1. Departments of Medicine and Dermatology University of Minnesota Minneapolis MN U.S.A
2. Departments of Medicine and Dermatology Minneapolis Veterans Affairs Health Care System Minneapolis MN U.S.A
3. Welsh Institute of Dermatology University Hospital of Wales Cardiff U.K
4. Department of Dermatology Zealand University Hospital Roskilde Denmark
5. Department of Dermatology University of Copenhagen Copenhagen Denmark
6. Department of Dermatology University of California San Francisco San Francisco CA U.S.A
7. Department of Medicine Division of Dermatology Women's College Hospital University of Toronto Toronto ON Canada
8. The Rockefeller University New York NY U.S.A
9. Biostatistical Design and Analysis Center Clinical and Translational Science Institute University of Minnesota Minneapolis MN U.S.A