ACE2 and immune system disorder: On the other hand, while ACE2 mRNA expression in the colon is induced by inflammation, and while enhanced expression of colon ACE2 mRNA does not reduce the efficacy of pharmacological treatments in IBD patients [42], the fact that CD patients harboring a higher expression of ACE2 mRNA seem to develop a more aggressive disease [41] and are at higher risk for surgery [41], suggests that ACE2 could be considered a potential biomarker of inflammation and immune dysfunction in IBD.