Indeed, as shown by the high IL-2 levels detectable in severe asthmatic patients, this cytokine is involved in the pathophysiology of both T2-low and T2-high severe asthma by promoting the differentiation of Th1 and Th2 cells, as well as by inducing airway remodeling through up-regulation of type-1 collagen expression (107–109). The gene discussed is IL2; the disease is asthma.