Correlation of Clinical Atopic Dermatitis Scores with Levels of Eosinophil Progenitors in Skin after Intradermal Allergen Challenge

Systemic and local eosinophilia is thought to contribute to disease progression in acute and chronic lesions of patients with atopic dermatitis. We have previously shown an increase in eosinophil lineage-committed progenitors (EoP) in skin during the late cutaneous response after intradermal allergen challenge, and in chronic skin lesions from patients with atopic dermatitis. This study examined the relationship between levels of EoP in the skin, and atopic dermatitis clinical scores, EASI and SCORAD. Sixteen patients with moderate-to-severe atopic dermatis underwent full skin assessments using EASI and SCORAD scores. After 8 days of systemic steroid washout, intradermal challenge was performed with allergen and saline control. 24 hours later, biopsies were obtained from the site of the late cutaneous response and from a chronic lesion. Immunofluorescence staining was performed on skin biopsies. EoP defined as CD34+ve/IL-5Ra+ve/Von Willebrand factor-ve were measured in the papillary dermis using Nikon Imaging Software Analysis. Levels of EoP were compared to EASI and SCORAD using non-parametric Spearman correlation. The level of EoPs in chronic lesions positively correlated with disease severity measured by EASI (r=0.71, p<0.05) and SCORAD (r=0.65, p<0.05). In allergen-challenged skin there were trends for a positive relationship between EoP and disease severity measured by EASI (r=0.48, p=0.07) and SCORAD (r=0.46, p=0.09). These results highlight the potential involvement of EoP in the pathogenesis and clinical presentation in patients with atopic dermatitis.