Expression of IL‐33 in chronic lesional skin of canine atopic dermatitis

BACKGROUND: In humans, interleukin (IL)-33 plays a critical role in the enhancement of allergic skin inflammation. However, it currently remains unclear whether IL-33 is involved in the pathogenesis of canine atopic dermatitis (cAD). OBJECTIVES: To examine the expression of IL-33 in chronic lesional skin of cAD. ANIMALS: Eight dogs with spontaneous cAD and five healthy dogs were used. METHODS: The transcription of il-33 in chronic lesional skin of cAD was quantified by quantitative reverse transcription PCR. The expression of IL-33 was evaluated immunohistochemically using an anti-human IL-33 monoclonal antibody with cross-reactivity to canine IL-33. RESULTS: The transcription levels of il-33 in chronic lesional skin of cAD were significantly higher than those in normal skin of healthy dogs. Keratinocytes were a major cellular source of IL-33 production in chronic lesional skin of cAD. CONCLUSIONS AND CLINICAL IMPORTANCE: The results indicate that IL-33 is involved in chronic lesional skin of cAD.