Demonstration of oligoclonal immunoglobulin G in Guillain-Barré syndrome and lymphocytic meningoradiculitis by isoelectric focusing.

Isoelectric focusing (IEF) of serum and CSF revealed oligoclonal IgG in 13 out of 16 patients with the Guillain-Barré syndrome (GBS), in 10 of them in serum only and in 3 in serum and CSF. Seventeen out of 19 patients with lymphocytic meningoradiculitis (LMR) showed oligoclonal IgG, 12 of them in CSF only. These findings, together with additional results, mean that in GBS oligoclonal IgG is synthesized mainly outside the CNS and in LMR within the CNS. Follow-up studies revealed changes in the oligoclonal IgG during the course of GBS and LMR. After treatment by plasma exchange the disappearance of oligoclonal IgG bands was followed by an improvement of GBS symptoms. The oligoclonal IgG bands returned in correlation with worsening of the disease. We were not able to elucidate the antibody character of oligoclonal IgG in GBS or LMR. No antibodies against the myelin basic protein (fragment 89-169) were detectable in the sera and CSF in any of the patients tested.