Abstract
BackgroundIndoleamine 2,3-dioxygenase (IDO) is a tryptophan catalyzing enzyme. It has been suggested that it has a role in lower airway allergic inflammations, but its role in allergic rhinitis has not been investigated.ObjectiveOur aim was to evaluate the expression of IDO in the nasal mucosa of allergic rhinitis patients allergic to birch pollen during peak exposure to birch pollen allergen and compare it to non-atopic patients.MethodsIDO expression was immunohistochemically evaluated from nasal specimens obtained in- and off-season from otherwise healthy non-smoking volunteers both allergic to birch pollen (having mild or moderate allergic rhinoconjunctivitis) and non-allergic controls. Results: The IDO expression levels were low in healthy controls and remained low also in patients allergic to birch pollen. There were no differences in the expression of IDO in- and off-season in either healthy or allergic subjects.ConclusionsThere is a controversy in the role of IDO in upper and lower airways during allergic airway disease. It seems that IDO is associated to allergic inflammations of the lower airways, but does not have a local role in the nasal cavity at least in mild or moderate forms of allergic rhinitis.
Highlights
Indoleamine 2,3 dioxygenase (IDO) is an intracellular enzyme that initiates the first and rate-limiting step of tryptophan breakdown along the kynurenine pathway [1]
It seems that IDO is associated to allergic inflammations of the lower airways, but does not have a local role in the nasal cavity at least in mild or moderate forms of allergic rhinitis
The diagnosis of birch pollen-induced allergic rhinitis was based on a history of seasonal allergic rhinitis during spring, clinical examination, and skin prick test positivity
Summary
Indoleamine 2,3 dioxygenase (IDO) is an intracellular enzyme that initiates the first and rate-limiting step of tryptophan breakdown along the kynurenine pathway [1]. IDO is widely expressed in a variety of cell types including leukocytes and tumour cells [2]. The role of IDO was thought to be mainly antimicrobial by reducing the availability of the essential amino acid tryptophan in the inflammatory environment [3]. IDO is induced by interferon g (IFN-g) and other inflammatory cytokines during inflammation or as a consequence of normal tissue function [4]. IDO suppresses T cell activity and promotes T cell tolerance to further antigenic challenges, by promoting the differentiation of naïve CD4 T. Indoleamine 2,3-dioxygenase (IDO) is a tryptophan catalyzing enzyme. It has been suggested that it has a role in lower airway allergic inflammations, but its role in allergic rhinitis has not been investigated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
