Proteomic characterization of atopic dermatitis blood from infancy to adulthood
Background: Atopic dermatitis/AD patients have systemic biomarker dysregulation that differs by age group, but proteomic characteristics of these age-based changes are unknown. Objective: To profile blood proteins of AD patients across different age groups versus age-appropriate controls. Methods: Using the OLINK high-throughput proteomic platform, we profiled 375 serum proteins of 20 infants (0-5y/o), 39 children (6-11y/o), 21 adolescents (12-17y/o), and 20 adults (≥18y/o) with moderate-to-severe AD, and 83 age-appropriate controls. Results: Each group presented a distinct systemic proteomic signature. Th2-related proteins were increased in infant AD and further intensified with age through adolescence and adulthood (IL-4/CCL13/CCL17). In contrast, Th1 axis down-regulation was detected in infants with AD and gradually reversed to increased Th1 products (IFN/CXCL9/CXCL10/CCL2) in AD patients from childhood to adulthood. Despite their short disease duration, infants already have evidence of systemic inflammation, with significant up-regulation of general inflammatory (MMP12), innate (IL-17C/IL-1RN), T-cell activation/migration (CD40LG/CCL19), Th2 (IL-10/CCL13/CCL17), and Th17 (PI3) proteins (p<0.05). AD Adults present unique up-regulation of cardiovascular proteins related with coagulation and diabetes. Limitations: Cross-sectional observational study with a single time-point. Conclusions: Systemic immune signatures of AD are age-specific beyond the shared Th2 immune activation. These data advocate for precision medicine approaches based on age-specific AD profiles.