Persistence of antibrain antibodies in cerebrospinal fluid during plasmapheresis for multiple sclerosis.

A man with chronic progressive multiple sclerosis received a 10 day course of treatment with adrenocorticotrophic hormone without beneficial effect. He then received six sessions of plasmapheresis, again without improvement. Treatment with adrenocorticotrophic hormone had no effect on serum antibrain antibody titres, but plasmapheresis virtually eliminated the antibodies from serum and caused a fall in serum IgG concentrations; neither treatment had any effect on the IgG concentration and antibody titre in the cerebrospinal fluid. Treatment with plasmapheresis may fail in patients with multiple sclerosis because it does not remove antibrain antibodies from the intrathecal space.