More recently, stratification has been based on inflammatory biomarkers, with sputum analysis and transcriptomic profiling demonstrating that ∼50% of patients with asthma have typical eosinophilic airway inflammation driven by ‘Type 2’ cytokines (T2 cytokines: interleukin (IL)-4, IL-5, IL-13); this T2-high asthma has been shown to respond well to CS therapy. Here, IL13 is linked to asthma.