The role of splenectomy in the setting of refractory humoral rejection after kidney transplantation

Early Versus Late Acute Antibody-Mediated Rejection Among Renal Transplant Recipients in Terms of Response to Rituximab Therapy: A Single Center Experience

OBJECTIVES

There are no comparable trials concerning the use of rituximab among renal transplant recipients with acute antibody-mediated rejection. Here, we compared early and late acute antibody-mediated rejection in renal transplant recipients in terms of response to rituximab therapy.

MATERIALS AND METHODS

Of 1230 kidney transplants performed at Hamed Al-Essa Organ Transplant Center (Kuwait) over the past 10 years, 103 recipients developed acute antibody-mediated rejections and were subcategorized into 4 groups according to the onset of rejection and rituximab treatment. All patients received the standard treatment for acute antibody-mediated rejection according to our protocol (plasma exchange and intravenous immunoglobulin). We added rituximab to the treatment regimen in 2 groups of patients: 27 patients with early rejection (group 1) and 38 patients with late rejection (group 2). Groups 3 and 4 represented nonrituximab groups, with 20 patients with early (group 3) and 18 patients with late rejection (group 4). We compared the 4 groups regarding graft and patient outcomes.

RESULTS

All patients were comparable regarding patient age, sex, pretransplant type of dialysis, viral profile, type of induction, donor criteria, and pretransplant comorbidities. We observed that delayed and slow graft function were significantly higher in groups 1 and 3 (P = .016); however, we found no significant differences in the 4 groups regarding new-onset diabetes after transplant, BK viral infection, and malignancy. Graft outcomes were significantly better in groups 1 and 2 than in groups 3 and 4 (P = .028). However, patient outcomes were comparable in the 4 groups (P > .05).

CONCLUSIONS

Early acute antibody-mediated rejection in renal transplant recipients had significantly better outcomes when rituximab was added to the standard treatment regimen.

Impact of donor-specific antibodies on the outcomes of kidney graft: Pathophysiology, clinical, therapy

Allo-antibodies, particularly when donor specific, are one of the most important factors that cause both early and late graft dysfunction. The authors review the current state of the art concerning this important issue in renal transplantation. Many antibodies have been recognized as mediators of renal injury. In particular donor-specific-Human Leukocyte Antigens antibodies appear to play a major role. New techniques, such as solid phase techniques and Luminex, have revealed these antibodies from patient sera. Other new techniques have uncovered alloantibodies and signs of complement activation in renal biopsy specimens. It has been acknowledged that the old concept of chronic renal injury caused by calcineurine inhibitors toxicity should be replaced in many cases by alloantibodies acting against the graft. In addition, the number of patients on waiting lists with preformed anti-human leukocyte antigens (HLA) antibodies is increasing, primarily from patients with a history of renal transplant failure already been sensitized. We should distinguish early and late acute antibody-mediated rejection from chronic antibody-mediated rejection. The latter often manifets late during the course of the post-transplant period and may be difficult to recognize if specific techniques are not applied. Different therapeutic strategies are used to control antibody-induced damage. These strategies may be applied prior to transplantation or, in the case of acute antibody-mediated rejection, after transplantation. Many new drugs are appearing at the horizon; however, these drugs are far from the clinic because they are in phase I-II of clinical trials. Thus the pipeline for the near future appears almost empty.

Acute Antibody-Mediated Rejection in Renal Transplantation: Current Clinical Management

Acute antibody mediated rejection (AMR) is recognized as a major cause of graft loss in renal transplant recipients. Early acute AMR in the first few days after transplantation occurs primarily in sensitized renal transplant recipients with donor-specific alloantibody at the time of transplant and is a relatively "pure" form of acute AMR. Late acute AMR occurs months to years after transplantation and is commonly a mixed cellular and humoral rejection. While there is no consensus regarding optimum treatment, we contend that rational therapeutic approaches are emerging and the acute episode can be managed in most instances. However, new therapies are needed to prevent ongoing chronic injury in these patients.

Issues in solid-organ transplantation in children: translational research from bench to bedside

In this review, we identify important challenges facing physicians responsible for renal and cardiac transplantation in children based on a review of the contemporary medical literature. Regarding pediatric renal transplantation, we discuss the challenge of antibody-mediated rejection, focusing on both acute and chronic antibody-mediated rejection. We review new diagnostic approaches to antibody-mediated rejection, such as panel-reactive antibodies, donor-specific cross-matching, antibody assays, risk assessment and diagnosis of antibody-mediated rejection, the pathology of antibody-mediated rejection, the issue of ABO incompatibility in renal transplantation, new therapies for antibody-mediated rejection, inhibiting of residual antibodies, the suppression or depletion of B-cells, genetic approaches to treating acute antibody-mediated rejection, and identifying future translational research directions in kidney transplantation in children. Regarding pediatric cardiac transplantation, we discuss the mechanisms of cardiac transplant rejection, including the role of endomyocardial biopsy in detecting graft rejection and the role of biomarkers in detecting cardiac graft rejection, including biomarkers of inflammation, cardiomyocyte injury, or stress. We review cardiac allograft vasculopathy. We also address the role of genetic analyses, including genome-wide association studies, gene expression profiling using entities such as AlloMap®, and adenosine triphosphate release as a measure of immune function using the Cylex® ImmuKnow™ cell function assay. Finally, we identify future translational research directions in heart transplantation in children.

Four-year allograft survival in a highly sensitized combined liver-kidney transplant patient despite unsuccessful anti-HLA antibody reduction with rituximab, splenectomy, and bortezomib

Although donor-specific lymphocytotoxic antibodies are regarded as a contraindication for kidney transplantation (KTx), the data available for liver or combined liver or kidney transplantation (cLKTx) are scarce. Here, we report a case of a highly sensitized young man receiving his sixth liver and second kidney graft. Multiple anti-HLA antibodies were present at the time of transplantation. As a result of suspected antibody-mediated graft damage, the patient was treated with rituximab, plasmapheresis, intravenous immunoglobulins, splenectomy, and bortezomib to decrease the antibody production. So far, patient and allograft survival has reached 4 years despite failure to achieve a permanent reduction of anti-HLA antibodies, and particularly nondonor directed antibodies.