Abstract: Objective To investigate the expression of interferon regulatory factor 5 （IRF5） and Toll like receptor-9 （TLR-9） in patients with systemic lupus erythematosus （SLE）. Methods General data on 92 patients with SLE and 88 normal human controls were collected. Peripheral blood was drawn from all the subjects, total RNA was extracted from the blood and transcripted to cDNA．SYBR green I real-time quantitative polymerase chain reaction （PCR） was used to amplify IRF5 and TLR-9 genes. Cycle threshold （CT） value was obtained from real-time quantitative PCR, and the mRNA expression level was expressed as the value of 2-?驻?驻CT. Anti-dsDNA antibody was detected by immunoblotting method. Results Expected fragments of IRF5 and TLR-9 genes were amplified by real-time quantitative PCR. The mRNA expression levels of IRF5 and TLR-9 were 0.232 ± 0.076 and 0.189 ± 0.054, respectively, in patients with SLE, significantly higher than those in normal controls （0.081 ± 0.040 and 0.066 ± 0.023, respectively, both P < 0.05）. The patients positive for anti-dsDNA antibody tended to have a high level of IRF5 and TLR-9 mRNA compared with those negative for anti-dsDNA antibody, but there was no statistical difference. Conclusion There is an abnormal expressions of IRF5 and TLR-9 mRNA, which may play a role in the pathogenesis of SLE.

Key words: systemic lupus erythematosus