Glucocorticoid-Induced TNFR-Related Ligand as a Biomarker for Diagnosis and Severity of Asthma in Children.

Currently, there are no reliable pediatric biomarkers for assessing the severity of asthma. Therefore, the study aimed to assess the potential of glucocorticoid-induced TNFR-related ligand (GITRL) in assessing asthma severity. Bone marrow-derived dendritic cells (BMDCs) were isolated and treated with phosphate-buffered saline (PBS) or house dust mites (HDM). Flow cytometry, immunofluorescence, and RT-qPCR results revealed that GITRL expression was increased in HDM-treated BMDCs (p < 0.05). An asthma mouse model was established using HDM. Asthmatic mice exhibited significantly increased lung inflammation scores, serum IgE, total cell counts, and eosinophil counts in bronchoalveolar lavage fluid (BALF) (p < 0.05). Tissue immunofluorescence and immunohistochemistry indicated elevated GITRL expression levels (p = 0.03). Flow cytometry analysis of peripheral blood mononuclear cells (PBMCs) isolated from children showed that the proportion of GITRL + dendritic cells (DCs) and the mean fluorescence intensity (MFI) of GITRL were significantly increased in asthmatic children compared with healthy individuals (p < 0.01). RT-qPCR analysis showed that GITRL mRNA expression levels were significantly elevated in children with moderate-to-severe asthma compared to those with mild asthma (p = 0.006), and GITRL mRNA levels were higher in both groups of asthmatic children than in healthy controls (p < 0.05). Correlation analysis indicated that GITRL expression was negatively correlated with lung function and the Children's Asthma Control Test (C-ACT) score (p < 0.001). ROC analysis assessed its diagnostic value, with AUC values of 0.89 (asthma vs. healthy diagnosis) and 0.70 (distinguishing moderate-to-severe from mild asthma). These findings suggest that GITRL is an important biomarker for assessing asthma severity.