Non-invasive approaches in the diagnosis of acute rejection in kidney transplant recipients. Part I.In vivoimaging methods

Abstract

Kidney transplantation (KTx) represents the best available treatment for patients with end-stage renal disease. Still, full benefits of KTx are undermined by acute rejection (AR). The diagnosis of AR ultimately relies on transplant needle biopsy. However, such an invasive procedure is associated with a significant risk of complications and is limited by sampling error and interobserver variability. In the present review, we summarize the current literature about non-invasive approaches for the diagnosis of AR in kidney transplant recipients (KTRs), including in vivo imaging, gene expression profiling and omics analyses of blood and urine samples. Most imaging techniques, like contrast-enhanced ultrasound and magnetic resonance, exploit the fact that blood flow is significantly lowered in case of AR-induced inflammation. In addition, AR-associated recruitment of activated leukocytes may be detectable by 18F-fluoro-deoxy-glucose positron emission tomography. In parallel, urine biomarkers, including CXCL9/CXCL10 or a three-gene signature of CD3ε, IP-10 and 18S RNA levels, have been identified. None of these approaches has been adopted yet in the clinical follow-up of KTRs, but standardization of procedures may help assess reproducibility and compare diagnostic yields in large prospective multicentric trials.

Diagnostic yield of 18F-FDG PET/CT imaging and urinary CXCL9/creatinine levels in kidney allograft subclinical rejection

“…The development and validation of alternative noninvasive approaches “ruling out” SCR may help avoid biopsy‐associated complications and limitations . In the present study, we confirm that the mean uCXCL9/Cr levels significantly discriminate SCR from nonrejection, with a diagnostic threshold set at 6.75 ng/mmol.…”

Observer variability in the assessment of renal 18F-FDG uptake in kidney transplant recipients

“…Still, it is associated with a substantial risk of complications, such as hemorrhage or infection 12 . Thus, non-invasive approaches have been developed over the past decades in order to help clinicians avoid potential side effects of TNB [13][14][15] . Particularly, promising preclinical and clinical observations have been reported on the role of 18 F-fluorodeoxyglucose ( 18 F-FDG) positron-emission tomography coupled with computed tomography (PET/CT) in kidney allograft AR, in both diagnosis and therapeutic monitoring [16][17][18] .…”

Page Kidney: An Unusual Complication of a Renal Transplant Biopsy

“…A high degree of suspicion for the condition and early utilization of imaging modalities, including fast and low-risk renal transplant ultrasounds, can confirm the diagnosis. While emerging noninvasive technologies [ 10 ] for rejection in the transplant kidney may reduce the need for invasive testing in the future, postprocedure monitoring should currently be considered paramount in these patients to prevent renal transplant failure.…”