OBJECTIVETo investigate the expression of the NLRP3 inflammasome signaling pathway in peripheral blood and its significance in children with Mycoplasma pneumoniae pneumonia (MPP).

METHODSAccording to the severity, 147 children with MPP were divided into mild group with 83 children and severe group with 64 children. According to the stage of disease, the children were divided into acute group with 77 children and recovery stage with 70 children. A total of 50 healthy children were enrolled as the control group. Quantitative real-time PCR was used to measure the mRNA expression of NLRP3, ASC, and caspase-1. ELISA was used to measure the serum levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18).

RESULTSCompared with the control group, the children with MMP had significantly higher relative mRNA expression levels of NLRP3, ASC, and caspase-1 in peripheral blood and serum levels of IL-1β and IL-18 (P<0.05). Compared with the control group, both mild and severe groups had significantly higher relative mRNA expression levels of NLRP3, ASC, and caspase-1 in peripheral blood and serum levels of IL-1β and IL-18 (P<0.05). The severe group had significantly higher levels of above mentioned parameters than the mild group (P<0.05). Both acute group and recovery group had significantly higher relative mRNA expression levels of NLRP3, ASC, and caspase-1 in peripheral blood and serum levels of IL-1β and IL-18 than the control group (P<0.05). The acute group had significantly higher levels of above mentioned parameters than the recovery group (P<0.05). The relative expression level of NLRP3 was positively correlated with the relative mRNA expression levels of ASC and caspase-1 and the serum levels of IL-1β and IL-18 (r=0.701, 0.717, 0.676, and 0.645 respectively; P<0.05).

CONCLUSIONSThe NLRP3 inflammasome signaling pathway might be involved in the pathogenesis of MPP in children and is closely associated with the severity and course of the disease.