Abstract:

Objective   To evaluate the expression of TLR4 in peripheral blood mononuclear cells(PBMCs) and its relationship with IL-6 and TNF α concentrations in the culture supernatant of PBMCs in order to study the function of Toll-like receptor 4(TLR4) in the pathogenesis of asthma in children. Methods   Forty children with asthma were averagely divided into asthma group and static asthma group. Twenty physical examination children were taken as normal control group. Quantitative reverse transcription PCR was applied to detect TLR4 mRNA expression level in PBMCs obtained from the three groups. The concentrations of IL-6 and TNFα in the supernatant were detected by double-antibody sandwich ELISA method. Results   TLR4 mRNA expression level in asthma group was significantly higher than those in static asthma group and normal control group(all P<0.05). The concentrations of IL-6 and TNFα in the supernatant of asthma group were also significantly higher than those in the other two groups(all P<0.05). After PBMCs from asthma groups were treated with TLR4 antagonist, supernatant IL-6 and TNFα concentrations declined, whereas TLR2 antagonist had no effect on them. Conclusion   TLR4 and its regulatory functions in innate immune response play an important role in childhood asthma, which might be realized by promoting the secretion of cytokines, such as IL-6 and TNFα.

Key words: Childhood asthma; Peripheral blood mononuclear cells; Tolllike receptor 4; Immune system; Inflammation