Indoleamine-2,3-Dioxygenase Activity in Pulmonary Tuberculosis

TB (Tuberculosis) continues to be a major health problem and there are few biomarkers for predicting prognosis. IDO (indoleamine-2,3-dioxygenase) is a potent immunoregulatory molecule that catalyzes the rate-limiting step of Trp (tryptophan) degradation in the Kyn (kynurenine) pathway. An increased SIDO (serum Indoleamine-2,3-dioxygenase) activity can be determined by serum Trp: Kyn ratio. In recent years, tryptophan metabolism and its rate limiting enzyme IDO have attracted increasing attention in the diagnosis and prognosis of infectious diseases. These studies suggest that serum IDO activity can be used as a novel prognostic maker in PTB (pulmonary tuberculosis).