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We reviewed 116 surveillance biopsies obtained approximately 1, 3, 6 and 12 months posttransplantation from 50 +XM live donor kidney transplant recipients to determine the frequency of subclinical cell-mediated rejection (CMR) and antibody-mediated rejection (AMR). Subclinical CMR was present in 39.7% of the biopsies at 1 month and >20% at all other time points. The presence of diffuse C4d on biopsies obtained at each time interval ranged from 20 to 30%. In every case, where histological and immunohistological findings were diagnostic for AMR, donor-specific antibody was found in the blood, challenging the long-held belief that low-level antibody could evade detection due to absorption on the graft. Among clinical factors, only recipient age was associated with subclinical CMR. Clinical factors associated with subclinical AMR were recipient age, positive cytotoxic crossmatch prior to desensitization and two mismatches of HLA DR 51, 52 and 53 alleles. Surveillance biopsies during the first year post-transplantation for these high-risk patients uncover clinically occult processes and phenotypes, which without intervention diminish allograft survival and function.

Most successful protocols for renal transplantation across ABO incompatible (ABOi) barriers have utilized splenectomy as part of the pre-conditioning process. We recently described successful ABOi transplantation using anti-CD20 monoclonal antibody in lieu of splenectomy. In the current study, we hypothesized that plasmapheresis (PP) and low dose CMV hyper-immunoglobulin (CMVIg) alone would be sufficient to achieve successful engraftment of ABOi kidneys. We describe four blood type incompatible patients who received live donor renal transplants from A1 (two patients), A2 (one patient), and B (one patient) donors. All patients started with antihuman globulin (AHG) phase titers of 64 or higher and were pre-conditioned with PP/CMVIg but not splenectomy or anti-CD20. All 4 patients underwent successful transplantation and have a mean current serum creatinine of 1.1 (range: 0.9-1.2). There were no episodes of antibody mediated rejection. Rapid allograft accommodation may limit the need for long-term antibody suppression provided by splenectomy or anti-CD20, thereby eliminating the added infectious risk of these modalities and removing another disincentive to ABOi transplantation.

Antibody-mediated barriers to renal transplantation, including donor specific anti-HLA and anti-blood group antibodies, have become an increasingly important issue over the last forty years as the organ shortage has continued to expand. The inevitable result of the unmet demand for compatible organs has been a continuous increase in recipient waiting times. Over the last decade, two treatment strategies have been developed to address this problem. These regimens rely on the immunomodulatory properties of intravenous immunoglobulin (IVIG) administered alone at relatively high doses, or at lower doses in combination with the non-selective depletion of antibodies from plasmapheresis. Both protocols have been successfully used for desensitization of patients with donor-specific anti-HLA antibody and have allowed for renal transplantation with excellent outcomes. The combined strategy of plasmapheresis/IVIG has also been successfully employed for renal transplantation in recipients of ABO blood group incompatible kidneys. This review will provide an overview of these therapies and their application to incompatible renal transplantation.

Context: Blood type and crossmatch incompatibility will exclude at least one third of patients in need from receiving a live donor kidney transplant. Kidney paired donation (KPD) offers incompatible donor/recipient pairs the opportunity to match for compatible transplants. Despite its increasing popularity, very few transplants have resulted from KPD., Objective: To determine the potential impact of improved matching schemes on the number and quality of transplants achievable with KPD., Design, Setting, and Population: We developed a model that simulates pools of incompatible donor/recipient pairs. We designed a mathematically verifiable optimized matching algorithm and compared it with the scheme currently used in some centers and regions. Simulated patients from the general community with characteristics drawn from distributions describing end-stage renal disease patients eligible for renal transplantation and their willing and eligible live donors., Main Outcome Measures: Number of kidneys matched, HLA mismatch of matched kidneys, and number of grafts surviving 5 years after transplantation., Results: A national optimized matching algorithm would result in more transplants (47.7% vs 42.0%, P<.001), better HLA concordance (3.0 vs 4.5 mismatched antigens; P<.001), more grafts surviving at 5 years (34.9% vs 28.7%; P<.001), and a reduction in the number of pairs required to travel (2.9% vs 18.4%; P<.001) when compared with an extension of the currently used first-accept scheme to a national level. Furthermore, highly sensitized patients would benefit 6-fold from a national optimized scheme (2.3% vs 14.1% successfully matched; P<.001). Even if only 7% of patients awaiting kidney transplantation participated in an optimized national KPD program, the health care system could save as much as $750 million., Conclusions: The combination of a national KPD program and a mathematically optimized matching algorithm yields more matches with lower HLA disparity. Optimized matching affords patients the flexibility of customizing their matching priorities and the security of knowing that the greatest number of high-quality matches will be found and distributed equitably.