Biomarkers Differentiating RRMS and SPMS in Multiple Sclerosis—A Systematic Review

Abstract

Background: This systematic review searched to identify a potential biomarker in serum/plasma or cerebrospinal fluid (CSF) to differentiate between relapsing-remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS). There is currently no definitive method for determining whether a patient is in the RRMS course or has converted to the SPMS course. A biomarker could therefore aid the clinician to make this diagnosis. The aim of this study is to assess if there are biomarkers or combinations of biomarkers in serum/plasma or CSF that can detect secondary progression in multiple sclerosis at an early stage. Methods: The PubMed and EMBASE databases were searched to identify relevant studies. Both MeSH terms and text words in the title/abstract were used in both search strategies. The method included forward and backward citation searches. A risk of bias tool was used to assess all the studies that were included. Results: A total of 7581 articles were identified from the initial search. Additionally, 3386 articles were added after the citation search. Of these, 39 articles fulfilled the inclusion criteria and none of the exclusion criteria. The review investigated 28 different biomarkers in CSF and serum/plasma. Discussion: Of the 28 different biomarkers, six biomarkers appeared to be the most promising: neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), Galectin-9, YKL-40/CHI3L1, osteopontin, and MCP-1. This review provides new insights into potential directions for future studies to investigate biomarkers as a diagnostic tool for SPMS.