Serum levels and activity of indoleamine2,3-dioxygenase and tryptophanyl-tRNA synthetase and their association with disease severity in patients with chronic kidney disease

Objective: This study aims to test the serum levels and activity of indoleamine2,3-dioxygenase(IDO) and tryptophanyl-tRNA synthetase (ITS) in patients with chronic kidney disease (CKD) and to evaluate their association with disease severity. Method: Serum concentrations of IDO and TTS in 61 patients with CKD and 16 healthy volunteers were tested by ELISA. Tryptophan and kynurenine concentrations were measured by high-performance liquid chromatography (HPLC). Results: Patients with CKD showed higher serum levels of IDO and TTS in comparison to healthy controls (p = 0.001). Patients with CKD showed lower serum levels of tryptophan and higher serum levels of kynurenine in comparison to healthy controls (p<0.001). The kyn/Trp ratio significantly correlated with the disease severity in CKD patients (r=0.721; p<0.001). Conclusions: IDO and US may play critical roles in the immune pathogenesis of CKD. The activity of IDO correlated with the disease severity of CKD.