In the setting of trinitro-benzene-sulfonic-acid (TNBS)-induced colitis in humanized mice, Goettel et al., demonstrated that activation of the transcription factor aryl hydrocarbon receptor (AhR)—an intracellular receptor for pollutants, toxins, and endogenous compounds—by indole-3′-carbonyl-thiazole-4-carboxylic-acid-methyl-ester, induced Tregs and this was linked to CD39 upregulation (38). Here, ENTPD1 is linked to colitis.