Proteomic characterization of atopic dermatitis blood from infancy to adulthood.

Background: Patients with atopic dermatitis (AD) have systemic biomarker dysregulation that differs by age group; however, the proteomic characteristics of these age-based changes are unknown.

Objective: To profile blood proteins of patients with AD across different age groups versus age-appropriate controls.

Methods: Using the Olink high-throughput proteomic platform, we profiled 375 serum proteins of 20 infants (age, 0-5 years), 39 children (age, 6-11 years), 21 adolescents (age, 12-17 years), and 20 adults (age, ≥18 years) 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 (interleukin 4/CCL13/CCL17). In contrast, Th1 axis down-regulation was detected in infants with AD and gradually reversed to increased Th1 products (interferon γ/CXCL9/CXCL10/CCL2) in patients with AD from childhood to adulthood. Despite their short disease duration, infants already had evidence of systemic inflammation, with significant upregulation of innate immunity (interleukin 17C/ interleukin-1RN), T-cell activation/migration (CCL19), Th2 (CCL13/CCL17), and Th17 (PI3) proteins. Adults with AD present unique upregulation of cardiovascular proteins related to coagulation and diabetes.

Limitations: Cross-sectional observational study with a single time point.

Conclusion: 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.