1. Department of Dermatology and Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea.
2. Division of Nephrology, Department of Internal Medicine, BK21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Dermatology, Yanbian University Hospital, Yanji, China.
4. Department of Biostatistics, Yonsei University College of Medicine, Seoul, Korea.