Abstract:[Objective] To investigate the mRNA expression and significance of RORC (the transcription factor of Th17 cells) and Foxp3 (the transcription factor of Treg cells) in PBMC in children with bronchial asthma.[Methods] To detect the mRNA expressions of RORC and Foxp3 in PBMC by quantitative real-time PCR in 40 asthmatic children

including 20 children of acute attack group(age 8.5 ± 2.3)

20 children of remission group(age 9.2 ± 1.8) and 10 chilren of healthy control(age 8.0 ± 1.6). To analyze the relationship between the RORC and Foxp3mRNA expressions and the FEV1 of pulmonary function in asthmatic children.[Results] It was showed that RORC mRNA expressions in asthmatic children was higher in attack stage than in remission stage and in control group (5.41 ± 0.12 vs 3.33 ± 0.27 vs 3.78 ± 0.13

P < 0.01). In contrast

Foxp3 mRNA in asthmatic children was lower in attack stage than in remission stage and in control group (3.34 ± 0.12 vs 4.43 ± 0.07 vs 4.13 ± 0.04，P < 0.01). However

there was no significant difference in the expressions of both RORC and Foxp3mRNA between asthmatic children in remission stage and healthy group（P > 0.05）. The ratio of RORC/Foxp3 mRNA in PBMCs of asthmatic children in attack stage were significantly higher than those in remission stage and healthy controls（1.68 ± 0.09 vs 0.76 ± 0.06 vs 0.92 ± 0.04

P< 0.01）. Pearson correlation analysis revealed that RORC mRNA was negatively correlated with FEV1

but Foxp3mRNA was positively correlated with FEV1(r =-0.58 and 0.52，P < 0.01).[Conclusions] The imbalance of RORC/Foxp3 mRNA expression exists in asthmatic children

suggesting a potential role for Th17 / Treg imbalance in the pathogenesis and reduction of lung function in asthmatic children.