Immunohistochemical Detection of Prekeratin and Keratin in Hair Follicles and Epidermis of Human Fetus

Chung, Byoung Soo; Shin, Dong Sik

Abstract

Authors attempted to examine the development of keratinocyte in the human fetal epiderrnis in term of the appearance of principal product of differentiation, the keratins. Immunohistochemical study (ABC method) using anti-prekeratin antibodies and anti-keratin antibodies was carried out on sampled skin from 9 human fetuses ranging in estirnated gestational age from 12 weeks to 27 weeks. As early as 12 weeks of embryonic life, the epidermis contained cytokeratin. At this stage of development, the embryonic epidermis consists of three-cell layer .' basal layer, intermediate layer, and periderm, all of them staining for prekeratin and keratin. A thick cornified layer developed at 24 weeks but was not stained for prekeratin and keratin. Hair germ of 12 week-fetus was recognized as bulges of basal cells that were stained for prekeratin and keratin. At 18 weeks of estimated gestational age, development has advanced to the bulbous hair peg stage at which point the primordia of nearly all the final structural components of follicles were established. In the final structureal cornponents of the follicles, outer root sheath and sebaceous gland were stained for prekeratin and keratin, whereas cortical and cuticular elements and inner root sheath were negative. There was no difference between immunostaining results for prekeratin and keratin except for the staining intensity. The appearance of these proteins early in development suggests their potential value in utero in the recognition of keratinization disorders.