title: Immunoglobulin E-bearing cells and mast cells in skin biopsies of horses with urticaria.
abstract: The pathogenesis of equine urticaria is not well understood. In man, urticaria has been associated with immunological and nonimmunological mechanisms leading to the release of various mediators by mast cells. Skin biopsies of 32 horses with a history of urticaria were stained with toluidine blue, a double-labelling method for chymase and tryptase, and immunohistochemistry for immunoglobulin (Ig)E. These horses were compared with horses with pemphigus foliaceus, insect bite hypersensitivity and control horses with healthy skin. Neither formalin fixation time nor biopsy site influenced the staining methods. No chymase-positive cells were found. In all groups of horses, cells staining with toluidine blue and for tryptase and IgE were found in the epidermis and hair follicle papilla and significantly more positively staining cells were observed in the subepidermal dermis compared with the deep dermis. Horses with urticaria had significantly more IgE-bearing cells in the subepidermal dermis than control horses. However, horses with urticaria had significantly fewer toluidine-blue-stained mast cells in both subepidermal and deep dermis compared with the insect bite hypersensitivity and pemphigus foliaceus groups. This study suggests that IgE-mediated reactions play a role in the pathogenesis of urticaria.
authors.affiliation: Dermatology Unit, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Switzerland. silvia.ruefenacht@itz.unibe.ch
authors.forename: Silvia
authors.initials: S
authors.lastname: Rüfenacht
authors.forename: Eliane
authors.initials: E
authors.lastname: Marti
authors.forename: Claudia
authors.initials: C
authors.lastname: von Tscharner
authors.forename: Marcus G
authors.initials: MG
authors.lastname: Doherr
authors.forename: Ursula
authors.initials: U
authors.lastname: Forster
authors.forename: Monika
authors.initials: M
authors.lastname: Welle
authors.forename: Petra J
authors.initials: PJ
authors.lastname: Roosje
mesh_terms: D000818:Animals; D001706:Biopsy / Q000662:veterinary; D016022:Case-Control Studies; D053818:Chymases; D005260:Female; D006734:Horse Diseases / Q000276:immunology* / Q000473:pathology; D006736:Horses; D007073:Immunoglobulin E / Q000032:analysis* / Q000276:immunology; D007150:Immunohistochemistry / Q000662:veterinary; D008297:Male; D008407:Mast Cells / Q000201:enzymology / Q000276:immunology; D012697:Serine Endopeptidases / Q000032:analysis; D012867:Skin / Q000201:enzymology / Q000276:immunology / Q000473:pathology*; D012882:Skin Tests / Q000662:veterinary; D013194:Staining and Labeling / Q000379:methods / Q000662:veterinary; D053802:Tryptases; D014581:Urticaria / Q000276:immunology / Q000473:pathology / Q000662:veterinary*
chemical_list: D007073:Immunoglobulin E; D012697:Serine Endopeptidases; D053818:Chymases; D053802:Tryptases