IgG ratios and oligoclonal IgG in multiple sclerosis and other neurological disorders

The findings are reported of various CSF abnormalities, including IgG indices and oligoclonal IgG, in 160 patients with multiple sclerosis of differing diagnostic certainty and 146 patients with other neurological disorders. An abnormal IgG index, defined as the ratio of IgG/albumin in CSF to that in serum, has been found in 77.7% of definite MS cases, falling to a figure of 32.1% in the single lesion group. A tendency, reported previously, for IgG levels to be higher in disabled patients, particularly those with a short history or early onset, has been confirmed. Oligoclonal IgG, on the other hand, has been found in 56% of definite MS cases, less frequently than in most other reported series. Analysis of the literature suggests considerable variability in the finding of oligoclonal IgG in other than definite MS, and in other neurological disorders. The possibility that subjective factors are partly responsible for this variability, rather than discrepancies in patient selection requires consideration, and suggests that CSF electrophoresis and IgG estimations are complementary aids in the diagnosis of multiple sclerosis. Differences have been expressed regarding the relationship of oligoclonal IgG to clinical parameters of the disease. Further sequential analysis of the development and variability of the oligoclonal pattern in MS is required.