Decreased soluble IFN-β receptor (sIFNAR2) in multiple sclerosis patients: A potential serum diagnostic biomarker

Background: The soluble isoform of the interferon- (IFN-) receptor (sIFNAR2) could modulate the activity of both endogenous and systemically administered IFN-. Previously, we described lower serum sIFNAR2 levels in untreated multiple sclerosis (MS) than in healthy controls (HCs). Objective: To assess sIFNAR2 levels in a new cohort of MS patients and HCs, as well as in patients with clinically isolated syndrome (CIS) and with other inflammatory neurological disorders (OIND) and to assess its ability as a diagnostic biomarker. Methods: The cross-sectional study included 148 MS (84 treatment naive and 64 treated), 87 CIS, 42 OIND, and 96 HCs. Longitudinal study included 94 MS pretreatment and after 1year of therapy with IFN-, glatiramer acetate (GA), or natalizumab. sIFNAR2 serum levels were measured by a quantitative ELISA developed and validated in our laboratory. Results: Naive MS and CIS patients showed significantly lower sIFNAR2 levels than HCs and OIND patients. The sensitivity and specificity to discriminate between MS and OIND, for a sIFNAR2 cutoff value of 122.02ng/mL, were 70.1%, and 79.4%, respectively. sIFNAR2 increased significantly in IFN--treated patients during the first year of therapy in contrast to GA- and natalizumab-treated patients who showed non-significant changes. Conclusion: The results suggest that sIFNAR2 could be a potential diagnostic biomarker for MS.