Detection of IgG oligoclonal bands in unconcentrated CSF by means of agarose isoelectric focusing, double immunofixation peroxidase staining and avidin-biotin amplification.

To detect immunoglobulin G (IgG) oligoclonal bands in unconcentrated cerebrospinal fluid (CSF) we used a recently developed method combining agarose isoelectric focusing (IEF) and double immunofixation peroxidase staining with Avidin-Biotin amplification. We studied 65 CSF and serum paired specimens from normals, multiple sclerosis (MS), other neurological diseases (OND) and benign monoclonal gammopathies (BMG). We found that the oligoclonal IgG pattern can be demonstrated after IEF of 15 microliter of CSF specimens with an IgG concentration of 15 mg/L. In 98% of CSF from patients with clinically definite MS a sharp oligoclonal band pattern was detected. The reliability and the sensitivity of this powerful technique is compared to agarose IEF of concentrated CSF, followed by Coomassie Brilliant Blue staining. This method constitutes a real improvement in the detection of CSF IgG oligoclonal bands because it avoids CSF concentration and allows the detection of IgG bands only.