MRZH reaction increases sensitivity for intrathecal IgG synthesis in IgG Oligoclonal band negative Multiple Sclerosis patients

Given the low detection rates of CSF IgG-Oligoclonal bands (IgG-OCB) in non-European Multiple Sclerosis (MS) patients and higher specificity of the MRZH-reaction, we evaluated whether associating MRZH-reaction to CSF IgG-OCB detection improved investigation of suspected MS. Paired CSF and sera were analyzed for IgG-OCB and polyspecific viral antibodies. IgG-OCB were detected in 72% of MS patients and an MRZH-reaction in 67%. Combining IgG-OCB and MRZH raised detection of IgG abnormalities to 97% of studied MS patients. Detection of IgG-OCB and/or ≥2 MRZH antibodies showed sensitivity of 88% and specificity of 92% for MS, versus 72% and 96% for IgG-OCB alone. [Display omitted] •MRZH reaction was present in 67% MS patients and IgG-OCB in 72%.•Bispecific or higher MRZH reaction was present in 67% of IgG-OCB negative patients.•Analyzing IgG-OCB and MRZH, intrathecal IgG synthesis was seen in 97% MS patients.•Detection of either two viral antibodies or IgG-OCB had sensitivity of 88% for MS.•Detection of either two viral antibodies or IgG-OCB had specificity of 92% for MS.