Transcriptome analysis of selected cytokine and chemokines in the eosinophilic plaques of cats with atopic skin syndrome

Abstract

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.