Cerebrospinal fluid chitinase-3-like protein 1 level is not an independent predictive factor for the risk of clinical conversion in radiologically isolated syndrome

Background: Younger age, male sex and presence of spinal cord lesion(s) increase the risk of conversion from radiologically isolated syndrome (RIS) to relapsing-remitting multiple sclerosis (RRMS). Elevated cerebrospinal fluid (CSF) chitinase-3-like protein 1 (CHI3L1) levels predict conversion from clinically isolated syndrome (CIS) to RRMS. Objective: To evaluate the prognostic value of CSF CHI3L1 in RIS patients for conversion to RRMS. Methods: We compared CSF CHI3L1 concentrations in RIS, CIS, RRMS and symptomatic controls (SCs). We analysed the influence of epidemiological, radiological and CSF parameters on the risk of clinical event. Results: A total of 211 patients (71 RIS, 48 CIS, 50 RRMS and 42 SC) were included. CSF CHI3L1 levels were lower in RIS than in RRMS and higher in RIS with positive CSF versus negative CSF and SC. The presence of at least one spinal cord lesion was the only independent predictor of faster conversion to RRMS. Association of high CSF CHI3L1 levels, positive CSF (presence of oligoclonal bands and/or an elevated IgG index) or four Barkhof criteria with any spinal cord lesion showed a tendency for reduced mean conversion time. Conclusion: CSF CHI3L1 correlates with positive CSF but is not an independent predictor of the risk of conversion from RIS to RRMS.