[1] Keio Univ Hosp, Ctr Diagnost & Therapeut Endoscopy, Shinjuku Ku, Tokyo 1608582, Japan
[2] Keio Univ Hosp, Div Diagnost Pathol, Tokyo 1608582, Japan
[3] Keio Univ, Sch Med, Dept Internal Med, Div Gastroenterol, Tokyo, Japan
[4] Keio Univ, Sch Med, Dept Internal Med, Div Hematol, Tokyo, Japan
[5] Saitama Med Univ, Saitama Med Ctr, Dept Hematol, Saitama, Japan