[1] Nottingham Univ Hosp NHS Trust, NIHR Nottingham Digest Dis Biomed Res Unit, Nottingham NG7 2UH, England
[2] Univ Nottingham, Nottingham NG7 2UH, England
[3] Univ Leeds, Inst Biomed & Clin Sci, Mol Gastroenterol, Leeds, W Yorkshire, England
[4] St James Univ Hosp, Ctr Digest Dis, Leeds LS9 7TF, W Yorkshire, England
[5] Univ Calif San Diego, Div Gastroenterol, La Jolla, CA 92093 USA
[6] Mayo Clin, Gastroenterol & Hepatol, Rochester, MN USA