Inclusion Criteria:

• Age ≥ 18 years

• Rouen University Hospital patient monitored in the Nephrology and Kidney Transplantation Department, registered on the national kidney transplant waiting list

• Carrier of HLA antibodies, including at least anti-HLA2, identified during the last screening

• Notion of classic immune-promoting events including at least one previous transplant or pregnancy, or absence of a known immune-promoting event (naïve patient group)

• Incompatible graft rate (IGR)

  • IGR ≥ 85% (hyperimmunized patient group with anti-HLA polyreactivity) or
  • IGR between 50% and 85% (immunized patient group with a more restricted repertoire of HLA reactivities) or
  • IGR < 50% (naïve patient group with no known history of immune-promoting events)

• Person who has read and understood the information letter and does not object Not participating in the study

• Affiliation to a social security scheme

Exclusion Criteria:

• Patients who have received rituximab in the previous year (B-cell depleting therapy)
• Patients undergoing an HLA desensitization protocol using plasmapheresis and/or rituximab
• Patients with an active infection
• Persons deprived of their liberty by an administrative or judicial decision or persons placed under judicial protection/guardianship or curatorship