Chemokine levels in serum of children with atopic dermatitis with regard to severity and sensitization status.

BACKGROUND: Many infants with atopic dermatitis (AD) are sensitized against food or airborne allergens. The severity of AD, using the SCORAD, seems to correlate with elevated serum levels of TARC/CCL17. Other chemokines, such as CCL20 or CCL25, have been described in the context of allergic inflammation. The aim of this study was to analyze whether chemokine serum levels differ within a cohort of infants suffering from varying severities of AD with or without allergic sensitization.

METHODS: Chemokine serum levels (CCL8, CCL17, CCL20, CCL25) as well as food and airborne allergen-specific IgE were analyzed in infants with AD.

RESULTS: About 60.9% (78/128) infants with AD (median age 8.8 months, 49 (38%) girls and 79 (62%) boys) showed a positive screening test to common food allergens and 26.6% to common airborne allergens. There was a strong correlation between serum levels of CCL17 and SCORAD in food-sensitized infants (r(s) = 0.646, p = <1e-04) and airborne-sensitized infants (r(s) = 0.587, p = 0.00065) in contrast to non-sensitized ones. Moreover, food-sensitized infants showed significantly higher levels of CCL25 compared to non-food-sensitized ones (p = 0.007).

CONCLUSION: The strong correlation between TARC/CCL17 and SCORAD in infants with specific sensitizations may be accounted for by the impaired skin barrier. As TARC/CCL17 has been found mainly in the (inflamed) skin but not in the gut, the detection of significantly higher levels of CCL25, ligand of CCR9, localized primarily in the gastrointestinal tract, suggests its impact on food allergen-induced inflammation processes in food-sensitized infants.