Stable pediatric kidney transplant recipients run higher urine indoleamine 2, 3 dioxygenase (IDO) levels than healthy children.
Immune cells utilize the IDO enzymatic conversion of trp to kyn to determine T-cell activation vs. anergy/apoptosis. In prior studies, urine IDO levels were higher in rejecting renal allografts than in stable state. However, urine IDO levels in healthy subjects or children are unknown. As a corollary to a larger longitudinal and prospective study of serum and urine IDO levels for transplant immune monitoring, here, we analyzed the difference between urine IDO levels in stable post-transplant vs. healthy children. IDO levels were measured by tandem mass spectrometry and expressed as kyn/trp ratios. We compared one-time urine samples, from 34 well children at general pediatric clinics, to the first-month post-transplant urine samples from 18 children, while in stable state (no acute rejection or major infection event in next 30 days). Urine kyn/trp ratios were significantly higher in stable children in first-month post-kidney transplant (median 16.6, range 3.9-44.0) vs. healthy children (median 9.2, range 3.51-17.0; p = 0.0057 by nonparametric Mann-Whitney test). Higher urine IDO levels even with stable transplant suggest a continuous ongoing low-grade allorecognition/inflammatory process. Our data also provide baseline urine IDO levels in healthy subjects for use in future studies.
College of Medicine, University of Florida, Gainesville, FL, USA.
Eihab
E
Al Khasawneh
Sushil
S
Gupta
Sanjeev Y
SY
Tuli
Amir H
AH
Shahlaee
Timothy J
TJ
Garrett
Kenneth B
KB
Schechtman
Vikas R
VR
Dharnidharka
D000293:Adolescent; D000906:Antibodies / Q000276:immunology; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D007165:Immunosuppression Therapy / Q000379:methods; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000652:urine*; D016030:Kidney Transplantation / Q000379:methods*; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D051437:Renal Insufficiency / Q000601:surgery* / Q000652:urine*; D066027:Transplant Recipients
D000906:Antibodies; D006680:HLA Antigens; D007166:Immunosuppressive Agents; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase
indoleamine 2, 3 dioxygenase; pediatric; transplant; urine