Serum activity of indoleamine 2,3-dioxygenase predicts prognosis of community-acquired pneumonia.

Abstract

OBJECTIVES:

Indoleamine 2,3-dioxygenase (IDO) catalyzes the rate-limiting step of tryptophan (Trp) degradation in the kynurenine (Kyn) pathway. By depleting Trp, IDO plays a critical role in inducing immune suppression and tolerance. The aim of present study was to investigate serum IDO activity, determined by Kyn-to-Trp ratio (Kyn/Trp ratio), in community-acquired pneumonia (CAP) and to examine its clinical significance.

METHODS:

This study subjects consisted of 129 consecutive patients with CAP and 64 healthy controls. The concentrations of Kyn and Trp were measured simultaneously by liquid chromatography/electrospray ionization tandem mass spectrometry.

RESULTS:

The CAP patients had significantly higher Kyn concentrations and significant lower Trp concentrations than the controls (p < 0.0001 and p < 0.0001, respectively). Accordingly, IDO activity was significantly higher (2.4-fold) in the patients than in the controls (p < 0.0001). IDO activity correlated well with PSI (Pneumonia Severity Index) and CURB65 (p = 0.0005 and p < 0.0001, respectively). Moreover, the IDO activity and Kyn concentration were significantly higher in the nonsurvivors and were found to predict mortality in multivariate analysis.

CONCLUSIONS:

IDO activity was increased in CAP, and this activity was associated with the severity and outcome of this disease. These results suggest that IDO activity can predict prognosis of CAP.

• Authors: Yuzo Suzuki, Takafumi Suda, Koushi Yokomura, Masako Suzuki, Michio Fujie, Kazuki Furuhashi, Dai Hahimoto, Noriyuki Enomto, Tomoyuki Fujisawa, Yutaro Nakamura, Naoki Inui, Yutaka Nakano, Hirotoshi Nakamura, Kingo Chida
• Journal: The Journal of infection (J Infect) Vol. 63 Issue 3 Pg. 215-22 (Sep 2011) ISSN: 1532-2742 [Electronic] England
• PMID: 21784100 (Publication Type: Journal Article)
• Copyright: Copyright © 2011 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Chemical References

• Biomarkers
• Indoleamine-Pyrrole 2,3,-Dioxygenase
• Kynurenine
• Tryptophan

Topics

• Adult
• Aged
• Aged, 80 and over
• Biomarkers (blood)
• Community-Acquired Infections (enzymology, mortality, pathology)
• Female
• Humans
• Indoleamine-Pyrrole 2,3,-Dioxygenase (blood, metabolism)
• Kynurenine (blood, metabolism)
• Male
• Middle Aged
• Pneumonia (enzymology, mortality, pathology)
• Prognosis
• Severity of Illness Index
• Tryptophan (blood, metabolism)
• Young Adult