Early skin inflammatory biomarker is predictive of development and persistence of atopic dermatitis in infants

Background The STOP AD study, a randomized, open-label trial evaluating the effect of short-term (first four postnatal days to 8 weeks) skin barrier protection using AVEENO® Dermexa Fast & Long-Lasting Balm in infants with a parent with allergic disease, demonstrated decreased cumulative incidence and decreased prevalence of AD at 12 months of age. Objective We aimed to identify skin biomarkers in the STOP AD study that are associated with risk of development of AD. Methods Skin swabs were collected from the cheek and antecubital fossa (AF) at baseline, 8 weeks, and 12 months from subsets of study participants from each of the intervention arm (43 of 119) and control arm (43 of 138) and were analyzed for specific cytokines (CCL27, CXCL2, hBD1, IL18, IL8, IL1α, IL1RA, IL1β, S100A8/9, IL36γ) by ELISA. Results Higher titers of S100A8/9 at the AF at 8 weeks in infants with filaggrin wild type genotype (FLGwt), but not in those with filaggrin loss-of-function mutations (FLGmut), predicted: 1) Development of AD in the first year of life (p=0.033); 2) Presence of AD at 6 months or 12 months of age (p=0.009 and 0.035, respectively); 3) Persistence of AD between 6 and 12 months of age (p<0.001); 4) Development of AD with the emollient intervention. Conclusion Increased titers of S100A8/9 from skin swabs of the AF in high-risk infants at 8 weeks with FLGwt was predictive of AD developing in the first year of life and of other AD features. These findings suggest that there are different molecular pathways leading to AD in FLGmut individuals and in FLGwt individuals. Early identification of infants who are likely to develop AD will allow more targeted interventions.