OBJECTIVETo investigate the expression of microRNA-155 and microRNA-146a in the CD19(+) B cells of chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), splenic marginal zone lymphoma (SMZL), and to analyze its clinical significance.

METHODSPeripheral blood (PB) (78 cases) and bone marrow (BM) samples (9 cases) from 53 CLL patients, 13 MCL patients, 19 SMZL patients, and 12 healthy donors were collected. Mononuclear cells were isolated and B cells were purified with a CD19(+) magnetic-bead system. Total RNA was extracted from purified CD19(+) cells and microRNAs expression were measured using the TaqMan microRNA quantitative PCR. The results combined with the clinic data of patients were analysed.

RESULTS(1) The expression of microRNA-155 in CLL (4.49 ± 0.83) was significantly higher than in MCL (3.83 ± 0.45) and SMZL (3.80 ± 0.61) (P < 0.05); (2) The level of microRNA-146a in SMZL (3.81 ± 0.59) was significantly higher than in CLL (2.58 ± 0.90) and MCL (2.27 ± 0.88) (P < 0.01); (3) The level of microRNA-155 was significantly higher in IgVH unmutated patients than in mutated patients in CLL (P = 0.012); (4) The microRNAs expression had no statistical difference between two prognostic groups in CLL.

CONCLUSION(1) The expression of microRNA-155 and microRNA-146a is different in malignant lymphoproliferative disorders (LPD); (2) Deregulation of the microRNAs expression might play a critical role in the pathogenesis and prognosis in the LPD.