Localization of tumour necrosis factor-α converting enzyme in normal human skin

The tumour necrosis factor (TNF)-alpha converting enzyme (TACE) is a metalloproteinase-disintegrin that releases soluble TNF-alpha from cells by cleaving within the extracellular domain of membrane-bound pro-TNF-alpha. TACE knockout mice display a range of epithelial abnormalities. However, the localization of TACE in normal human skin is unclear. In this study, we examined the expression of TACE in normal skin by immunohistochemical analysis. The expression of TACE was seen throughout all layers of the epidermis, the hair follicles, eccrine ducts and glands, and sebaceous glands. There was also staining of blood vessels in the dermis. In particular, TACE was localized predominantly in mast cells, suggesting that these cells are an important source of TNF-alpha.