NCT06956469

BmemHLA : Origins of the Heterogeneity of the Anti-HLA Memory B Cells in Kidney Transplantation

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 75 (estimated)
• Sponsor: University Hospital, Bordeaux · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

This study will describe the transcriptomic and phenotypic characteristics of anti-HLA memory B cells by comparing five groups of patients awaiting renal transplantation: patients with a single history of pregnancy, transfusion or failure of a first renal transplant requiring transplantectomy within 3 months of transplantation, or after 3 months, and patients without an immunizing allogeneic event. The hypothesis is that these five contexts induce different types of memory B cells with different modalities of reactivation and post-transplant pathogenicity.

Detailed description

In kidney transplantation, the production of anti-HLA antibodies directed against the donor (DSA for Donor Specific Antibodies) can be responsible for humoral rejection, the main cause of long-term graft loss. Reactivation of anti-HLA memory B cells after transplantation is thought to play a major role in DSA production and the occurrence of humoral rejection. The investigators hypothesize that the nature and the function of anti-HLA memory B cells could differ depending on how they were initially generated. Several sensitizing events can lead to the production of anti-HLA memory B cells, but differ in terms of their inflammatory environment and the duration of allo-antigen exposure: pregnancy, transfusion or a previous transplantation. For the last group, the investigators want to distinguish two situations: kidney-transplanted patients that had an early transplantectomy due to thrombosis or that had an antibody-mediated rejection. Finally, patients can have anti-HLA antibodies without any sensitizing event identified. The investigators will first use an unbiased approach to test if anti-HLA memory B cells are heterogeneous. The investigators will perform single cell RNA sequencing of sorted anti-HLA B cells, identified with HLA tetramers, of five groups of patients based on their immunization histories. The investigators will further perform a phenotypic characterization of the tetramer+ anti-HLA B cells using spectral cytometry to study their nature and identify novel markers of memory subgroups.

Conditions

• Kidney Transplantation
• Immunology

Interventions

Type	Name	Description
OTHER	Identification of types of anti-HLA-specific memory LBs	Using blood sample, it will be perform single cell RNA sequencing of sorted anti-HLA B cells, identified with HLA tetramers, of five groups of patients based on their immunization histories. It will be further perform a phenotypic characterization of the tetramer+ anti-HLA B cells using spectral cytometry to study their nature and identify novel markers of memory subgroups.

Timeline

• Start date: 2025-06-15
• Primary completion: 2025-06-15
• Completion: 2028-12-15
• First posted: 2025-05-04
• Last updated: 2025-05-28