title: Epithelium-lining macrophages in psoriasis.
abstract: Epithelium-lining macrophages are spindle-shaped cells which line the epidermis and hair follicles. We studied the distribution and phenotype of this hitherto neglected member of the dermal monocyte/macrophage system in 25 lesional psoriatic, and five normal skin biopsies. Epithelium-lining macrophages were inconspicuous in normal skin, whereas their number was increased in almost two-thirds of psoriatic cases; in nine out of 25 lesional skin biopsies, these flattened cells formed an almost continuous single-cell row at the dermo-epidermal junction. Immunophenotyping revealed that these cells expressed the leucocyte common antigen CD45, and the macrophage markers CD14, CD36 and CD4, but not CD11b. Epithelium-lining macrophages strongly expressed HLA-DR-antigens and CD11a, but lacked the Langerhans cell marker CD1, and CD34. The dermal dendrocyte marker factor XIIIa was expressed in only a minority of these cells. It is concluded that epithelium-lining macrophages represent a separate subset of dermal monocytes/macrophages with a distinct tissue localization and immunophenotype. Their restricted distribution and close association with the epidermis may suggest a role in the regulation of epidermal growth. Alternatively, the expression of several immune-associated molecules may indicate that epithelium-lining macrophages are involved in the antigen-dependent or -independent activation of T cells.
authors.affiliation: Department of Pathology, University Hospital St Rafael, Catholic University of Leuven, Belgium.
authors.forename: J J
authors.initials: JJ
authors.lastname: van den Oord
authors.forename: C
authors.initials: C
authors.lastname: de Wolf-Peeters
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D018845:CD11 Antigens; D018955:CD36 Antigens; D015704:CD4 Antigens / Q000032:analysis; D004848:Epithelium / Q000473:pathology; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D016130:Immunophenotyping; D017493:Leukocyte Common Antigens / Q000032:analysis; D018950:Lipopolysaccharide Receptors; D008264:Macrophages / Q000276:immunology / Q000473:pathology*; D011565:Psoriasis / Q000276:immunology / Q000473:pathology*; D012867:Skin / Q000276:immunology / Q000473:pathology*
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D018845:CD11 Antigens; D018955:CD36 Antigens; D015704:CD4 Antigens; D006684:HLA-DR Antigens; D018950:Lipopolysaccharide Receptors; D017493:Leukocyte Common Antigens