Agarose isoelectric focusing, antiserum immunofixation and silver staining for detection of oligoclonal bands in unconcentrated cerebrospinal fluid

Unconcentrated cerebrospinal fluid (CSF) and corresponding serum from 30 patients with multiple sclerosis (MS), 30 with other neurological disease and 30 controls suffering from tension headache or psychoneurosis, were examined for oligoclonal IgG bands by initial separation employing agarose isoelectric focusing (AIF) followed by a modified procedure of immunofixation with monospecific antiserum and silver staining. This method is specific for demonstration of IgG and has a limit for detection of 0.4 microgram of IgG. Comparing the results with those obtained by AIF followed by capillary blotting to nitrocellulose membrane, double antibody peroxidase labeling and avidin-biotin amplification, both methods revealed similar frequencies of positive findings for oligoclonal IgG bands in the three patient groups. AIF followed by antiserum immunofixation and silver staining is a simple, sensitive and specific method for detection of oligoclonal IgG in unconcentrated CSF.