Localization of Merkel cells in cross-sections of ESS after grafting to mice.

Immunohistochemistry was performed using antibodies against KRT20 (green) and KRT18 (red); DAPI was used to counterstain nuclei (blue). Shown are representative sections of ESS excised from mice at week 2 (A), week 4 (B), week 6 (C), week 8 (D), week 10 (E), week 12 (F), and week 14 (G) after grafting. H, Section of normal human skin (control). Dashed lines indicate locations of dermal-epidermal junctions. Rare KRT20-positive cells were observed at 2 weeks after grafting (arrow in A); co-localization of KRT20 and KRT18 was observed at later time points (B-G). Examples of oval (red arrow) and dendritic (yellow arrows) Merkel cell shapes are indicated (C). Scale bar in A (50 μm) is same for all panels.