title: Cutaneous expression of Thy-1 in mycosis fungoides.
abstract: Dermal dendritic cells from eleven cases of mycosis fungoides (MF) (six patch and five plaque stage), two cases of pre-MF, and five specimens of normal human skin, were characterized immunohistochemically using a panel of antibodies including anti-human Thy-1, intercellular adhesion molecule-1 (ICAM-1; CD54), endothelial leukocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), CD1a, CD2, CD14, CD18, CD34, MAC387, KP-1, EBM-11, factor XIIIa, factor XIIIs, and S100. Thy-1 expression in normal skin was limited to the microvascular endothelium and perivascular dendritic cells. An extensive interstitial network of Thy-1+ dendritic cells was seen in the papillary dermis of all cases of MF, whereas no epidermal cells were Thy-1+. The mean +/- standard deviation of interstitial Thy-1+ cells per high power field in the dermis was: normal skin, 2.86 +/- 0.34; pre-MF, 15; patch stage MF, 13.4 +/- 7.08; plaque stage MF, 49.96 +/- 21.29. Thy-1+ dendritic cells morphologically resembled the factor XIIIa+ "dermal dendrocyte" (DD) and shared their VCAM-1+, ICAM-1+, CD1a, CD2-, CD14+, CD18+, EMB11+, factor XIIIa+, factor XI-IIs-, S100-, MAC387- and KP-1-immunophenotype in MF. Double labeling studies revealed up to 50% of Thy-1+DD were also factor XIIIa+ in MF. Immediately beneath these cells was a similar network of CD34+, Thy-1-, factor XIIIa- dendritic cells limited to the reticular dermis. Strong microvascular endothelial cell expression of Thy-1 and VCAM-1, and focal vascular ELAM-1 expression were also seen in MF. Distinct cellular compartmentalization (papillary dermis versus reticular dermis versus epidermis) of dendritic cells is demonstrated by the differential expression of Thy-1, factor XIIIa, and CD34 antigens. The extensive number and prominent dermal dendritic network in the papillary dermis juxtaposed between epidermal keratinocytes (KC) and dermal/epidermal T cells, suggests an important pathophysiologic role for this newly recognized and immunophenotypically distinctive cell population in MF.
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34; D000954:Antigens, Surface / Q000032:analysis* / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000032:analysis; D019040:E-Selectin; D005455:Fluorescent Antibody Technique; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000378:metabolism; D009182:Mycosis Fungoides / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology; D012867:Skin / Q000737:chemistry* / Q000276:immunology / Q000473:pathology; D012878:Skin Neoplasms / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology; D018800:Thy-1 Antigens; D011503:Transglutaminases / Q000032:analysis; D019010:Vascular Cell Adhesion Molecule-1
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D019040:E-Selectin; D008562:Membrane Glycoproteins; D018800:Thy-1 Antigens; D019010:Vascular Cell Adhesion Molecule-1; D011503:Transglutaminases