[1] Seoul Natl Univ, Bundang Hosp, Dept Internal Med, Seongnam 463707, Kyunggi Do, South Korea
[2] Seoul Natl Univ, Coll Med, Dept Internal Med, Liver Res Inst, Seoul 151, South Korea
[3] Hanyang Univ, Coll Med, Dept Microbiol, Seoul 133791, South Korea
[4] Hanyang Univ, Coll Med, Inst Biomed Sci, Seoul 133791, South Korea