title: Immunoglobulin-E-bearing cells in skin biopsies of horses with insect bite hypersensitivity.
abstract: The aim of the present study was to investigate, with immunohistochemistry and in situ hybridisation, if immunoglobulin-E (IgE) and mast cells are involved in the pathogenesis of insect bite hypersensitivity (IBH), an allergic dermatitis of horses. In tissue sections fixed in paraformaldehyde (PFA) for <24 h, significantly more IgE protein-bearing cells were found in the dermis and epidermis of acute and chronic IBH lesions than in skin biopsies from healthy horses (medians = 466, 236 and 110 cells/mm2, respectively; P < or = 0.01). More IgE-mRNA positive (+) cells were observed in the dermis of acute IBH lesions than in the dermis of healthy skin (median = 2.8 vs. 0.0 cells/mm2; P < or = 0.01). Significantly, more mast cells were detected with metachromatic (median = 160 vs. 62 cells/mm2; P < or = 0.001) and tryptase-specific stainings (median = 120 vs. 69 cells/mm2; P < or = 0.001) in the dermis of acute IBH biopsies compared to healthy skin. No chymase+ mast cells were found in any skin biopsy. IBH lesions fixed in PFA for >24 h were compared to dermatomycosis (DM) lesions; IBH biopsies contained a similar number of IgE-protein+ cells to DM biopsies (median = 249 vs. 192 cells/mm2; P = 0.08) but had significantly more IgE-mRNA+, metachromatic and tryptase+ mast cells than DM biopsies. This study suggests an involvement of IgE-mediated immune reactions in the pathogenesis of IBH as well as, sometimes, in dermatomycosis. Using double labelling, cells which expressed IgE protein and contained mast cell enzymes were detected.
authors.affiliation: Institute of Animal Breeding, Berne, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: van der Haegen
authors.forename: M
authors.initials: M
authors.lastname: Griot-Wenk
authors.forename: M
authors.initials: M
authors.lastname: Welle
authors.forename: A
authors.initials: A
authors.lastname: Busato
authors.forename: C
authors.initials: C
authors.lastname: von Tscharner
authors.forename: A
authors.initials: A
authors.lastname: Zurbriggen
authors.forename: E
authors.initials: E
authors.lastname: Marti
mesh_terms: D000818:Animals; D001706:Biopsy / Q000662:veterinary; D003872:Dermatitis / Q000276:immunology / Q000662:veterinary*; D005404:Fixatives; D005557:Formaldehyde; D006734:Horse Diseases / Q000276:immunology*; D006736:Horses; D006969:Hypersensitivity, Immediate / Q000276:immunology / Q000662:veterinary*; D007073:Immunoglobulin E / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D007150:Immunohistochemistry / Q000662:veterinary; D017403:In Situ Hybridization / Q000662:veterinary; D007299:Insect Bites and Stings / Q000276:immunology / Q000662:veterinary*; D008407:Mast Cells / Q000276:immunology; D011108:Polymers; D012333:RNA, Messenger / Q000032:analysis; D012867:Skin / Q000276:immunology* / Q000473:pathology; D012882:Skin Tests / Q000662:veterinary; D013997:Time Factors
chemical_list: D005404:Fixatives; D011108:Polymers; D012333:RNA, Messenger; D005557:Formaldehyde; D007073:Immunoglobulin E; C003043:paraform