Fig. 1.

CD99 expression in normal adult epidermis and hair follicles. (A) Overall CD99 expression pattern in normal adult skin. (B) Basal cells of the epidermis show strong immunopositivity for CD99. Epidermal Langerhans cells are also strongly immunopositive for CD99 (arrow). (C) Basaloid cells in the bulge, the insertion of the arrector pili muscle, show high CD99 expression. (D) In a terminal anagen hair follicle, the outer root sheath cells are strongly positive for CD99 stain. The inner root sheath cells are weakly positive for CD99 stain. O, outer root sheath; I, inner root sheath.