Functional identification of pathogenic autoantibody responses in patients with multiple sclerosis.
Researchers who study multiple sclerosis have long debated whether MS is a bona fide autoimmune disease in part because a clear, disease-causing autoantigen has never been identified despite extensive efforts to find one. In this study, Elliott et al. used a novel assay for the search: They exposed myelinated rat neurons cultured from spinal tissue to blood serum taken from individuals with MS (n = 37), healthy controls (n = 13), and those with other neurological diseases (n = 10) to test whether antibodies in the serum could attack myelin antigens and cause demyelination. They identified pathogenic immunoglobulin G responses in the serum of approximately a third of the MS group but not in serum from any other subjects. This observation suggests that autoantibodies can contribute to demyelination by targeting oligodendrocytes and the myelin sheaths they extend. Three people from that subgroup who had undergone plasma exchange therapy showed significantly reduced demyelinating IgG activity after the procedure. Further work is necessary to determine the relation between the antibodies, such treatment, and disease course.