A Serum MicroRNA Signature Is Associated with the Immune Control of Chronic Hepatitis B Virus Infection

Background and Aims: The virus/host interplay mediates liver pathology in chronic HBV infection. MiRNAs play a pivotal role in virus/host interactions and are detected in both serum and HBsAg-particles, but studies of their dynamics during chronic infection and antiviral therapy are missing. We studied serum miRNAs during different phases of chronic HBV infection and antiviral treatment. Methods: MiRNAs were profiled by miRCURY-LNA-Universal-RT-miRNA-PCR (Exiqon-A/S) and qPCR-panels-I/II-739-miRNA-assays and single-RT-q-PCRs. Two cohorts of well-characterized HBsAg-carriers were studied (median follow-up 34-52 months): a) training-panel (141 sera) and HBsAg-particles (32 samples) from 61 HBsAg-carriers and b) validation-panel (136 sera) from 84 carriers. Results: Thirty-one miRNAs were differentially expressed in inactive-carriers (IC) and chronic-hepatitis-B (CHB) with the largest difference for miR-122-5p, miR-99a-5p and miR-192-5p (liver-specific-miRNAs), over-expressed in both sera and HBsAg-particles of CHB (ANOVA/U-test p-values: <0.000001/0.000001; <0.000001/0.000003; <0.000001/0.000005, respectively) and significantly down-regulated during-and after-treatment in sustained-virological-responders (SVR). MiRNA-profiles of IC and SVR clustered in the heatmap. Liver-miRNAs were combined with miR-335, miR-126 and miR-320a (internal controls) to build a MiR-B-Index with 100% sensitivity, 83.3% and 92.5% specificity (-1.7 cut-off) in both training and validation cohorts to identify IC. MiR-B-Index (-5.72, -20.43/14.38) correlated with ALT (49, 10/2056 U/l, rho = -0.497, p<0.001), HBV-DNA (4.58, undetectable/>8.3 Log(10) IU/mL, rho = -0.732, p<0.001) and HBsAg (3.40, 0.11/5.49 Log(10) IU/mL, rho = -0.883, p<0.001). At multivariate analysis HBV-DNA (p = 0.002), HBsAg (p<0.001) and infection-phase (p<0.001), but not ALT (p = 0.360) correlated with MiR-B-Index. In SVR to Peg-IFN/NUCs MiR-B-Index improved during-therapy and post-treatment reaching IC-like values (5.32, -1.65/10.91 vs 6.68, 0.54/9.53, p = 0.324) beckoning sustained HBV-immune-control earlier than HBsAg-decline. Conclusions: Serum miRNA profile change dynamically during the different phases of chronic HBV infection. We identified a miRNA signature associated with both natural-occurring and therapy-induced immune control of HBV infection. The MiR-B-Index might be a useful biomarker for the early identification of the sustained switch from CHB to inactive HBV-infection in patients treated with antivirals.