OBJECTIVETo evaluate the expression of microRNA (miR)-let-7b in peripheral blood cells of patients with primary biliary cirrhosis (PBC) and investigate its relationship to clinical disease parameters.

METHODSPeripheral blood and serum samples were obtained for study from 60 PBC patients and 60 healthy controls. Peripheral blood cells were extracted and subjected to real-time PCR to measure miR-let-7b expression. Serum levels of interleukin (IL)-18, total bilirubin (TBIL), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT) were measured by standard biochemical assays. The relationship between miR-let-7b expression and disease parameters was assessed by Spearman's rank correlation test.

RESULTSPBC patients showed significantly lower expression of miR-let-7b in peripheral blood cells than healthy controls (P less than 0.001); moreover, the miR-let-7b expression level decreased in parallel to increases in disease severity (stage I > II / III > IV). In PBC patients, the miR-let-7b expression was significantly correlated with Mayo risk scores (r = -0.4930, P less than 0.001), IL-18 (r = -0.4643, P less than 0.001) and ALP (r = -4119, P less than 0.001), but not with TBIL or GGT.

CONCLUSIONDecreased expression of miR-let-7b may be associated with development and progression of PBC, and this miRNA may represent a novel target of improved diagnostic and preventive strategies for PBC.