Other potential mechanisms through which LEKTI can influence common atopic diseases, such as asthma, atopy, and atopic dermatitis, have been proposed: (i) proteinase-activated receptors are found in keratinocytes, and can act as targets for mast cell proteinases [23]; (ii) in the thymus, LEKTI seems to play a key role in T and B lymphocyte maturation and in antigen handling within other thymic cells [24]; and (iii) many allergens are serine proteinases, and this proteinase activity could be involved in the presence of different proteinase inhibitors [8]. Here, SPINK5 is linked to atopic eczema.