Limitations of Peroxidase Staining in the Detection of CSF IgA Separated by Agarose Isoelectric Focusing

Abstract

Cerebrospinal fluid immunoglobulin electrophoretic abnormalities are characteristic of multiple sclerosis (MS). Intrathecal synthesis of IgG has been intensively investigated, while little attention has been directed to CSF IgA and IgM. The detection of intrathecally synthesized IgA oligoclonal bands (OBs) in MS CSF has been reported by Arnason’s group [1] : IgA oligoclonal bands were found in 16 of 20 MS CSFs studied by agarose isoelectric focusing (AIEF), transfer of protein to nitrocellulose membrane, specific immunofixation, and peroxidase staining. However, there are several reasons to question the possibility of a reliable detection of IgA OBs by AIEF of native as well as concentrated CSF. We investigated the occurrence of IgA OBs in CSF from MS and normal subjects to verify the previously reported data.