The significance of oligoclonal bands in multiple sclerosis in Japan: relevance of immunogenetic backgrounds.

We compared clinical and demographic features, MRI findings, and HLA profiles of 57 Japanese patients with multiple sclerosis (MS) between groups with and without oligoclonal IgG bands (OCB) in the cerebrospinal fluid (CSF). Patients with the optic-spinal form of MS (OpS-MS) or acute transverse myelopathy (ATM), which are distinctive and relatively common in Japanese MS, were excluded in this study. The OCB-positive rate was only 56.1% (32/57) among these 57 'conventional' MS patients, of whom clinical features were similar to those of Western MS patients. The demographic features, clinical course, disability, and cerebral abnormalities seen on MRI were similar in the OCB-negative and OCB-positive patient groups. HLA-DR2 antigen, which has been confirmed to be associated with MS in many populations, was more common in the OCB-positive than in the OCB-negative and control groups. Furthermore, DR4 antigen was statistically more common in the OCB-negative patient group. These results raise the possibility that the presence of OCB is related to the immunogenetic background of the patient, and that there may be at least two subpopulations in Japanese patients with 'conventional' MS from the viewpoint of immunogenetics. In one subpopulations, MS is associated with the DR2 antigen, and shows a stronger humoral immune response in the CSF, while in the other MS is associated with DR4, which has a milder humoral response. Further investigations involving more patients are warranted.