ObjectiveTo determine whether there is an imbalance of KLF2/RelA in peripheral blood neutrophils in patients with bronchial asthma, and explore the relationship between KLF2/RelA imbalance and neutrophil apoptosis.MethodsFrom April 2011 to April 2012, a total of 39 patients with acute attack of asthma in Hunan People's Hospital and Third People's Hospital of Changsha were enrolled, with 13 cases in mild asthma group, 17 cases in moderate asthma group, and 9 cases in severe asthma group. Fifteen healthy subjects were recruited as control group. Peripheral blood were collected from all subjects followed by separation of neutrophils. The apoptosis of neutrophils were measured by flow cytometry. The expression of KLF2 and RelA were detected by Western blot. The relationship between the ratio of KLF2/RelA and neutrophil apoptosis rate was analyzed by Pearson correlation test.ResultsNeutrophil apoptosis rates in the mild, moderate and severe asthma groups [(4.45±0.76)%, (2.10±0.25)%, (1.81±0.67)%, repectively] were lower than that in the healthy control group [(5.36±0.57)%, all P<0.01]. The apoptosis rates of neutrophils in the moderate and severe asthma groups were lower than that in the mild asthma group (bothP<0.01), but there was no significant difference between the moderate asthma group and the severe asthma group (P>0.05). The ratios of neutrophil KLF2/RelA in the mild, moderate and severe asthma groups were lower than that in the normal control group (0.667±0.351, 0.384±0.203, 0.536±0.293vs. 4.038±2.011, all P<0.01). There was no significant difference between the groups of mild, moderate and severe asthma (P>0.05). The neutrophil apoptosis rate was positively correlated with the percentage of neutrophil KLF2/RelA (r=0.592 0, P<0.000 1).ConclusionThere is an imbalance of KLF2/RelA in peripheral blood neutrophils in patients with bronchial asthma, and the imbalance of KLF2/RelA may be the mechanism of apoptosis of peripheral blood neutrophils.