Detection of Oligoclonal Immunoglobulins in Cerebrospinal Fluid by an Immunofixation-Peroxidase Method

BACKGROUND: The detection of intrathecal synthesis of immunoglobulins is used in the diagnosis of multiple sclerosis (MS). We tested the semiautomated immunofixation-peroxidase (IFPOD) technique, which uses high-resolution agarose gel electrophoresis (HRAGE) directly followed by immunofixation with a peroxidase-labeled anti-IgG antiserum to detect oligoclonal immunoglobulins in cerebrospinal fluid (CSF). METHODS: We analyzed 230 consecutive matched serum/CSF pairs that arrived in the laboratory over a 6-month period with both IFPOD and our routine techniques, immunofixation electrophoresis (IFE) and HRAGE. For IFPOD, CSF samples were not concentrated before testing. RESULTS: Among the 230 samples were 12 clinically definite MS, 33 clinically probable, and 20 clinically possible MS samples. IFPOD and HRAGE + IFE each detected oligoclonal IgG in CSF in 10, 16, and 7 cases of these respective groups. For clinically definite MS, sensitivity and specificity (95% confidence intervals) were, respectively, 83% (51-97%) and 79% (73-84%). CONCLUSIONS: The IFPOD technique performs comparably to other analytical methods, without the requirement for sample concentration, and may represent an attractive alternative in testing for intrathecal immunoglobulin synthesis.