The identity of oligoclonal bands in patients with multiple sclerosis

Multiple sclerosis (MS) is the most common autoimmune inflammatory demyelinating disease of the central nervous system with a frequently relapsing or progressive course. A characteristic feature of MS is the increased intrathecal synthesis of IgG and the presence of oligoclonal bands (OCBs) in the brain and CSF. Once present, the intrathecal synthesis of IgG remains stable over time. Furthermore, OCBs are associated with a more rapid conversion from clinically isolated syndrome to clinically definite MS, and treatment with Natalizumab decreases CSF IgG levels and eliminates OCB. The combined studies provide evidence that the increased intrathecal IgG and OCBs play critical role in disease pathogenesis of MS. Using various immunoassays, we investigated the antigen-specific antibody profiles of CSF with paired sera in 7 OCB-positive MS patients. We found that the significantly increased levels of antigen-specific IgG in the CSF consisted of antigen–antibody immune complexes which correspond to OCB. Furthermore, the OCB can be completely eliminated by immunoadsorption, and can be recovered after binding to the specific antigen. The identification of the nature of OCB in MS opens up opportunities for novel diagnostics and prognostics, and provides strategies to design safer and more effective treatments for MS and other CNS inflammatory demyelinating diseases.