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NCT Number: NCT07275541

Platelet Aggregation in the Diagnosis of Acute Graft Rejection

The study titled "Platelet Aggregation in the Diagnosis of Acute Graft Rejection" is a pilot observational study evaluating whether alterations in platelet function can serve as non-invasive markers of acute rejection in kidney transplant recipients. Platelet aggregation is assessed using optical aggregometry, flow-cytometric P-selectin (CD62-P) expression, and soluble P-selectin levels before kidney transplantation and at the time of protocol biopsies performed at 3 and 12 months after kidney transplantation. Patients with suspected graft dysfunction undergoing indication biopsy are also included. Platelet activation markers are correlated with histopathological findings, donor-specific antibodies, metabolic parameters, and clinical outcomes. The goal is to determine whether platelet activation profiles can identify acute cellular or antibody-mediated rejection and contribute to the development of a non-invasive diagnostic tool.

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Key information

Conditions

Platelet Aggregation Kidney Transplant Rejection

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

About this study

Platelets play a key role not only in hemostasis but also in inflammation and immune responses. Their activation, characterized by adhesion, integrin-mediated aggregation, thromboxane A₂ production, and surface expression of markers such as P-selectin, contributes to interactions with T lymphocytes and amplification of immune signaling. Emerging evidence suggests that platelet activation may participate in early mechanisms of kidney graft injury. Studies have demonstrated platelet accumulation in glomerular and peritubular capillaries during antibody-mediated rejection, likely mediated by donor-specific antibodies and endothelial activation via von Willebrand factor. Elevated platelet activation markers such as PF4 and P-selectin have also been associated with T-cell-mediated rejection.

This pilot study investigates whether changes in platelet aggregation and platelet activation markers can serve as non-invasive indicators of acute kidney allograft rejection. Platelet function is measured using optical aggregometry, flow cytometry of P-selectin (CD62-P), and soluble P-selectin levels. These parameters are correlated with histological findings from protocol biopsies at 3 and 12 months post-transplant, as well as from indication biopsies performed for suspected rejection. The study includes adult kidney transplant recipients monitored longitudinally and a cohort of patients with graft dysfunction requiring indication biopsy. Concurrent assessments include renal function, donor-specific antibodies, levels of immunosupression (tacrolimus), metabolic parameters, and imaging. By comparing platelet activation profiles with biopsy-proven rejection, the study aims to determine whether platelet-based biomarkers can support early, non-invasive detection of cellular or antibody-mediated allograft injury and complement traditional biopsy-based diagnostics.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • adult patients (≥18 years)
  • primary kidney transplantation
  • living / deceased donor kidney transplantation
  • ability and consent to participate

Exclusion criteria

  • non-adult patients
  • secondary / tertiary kidney transplantation
  • antiplatelet therapy
  • patients unable to provide informed consent

Treatment and study plan

Primary outcomes

  1. To compare changes in platelet aggregation in patients before and after kidney transplantation

    Time frame: Pre-transplant baseline; 3 months post-transplant; 12 months post-transplant

    Platelet aggregation measured by optical aggregometry before kidney transplantation will be compared with platelet aggregation measured at 3 and 12 months after transplantation to assess changes in platelet function over time.

  2. To evaluate the changes in platelet aggregation in the diagnosis of humoral/cellular graft rejection (at the time of biopsy due to graft dysfunction)

    Time frame: At the time of indication biopsy (any time after transplantation)

    Platelet aggregation will be assessed at the time of an indication biopsy performed for graft dysfunction and compared between patients with biopsy-proven humoral or cellular rejection and those without rejection. The aim is to determine whether altered platelet aggregation is associated with acute graft rejection identified on histopathology.

  3. To investigate the use of P-selectin as a potential marker of platelet activation in the diagnosis of acute graft rejection as part of a non-invasive investigation

    Time frame: Pre-transplant baseline; at 3- and 12-month protocol biopsies; and at the time of any indication biopsy after kidney transplantation

    Flow-cytometric P-selectin (CD62-P) expression on platelets and soluble P-selectin levels in plasma will be measured before and after kidney transplantation and at the time of protocol or indication biopsy. These values will be compared between patients with and without biopsy-proven rejection to assess whether P-selectin can serve as a reliable marker of platelet activation associated with acute graft injury and support the development of a non-invasive diagnostic approach.

Study contacts

Contact information is provided by the study sponsor or research team.

Patricia Kleinova, MD

CONTACT

[email protected]

+421434203184

Timea Blichova, MD

CONTACT

[email protected]

+421434203184

Sponsors and collaborators

Lead sponsor

University Hospital, Martin

Other

Registry information

Important dates

Study start
2024
Primary completion
2026
Study completion
2027
First posted
Dec 10, 2025
Registry last updated
Dec 10, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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