Objective To analyze the expression levels and the clinical significance of serum interleukin (IL)-4, IL-5, IL-6, IL-13 and IL-17 in children with mycoplasma pneumoniae (MP) infection accompanied by airway hyperresponsiveness (AHR).

Methods A total of 120 children diagnosed with MP infection pneumonia and admitted to Nantong First People's Hospital between June 2022 and April 2024 were enrolled in the study group. According to whether their MP infection pneumonia was accompanied by AHR, the participants were divided into an AHR group (n = 41) and a non-AHR group (n = 79). An additional 90 healthy children undergoing physical examination were included in the control group. Baseline data, fractional exhaled nitric oxide (FeNO), tidal breathing lung function—including the ratio of volume at peak tidal expiratory flow to total expiratory volume (VPTEF/VE), the ratio of time to peak tidal expiratory flow to total expiratory time (TPTEF/TE), and inspiratory-to-expiratory time ratio (TI/TE)—as well as the levels of serum IL-4, IL-5, IL-6, IL-13 and IL-17 were compared among the 3 groups. The correlation between serum IL-4, IL-5, IL-6, IL-13 and IL-17 and clinical data of children with MP infection pneumonia accompanied by AHR was analyzed. Logistic regression analysis was used to identify the independent influencing factors of AHR in children with MP infection pneumonia. Receiver operating characteristic (ROC) curves were plotted to assess the diagnostic value of serum IL-4, IL-5, IL-6, IL-13 and IL-17 for MP infection pneumonia accompanied by AHR in children.

Results Significant differences were observed among the AHR, non-AHR, and control groups in white blood cell (WBC) count, neutrophil percentage, eosinophil (EOS) count, platelet (PLT) count, C-reactive protein (CRP), FeNO, VPTEF/VE, TPTEF/TE, TI/TE, forced vital capacity (FVC), and forced expiratory volume in one second (FEV₁) (all P < 0.05).Serum IL-4, IL-5, IL-6, IL-13 and IL-17 levels showed significant differences among the 3 groups (P < 0.05). Correlation analysis showed that these cytokines were positively correlated with WBC count, neutrophil percentage, EOS count, CRP, and FeNO (P < 0.05), and negatively correlated with VPTEF/VE, TPTEF/TE, TI/TE, FVC, and FEV₁ (P < 0.05). Binary logistic regression analysis identified neutrophil percentage (odds ratio OR = 1.923; 95% CI, 1.496-2.472), EOS count (OR = 3.074; 95% CI, 1.228-7.693), CRP (OR = 2.382; 95% CI, 1.854-3.061), FeNO (OR = 1.931; 95% CI, 1.635-2.281), VPTEF/VE (OR = 0.294; 95% CI, 0.200-0.432), TPTEF/TE (OR = 0.358; 95% CI, 0.177-0.722), TI/TE (OR = 0.399; 95% CI, 0.221-0.722), IL-4 (OR = 1.064; 95% CI, 1.019-1.111), IL-5 (OR = 1.234; 95% CI, 1.095-1.390), IL-6 (OR = 1.013; 95% CI, 1.001-1.025), IL-13 (OR = 1.058; 95% CI, 1.005-1.113), IL-17 (OR = 1.759; 95% CI, 1.293-2.393), and allergy history (OR = 2.989; 95% CI, 1.058-8.447) as independent factors associated with with AHR in children with MP infection pneumonia (P < 0.05). ROC curves revealed that the areas under the ROC curves (AUC) of serum IL-4, IL-5, IL-6, IL-13 and IL-17 for predicting AHR in children with MP infection pneumonia were 0.815, 0.769, 0.782, 0.793, and 0.815, respectively, with the sensitivities being 85.37%, 75.61%, 87.80%, 75.61%, and 80.49%, and 95% CI being 0.739-0.892, 0.677-0.861, 0.679-0.867, 0.715-0.882 and 0.732-0.899, respectively.

Conclusion The levels of serum IL-4, IL-5, IL-6, IL-13, and IL-17 in children with MP infection pneumonia and AHR are abnormally elevated. These cytokines may serve as valuable biomarkers for assessing the risk of AHR in children with MP infection pneumonia.