Objective To investigate the relationship between the levels of quinone oxidoreductase 1 (NQO-1), human β-defensin 3 (HBD-3) and chest CT imaging features and prognosis of children infected with mycoplasma pneumoniae (MP).

Methods A total of 78 children with MP infection who were treated at the First Affiliated Hospital of University of Science and Technology of China from January 2022 to January 2024 were selected (study group), including 43 male children and 35 female children, with an age of (5.7±0.7) years. Meanwhile, 50 healthy children were selected (control group), including 27 healthy male children and 23 healthy female children. A retrospective study was conducted at an age of (5.6±0.6) years. The children were divided into the mild group and the severe group according to the Diagnosis and treatment Guidelines for Mycoplasma pneumoniae Pneumonia in Children (2023 Edition). Observe the chest CT image characteristics of the children patients and healthy children, and detect the relative expression level of NQO-1 and the level of HBD-3. The children were divided into the good prognosis group and the poor prognosis group according to the conditions after treatment. The paired t-test (homogeneous variance) was used for the comparison between groups of measurement data conforming to the normal distribution, and analysis of variance was used for the comparison among multiple groups. The intergroup comparison of counting data was conducted using the χ² test. The correlation analysis between the characteristics of chest CT images and the relative expression level of NQO-1 and the level of HBD-3 was conducted using the Spearman correlation coefficient model. Univariate analysis and multivariate Logistic regression analysis were used to analyze the risk factors for poor prognosis in children with MP infection.

Results Compared with the mild group, the incidences of ground-glass opacity, nodular opacity and consolidation opacity were higher in the severe group 8 (24.24%) vs. 22 (48.89%); 19 (57.58%) vs. 5 (11.11%); 6 (18.18%) vs. 18 (40.00%) (χ²=2.196, 19.296, 4.255; all P<0.05). Compared with the control group, the relative expression level of NQO-1 in the mild group and the severe group was lower (0.48±0.05 vs. 0.98±0.10 vs. 1.23±0.24), and the level of HBD-3 was higher (65.43±7.68 vs. 51.25±6.23 vs. 33.52±4.36) (t=210.365, 289.732; both P<0.05). The results of the correlation analysis showed that the relative expression level of NQO-1 was negatively correlated with the image features of chest CT (ground-glass opacity, nodule shadow, consolidation shadow) (r=−0.556, −0.612, −0.445; all P<0.05). The level of HBD-3 was positively correlated with the imaging characteristics of chest CT (r=0.714, 0.563, 0.648; all P<0.05). Compared with the good prognosis group, The number of cases of myocardial injury (15 vs. 20), ground-glass opacity (14 vs. 21), nodular opacity (18 vs. 17) and consolidation opacity (16 vs. 19) (χ²=8.193, 8.193, 19.378, 11.395; all P<0.01), NLR (2.88±0.39) vs. (2.03±0.31), PCT ((0.57±0.21) ng/ml vs. (0.41±0.26) ng/ml), CRP ((13.58±2.45) mg/L vs. (9.33±1.25) mg/L), in the poor prognosis group the levels of HBD-3 ((80.65±9.11) pg/ml vs. (50.12±7.57) pg/ml) were relatively high (t=10.002, 2.491, 10.075, 14.943; all P<0.01). PLT ((187.25±27.69)×10⁹/L vs. (224.25±31.47)×10⁹/L), FVC ((71.35±8.22) % vs. (87.41±9.68)%), FEV1 ((61.49±7.17) %vs. (77.25±8.66)%),The level of FEF ((60.36±7.08) % vs. (75.33±8.02)%) and the relative expression level of NQO-1 (0.38±0.11) vs. (0.93±0.17) (t=4.749, 6.752, 7.444, 7.534, 13.115; all P<0.001) were relatively low. The results of multivariate Logistic regression analysis showed that myocardial injury (OR: 4.625, 95%CI: 1.552−13.782), PLT (OR: 4.740, 95%CI: 3.518-5.962), and NLR (OR: 10.930, 95%CI: 2.654−45.013), FVC (OR: 4.104, 95%CI: 2.900-5.308), FEV1 (OR: 3.888, 95%CI: 2.604−5.172), FEF (OR: 5.376, 95%CI: 4.292−6.460), PCT (OR: 9.572, 95%CI: 1.443−63.498), CRP (OR: 2.933, 95%CI: 1.786−4.817), NQO-1 (OR: 5.392, 95%CI: 1.012−23.451), HBD-3 (OR: 1.263, 95%CI: 1.137−1.402), ground-glass opacity (OR: 3.429, 95%CI: 1.194-9.846), nodular opacity (OR: 14.118, 95%CI: 3.669−54.325), consolidation opacity (OR: 6.400, 95%CI: (2.036−20.117) were risk factors affecting the prognosis of children with MP infection (all P<0.05).

Conclusion The levels of NQO-1 and HBD-3 are related to the characteristics of chest CT images. In MP-infected children, the expression of NQO-1 is low and the level of HBD-3 is high. With the severity of the disease, the expression of NQO-1 decreases and the level of HBD-3 increases. Detecting its expression can be used to judge the prognosis.