Objective To analyze miR-92a expression and its clinical significance in the plasma of systemic lupus erythematosus (SLE) patients.Methods Plasma samples from 44 SLE patients,16 rheumatoid arthritis (RA) patients and 20 healthy controls were collected.The small RNAs in these plasma samples were isolated and reversely transcribed.Using cel-miR-39 as the external reference,the levels of miR-92a expression were detected by real-time polymerase chain reaction (PCR) method.MiR-92a and cel-miR-39 were analyzed by real-time fluorescence quantitative PCR and agarose gel electrophoresis.The sensitivity and specificity of miR-92a as SLE were analyzed by receiver-operating characteristic (ROC) curve.The correlation between the levels of miR-92a expression and the clinic pathological features of SLE and biological significance of miR-92a expression in SLE were further analyzed by Pearson or Chi-square test.Results Our data indicated that the plasma levels of miR-92a expression was 49.20 (5.33,95.17) in SLE patients,411.30 (320.84,504.69) in healthy controls,and 25.59(11.20,30.54) in RA patients.The difference was significant (x2=40.77,P＜0.01).The area under the ROC curve (AUC) was 0.958 for discriminating between SLE patients and normal subjects and 1.00 for discriminating between RA patients and healthy controls.The levels of miR92a expression cutoff values were set the as 198.59 for healthy control and 85.35 for RA patients,the diagnostic sensitivity and specificity were 93.2％,90％,and 100％,100％,res-pectively.The analysis of the correlation between miR-92a expression and the clinic pathological features of SLE had shown that the levels of plasma miR-92a expressions were much lower in SLE patients with down-regulated complement C3,and up-regulated urea nitrogen,creatinine,LDH,ATH (all P＜0 05).Conclusion Down-regulated miR-92a expression in plasma of SLE may be involved in the SLE disease occurrence or development and could be used as a novel potential diagnostic biomarker for SLE.