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NCT Number: NCT07347769

Study of the Serotype and Genotype of BK Virus in Kidney Transplant Recipients and Their Donors to Identify Individuals at Risk of Nephropathy

The aim of this observational study is to characterize the urinary replication of BK polyomavirus (BKV) in kidney transplant recipients. Although BKV reactivation after transplantation is well established, the origin of the replicating virus remains uncertain. Current evidence suggests that BKV detected in recipients may originate either from the transplanted kidney (donor-derived) or from viral reactivation in the recipient. The evaluation of new biomarkers to predict BKV replication are needed.

This study seeks to address the following key questions:

* Origin of the replicating virus: Is the BKV detected in the recipient identical to the virus originating from the donor kidney? * Host immune response and viral genotype: Is there an association between the recipient's immune response and the genotype of the replicating BKV? * Differences in immune response according to viral replication profile: Does the immune response differ between patients presenting isolated BKV viruria and those with both viruria and viremia? * Can new biomarkers help predict BKV replication and viremia?

Patients will be grouped according to their BKV replication profile:

Group 1: patients with BKV viruria without viremia Group 2: patients with both BKV viruria and viremia Comparisons between these two groups will help identify whether different viral genotypes or immune responses are associated with systemic dissemination (viremia).

Kidney transplant recipients will be included if they present BKV viruria during their post-transplant follow-up. Additional blood samples will be collected during scheduled follow-up visits at the university hospital. These visits are part of routine clinical care, and no extra visits will be required specifically for the study.

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Key information

Conditions

Nephropathy BK Nephropathy BK Polyomavirus BK Viremia; BKV DNAemia BK Virus Infection Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Immune Response Kidney Diseases Male Urogenital Diseases Neutralizing Antibodies Opportunistic Viral Infection Polyoma Virus Nephropathy Urogenital Diseases Urologic Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Kidney transplant patients with a first positive BK virus viral load in urine. - BK virus viral load in urine > 3 log copies/mL.
  • More than 3 months post-transplant and less than 2 years post-transplant.
  • Men or women aged 18 years and older.
  • Followed up at Grenoble Alpes University Hospital.
  • Affiliated with social security or beneficiary of such a scheme.
  • Patients who are not opposed to the TYPIK study.

Exclusion criteria

  • Expected renal graft survival is < 6 months, estimated by an eGFR < 15 mL/min/1.73 m² at the time of BKPyV viruria
  • Patients who object to the use of their data and/or samples for research purposes
  • Subjects who are excluded from another study
  • Subjects under administrative or judicial supervision

Treatment and study plan

Primary outcomes

  1. To describe the prevalence and variability of different BKPyV genotypes and serotypes in a population of kidney transplant patients with BKPyV viruria/viremia.

    Time frame: up to 2 years

    The primary endpoint will be the classification by genotyping/serotyping of BKPyV obtained during the first viruria and the first viremia, performed using NGS and serotyping using a seroneutralization technique. The search for SNPs (single nucleotide polymorphisms) will also enable the subclassification of genotypes and better identification of patients at risk of BKPyV viremia and therefore BKPyV-induced nephropathy.

Secondary outcomes

  1. Compare the viral genotype at the first viruria/viremia with the donor serotype and with the recipient serotype.

    Time frame: up to 2 years

    The donor serotype and recipient serotype will be obtained by seroneutralization (from I to IV) and the viral genotype at the first viremia and first viruria will be obtained by a complete sequencing technique (NGS).

  2. Describe the evolution of urinary BKPyV viral load during infection and compare viruria between viruric-only and viremic patients.

    Time frame: up to 2 years

    The urinary viral load for BKPyV will be obtained by qPCR (R-Gene) and expressed in log IU/mL at the time of inclusion in the two groups and then up to 6 months post-inclusion.

  3. Describe associations between urinary and blood BKPyV viral load and associated genotypes/the presence of a mismatch between the donor serotype and the recipient genotype.

    Time frame: up to 2 years

    Urinary viral load at inclusion and at the time of viremia (qPCR R-Gene technique in log IU/mL) and serotype mismatch obtained from serological data at the time of transplantation.

  4. Describe the associations between the waiting time until the first viremia and the presence or absence of a serotype mismatch at the time of transplantation, the genotype at the time of the first viruria, the viral load at the time of the first viruria,

    Time frame: up to 2 years

    The time will be recorded in days between the first post-transplant viruria and viremia.

  5. Compare the evolution of the anti-BKPyV T-cell functional response in patients with viruria alone and those also with viremia between inclusion and 6 months later.

    Time frame: up to 2 years

    Functional anti-BKPyV T cell response obtained by ELISpot and expressed in spots/350,000 PBMC evaluated at the time of the first viremia and the first viruria.

  6. Describe the link between the functional response and the presence of viremia, the evolution of the BKPyV viral load in the blood, and the genotype.

    Time frame: up to 2 years

    Functional anti-BKPyV T cell response obtained by ELISpot and expressed in spots/350,000 PBMC at the time of viruria and urinary and blood viral load of BKPyV by qPCR (log IU/mL)

  7. Compare the BKPyV genotype present in the renal biopsy at M3 with the urinary replicative genotype at inclusion and the donor serotype.

    Time frame: up to 2 years

    Genotyping of BKPyV in the renal biopsy at M3 and of replicative BKPyV in urine at inclusion will be provided by NGS.

    The donor serotype will be obtained by a seroneutralization technique.

  8. Quantitatively describe the presence of BKPyV microRNAs in urine and compare the two groups (viremic and viruric alone).

    Time frame: up to two years

    The presence of BKPyV microRNA will be obtained by qPCR and given in copies/mL just before inclusion and during viruria

  9. Describe the link between the quantity of BKPyV microRNAs and the replicative genotype.

    Time frame: up to 2 years

    BKPyV microRNA will be obtained by qPCR and given in copies/mL just before inclusion and genotyping of BKPyV in urine during the first viremia

  10. Quantitatively describe the presence of urinary chemokines and compare the two groups (viremic and viruric alone).

    Time frame: up to 2 years

    The amount of chemokine obtained by ELISA will be given in µg/mL and will be obtained at all visits.

  11. Describe the link between the quantity of B-KPyV chemokines at inclusion and the replicative genotype.

    Time frame: up to 2 years

    Obtaining urinary chemokine concentrations at inclusion in µg/mL and genotyping of BKPyV in urine at inclusion

  12. Monitor the number of BKV viruria or viremia depending on the immunosuppressive treatment received.

    Time frame: up to 2 years

    Type of immunosuppressant and blood concentration of these at the time of viremia/viruria

  13. Comparison of number of positive ELISpot in group with and without viremia (identify risk factor of viremia)

    Time frame: up to 2 years

    Occurrence of viremia in days relative to transplantation, number of spots on ELISpot during first viremia (BKPyV microRNA in copies/mL, serotyping of donor and recipient, and genotyping in recipient's urine)

  14. Comparison of SV40 immunohistochemistry staining results and BKPyV PCR results on M3 biopsy

    Time frame: up to 2 years

    Estimate the proportion of concordances between SV40 positivity in immunohistochemistry and BKPyV PCR on the M3 biopsy (copies/µg DNA) (pos/pos; pos/neg; neg/neg; neg/pos)

Study contacts

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

Aurélie TRUFFOT, PHD

CONTACT

[email protected]

0786498337

Sponsors and collaborators

Lead sponsor

University Hospital, Grenoble

Other

Registry information

Acronym: TYPIK

Important dates

Study start
2026
Primary completion
2028
Study completion
2030
First posted
Jan 16, 2026
Registry last updated
May 27, 2026

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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