642 The serum proteomic signature of pediatric AD suggests early Th2/Th17 skewing and an inverse correlation of disease severity with Th1 markers

Abstract

Increasing evidence supports the systemic inflammatory nature of atopic dermatitis (AD), but data has been based on studies in adults with decades of chronic disease. No studies have sought systemic inflammation in early AD, although 85% of cases begin before 5 years of age. Using a high-throughput proteomic platform (OLINK), we assessed 257 inflammatory and cardiovascular risk proteins in the serum of 30 children with moderate-to-severe AD < 5 years of age and within 6 months of disease onset, compared to age-matched controls (n¼20). As in studies of skin mRNA expression, Th2 (CCL13, CCL22, IL-13) and Th17 (PI3, S100A12) markers were increased compared to controls (p < 0.05). We also found increases in markers of tissue remodelling (MMP3/9/10), T-cell activation (CD5, IL2RA), lipid metabolism (FABP4), and growth factors (FGF21, TGF-alpha, PDGF). Positive correlations with disease severity/ SCORAD were detected with inflammatory markers (e.g. vascular activation marker E-selectin, heat shock protein 27, KLK6, IL1RT2; p < 0.05) and inverse correlations with Th1 markers (IFNg, CXCL11). The blood profile of early pediatric AD shows Th2/Th17 proteomic skewing, attesting to systemic alterations within months of onset and suggesting the need for more aggressive intervention before disease chronicity. The negative correlation of severity with Th1 markers may explain the propensity to infections in pediatric AD.