1. Department of Dermatology and Allergy; Herlev and Gentofte Hospital; University of Copenhagen; DK-2900 Hellerup Denmark
2. National Allergy Research Centre; Herlev and Gentofte Hospital; University of Copenhagen; DK-2900 Hellerup Denmark
3. Coronel Institute of Occupational Health; Academic Medical Centre; Amsterdam the Netherlands
4. Laboratory for Analytical Chemistry; Department of Chemistry and Biochemistry; Faculty of Food Technology and Biotechnology; University of Zagreb; Zagreb Croatia
5. Department of Dermatology; University of California San Francisco; San Francisco CA U.S.A.