However, after Trp loading, urinary excretion of Kyn, KA, 3-HK and XA was greatly elevated in acute AIP patients compared with controls, suggesting not only enhanced transamination of Kyn and 3-HK, but also increased production of Kyn from Trp, almost certainly by TDO activation [84]. Here, TDO2 is linked to autoimmune pancreatitis.