The value of oligoclonal bands in the multiple sclerosis diagnostic criteria

The presence of oligoclonal bands in clinically isolated syndromes is an independent risk factor for developing multiple sclerosis and has been largely excluded from the more recent multiple sclerosis diagnostic criteria. Therefore, our objective was to explore the value of oligoclonal bands in the context of the 2010 McDonald criteria, especially in patients fulfilling exclusively dissemination in space at baseline. For this purpose, we selected 566 patients from a clinically isolated syndrome inception cohort who had IgG oligoclonal bands determination and sufficient data on baseline brain MRI to assess dissemination in space and time. We excluded the cases already fulfilling both dissemination in space and time and divided the remaining 398 into 'no dissemination in space and time' (n = 218), 'dissemination in space' (n = 164) and 'dissemination in time' (n = 16). We assessed Cox proportional hazards regression models with 2010 McDonald as the outcome, using 'no dissemination in space and time' with 0 lesions and negative oligoclonal bands as the reference for different subgroups according to oligoclonal bands status (positive/negative). To assess the diagnostic properties, we selected cases with a follow-up ≥3 years or fulfilling 2010 McDonald within 3 years of the clinically isolated syndrome (n = 314), and compared the performance of all 'dissemination in space' cases (n = 137) versus patients with 'dissemination in space' and positive oligoclonal bands (n = 101). The remaining patients classified as fulfilling 'dissemination in time' or 'no dissemination in space and time' were taken into account to calculate the diagnostic properties. The respective adjusted hazard ratios (95% confidence interval) were 1.5 (0.4-5.7) for 'no dissemination in space and time' with 0 lesions and positive oligoclonal bands, 3.1 (1.4-7.2) for 'no dissemination in space and time' with ≥1 lesions and negative oligoclonal bands, 7.4 (3.5-15.7) for 'no dissemination in space and time' with ≥1 lesions and positive oligoclonal bands, 10.4 (4.8-22.6) for 'dissemination in space' with negative oligoclonal bands, 15.3 (7.5-31.3) for 'dissemination in space' with positive oligoclonal bands, and 9.1 (3.5-23.4) for 'dissemination in time' (not subdivided due to the sample size). The specificity for all cases with 'dissemination in space' was 80.6 and increased to 88.1 after selecting those with positive oligoclonal bands. According to these results, we propose radiological dissemination in space at any time plus positive oligoclonal bands as an additional criterion for diagnosing multiple sclerosis.