In France, 3,500 kidney transplants are carried out per year; and 40,000 people succeed in 2019 with a kidney transplant. Despite regular medical monitoring, nearly 30% of transplant patients will develop rejection. Currently, only solid biopsy of the graft makes it possible to establish the diagnosis of graft rejection, and to characterize its cellular origin based on the Banff classification. Several studies have shown the possibility of identifying the tissue origin of DNA circulating in the blood, in healthy subjects, on the basis of the epigenetic properties of circulating DNA. In addition, in kidney transplant subjects, an increase in the quantity of circulating DNA originating from the graft in the blood and urine has been shown as well as an increase in urinary chemokine levels during renal dysfunction (notably dismiss). Thus, the company CGenetix in partnership with INSERM units 1155 and 1151 is developing a method to identify and characterize kidney transplant rejection early, through the detection of epigenetic biomarkers on circulating DNA targeting different fractions of the kidney (glomerular, tubular, peritubular capillary and vascular). The main objective is to study the diagnostic performance of the quantity of DNA of renal origin in kidney transplant patients in the blood and in the urine (expressed in copies/ml) for the diagnosis of type Rejection mediated by kidneys. antibody (ABMR) established by kidney graft biopsy (gold standard) and according to the Banff 2022 classification.