Toward a canine model of atopic dermatitis: amplification of cytokine-genetranscripts in the skin of atopic dogs

The objectives of the present study were to characterize and compare the re pertoire of cytokine-genes transcribed in skin homogenates obtained from no rmal dogs and dogs with atopic dermatitis (AD) using a reverse-transcriptas e polymerase chain reaction and canine-specific cytokine-gene primers. Wher eas IL-4 and IL-5 cytokine-gene transcripts were detected more commonly in atopic skin biopsy homogenates, IL-2 mRNA was amplified more often from nor mal control specimens. IFN-gamma mRNA was detected in 5/29 atopic specimens , 4 of them obtained from the only dog with chronic skin lesions. One-fourt h of atopic samples exhibited clear type-2 cytokine profiles; the remainder did not demonstrate polarized repertoires. Conversely, type-1 cytokine pro files were characterized in one-fourth of normal control specimens. The pre sent study establishes, for the first time, the transcription of type-2 cyt okine-genes in the skin of dogs with AD. Future experiments investigating t he cellular origin and dynamics of allergic cytokine-gene transcription are needed to confirm whether or not canine AD could be considered an immunolo gical model for a human disease.