Paraneoplastic antibodies detected by isoelectric focusing of cerebrospinal fluid and serum.

Patients with paraneoplastic neurological syndromes often produce intrathecal antibodies. We have employed isoelectric focusing and peroxidase-labeled anti-IgG or 35S-labeled Hu or Yo antigens to identify oligoclonal bands (OCB) representing either total IgG or Hu or Yo antibodies in serum and CSF of patients with paraneoplastic encephalomyelitis (PEM) or paraneoplastic cerebellar degeneration (PCD). OCBs representing paraneoplastic antibodies were found in all CSF, but in only three sera. Yo antibodies represented the majority of IgG bands in PCD-CSF, which may reflect a limited immune response, whereas in PEM/SN, there were numerous additonal IgG bands of unknown specificity, indicating a broader immune response in these patients.