1. Division of Nephrology, Department of Internal Medicine, Chung-Ang University Hospital, Seoul, Korea.
2. Hankook Renal Pathology Lab, Seoul, Korea.
3. Division of Nephrology, Department of Internal Medicine, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong, Korea.
4. Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.