1. National Allergy Research Centre; Department of Dermatology and Allergy; Herlev and Gentofte Hospital; University of Copenhagen; DK 2900 Hellerup Denmark
2. Department of Dermatology and Allergy; Herlev and Gentofte Hospital; University of Copenhagen; DK 2900 Hellerup Denmark
3. Institute of Environmental Medicine; Karolinska Institutet; SE 171 77 Stockholm Sweden