[1] Univ North Carolina Chapel Hill, Div Pediat Gastroenterol, Chapel Hill, NC USA
[2] Univ North Carolina Chapel Hill, Multidisciplinary Ctr Inflammatory Bowel Dis, Chapel Hill, NC USA
[3] Univ North Carolina Chapel Hill, Ctr Gastrointestinal Biol & Dis, Chapel Hill, NC USA
[4] Univ North Carolina Chapel Hill, Dept Pediat Gastroenterol, 333 S Columbia St,247 MacNider Hall,Campus Box 722, Chapel Hill, NC 27514 USA