[IGG index or oligoclonal bands in the diagnosis of disseminated sclerosis].

Intrathecal synthesis of IgG was measured in 136 patients using agarose isoelectric focusing followed by immunoperoxidase staining for the detection of oligoclonal bands, and separate measurement of the IgG-index by immune electrophoresis. Oligoclonal bands were detected in 10/52 patients with other neurological diseases (OND). Five of these patients had possible multiple sclerosis (MS), and five had infections of the central nervous system. Oligoclonal bands were detected significantly more often in patients with clinically definite MS (24/26 patients (92%): p < 10(-9)) and in patients with acute optic neuritis, which is often an early manifestation of MS (34/58 patients (56%): p = 0.00005). An elevated IgG-index was detected in 15/25 MS-patients (60%), and in 13/56 patients with optic neuritis (20%). We conclude that isoelectric focusing is a valuable method for the detection of intrathecal production of IgG, and, especially in optic neuritis, has a higher sensitivity than the IgG-index. The method is recommended in the routine diagnosis of MS.