OBJECTIVE To explore the clinical characteristics of bronchial asthma with secondary pulmonary infections in children and compare the expressions of transcriptomes in peripheral blood between the bronchial asthma with secondary pulmonary infections and the bronchial asthma without the secondary pulmonary infections.

METHODS The clinical data were collected from 425 children with bronchial asthma who were treated in respiratory medicine department of Children′s Hospital of Anhui Province from Apr. 2022 to Feb. 2025 and were retrospectively analyzed. The enrolled children were divided into the infection group with 60 cases and the non-infection group with 365 cases according to the status of complication with pulmonary infections. The clinical characteristics were compared between the infection group and the non-infection group. The gene expression profile sequencing was carried out for peripheral blood mononuclear cells by transcriptome high throughput technology, and the biological information was analyzed.

RESULTS There were significant differences in course of asthma, frequencies times of acute attack, complication with nasosinusitis or allergic rhinitis, standardized use of antibiotics and intravenous use of glucocorticoids between the two groups of children (P < 0.05). Totally 60 children had secondary pulmonary infections, with the infection rate 14.12%. Totally 73 strains of pathogens were isolated, 43.84% of which were gram-positive bacteria, and 56.16% were gram-negative bacteria. As compared with the non-infection group, there were 1578 genes with the changed expression in the infection group, and the expressions of the genes such as nuclear factor κB were upregulated. The differentially expressed genes were primarily enriched in immunoregulation-related pathways, including proinflammatory factor signal transduction, interacted networks of cytokines and its receptors, T lymphocyte activation signal transduction and other biological processes.

CONCLUSION The specific clinical characteristics and abnormal immune pathways may jointly result in the pulmonary infections in children with the asthma and provide theoretical bases for early identification of the children at high risk of pneumonia and targeted intervention.