Does MRZ Reaction Have a Real Significance in the Diagnosis of Multiple Sclerosis?

Abstract

Despite the diagnostic criteria for multiple sclerosis have been well established, there still remain a significant group of patients presenting with various clinical symptoms suspicious of demyelinating disease but not fulfilling these diagnostic criteria. MRZ reaction evaluates intrathecal synthesis of specific IgG antibodies against neurotrophic viruses of morbilli (M), rubella (R) and zoster (Z). MRZ reaction (positive was evaluated 2/3 or 3/3 for clinically isolated syndrome (CIS) or multiple sclerosis (MS) and negative 0/3 or 1/3), brain magnetic resonance imaging (MRI) (positive vs. negative regarding fulfilling diagnostic criteria for MS) and oligoclonal bands (OCB) in the cerebrospinal fluid (CSF) were examined in 57 subjects with CIS and 55 with MS. At the time of lumbar puncture the diagnosis was not yet known. In the subgroup of CIS the sensitivity of brain MRI was 63.16%, of OCB 87.72% and MRZ 35.09%, and the specificity of brain MRI was 83.44%, of OCB 65.23 and of MRZ 91.72%. In the subgroup of MS the sensitivity of brain MRI was 81.82%, of OCB 87.27% and MRZ 38.18%, and the specificity of brain MRI was 86.51%, of OCB 64.80 and of MRZ 92.11%. In the subgroup analysis we found 4 out of 55 subjects with final diagnosis of MS (7.27%) and 7 out of 57 in the final CIS group (12.28%) with positive MRZ reaction (2/3 or 3/3) and brain MRI not fulfilling the diagnostic criteria for MS. Of course in vast majority (but not all) of cases the diagnosis of CIS or MS is easily made by fulfilling revised McDonald criteria – with contribution of brain and spinal cord MRI. Despite low sensitivity of MRZ reaction found in our cohort this diagnostic tool can be of special significance in the cases with clinical symptoms consistent with demyelinating disease of the CNS, but with initial brain MRI not fulfilling the diagnostic criteria. In these cases very high specificity of MRZ reaction can shift the diagnosis to either CIS or MS and thus contribute to earlier diagnosis and treatment.