1. Psoriasis-Centre at the Department of Dermatology; University Medical Centre Schleswig-Holstein; Kiel Germany
2. St John's Institute of Dermatology; King's College London; London UK
3. Division of Dermatology and Venereology; Geneva University Hospitals; Geneva Switzerland
4. Department of Pathology and Immunology; Faculty of Medicine; University of Geneva; Geneva Switzerland
5. Department of Dermatology; Aarhus University Hospital; Aarhus Denmark
6. Department of Dermatology; St. Vincent's University Hospital; Dublin Ireland
7. Centro Studi GISED; Bergamo Italy
8. Department of Dermatology; Ospedale san Bortolo di Vicenza; Vicenza Italy
9. Dermatologikum Berlin and SCIderm Research Institute; Hamburg Germany
10. Department of Dermatology; Medical University of Vienna; Vienna Austria
11. Department of Dermatology; Radboud University Nijmegen Medical Centre; Nijmegen The Netherlands
12. Dermatology Centre; Salford Royal NHS Foundation Trust; Salford UK
13. Manchester Academic Health Science Centre; Manchester NIHR Biomedical Research Centre; The University of Manchester; Manchester UK