[1] Seoul Natl Univ, Coll Med, Dept Internal Med, Seoul 151, South Korea
[2] Seoul Natl Univ, Inst Allergy & Clin Immunol, Med Res Ctr, Seoul, South Korea
[3] Seoul Natl Univ, Bundang Hosp, Dept Internal Med, Songnam, South Korea
[4] Seoul Natl Univ, Coll Med, Dept Trop Med & Parasitol, Seoul, South Korea
[5] Seoul Natl Univ, Coll Med, Inst Endem Dis, Seoul, South Korea
[6] Natl Canc Ctr, Natl Canc Control Res Inst, Goyang, Gyonggi, South Korea