Abstract: Objective: To investigate the changes of expressions of NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome in the peripheral blood mononuclear cells and downstream factors interleukin-1β (IL-1β) and interleukin-18 (IL-18) in serum in the children with asthma, and to explore their significances on assessing the condition of the children.Methods: A total of 176 cases of children with asthma were divided into acute exacerbation group (n=91), chronic persistent group (n=49) and clinical remission group (n=36) according to the clinical manifestation. During the same period, 60 healthy children were selected from the outpatient physical examination center as control group.The pulmonary function of children was checked with lung function instrument. The expression levels of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC) and cysteinyl aspartate-specific proteinase-1 (Caspase-1) mRNA in peripheral blood mononuclear cells of the subjects in various groups were detected by using real-time quantitative PCR. The serum levels of IL-1β and IL-18 of the subjects in various groups were detected by using enzyme-linked immunosorbent assay (ELISA).Results: Compared with control group, the forced expiratory volume in 1 second percentage of predicted value (FEV1%) and fixed ratio of forced expiratory volume in the first second/forced vital capacity (FEV1/FVC) of the children in acute exacerbation, chronic persistent and clinical remission groups were decreased (P<0.05);acute exacerbation groupP<0.05).The levels of NLRP3, ASC and Caspase-1 mRNA in the peripheral blood mononuclear cells and serum levels of IL-1β and IL-18 in the children with asthma were higher than those in control group (P<0.01).The expression levels of NLRP3, ASC and Caspase-1 mRNA in the peripheral blood mononuclear cells of the children in acute exacerbation group were higher than those in chronic persistent and clinical remission groups (P<0.05), and the expression levels of NLRP3,ASC and Caspase-1 mRNA in chronic persistent group were higher than those in clinical remission group (P<0.05).Pearson correlation analysis showed that the expression level of NLRP3 mRNA in the peripheral blood mononuclear cells of asthmatic children was positively correlated with the expression levels of ASC, Caspase-1 mRNA and the serum levels of IL-1β and IL-18 (P<0.05), while it was negatively correlated with FEV1% and FEV1/FVC; the expression level of ASC mRNA was positively correlated with the expression level of Caspase-1 mRNA and the serum levels of IL-1β and IL-18 (P<0.05), while it was negatively correlated with FEV1% and FEV1/FVC (P<0.05); the expression level of Caspase-1 mRNA was positively correlated with the expression level of Caspase-1 mRNA and the serum levels of IL-1β and IL-18 (P<0.05), while it was negatively correlated with FEV1% and FEV1/FVC (P<0.05); the serum level of IL-1β was negatively correlated with FEV1% and FEV1/FVC (P<0.05), and the serum level of IL-18 was negatively correlated with FEV1% and FEV1/FVC (P<0.05).Conclusion: The expression levels of NLRP3 inflammasome and the downstream factor IL-1β and IL-18 in peripheral blood of the children with asthma are increased, and they are related to the clinical stage of the children with asthma. NLRP3 inflammasome pathway might promote the pathogenesis of asthma in the children.

Key words: children, bronchial asthma, NOD-like receptor family pyrin domain containing 3, inflammasome, interleukin-1β, interleukin-18