MiRNome Profiling of Circulating Extracellular Vesicles in Patients With Chronic Hepatitis D Undergoing Pegylated Interferon Alpha Treatment.

Micro-RNAs (miRNAs) are involved in the modulation of viral replication and host immune antiviral response. Using next-generation sequencing, we investigated the miRNome profile of circulating extracellular vesicles in 20 patients with chronic hepatitis D virus (HDV) infection undergoing pegylated interferon alpha (Peg-IFNα) treatment. Circulating miRNAs' expression was analysed according to virologic response (i.e., HDV RNA clearance maintained at least 6 months after the end of therapy). Overall, 8 patients (40%) achieved a virologic response to Peg-IFNα treatment. At baseline, 14 miRNAs were differentially expressed between responders and non-responders; after 6 months of Peg-IFNα treatment, 7 miRNAs (miR-155-5p, miR-1246, miR-423-3p, miR-760, miR-744-5p, miR-1307-3p and miR-146a-5p) were consistently de-regulated. Among de-regulated miRNAs, miR-155-5p showed an inverse correlation with HDV RNA (at baseline: r s  = -0.39, p = 0.092; at 6 months: r s  = -0.53, p = 0.016) and hepatitis B surface antigen (HBsAg) (at baseline: r s  = -0.49, p = 0.028; at 6 months: r s -0.71, p < 0.001). At logistic regression analysis, both miR-155-5p (at baseline: OR = 4.52, p = 0.022; at 6 months: OR = 5.30, p = 0.029) and HDV RNA (at baseline: OR = 0.19, p = 0.022; at 6 months: OR = 0.38, p = 0.018) resulted significantly associated to virologic response. Considering that Peg-IFNα still has a relevant role in the treatment of patients with chronic hepatitis D infection, the assessment of EV miR-155-5p may represent an additional valuable tool for the management of HDV patients undergoing Peg-IFNα treatment.