Localization of Merkel Cells at Hairless and Hairy Human Skin Sites Using Keratin 18

The study aimed to localize Merkel cells in human skin, both hairless and hairy, using immunohistochemistry with antibodies against keratins 18 and 19. It was found that Merkel cells, which are neurosecretory and mechanosensory, were more densely distributed in hairless areas like the palms and soles, specifically in the epidermal basal layer at the bottom of the rete ridges. In hairy skin, such as breast skin with small hair follicles, Merkel cells were present in the interfollicular epidermis and the isthmus region of hair follicles. Despite their known presence and sensory innervation, the precise origin and function of Merkel cells were not clearly established at the time.