Isoelectric focusing and quantitative estimation of cerebrospinal fluid and serum IgG in idiopathic polyneuropathy.

Isoelectric focusing and quantitative estimation of serum and CSF IgG were performed in 85 patients with idiopathic polyneuropathy (IP), subdivided according to the clinical course (acute, subacute, recurrent, chronic). Acute IP very frequently had an increase of oligoclonal and/or polyclonal serum IgG during the progressive phase and blood-CSF barrier damage accompanied by polyclonal IgG intrathecal synthesis during the stationary phase. Polyclonal IgG intrathecal synthesis was also present in several not acute IP and seemed to forecast unfavorable course. Oligoclonal IgG synthesis occurs very rarely within CSF but is a frequent finding in serum of patients with IP. Abnormalities of the IgG serum pattern are neither specific for any clinical course of IP nor of prognostic value. The possible significance of such findings is discussed.