Expression of E-selectin in TNF-–stimulated skin organ cultures. Immunohistochemical staining of skin organ cultures stimulated for 8 hours with TNF- (12,000 U/mL). Serial sections of unstimulated normal skin (A through C), stimulated normal skin (D through F) and stimulated skin from the patient (G through I) were stained with antibody against PECAM-1 (A, D, and G) to identify the vessels (arrows and arrowheads), ICAM-1 (B, E, and F) and E-selectin (C, F, and I). The epidermis (Epi) is indicated for the stimulated normal skin. In unstimulated normal skin there was some expression of ICAM-1 (B, arrowheads), although most of the vessels did not express it (B, double arrows), and negligible expression of E-selectin (C). A similar pattern was seen for unstimulated skin from the patient (data not shown). In stimulated normal skin, there was marked upregulation in the number of vessels expressing ICAM-1 (E) and a smaller but clearly significant increase in the number of vessels expressing E-selectin (F). In contrast to normal skin, stimulated skin from the patient showed upregulation of ICAM-1 on the vasculature (H) but no increased E-selectin expression (I). The asterisk indicates dermal interstitium in which there is also upregulate expression of ICAM-1 on the dermal stroma particularly evident in the sample of stimulated normal skin (E).