[1] Harvard Univ, Brigham & Womens Hosp, Div Gastroenterol, Dept Med,Med Sch, Boston, MA 02115 USA
[2] Kobe Univ, Grad Sch Med, Dept Gastroenterol, Chuo Ku, Kobe, Hyogo 6500017, Japan
[3] Kobe Univ, Grad Sch Med, Integrated Ctr Mass Spectrometry, Chuo Ku, Kobe, Hyogo 6500017, Japan
[4] Univ Oslo, Rikshosp, Inst Immunol, N-0027 Oslo, Norway
[5] Harvard Univ, Div Gastroenterol, Childrens Hosp, Harvard Digest Dis Ctr,Med Sch, Boston, MA 02115 USA