New hope for kidney transplant patients: belatacept trial targets hidden rejection

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Screening inclusion criteria: * Kidney transplant recipient * Adult * De novo DSA (MFI \> 1000 using the Luminex single antigen beads assay or positive with the manufacturer criteria according to the Luminex assay) absent on the day of kidney transplantation and in the sera prior to kidney transplantation * No clinical graft dysfunction at time of DSA detection (\< 20 % variation of eGFR compared to last 3 months before detection and \< 0,5 g/g proteinuria/creatinuria ratio) * Affiliation with, or beneficiary of a Social security (national health insurance) category * Person having read and understood the information letter and signed the consent form * Women of childbearing potential with effective contraception/very-effective contraception (Cf. CTFG) (oestro-progestatives or intra-uterine device or tubal ligation) and a negative blood pregnancy test. * Women surgically sterile (absence of ovaries and/or uterus) * Postmenopausal women: confirmation diagnostic (non-medically induced amenorrhea for at least 12 months prior to the inclusion visit) 2. Randomization inclusion criteria: * Patients with active sABMR, according Banff 2019 classification, with very slight transplant glomerulogathy (cg = 0 or 1). Exclusion Criteria: 1. Screening exclusion criteria: * Minor * Specific treatment for DSA occurrence before kidney graft biopsy: IVIG or rituximab or plasmapheresis or immunoabsorption * ABO incompatible kidney transplantation * Combined transplantation * Transplant recipients who are Epstein-Barr virus (EBV) seronegative or serostatus unknown. * Hypersensitivity to the active substance or to any of the excipients - Pregnant or parturient or breastfeeding woman or absence of contraception * Person deprived of liberty by an administrative or judiciary decision or person placed under judicial protection, under guardianship or supervision * Person consenting to the research participating to another trial * Medical history or psychological or sensorial abnormality prone to inhibit the subject to understand the conditions required for his/her participation to the protocol or unable him/her to give an informed consent * No signed ICF 2. Randomization exclusion criteria: * No sABMR or chronic active sABMR (cg \> 1) on initial biopsy * History of severe opportunistic infection before randomization * Acute or chronic infection with HBV, HCV or HIV * EBV negative serology * History of post-transplant lymphoproliferative disorder.