Fig. 8. A schematic representation of the context-dependent role of TSLP and IL-1β in promoting skin allergic sensitization and the atopic march.

When allergen HDM sensitization occurs superficially in the skin (epicutaneous sensitization), TSLP derived from keratinocytes located in the epidermis plays a dominantly crucial role for allergic sensitization through the lymph node (LN; generating Th2, Tfh and B cell responses) and the subsequent allergic inflammation in the lung. When allergen sensitization occurs deeply in the skin (dermacutaneous sensitization), IL-1β derived from the infiltrated neutrophils and monocytes/macrophages contributes together with TSLP, to generate a stronger allergen sensitization and subsequently a more severe lung allergic inflammation.