RESUMO
BACKGROUND: Previous evaluations of cytokine and chemokine gene expressions [messenger (m)RNA] in the skin of allergic cats were mostly unsuccessful in detecting the T-helper 2 (Th2) pathway, which is associated with the major effector cytokines interleukin (IL)-4, IL-5 and IL-13. HYPOTHESIS/OBJECTIVE: To evaluate differences in the mRNA expression in eosinophilic plaques of cats diagnosed with feline atopic skin syndrome (FASS) compared to healthy controls. ANIMALS: Four client-owned cats with FASS with eosinophilic plaques and five healthy control cats. MATERIALS AND METHODS: Gene expressions (mRNA) of 14 cytokines and chemokines from eosinophilic plaque skin of cats with FASS and site-matched skin samples from healthy controls were analysed using quantitative reverse-transcription PCR analysis. RESULTS: Eosinophilic plaques were characterized by upregulation of Th2 cytokines IL-4 (p ≤ 0.01), IL-5 (p ≤ 0.01) and IL-13 (p ≤ 0.01) and Th2-attracting chemokine CCL17 (p ≤ 0.05). Moreover, there was higher expression of S100 calcium-binding protein A 8 (p ≤ 0.01) as well as C-X-C Motif chemokine ligand 10 (CXCL10; p ≤ 0.01), IL-10 (p ≤ 0.05) and the Th17 cytokine IL-17A (p ≤ 0.01) in lesional skin compared to healthy samples. There was no difference in gene expressions of IL-12A, IL-31, IL-33, thymic stromal lymphopoietin (TSLP), tumour necrosis factor-α (TNF-α) or CCL5. CONCLUSIONS AND CLINICAL RELEVANCE: Results demonstrate that eosinophilic plaques feature dominant Th2 and IL-17A inflammatory responses in the skin. Further larger-sample transcriptome studies are needed to advance our understanding of the pathogenesis of different skin lesions in FASS.