Clinical Utility serum TARC/CCL17 for monitoring clinical couse of atopic dermatitis in children

Abstract

Thymus and activation-regulated chemokine/CCL17 (TARC/CCL17) is a ligand for CCR4 expressed on Th2 cells and possibly involved in the pathogenesis of Th2-driven atopic dermatitis (AD). We investigated clinical utility of serum TARC/CCL17 measurement as a marker for disease activity of AD in children. Subjects included 202 children aged 6 months to 14 years, 65 patients with AD, 32 with allergic rhinitis, 43 with asthma, and 62 normal non-atopic children. Serum TARC/CCL17 levels in normal children less than 2 years old were significantly higher than the older counterparts and normal levels of TARC/CCL17 were defined as 1367, 998, 743pg/ml for children less than 1 year old, those less than 2, and those of 2 and over, respectively. Serum TARC/CCL17 levels in patients with AD and asthma, not in allergic rhinitis were significantly higher than in normal subjects and positively correlated with severity of disease only in AD, not in asthma. With ROC curve analysis, TARC/CCL17 was found to be a more specific and sensitive marker for AD than LDH, eosinophil counts, and IgE. Although eosinophil counts were correlated the disease severity, changes in serum TARC/CCL17 according to the severity were much larger than eosinophil counts. These results suggest that serum TARC/CCL17 measurement well represents the disease activity of AD and may serve as a useful clinical marker for guideline-based treatment.