The value of serum CARDS toxin and NETs formation in children with MPP

Background Cardiopulmonary Distress Syndrome Toxin (CARDS TX) is a key virulence factor of Mycoplasma pneumoniae . Neutrophil extracellular traps (NETs) constitute an important component of innate immunity. This study aims to investigate the changes in CARDS TX and NETs in pediatric severe Mycoplasma pneumoniae pneumonia (SMPP) and evaluate their predictive value for SMPP. Methods Children hospitalized at Henan Children’s Hospital in 2023 with MPP were enrolled and divided into the GMPP group and SMPP group. Serum levels of CARDS TX, citrullinated histone 3 (CitH3) and myeloperoxidase (MPO), were measured in both groups. Comparative analysis of marker levels between groups was conducted. Diagnostic utility for identifying SMPP was evaluated using logistic regression analysis and receiver operating characteristic ROC curves. Results A total of 147 children with mycoplasma pneumonia were included in this study, among which 74 were in the SMPP group and 73 were in the GMPP group. The levels of serum CARDS TX, MPO, and CitH3 in the SMPP group were significantly higher than those in the GMPP group. The levels of serum CARDS TX, MPO, and CitH3 were significantly positively correlated with SMPP, with correlation coefficients of 0.433, 0.357, and 0.396 respectively. The results of multivariate logistic analysis showed that CARDS TX, MPO, and CitH3 were risk factors for SMPP. The AUC of serum CARDS TX, MPO, and CitH3 levels for predicting SMPP were 0.750, 0.706, and 0.729 respectively, with cut-off values of 7.9 pg/ml, 181.16 ng/ml, and 150.38 ng/ml. Conclusion The elevated levels of serum CARDS TX, MPO, and CitH3 are independent risk factors for SMPP, and these three indicators have good predictive value for SMPP. CARDS TX secreted by MP may contribute to SMPP development by inducing excessive NET formation.