Cerebrospinal fluid oligoclonal bands in multiple sclerosis and clinically isolated syndromes: a meta-analysis of prevalence, prognosis and effect of latitude.

BACKGROUND Oligoclonal bands (OCBs) unique to the cerebrospinal fluid are used in the diagnosis of multiple sclerosis (MS). The precise prevalence of OCBs in MS and clinically isolated syndrome (CIS) is unknown. The influence of OCBs on clinical outcomes has not been quantified. OCB prevalence has been associated with latitude in a single study, if confirmed this would provide avenues for further study. METHODS Using a systematic review and meta-analysis approach, the proportion of OCB-positive MS and CIS and the influence of OCBs on clinical outcomes were calculated. The relationship between latitude and OCB prevalence was calculated using linear regression. RESULTS Seventy-one articles were included. Overall, 87.7% of 12 253 MS and 68.6% of 2685 CIS patients were OCB positive. OCB-positive MS patients had an OR of 1.96 of reaching disability outcomes, although a number of negative studies did not provide data. OCB-positive CIS patients had an OR of 9.88 of conversion to MS. Latitude predicted OCB status in MS patients (p=0.009) but not in CIS patients. CONCLUSIONS This is the largest study of OCB prevalence in MS and CIS. OCB positivity strongly predicts conversion from CIS to MS. The relationship between latitude and OCBs is confirmed, and this finding warrants further investigation.