The dynamics of the response of normal skin to single and multiple epicutaneous leukotriene B4 applications analysed by three-colour flow cytometry.

Leukotriene B4 (LTB4) is a potent chemoattractant and a well-established stimulator of DNA-synthesis in keratinocytes. Previously, repeated applications of LTB4 have been reported to induce a topically defined tachyphylaxis with respect to the extravasation of polymorphonuclear neutrophils. The aim of the present study was to quantify epidermal proliferation (% basal keratinocytes in S- and G2M phase), epidermal keratinization (% keratin 10-positive keratinocytes) and the appearance of "non-keratinocytes", including melanocytes, Langerhans' cells and infiltrate cells (% vimentin-positive cells) in order to further elucidate the effect of chronic exposition of normal skin to LTB4.