Agarose isoelectric focusing of unconcentrated CSF and radioimmunofixation for detection of oligoclonal bands in patients with multiple sclerosis and other neurological diseases.

Agarose isoelectric focusing (AIEF) of concentrated CSF was compared with AIEF of unconcentrated CSF and subsequent immunofixation with radiolabeled antihuman IgG Fc Fragment antiserum and autoradiography for the demonstration of oligoclonal bands in CSF from 287 neurological patients. Oligoclonal bands were demonstrated by AIEF in 98% of 43 patients with multiple sclerosis, 72% of 18 patients with infectious CNS diseases, and 23% of 226 patients with other neurological diseases. The corresponding figures obtained with AIEF of unconcentrated CSF and radioimmunofixation were 98%, 67% and 21%, respectively. In 15 of the patients, oligoclonal bands were demonstrated in CSF and serum by both techniques. They are both useful alternatives for the demonstration of oligoclonal bands in CSF, and the method for unconcentrated CSF can be safely applied when only small CSF volumes are available. The oligoclonal IgG pattern obtained by AIEF was not influenced by concentration of CSF by ultrafiltration and subsequent dilution to the original IgG concentration, nor by storage for 6 months.