Assessing the value of oligoclonal band count in multiple sclerosis: insights from a large cohort analysis

Cerebrospinal fluid (CSF) specific oligoclonal bands (OCB) are a key diagnostic marker in multiple sclerosis (MS). Recent studies suggest that OCB reduction may reflect treatment efficacy and propose it as a potential endpoint in trials with chimeric antigen receptor (CAR) T-cell therapy. However, the prognostic value of baseline OCB count remains unclear. This study analyzed data from 454 persons (314 had MS, 140 clinically isolated syndrome). OCB analysis was performed by isoelectric focusing in polyacrylamide gel, followed by silver staining. The correlation of the number of OCBs with clinical and paraclinical parameters as well as follow-up outcomes was evaluated. Our results showed that in OCB positive persons with MS, the median number of CSF specific bands was 19. No significant correlation was found between OCB count and age, sex, initial EDSS, or MRI lesion load. OCB count also did not predict relapse risk or EDSS progression. However, strong correlations were observed with intrathecal synthesis of IgG and kappa free light chains. Therefore, our conclusion is that OCB count does not reflect clinical disease activity at diagnosis nor predict clinical progression within the observed median follow-up period of 9 months. Whether a decrease in OCB count indicates reduced humoral immune response in the CNS under certain therapies remains unclear and requires further prospective studies.