Evaluating Urinary CXCL10 for Enhanced Detection of Acute Rejection in Kidney Transplant Patients With Low DD-CFDNA

Evaluating Urinary CXCL10 for Enhanced Detection of Acute Rejection in Kidney Transplant Patients With Low DD-CFDNA: Diagnostic Performance and Transport Stability Across Shipping Conditions (CLEAR-CXCL10)

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.

Prospective Inclusion Criteria:

• Age ≥18 years
• Undergoing a clinically indicated biopsy
• Able to provide informed consent
• Willing to provide a urine sample and allow access to relevant clinical

Retrospective Inclusion Criteria:

• Age ≥18 years
• Biopsy-confirmed rejection (positive histology)
• Donor-derived cell-free DNA<1% result at time of biopsy
• Availability of stored urine sample collected at time of biopsy

Exclusion Criteria (applies to both arms):

• Individuals under 18 years of age
• Individuals unable to provide informed consent (for prospective enrollment)
• Pregnant women
• Prisoners
• Adults unable to consent