Serum canine thymus and activation-regulated chemokine (TARC/CCL17) concentrations correlate with disease severity and therapeutic responses in dogs with atopic dermatitis.

Abstract

BACKGROUND: Thymus and activation-regulated chemokine (TARC/CCL17) has been implicated in the pathogenesis of canine atopic dermatitis (cAD). Serum TARC concentrations are a reliable biomarker for human atopic dermatitis; however, their potential as a biomarker for cAD has not been investigated. HYPOTHESIS/OBJECTIVES: To investigate whether serum TARC concentrations correlate with disease severity and therapeutic responses for cAD. ANIMALS: Thirty-nine dogs with cAD and 42 healthy dogs were recruited. METHODS AND MATERIALS: Serum TARC concentrations in dogs with cAD and healthy dogs were measured by sandwich ELISA with anti-canine TARC antibodies. The clinical severity of cAD was scored using the validated Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04). Serum TARC concentrations were compared between dogs with cAD and healthy controls, and their relationship with CADESI-04 was examined. Serum TARC concentrations also were measured in 20 dogs with cAD treated with prednisolone or oclacitinib for four weeks. RESULTS: Serum TARC concentrations were significantly higher in dogs with cAD than in healthy dogs (P&#xa0;<&#xa0;0.001). In dogs with cAD, serum TARC concentrations correlated with CADESI-04 scores (&#x3c1;&#xa0;=&#xa0;0.457, P&#xa0;<&#xa0;0.01). Furthermore, serum TARC concentrations significantly decreased in treated dogs with the attenuation of clinical signs (P&#xa0;<&#xa0;0.001). Changes in serum TARC concentrations before and after treatment correlated with those in CADESI-04 scores (&#x3c1;&#xa0;=&#xa0;0.746, P&#xa0;<&#xa0;0.001). CONCLUSIONS AND CLINICAL RELEVANCE: Serum TARC concentrations have potential as a clinical and research tool for the objective evaluation of disease severity and therapeutic responses for cAD.