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

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 fo