Chronic AntiBody-Mediated Rejection (cABMR) is the leading cause of late kidney transplant loss (after 1 year of kidney transplantation). Its therapeutic management is poorly codified and there is currently no treatment referring.

Extracorporeal phototherapy (ECP) is a therapeutic apheresis that involves purifying mononucleated cells in the blood, exposing them to UltraViolet A (UVA) and re-injecting them to the patient. This treatment is used as common care in the first line as part of the treatment of cutaneous T lymphoma and in the second line as part of the graft versus host reaction after bone marrow allograft.

The mechanisms underlying the action of the ECP are not well known. They are mediated by the reinjection of cells exposed to UVA which enter apoptosis and induce immunomodulation. Recent work during cABMR shows that TFH lymphocytes, the maturing population of B lymphocytes, are deregulated and activated.

The hypothesis is that ECP can modulate T Follicular Helper (TFH) lymphocytes during cABMR.

Inclusion Criteria:

• ECP treatment decision based on transplant team habits (care management)

• Age ≥ 18 years

• Affiliation to a French social security scheme

• Kidney transplant at least 6 months prior to inclusion

• cABMR proven by a renal graft biopsy less than 3 months and meeting the following histological criteria:

  • allograft glomerulopathy (cg>0, and maximum score cg2) or intimal fibrosis
  • C4d positive or ptc+g greater than or equal to 2
  • Presence of Donor Specific Antibody (DSA)
  • Interstitial Fibrosis and Tubular Atrophy (IFTA) less than or equal to 2

• Glomerular filtration rate > 30 mL/min/1.73 m2

• Signed informed consent to participate in the study

Exclusion Criteria:

• Active infection or infection with hepatitis B, C or HIV virus
• Pregnant, breastfeeding or parturient woman
• Person deprived of liberty by judicial or administrative decision
• Person receiving psychiatric care under duress
• Person subject to legal protection
• Person out of state to express consent

Data will be shared upon reasonable request. Only de-identified data will be shared. Any data collected during the study may be shared. The protocol will be shared initially. Other documents may be shared at a later date upon request (e.g., the CRF to allow a collaborator to select the data they wish to access). The recipients of the data will be researchers. The data will be available for any purpose deemed relevant by the study investigator, based on a protocol provided by the requester, after verification of the obtaining of regulatory approvals, including the favorable opinion of an ethics committee.

The data will be shared after signing a negotiated data transfer agreement ( data access agreement), for the duration specified in the agreement.

The data will be made available via secure transfer (sharing platform approved by the university hospital: BlueFiles or Oodrive).