TY - JOUR
T1 - Asymptomatic atopy is associated with increased indoleamine 2,3-dioxygenase activity and interleukin-10 production during seasonal allergen exposure
AU - Von Bubnoff, D.
AU - Fimmers, R.
AU - Bogdanow, M.
AU - Matz, H.
AU - Koch, S.
AU - Bieber, T.
PY - 2004/7
Y1 - 2004/7
N2 - Background: Indoleamine 2,3-dioxygenase (IDO) is a tryptophan (TRP)-catabolizing enzyme with regulatory effects on T cells. T cell inhibition is achieved through both TRP depletion and TRP metabolite accumulation in specific local tissue microenvironments. The expression of IDO activity by different types of antigen-presenting cells (APCs) has been shown to play a role in many instances of immunoregulation and tolerance induction. Induction of IDO after the engagement of the high-affinity receptor for IgE, FcεRI, on atopic monocytes has been suggested to regulate T cell responses in atopic disorders. Interleukin-10 (IL-10), a cytokine known for its down-regulatory functions in the immune system, has recently been associated with the stable expression of IDO in mature tolerogenic dendritic cells. Objective: This study was devised to understand the role of systemic IDO and IL-10 in the prevention of clinical apparent allergy. Methods: The concentration of TRP and the break-down product kynurenine were measured by high-performance liquid chromatography in- and off-season in sera from patients with seasonal allergic rhinitis (n = 12) and from clinically asymptomatic atopic patients sensitized to specific aeroallergens (n = 12). Non-atopic (NA) individuals (n = 12) served as control. The concentration of plasma IL-10 was determined in parallel from these donors by ELISA in- and off-season. Results: In clinically unresponsive but aeroallergen-sensitized atopic individuals significantly higher systemic activity of IDO and increased plasma IL-10 levels were found during allergen exposure but not off-season compared to symptomatic atopic individuals with allergic rhinitis and NA individuals. Conclusion: Enhanced systemic IDO activity as well as increased systemic levels of IL-10 may contribute to the containment of allergic T cell responses and could be involved in the maintenance of a state of clinical unresponsiveness.
AB - Background: Indoleamine 2,3-dioxygenase (IDO) is a tryptophan (TRP)-catabolizing enzyme with regulatory effects on T cells. T cell inhibition is achieved through both TRP depletion and TRP metabolite accumulation in specific local tissue microenvironments. The expression of IDO activity by different types of antigen-presenting cells (APCs) has been shown to play a role in many instances of immunoregulation and tolerance induction. Induction of IDO after the engagement of the high-affinity receptor for IgE, FcεRI, on atopic monocytes has been suggested to regulate T cell responses in atopic disorders. Interleukin-10 (IL-10), a cytokine known for its down-regulatory functions in the immune system, has recently been associated with the stable expression of IDO in mature tolerogenic dendritic cells. Objective: This study was devised to understand the role of systemic IDO and IL-10 in the prevention of clinical apparent allergy. Methods: The concentration of TRP and the break-down product kynurenine were measured by high-performance liquid chromatography in- and off-season in sera from patients with seasonal allergic rhinitis (n = 12) and from clinically asymptomatic atopic patients sensitized to specific aeroallergens (n = 12). Non-atopic (NA) individuals (n = 12) served as control. The concentration of plasma IL-10 was determined in parallel from these donors by ELISA in- and off-season. Results: In clinically unresponsive but aeroallergen-sensitized atopic individuals significantly higher systemic activity of IDO and increased plasma IL-10 levels were found during allergen exposure but not off-season compared to symptomatic atopic individuals with allergic rhinitis and NA individuals. Conclusion: Enhanced systemic IDO activity as well as increased systemic levels of IL-10 may contribute to the containment of allergic T cell responses and could be involved in the maintenance of a state of clinical unresponsiveness.
UR - http://www.scopus.com/inward/record.url?scp=3242762097&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2222.2004.01984.x
DO - 10.1111/j.1365-2222.2004.01984.x
M3 - Journal articles
C2 - 15248850
AN - SCOPUS:3242762097
SN - 0954-7894
VL - 34
SP - 1056
EP - 1063
JO - Clinical and Experimental Allergy
JF - Clinical and Experimental Allergy
IS - 7
ER -
