Serum miR-199a-3p and miR-103a-3p are possible biomarkers for the onset of multiple sclerosis.

Multiple Sclerosis (MS) is a multifactorial and complex disease; currently only few and relatively invasive biomarkers have shown a moderate prognostic value. Finding new, more reliable and non-invasive biomarkers could allow earlier MS diagnosis and improve the conduction of therapeutic and rehabilitative protocols. We investigated whether miR-199a-3p and miR-103a-3p can be useful for this purpose. Fifty-seven healthy controls (HC) and 185 people with a diagnosis of either progressive (P-MS; N=63), relapsing (R-MS; N=63), or within 2 years since the diagnosis (short disease duration, S-MS; n=59) MS were enrolled, serum concentration of miR-199a-3p and miR-103a-3p was measured in all individuals by droplet digital PCR (ddPCR). Whereas miR-199a-3p was significantly up-regulated in the overall group of MS patients compared to HC, miR-103a-3p was significantly up-regulated in S-MS and R-MS, but not in P-MS. Interestingly, both miRNAs were up-regulated in S-MS, and their combined measurement had a good power to discriminate between S-MS and HC. These results suggest that the measurement of miR-199a-3p and miR-103a-3p serum concentration might be a useful biomarker for MS, particularly in the very initial stages of disease.