In France around 90,000 cases of end-stage chronic kidney disease patients treated either by dialysis (60%) or renal transplantation (just over 40%). In terms of patient survival and quality of life and also economic reasons, the goal in France is to increase renal transplantation instead of patients on dialysis. After renal transplant, two main causes of the graft loss after the first years are death of patient with functioning graft, and chronic AntiBody Mediated Rejection (ABMR). Double Filtration PlasmaPheresis (DFPP) has never been evaluated for this indication. DFPP makes it possible to treat larger volumes of plasma than plasma exchange, and essentially eliminates higher molecular weights molecules including immunoglobulins comprising DSA (donor-specific alloantibody) but also the C1q involved in the lesions of(ABMR). It is postulated that it will be more effective in treating ABMR than usual plasma exchanges. A chronic ABMR is the result of the appearance de novo production of anti-Human Leucocyte Antigen antibodies (HLA) against one or more graft antigens (DSA: donor-specific alloantibody).These DSAs will lead to accelerated arteriosclerosis in the graft vessels, which will result in rapidly progressive renal failure, usually associated with a high rate of proteinuria. Numerous studies have shown that up to 20% of renal transplant patients develop DSA within 5 years of renal transplantation. Today, no treatment has been shown to be effective in the case of chronic ABMR: the basis of treatment is the reduction/elimination of DSA ( by apheresis for example) and the prevention of its re-synthesis B lymphocytes/plasma cells of the patient (with rituximab for example). The investigators of this study propose in the context of the active ABMR demonstrated by renal biopsy to evaluate in combination with rituximab, a new apheresis technique double Plasma filtration (DFPP) instead of plasma Exchange.
Inclusion Criteria: To be enrolled into the study, subjects must meet all of the following inclusion criteria * Kidney transplantation for more than 6 months * The presence of one or more DSAs with MFI greater than 1000 * Renal Graft dysfunction with renal biopsy of humoral rejection or chronic active antibody mediated rejection lesions based on the 2017 banff score ( with/without C4d) * Written informed consent in patients Exclusion Criteria: Subjects must not be enrolled into the study if they meet any of the following exclusion criteria: * Kidney transplant for less than 6 months. * MFI\<1000 * Hemoglobin level\<110 g/l * No vascular access patients * Pre terminal histological lesions of chronic ABMR * Subject in exclusion period of another study * Pregnant women, parturient or breastfeeding * Subject under administrative or judicial control