Identification of IgG subclasses'' oligoclonal bands in multiple sclerosis CSF

IgG subclasses' oligoclonal bands in unconcentrated CSF from MS patients were detected by isoelectric focusing in agarose gel with subsequent immunoblotting using mouse monoclonal antibodies to human IgG subclasses and double-antibody avidin-biotin-alkaline phosphatase system. All MS CSF showed presence of oligoclonal bands specific to the IgG1 subclass; in addition, several of these samples also had oligoclonal bands specific to IgG3, IgG2, or IgG4, in order of decreasing frequency. Since the CSF of a greater number of MS patients showed oligoclonal bands specific to the IgG1 and IgG3 subclasses, the findings are consistent with those reported in patients with chronic viral infections and autoimmune diseases.