To investigate the expression of microRNA-548ah in blood at different stages of chronic hepatitis B virus (HBV) infection and to analyze its clinical value.

Total of 108 patients with chronic HBV infection admitted to the Central Hospital of Enshi Tujia and Miao Autonomous Prefecture from January 2015 to January 2019 were selected as HBV infection group. According to their different stages, 108 patients were divided into immune tolerance period group (32 cases), immune clearance period group (28 cases), low replication period group (25 cases) and reactivation period (23 cases). While 100 healthy people taking physical examination were selected as healthy control group. ExoQuick kit was used to extract blood exosomes, and protein imprinting was used to verify the authenticity of exosomes. The serum levels of HBV DNA and alanine aminotransferase (ALT) were measured by fluorescence quantitative RT-PCR. The difference of miRNA-548ah in blood exosomes between HBV infection group and healthy control group were compared, respectively, and the value of serum exosomes miRNA-548ah for chronic HBV infection and staging were analyzed by receiver operating curve (ROC). The relationship between serum exosome miRNA-548ah and HBV DNA and ALT were analyzed by Pearson correlation method.

The positive expression of CD63 and Tsg101 protein were detected by Western blot, which indicated that exosome was successfully extracted. The levels of microRNA-548ah in blood exosomes of HBV infection group and control group were (3.46 ± 0.83) and (0.72 ± 0.15), respectively, with significant difference (t = 32.518, P < 0.001). ROC analysis showed that exosome microRNA-548ah had a certain value in the diagnosis of chronic HBV infection (AUC: 0.785, 95%CI: 0.723-0.877, truncation value: 1.04, sensitivity: 84.5%, specificity: 82.6%). The levels of microRNA-548ah in blood exosomes of the immune tolerance period group, the immune clearance period group, the low replication period group and the reactivation period group were (4.18 ± 1.34), (1.41 ± 0.45), (1.32 ± 0.31) and (1.48 ± 0.42), respectively, with significant difference (F = 27.435, P < 0.001); there was significant difference between immune tolerance period group and immune clearance period group (t = 10.427, P < 0.001), but without significant difference between immune clearance group and low replication period group (t = 0.838, P = 0.406) , neither between low replication group and reactivation group (t = 1.510, P = 0.138). Pearson correlation analysis showed that microRNA-548ah was positively correlated with HBV DNA (r = 0.857, P < 0.001) and ALT (r = 0.763, P < 0.001). There were significant positive correlations between microRNA-548ah and HBV DNA (r = 0.776, P = 0.001) and ALT (r = 0.711, P = 0.001); and microRNA-548ah in the immune clearance stage of HBV infection was positively correlated with HBV DNA (r = 0.572, P = 0.035) and ALT (r = 0.531, P = 0.042), but the correlation was not significant; microRNA-548ah in the low replication stage of HBV infection was positively correlated with HBV DNA (r = 0.541, P = 0.039) and ALT (r = 0.502, P = 0.048), but the correlation was not significant.

High expression of microRNA-548ah in blood exosome of patients was expected to become a new marker for the diagnosis of chronic HBV infection. There were significant differences in the expression of microRNA-548ah in different stages of natural history of HBV infection. It was also related to serum HBV DNA and ALT levels, which could guide the clinical medication and timely adjustment.