Figure 1.

In situ phenotypic characterization of CD123^high P-DCs and related MxA and PNAd expression. Multicolor immunofluorescence staining for: CD123 (Cy3, red), CD45RA (FITC, green), and cytokeratin (AMCA, blue in c) (a, c, and d); human MxA (Cy3, red) with nuclear counterstain (DAPI, blue) (b); CD123 (Cy3, red) (e–g) and HLA-DR (FITC, green) (e), CD68 (FITC, green) (f), human c-kit (Alexa Fluor 488, green) (g); CD3 (Cy3, red) and CD45RA (FITC, green) (h); and PNAd revealed with mAb MECA-79 (Cy3, red) and endothelium with Ulex europaeus lectin-1 (FITC, green) (i) in serial sections (comparable fields in a and b) of cutaneous DLE lesion. Characteristic accumulation of CD123^highCD45RA⁺ cells (yellow staining) along the dermal-epidermal junction (a), around hair follicles (c), and adjacent to dermal vessel (asterisk) with endothelial CD123 expression (d); note strong expression of MxA in keratinocytes and infiltrating cells in dermis (b) in field comparable to high numbers of P-DCs (a). CD123^high cells also express HLA-DR (e) and CD68 (f); the intracellular dot-like staining pattern for CD68 was similar in tonsillar tissue (not shown) and found characteristic for DCs by others. 20 Dermal c-kit⁺ mast cells do not express CD123 (g, arrowhead); note the large number of naïve (CD3⁺CD45RA⁺) T cells (yellow staining, some arrowed) (h). Medium–sized vessels (diameter, ≥10 μm) with strong PNAd expression appears yellow (i); note that some keratinocytes also react with MECA as previously noted. 25 Basement membrane of epidermis is indicated by dashed line. Original magnifications: ×200 (a and b); ×400 (c, d, g, and h); ×630 (e and f); ×100 (i).