CD10 and CD13 immunohistochemisty was performed on polydactyly and adult cadaveric nail units, and on hair follicles in scalp nevus sebaceus excision specimens.
CD10 and CD13 were expressed in the mesenchyme below the nail matrix and nail bed. Stronger CD13 expression was observed in the mesenchyme containing onychofibroblasts below the nail matrix compared to that below the nail bed. CD10 was expressed in the dermal sheath of terminal hair follicles, but it was expressed in the dermal sheath and follicular dermal papilla of primitive hair follicles within nevus sebaceus lesions. CD13 was expressed in the dermal sheath and dermal papilla of terminal and primitive hair follicles.
CD13 may be a marker for onychofibroblasts within nail matrix onychodermis. We demonstrate CD13 expression in the specialized mesenchymes of both nail and hair.