Viral infections cause the release of IL‐33 from bronchial epithelial cells, which enhances IL‐13 and IL‐5 production in naive (CD45RO−), activated (anti‐CD2/CD3/CD28‐stimulated), nonpolarized human CD1+T cells (Th0 cells) and ILC‐2s,6 providing a mechanism by which eosinophilic and Th2‐type asthma commonly overlap. Here, CD28 is linked to viral infectious disease.