Isoelectric focusing and crossed immunoelectrofocusing of CSF immunoglobulins in MS

The 3 main Ig classes and the presence of free light chains were studied by isoelectric focusing and crossed immunoelectrofocusing in 100 CSF samples from patients with clinically definitie or probable MS. Minute quantities of IgM and free light-chain (mostly lambda) components were found in 2 out of 11 and 5 out of 14 samples respectively. IgG and IgA were detected in all samples examined for these proteins and were found in the pI-ranges of 5.3-9.8 and 4.6-6.4 pH-units respectively. The gammaglobulin abnormalities found on isoelectric focusing were identified as microheterogeneous, oligoclonal IgG with predominantly kappa light-chain determinants. The IgG immunoprecipitates differed from those of normal subjects and the major abnormal components most frequently exhibited pI-values greater than 8 pH-units. The IgA immunoprecipitates had 2-4 main components with some tendency to discontinuous subfractionation. This Ig class, however, did not exhibit the marked tendency to oligoclonal distribution found for IgG.