Large Thymus Size at 2 Months Is Associated With Increased Risk of Atopic Dermatitis at Age 2

Area of Science:

• Immunology
• Pediatrics
• Dermatology

Background:

• Atopic dermatitis (AD) involves skin barrier dysfunction and immune dysregulation, particularly T-cell responses.
• The thymus is crucial for T-cell development and maturation in early life.

Purpose of the Study:

• To investigate the association between infant thymus size and the incidence of atopic dermatitis (AD) within the first two years of life.

Main Methods:

• Followed 300 newborns for 2 years, measuring thymus size via ultrasound at birth, 2, and 12 months.
• Calculated thymic index and analyzed immune biomarkers from skin tape strips.
• Used hazard ratios (HR) and adjusted analyses (aHR) to assess AD risk, controlling for confounding factors.

Main Results:

• A higher thymic index at 2 months was significantly associated with increased AD risk (aHR: 6.32) and early-onset AD (aHR: 5.35).
• The 2-year cumulative prevalence of AD was 34.1%.
• A moderate correlation was found between thymic index and Eczema Area and Severity Index (EASI) scores at 2 months (r=0.39).

Conclusions:

• Increased thymic activity and T-cell development in infancy may be linked to a higher risk of AD onset.
• Early-life T-cell maturation appears to play a potential role in the pathogenesis of atopic dermatitis.