Profiling of Epstein-Barr Virus microRNAs in Whole Blood and Exosomes in Multiple Sclerosis.

Background: Multiple sclerosis (MS) is a neuroinflammatory, demyelinating disease with Epstein-Barr virus (EBV) suggested as a prerequisite for disease development. EBV expresses 44 microRNAs (miRNAs) with largely unknown functions, but they have been implicated in EBV-infected cell proliferation and immune evasion.

Objectives: This study investigates EBV miRNAs levels in whole blood and plasma exosomes at baseline and after treatment, and in relation to disease activity based on age-adjusted NfL ratios, in 50 newly diagnosed patients with relapsing-remitting MS (RRMS).

Methods: EBV miRNAs purified from whole blood and isolated plasma exosomes were measured by qPCR, using TaqMan Array Cards, and correlated to mRNA of GZMA, GZMH, IFN-γ, TNF-α, IL-10, IL-1B, and IL-1R1 in whole blood, measured by qPCR. Serum neurofilament light chain (NfL) and IL-6, plasma anti-EBNA1 antibody titers, occludin, and zonula occludens-1 were measured by various immunoassays.

Results: The miRNA profiling of whole blood revealed expression of BHRF1 miRNAs in most patients, indicating that EBV is in lytic phase or latency phase III. Higher levels of miR-BART14-3p were observed in patients classified with high disease activity. EBV miRNA levels correlated with anti-EBNA1 antibody titers, biomarkers of inflammation and tight junction proteins.