Peripheral and Intrarenal B Cell Study in Antibody Mediated Transplant Rejection : Phenotypic and Transcriptional Study, Study of Reactivity (B-KiMi)

Humoral rejection of kidney transplants is responsible for a large number of kidney graft losses in a context of increasing shortage.

Although it has been established that it is largely mediated by the alloreactive B lymphocyte, anti-B therapies are only partially effective.

The mechanisms behind the loss of tolerance are also poorly understood, and the triggers of rejection remain to be elucidated.

During this study, patients admitted for kidney graft biopsy for suspicion of rejection will be included ; patients presenting non inflammatory biopsies will be studied as controls. B cells will be extracted and cultured. Their antibodies will be studied along with reactivity towards HLA, non HLA targets and the gut microbiome. The same study will be led for late rejections needing graft removal : B cells extraction, culture, antibodies reactivity testing. Controls will be graft removal for non inflammatory causes. In both cases hight throughput sequencing the immunoglobulin genes will be performed.

Study Overview

• Status: Recruiting
• Conditions: Antibody Mediated Rejection After Kidney Transplantation
• Intervention / Treatment: Biological: Piece of kidney removal; Biological: Stool collection; Biological: Blood collection

• Study Type: Observational
• Enrollment (Estimated): 45

Contacts and Locations

• Study Contact: Name: Yanis TAMZALI, MD, MsC; Phone Number: +33 681402564; Email: yanis.tamzali@aphp.fr

Study Locations

• France
  • Paris, France, 75013
    • Recruiting
    • Nephrology department, Hôpital Pitié Salpêtière
    • Contact: Yanis TAMZALI, MD, MsC; Phone Number: +33 01 84 82 82 21; Email: yanis.tamzali@aphp.fr
  • Paris, France, 75020
    • Not yet recruiting
    • Nephrology department, Tenon hospital
    • Contact: Emmanuel ESTEVE; Phone Number: +33 01 56 01 54 49; Email: emmanuel.esteve@aphp.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

This study covers a population of adult kidney transplant patients admitted for biopsy or graft removal in the participating nephrology departments.

Description

Inclusion Criteria:

• Adult kidney transplant recipients admitted for biopsy or graft removal in the participating nephrology departments.
• Patient participation agreement and signed consent form
• Affiliation to a health insurance system

Exclusion Criteria:

• Confounding factor of renal inflammation: acute or recurrent pyelonephritis, BK virus nephropathy
• Pregnant or breast-feeding women
• Persons under legal protection

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
kidney biopsy or graft removal for rejection; Renal transplant recipients with suspicion of rejection or undergoing kidney biopsy or graft removal	Biological: Piece of kidney removal; removal for a piece of kidney for research purposes during biopsy or graft removal performed as part of routine care; Biological: Stool collection; Stool collection for research purposes; Biological: Blood collection; Additional blood volume for research purposes during a routine blood collection
kidney biopsy or graft removal for reasons other than rejection; Renal transplant recipients with undergoing kidney graft removal or biopsy for reansons other than rejection	Biological: Piece of kidney removal; removal for a piece of kidney for research purposes during biopsy or graft removal performed as part of routine care; Biological: Stool collection; Stool collection for research purposes; Biological: Blood collection; Additional blood volume for research purposes during a routine blood collection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Characterization of lymphocytes in humoral rejection	Using Flow cytometry analysis	Day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Analyze of gut microbiota of kidney transplant patients	Using Flow cytometry analysis	Day 1

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris

Study record dates

Study Major Dates

• Study Start (Actual): March 13, 2026
• Primary Completion (Estimated): March 13, 2029
• Study Completion (Estimated): March 13, 2029

Study Registration Dates

• First Submitted: July 8, 2025
• First Submitted That Met QC Criteria: August 19, 2025
• First Posted (Actual): August 21, 2025

Study Record Updates

• Last Update Posted (Actual): March 18, 2026
• Last Update Submitted That Met QC Criteria: March 16, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Rejection; Microbiome; Kidney transplantation; Human Leukocyte Antigen; Donor-specific antibodies
• Additional Relevant MeSH Terms: Behavior; Social Behavior; Rejection, Psychology; Investigative Techniques; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative; Blood Specimen Collection
• Other Study ID Numbers: APHP250908

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

The procedures carried out with the French data privacy authority (CNIL, Commission nationale de l'informatique et des libertés) do not provide for the transmission of the database, nor do the information and consent documents signed by the patients.

Consultation by the editorial board or interested researchers of individual participant data that underlie the results reported in the article after deidentification may nevertheless be considered, subject to prior determination of the terms and conditions of such consultation and in respect for compliance with the applicable regulations.

• IPD Sharing Time Frame: Beginning 3 months and ending 3 years following article publication. Requests out of these time frame can also be submitted to the sponsor
• IPD Sharing Access Criteria: Researchers who provide a methodologically sound proposal.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No