Effects of natalizumab on oligoclonal bands in the cerebrospinal fluid of patients with multiple sclerosis: a systematic review and meta-analysis.

INTRODUCTION: Oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) are utilized for diagnosing multiple sclerosis (MS), as they are found in 95% of patients. Additionally, OCBs are linked to disease prognosis. The primary contributors to OCB production are long-lived plasma cells. This study aims to quantify the impact of natalizumab (NTZ) on OCB levels in the CSF of MS patients. METHODS: A systematic search on MEDLINE, SCOPUS and Web of Science for English-written and peer-reviewed longitudinal studies on adults was performed. Methodological quality was assessed with the Newcastle-Ottawa Scale. Proportional meta-analysis was performed in R using a generalized linear mixed-effects model. We investigated heterogeneity with influence diagnostics, sensitivity analysis and meta-regression. RESULTS: Eight eligible studies of adequate quality with a total sample of 326 relapsing-remitting MS patients were included. A summary rate of 14.07% [95% CI, 4.48%-36.36%] for complete loss of OCBs and 42.02% [95% CI, 15.23%-74.51%] for reduction in OCB number or intensity was observed, both with considerable heterogeneity. Pooled estimates dropped (11% [95% CI, 0.04%-0.29%] and 34% [95% CI, 0.11%-0.68%] respectively) after the identification of an influential study. Multivariable meta-regression identified IgG index as a factor contributing to heterogeneity (adj. p = 0.0279), regarding reduction of OCB number or intensity. DISCUSSION: In conclusion, our systematic review and meta-analysis showed that NTZ can lead to reduction of intrathecal OCBs in MS patients, indicating a possible effect of NTZ on memory plasma cells, which are the main source of OCBs in MS.