RESUMO
BACKGROUND: This study aims to determine whether relative miR-122 levels in peripheral blood are correlated with chronic hepatitis B (CHB) and chronic hepatitis C (CHC) virus infection and viral replication to determine whether miR-122 can be a new marker for liver injury. METHODS: MicroRNA (miRNA) was extracted from the peripheral blood of 20 CHB patients, 20 CHC patients, and 20 healthy controls. The levels of miR-122 were determined using fluorescence real-time reverse transcription PCR. Then, the associations of miR-122 with CHB and CHC were analyzed, and its correlation with other markers of liver function and viral replication were determined. RESULTS: The expression level of miR-122 in patients with CHB was significantly higher when compared to subjects in the control group (P = 0.007) or CHC patients (P = 0.005). Furthermore, the miR-122 level in patients with CHC was somewhat higher when compared to healthy controls (66% higher), but the difference was not statistically significant (P = 0.229). MiR-122 levels were significantly correlated with ALT (correlation coefficient [R] = 0.7, P < 0.001), AST (R = 0.71, P < 0.001), and HBV NA (R = 0.9, P < 0.001). The regression analysis indicated that the AUC of miR-122 levels in the diagnosis of CHB was 0.87, with a sensitivity of 0.8 and a specificity of 0.8. CONCLUSION: MiR-122 can be used to distinguish healthy persons and patients with CHB infection with high sensitivity and specificity. These present findings presented that the complex and context-specific associations of miR-122 with liver diseases, suggesting that this may be a promising marker for liver injury.