

Sera from 21 patients with multiple sclerosis were applied to myelinated spinal cord cultures and evaluated for demyelinating activity. Samples were collected at various times when patients were on or off therapy with myelin basic protein or prednisone or both, and at various stages of disease. Five of 31 serum samples from 17 patients exhibited demyelinating activity when tested in a 40% concentration in tissue culture nutrient medium. Four of the 10 serum samples taken from patients with active or remitting multiple sclerosis (2 samples from the same patient) were demyelinative; 1 of 21 sera collected during stationary periods of disease was positive. There was no correlation between serum demyelinating activity and the presence or absence of treatment. Sera positive for demyelinating activity failed to inhibit myelin formation in initially unmyelinated cerebellar cultures.