Measurement of cerebrospinal fluid IgG in the diagnosis of multiple sclerosis

CSF IgG was measured in 190 patients by Single Radial Immunodiffusion, A high value for the ratio CSF IgG/total protein (normal values being up to 14%) was obtained in 13 of 22 patients (54%) with definite or probable multiple sclerosis and in 16 of 137 patients (12%) with other neurological disorders excluding acute infections, subarachnoid haemorrhage and neurosyphilis. In 56 patients IgG and albumin were measured in CSF and serum using Rocket Immunoelectrophoresis (Electroimmunodiffusion) and results assessed by dividing the radio IgG/albumin in the CSF by the same ratio in the serum to obtain an Index. Because of the small number of normal patients, it was not possible to define a normal range but separation of patients with multiple sclerosis from those with other neurological disorders was even less clear-cut than with first method. Minor technical difficulties with the Rocket technique and prolonged storage of some of the specimens may at least partly explain the discouraging results with this method. It was concluded that the measurement of CSF IgG was of limited value to a clinican attempting to make a diagnosis in an individual patient with neurological disease.