Pediatric Atopic Dermatitis Exhibits Distinctive Patterns in JAK/STAT Pathway Activation and CD6-ALCAM Signaling

Pediatric atopic dermatitis (AD) shows distinct clinical characteristics compared to adult AD, suggesting unique inflammatory profiles that may influence disease prognosis and treatment response. We aimed to identify unique immune signatures of pediatric AD and investigate the differences between pediatric and adult AD patients. Nine pediatric (6-16 years) and 12 adult (20-60 years) were enrolled. PBMCs were collected from AD patients and age- and sex-matched healthy controls (HCs). Transcriptomic profiles were analyzed using single-cell RNA sequencing, and the immune phenotypes of adult and pediatric AD were compared. Th2 gene expression was elevated in both adult and pediatric AD, while Th1, Th17, and Th22 gene expression was downregulated in pediatric AD but not in adults. Genes involved in JAK/STAT signaling pathway, which were upregulated in adult AD, were not significantly increased in pediatric AD. The CD6-activated leukocyte cell adhesion molecule (ALCAM) pathway was upregulated in pediatric AD compared to pediatric HCs, but not in adult AD. Pediatric AD reveals distinct immune signatures, including a lack of JAK/STAT pathway upregulation observed in adult AD and a unique activation of the CD6-ALCAM pathway. These findings highlight the importance of age-specific treatment strategies in AD patients.