[1] Stanford Univ, Med Ctr, Dept Med, Palo Alto, CA 94304 USA
[2] Univ Michigan Hlth Syst, Div Gastroenterol, Ann Arbor, MI USA
[3] Stanford Univ, Med Ctr, Div Gastroenterol & Hepatol, Palo Alto, CA 94304 USA
[4] Gilead Sci, Foster City, CA USA
[5] Boston Univ, Sch Med, Boston, MA 02118 USA
[6] Rush Univ, Med Ctr, Dept Med, Chicago, IL 60612 USA
[7] Stanford Univ, Sch Med, Dept Hlth Res & Policy Epidemiol, Stanford, CA 94305 USA
[8] Stanford Univ, Sch Med, Inst Immun Transplantat & Infect Operat, Stanford, CA 94305 USA