1. Harvard Skin Disease Research Center and the Department of Dermatology,
2. Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115
3. Department of Dermatology, Ghent University Hospital, B-9000 Ghent, Belgium
4. Department of Dermatology, Utrecht University Medical Center, 3508 GA Utrecht, Netherlands
5. University of Maryland, Program in Molecular and Cell Biology, College Park, MD 20742