Immunoglobulin-E-bearing cells in skin biopsies of horses with insect bite hypersensitivity.
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.
van der Haegen
A
A
Institute of Animal Breeding, Berne, Switzerland.
Griot-Wenk
M
M
Welle
M
M
Busato
A
A
von Tscharner
C
C
Zurbriggen
A
A
Marti
E
E
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
D005404:Fixatives; D011108:Polymers; D012333:RNA, Messenger; D005557:Formaldehyde; D007073:Immunoglobulin E; C003043:paraform