LANGERHANS CELL HYPERPLASIA AND IGE EXPRESSION IN CANINE ATOPIC-DERMATITIS

Langerhans cells appear to be critical for IgE-mediated allergen captu re and presentation in human atopic dermatitis, The present study soug ht to determine whether epidermal (i.e Langerhans cells) and dermal de ndritic cells in the skin of dogs with atopic dermatitis are hyperplas tic and expressed surface IgE, Frozen sections of lesional or nonlesio nal atopic and normal control canine skin were immunostained with CD1a -, CD1c-, and IgE-specific monoclonal antibodies, The enumeration of c ells was performed by morphometry in both the epidermis and the dermis , Cell counts were compared with each individual's total serum IgE lev els, Higher numbers of epidermal and dermal dendritic cells were prese nt in atopic dogs than in normal control animals. Epidermal Langerhans cell counts were significantly higher in lesional than in nonlesional atopic specimens, IgE(+) dendritic cells were observed in lesional at opic epidermis and dermis, and nonlesional atopic dermis, but not in n ormal control skin specimens, The percentages of IgE(+) dendritic cell s were correlated with each patient's total serum IgE levels, These re sults demonstrate dendritic cell hyperplasia and IgE expression in can ine atopic dermatitis, Increased epidermal Langerhans cell counts in l esional specimens suggest an epidermal allergen contact in canine atop ic dermatitis.