CD40 and Allergy: Tape stripping of the skin followed by EPIT results in keratinocyte secretion of pro-inflammatory cytokines (IL-1, IL-6, IL-8, TNF-α, IL-12, and IFN-γ), increased expression of MHC class II, CD86, CD40, CD54 and CD11c on Langerhans cells, enhanced Toll-like receptor 9 expression in keratinocytes, [21, 45–51] and, in these EPIT grass pollen studies, subsequently resulted in allergy-protective responses [9].