Expression of MicroRNA-155 is Downregulated in Peripheral Blood Mononuclear Cells of Chronic Hepatitis B Patients

Background: persistent hepatitis b virus (hbv) infection is sustained by inadequate immune responses, either natural or acquired. recent studies have suggested that immune responses to viral infection may be affected by microrna (mir)-155, via its involvement in immune cell differentiation and maturation. however, little is known on the specific interaction between mir-155 and hbv in host antiviral immunity. objectives: this study evaluated the levels of mir-155 in peripheral blood mononuclear cells (pbmcs) of chronic hepatitis b (chb) patients, relative to that of healthy subjects, and investigated an association between mir-155 levels and hbv dna or alanine aminotransferase (alt). patients and methods: total rna was extracted from peripheral venous blood samples of 90 treatment-naive patients with chronic hbv infection and 20 healthy volunteers. the levels of mir-155 in the pbmcs were measured by real-time quantitative polymerase chain reaction. serum hbv dna and liver enzymes were estimated using standard clinical laboratory methods. results: in the hbv-infected patients, the mir-155 levels were significantly lower than in the healthy controls (p = 0.001). chronic hbv-infected patients with elevated alt had higher levels of mir-155 compared with patients with normal alt (p = 0.014). no correlations were found between mir-155 and alt or hbv dna. conclusions: the mir-155 appeared to be suppressed during hbv infection. the significantly higher mir-155 levels in alt-elevated patients infected with hbv suggest that mir-155 levels in pbmcs correlate with the immune state of patients with chronic hbv infection.