ACE2 and inflammatory bowel disease: Our study identified the ACE2 expression with the public database and then validated RNA and protein expression using clinical samples from two independent cohorts including China and the UK aiming to determine the alter expression of intestinal ACE2 especially in enterocytes before and after biologic therapy including anti-tumor necrosis factor α (anti-TNFα), anti-integrin and anti-interleukin (IL) 12/23 in IBD patients.