Snapshots of CD4⁺ T cell plasticity in the pathogenesis of allergic asthma

Allergic asthma is one of the well-known type 2 inflammatory diseases and is mainly mediated by T helper type 2 (Th2) cells (1). Environmental allergens such as house dust mite (HDM) causes lung eosinophilia (2). Followed by activation of lung epithelial cells and subsequent release of alarmins such as thymic stromal lymphopoietin (TSLP), IL-25 and IL-33 (3,4), dendritic cells (DCs) and B cells participate to prime naïve CD4 T cells to differentiate them into Th2 effector cells to secrete Th2 cytokines (IL-4, IL-5 and IL-13) and to produce B cell-mediated humoral immune responses by Ig (immunoglobulin)-E (5,6).