Ma SL, et al. - Among 192 pediatric asthmatic patients with inhaled corticosteroid (ICS) therapy and 130 healthy controls, researchers assessed the serum OX40 ligand (OX40L) and studied its correlations with clinical characteristics and corticosteroid response. Clinical data were collected and enzyme-linked immunosorbent assay (ELISA) was used to measure serum levels of immunoglobulin (IgE), interleukin-6 (IL-6), thymic stromal lymphopoietin (TSLP), and OX40L. The serum level of OX40L has been compared between groups of steroid-sensitive asthma (SSA) and steroid-resistant asthma (SRA). According to results, the serum level of OX40L was significantly higher in asthmatic patients than in the healthy controls, and significantly higher in the SRA group than in the SSA group. The level of serum OX40L displayed a significant positive correlation with serum IgE, blood percentages of eosinophils and neutrophils, serum IL-6 and TSLP, and exhibited a negative correlation with asthma control test (ACT) score and forced expiratory volume in the first second (FEV1%). Overall, the investigators proposed that high serum OX40L can be used as a biomarker to identify corticosteroid-resistant asthma patients, and the change in the level of OX40L also reflects the response to ICS treatment. An association of OX40L with the pathophysiology, inflammation, and clinical outcomes of asthma was suggested. New OX40L targeting agents can provide more accurate and personalized asthma therapy.