Isoelectric focusing and agar electrophoresis of the cerebrospinal fluid in neurologic patients

: Both isoelectric focusing and routine agar gel electrophoresis have been carried out on the CSF, and in some cases also on the corresponding serum, from 452 control subjects and patients with neurological diseases among whom cases with multiple sclerosis (MS) predominated. Comparison of the results confirms the superiority of electrofocusing over gel electrophoresis for the evaluation of oligoclonal immune reactions of the CNS. Over 90% of the MS patients showed discontinuous subfractionation of the gamma-globulins, mostly confined to the CSF, whereas with agar gel electrophoresis an identical effect could be seen only in about 60% of the same patients. Of special interest is the fact that by isoelectric focusing an additional 20% of MS patients whose gamma-globulin content, cell count and plasma cell findings in the CSF are within normal limits show oligoclonal CSF immune reactions. Thus, after appropriate screening by routine electrophoresis to reduce the number of analyses, the relatively laborious method of isoelectric focusing is an effective addition to the usual CSF investigations.