Birch pollen influence the severity of atopic eczema – prospective clinical cohort pilot study and ex vivo penetration study

Regina Fölster-Holst,1 Jagoda Galecka,1 Sigo Weißmantel,1 Ute Dickschat,2 Frank Rippke,3 Kerstin Bohnsack,3 Thomas Werfel,4 Katja Wichmann,4 Matthias Buchner,1 Thomas Schwarz,1 Annika Vogt,5 Jürgen Lademann,5 Martina C Meinke5 1Department of Dermatology, Venerology and Allergy, University of Kiel, 2Wörth, 3Beiersdorf AG, Hamburg, 4Department of Dermatology, Venerology and Allergy, Division of Immunodermatology and Allergy Research, Hannover Medical School, Hannover, 5Department of Dermatology, Venerology and Allergology, Charité – Universitätsmedizin Berlin, Berlin, Germany Abstract: There is little clinical evidence for a correlation between the severity of atopic eczema (AE) and pollen exposition. To obtain more data, we performed a clinical cohort pilot study about the influence of pollen on AE between sensitized and nonsensitized subjects and an experimental study addressing the cutaneous penetration of pollen into the skin. Fifty-five patients were monitored during birch pollen season. To study the cutaneous penetration, grass pollen allergens were applied on excised skin and the uptake in CD1c-expressing dendritic cells was investigated. The correlation between environmental pollen load and severity of the Scoring Atopic Dermatitis (SCORAD) score and pruritus was observed, regardless of the status of sensitization. The sensitized group recovered significantly worse after the birch pollen season. Remarkably higher amounts of pollen allergens taken up by CD1c cells were detected in epidermal cells derived from skin explants with a disturbed epidermal barrier. These findings suggest an exacerbating role of pollen in AE utilizing the epidermal route. Keywords: aeroallergens, atopic eczema, seasonality, skin antigen-presenting cells, skin barrier penetratio