Department of Internal Medicine, Chonnam National University Medical School, 160, Baekseo-ro, Dong-gu, 61469, Gwangju, South Korea. Department of Pathology, Chonnam National University Medical School, 160, Baekseo-ro, Dong-gu, 61469, Gwangju, South Korea. Department of Internal Medicine, Chonnam National University Medical School, 160, Baekseo-ro, Dong-gu, 61469, Gwangju, South Korea. drkang@chonnam.ac.kr.