Kidney transplant rejection remains a significant challenge to long-term graft survival. While histological biopsy continues to be the gold standard for diagnosing rejection, noninvasive biomarkers such as donor-derived cell-free DNA (dd-cfDNA) have gained traction for their ability to detect allograft injury. However, dd-cfDNA may lack sensitivity in certain clinical scenarios particularly in cases of localized immune activation leading to false negatives despite biopsy-confirmed rejection.
One promising biomarker is CXCL10 (C-X-C motif chemokine ligand 10), a chemokine induced by interferon-γ that plays a central role in recruiting CXCR3+ T cells during immune responses. A 2021 study by Arnau et al. found that urinary CXCL10 levels were significantly associated with Banff scores of acute graft injury and donor-specific antibodies, and could discriminate both T-cell-mediated and antibody-mediated rejection in kidney transplant recipients, identifying CXCL10 as a promising candidate non-invasive biomarker for monitoring allograft rejection.
Study Type
OBSERVATIONAL
Enrollment
50
Subjects for this cohort will be selected from existing research database and criteria include: hx of kidney transplantation, clinically indicated biopsy, positive histology, \<1% circulating donor-derived cell-free DNA (dd-cfDNA) result at the time of biopsy, and Availability of frozen urine samples.
Subjects for this cohort will be selected based on ability to provide urine sample, recent kidney transplant recipient and underwent a clinically indicated biopsy
Virginia Commonwealth University
Richmond, Virginia, United States
RECRUITINGAssess urinary CXCL10 compared to dd-cfDNA for diagnosing acute rejection in kidney transplant recipients
Assess whether urinary CXCL10 concentration (pg/mL) demonstrates improved sensitivity compared to donor-derived cell-free DNA (dd-cfDNA) for diagnosing acute rejection in kidney transplant recipients, specifically among discordant cases with biopsy-confirmed rejection and dd-cfDNA levels below 1%. Urine sample collected prospectively, during clinically indicated biopsy visit. Urine sample collected retrospectively, during clinically indicated retrospective biopsy visit.
Time frame: From date of inclusion until loss of follow-up, graft loss or death assessed up to 5 years.
Assess the stability of urinary CXCL10 under different transport conditions
Assess the stability of urinary CXCL10 (percent recovery) under different transport conditions-refrigerated, and ambient (room temperature)-to determine whether ambient shipping is a viable alternative to cold-chain transport for clinical testing. Urine sample collected prospectively, during clinically indicated biopsy visit. Urine sample collected retrospectively, during clinically indicated retrospective biopsy visit.
Time frame: From date of inclusion until loss of follow-up, graft loss or death assessed up to 5 years.
Compare urinary CXCL10 concentrations to assess potential degradation or variability.
Compare urinary CXCL10 concentrations across the two transport conditions to assess potential degradation or variability. * Mean absolute difference (pg/mL) * Coefficient of variation (CV) * Bland-Altman plots to assess agreement Urine sample collected prospectively, during clinically indicated biopsy visit. Urine sample collected retrospectively, during clinically indicated retrospective biopsy visit.
Time frame: From date of inclusion until loss of follow-up, graft loss or death assessed up to 5 years.
Determine whether ambient shipping (urine sample) affects the clinical reliability of CXCL10 measurements
Determine whether ambient shipping (urine sample) affects the clinical reliability of CXCL10 measurements * CXCL10 results dichotomized using predefined clinical thresholds * Percent agreement and Cohen's kappa statistic calculated between transport conditions Urine sample collected prospectively, during clinically indicated biopsy visit. Urine sample collected retrospectively, during clinically indicated retrospective biopsy visit.
Time frame: From date of inclusion until loss of follow-up, graft loss or death assessed up to 5 years.
Assess the feasibility of implementing ambient (urine sample) shipping as a cost-effective alternative
Assess the feasibility of implementing ambient (urine sample) shipping as a cost-effective alternative to current cold-chain methods. * Proportion of samples meeting laboratory acceptance criteria * Shipping duration summarized in hours from collection to laboratory receipt Urine sample collected prospectively, during clinically indicated biopsy visit. Urine sample collected retrospectively, during clinically indicated retrospective biopsy visit.
Time frame: From date of inclusion until loss of follow-up, graft loss or death assessed up to 5 years.
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