Expression of Hair Keratins in the Adult Nail Unit: An Immunohistochemical Analysis of Onychogenesis in the Proximal Nail Fold, Matrix, and Nail Bed

The study analyzed the expression of hair keratins in the adult nail unit, revealing that the ventral matrix served as the primary source of the nail plate. The coexpression of hHb5 with K5 and K17 in specific cell layers led to the identification of a prekeratogenous zone in the ventral matrix. The dorsal matrix was identified as a transitional zone between the eponychium and the apical matrix, with the apical matrix contributing to the dorsal portion of the nail through a mix of hair and epithelial keratins, including K10.