In the context of allergic diseases like asthma or atopic dermatitis, TSLP secreted by epithelial cells stimulates DCs in an antigen-specific manner, increasing the expression of surface co-stimulatory molecules such as CD80 and CD86, and inducing inflammatory helper T (Th)-2 cell polarization through OX40/OX40L interaction with immature CD4+ T cells, secreting cytokines such as IL-4 and IL-13. Here, CD4 is linked to asthma.