Expression of Th1, Th2 and immunosuppressive cytokine gene transcripts in canine atopic dermatitis

Summary Background Atopic dermatitis is a common inflammatory skin disease of humans and dogs. Human atopic dermatitis is associated with Th2‐type responses, although Th1 cytokines can be identified in chronic lesions. In contrast, tolerance to environmental allergens in healthy individuals is mediated by regulatory T cells. Objective This study examined the expression of the immunosuppressive cytokines TGF‐β and IL‐10, the Th2‐type cytokines IL‐4 and IL‐6, and the Th1‐type cytokines IFN‐γ, TNF‐α, IL‐2, IL‐12p35 and IL‐12p40, in canine atopic dermatitis. Materials and methods RNA was isolated from lesional atopic, non‐lesional atopic and healthy canine skin samples. Semi‐quantitative reverse transcriptase polymerase chain reactions (RT‐PCRs) were carried out using specific primers and one‐way analyses of variance used to compare cytokine expression in each group. Results Canine atopic dermatitis was associated with over‐expression of IL‐4 mRNA and reduced transcription of TGF‐β compared with healthy skin (P