IL21 and Airway obstruction: Three groups of highly correlated cytokines and alarmins were identified: two T2 modules, the TSLPmod (TSLP, IL-4, IL-5, IL-9) and the IL-33mod (IL-33, IL-13, IL-21), and one non-T2 module, the IL-1βmod (IL-1β, IL-6, G-CSF). TheTSLPmod was associated with asthma severity, airway obstruction, eosinophilia, andelevated FeNO.