Waichi Wong

HLA-Mismatched Renal Transplantation without Maintenance Immunosuppression

Five patients with end-stage renal disease received combined bone marrow and kidney transplants from HLA single-haplotype mismatched living related donors, with the use of a nonmyeloablative preparative regimen. Transient chimerism and reversible capillary leak syndrome developed in all recipients. Irreversible humoral rejection occurred in one patient. In the other four recipients, it was possible to discontinue all immunosuppressive therapy 9 to 14 months after the transplantation, and renal function has remained stable for 2.0 to 5.3 years since transplantation. The T cells from these four recipients, tested in vitro, showed donor-specific unresponsiveness and in specimens from allograft biopsies, obtained after withdrawal of immunosuppressive therapy, there were high levels of P3 (FOXP3) messenger RNA (mRNA) but not granzyme B mRNA.

Outcome of Kidney Transplantation Using Expanded Criteria Donors and Donation After Cardiac Death Kidneys: Realities and Costs

Expanded criteria donors (ECDs) and donation after cardiac death (DCD) provide more kidneys in the donor pool. However, the financial impact and the long‐term benefits of these kidneys have been questioned. From 1998 to 2005, we performed 271 deceased donor kidney transplants into adult recipients. There were 163 (60.1%) SCDs, 44 (16.2%) ECDs, 53 (19.6%) DCDs and 11 (4.1%) ECD/DCDs. The mean follow‐up was 50 months. ECD and DCD kidneys had a significantly higher incidence of delayed graft function, longer time to reach serum creatinine below 3 (mg/dL), longer length of stay and more readmissions compared to SCDs. The hospital charge was also higher for ECD, ECD/DCD and DCD kidneys compared to SCDs, primarily due to the longer length of stay and increased requirement for dialysis (

Prevalence and significance of anti-HLA and donor-specific antibodies long-term after renal transplantation

70 030,

Tracking donor-reactive T cells: Evidence for clonal deletion in tolerant kidney transplant patients

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B-Cell Immunity in the Context of T-Cell Tolerance after Combined Kidney and Bone Marrow Transplantation in Humans

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Chronic humoral rejection of human kidney allografts associates with broad autoantibody responses.

47 462, respectively, p < 0.001). Early graft survival rates were comparable among all groups. However, after a mean follow‐up of 50 months, graft survival was significantly less in the ECD group compared to other groups. Although our observations support the utilization of ECD and DCD kidneys, these transplants are associated with increased costs and resource utilization. Revised reimbursement guidelines will be required for centers that utilize these organs.

Acute Renal Endothelial Injury During Marrow Recovery in a Cohort of Combined Kidney and Bone Marrow Allografts

Post‐transplant circulating anti‐human leukocyte antigens (HLA)‐antibodies and C4d in allograft biopsies may be important in chronic rejection in renal transplant recipients (RTR). We determined the prevalence and significance of anti‐HLA‐antibodies and donor‐specific antibodies (DSA). Sera were collected from 251 RTR >6 months post‐transplant. Sera were tested using enzyme‐linked immunosorbent assay (ELISA) screening for anti‐HLA antibodies. Positive sera were retested with ELISA‐specific panel for antibody specificity. A 11.2% of patients had anti‐HLA antibodies and 4.4% had DSA. Anti‐HLA antibodies were significantly associated with pretransplant sensitization, acute rejection and in multivariate analysis, higher serum creatinine (2.15 ± 0.98 vs. 1.57 ± 0.69 mg/dl in negative anti‐HLA antibodies group). Allograft biopsies performed in a subset of patients with anti‐HLA antibodies revealed that 66% had C4d in peritubular capillaries (0% in patients without antibodies). Anti‐HLA antibodies were associated with a worse allograft function and in situ evidence of anti‐donor humoral alloreactivity. Long‐term RTR with an increase in creatinine could be screened for anti‐HLA antibodies and C4d in biopsy.

2005 immunosuppressive strategies in kidney transplantation: which role for the calcineurin inhibitors?

Clonal deletion is a mechanism of graft tolerance after combined kidney and bone marrow transplantation in humans. Tolerating transplant Transplant rejection remains a formidable barrier to successful organ transplantation. Recent advances, such as combined kidney and bone marrow transplantation (CKBMT), hint that rejection can be overcome by the induction of immune tolerance. Now, Morris et al. have developed a way to track T cells to determine how this tolerance works. They used high-throughput T cell receptor sequencing to find donor-reactive T cells before transplant and then tracked these clones after CKBMT. These donor-reactive T cells were reduced in CKBMT patients who achieved tolerance but not in a CKBMT patient who failed to achieve tolerance or in recipients of conventional, nontolerizing transplant protocols. These data suggest that clonal deletion is a mechanism of graft tolerance after CKBMT in humans. T cell responses to allogeneic major histocompatibility complex antigens present a formidable barrier to organ transplantation, necessitating long-term immunosuppression to minimize rejection. Chronic rejection and drug-induced morbidities are major limitations that could be overcome by allograft tolerance induction. Tolerance was first intentionally induced in humans via combined kidney and bone marrow transplantation (CKBMT), but the mechanisms of tolerance in these patients are incompletely understood. We now establish an assay to identify donor-reactive T cells and test the role of deletion in tolerance after CKBMT. Using high-throughput sequencing of the T cell receptor B chain CDR3 region, we define a fingerprint of the donor-reactive T cell repertoire before transplantation and track those clones after transplant. We observed posttransplant reductions in donor-reactive T cell clones in three tolerant CKBMT patients; such reductions were not observed in a fourth, nontolerant, CKBMT patient or in two conventional kidney transplant recipients on standard immunosuppressive regimens. T cell repertoire turnover due to lymphocyte-depleting conditioning only partially accounted for the observed reductions in tolerant patients; in fact, conventional transplant recipients showed expansion of circulating donor-reactive clones, despite extensive repertoire turnover. Moreover, loss of donor-reactive T cell clones more closely associated with tolerance induction than in vitro functional assays. Our analysis supports clonal deletion as a mechanism of allograft tolerance in CKBMT patients. The results validate the contribution of donor-reactive T cell clones identified before transplant by our method, supporting further exploration as a potential biomarker of transplant outcomes.

Comparison of two dosages of thymoglobulin used as a short‐course for induction in kidney transplantation

Five patients with end‐stage kidney disease received combined kidney and bone marrow transplants from HLA haploidentical donors following nonmyeloablative conditioning to induce renal allograft tolerance. Immunosuppressive therapy was successfully discontinued in four patients with subsequent follow‐up of 3 to more than 6 years. This allograft acceptance was accompanied by specific T‐cell unresponsiveness to donor antigens. However, two of these four patients showed evidence of de novo antibodies reactive to donor antigens between 1 and 2 years posttransplant. These humoral responses were characterized by the presence of donor HLA‐specific antibodies in the serum with or without the deposition of the complement molecule C4d in the graft. Immunofluorescence staining, ELISA assays and antibody profiling using protein microarrays demonstrated the co‐development of auto‐ and alloantibodies in these two patients. These responses were preceded by elevated serum BAFF levels and coincided with B‐cell reconstitution as revealed by a high frequency of transitional B cells in the periphery. To date, these B cell responses have not been associated with evidence of humoral rejection and their clinical significance is still unclear. Overall, our findings showed the development of B‐cell allo‐ and autoimmunity in patients with T‐cell tolerance to the donor graft.

Slowing the progression of chronic allograft nephropathy by conversion from cyclosporine to tacrolimus: a randomized controlled trial.

Background. Chronic humoral rejection (CHR) is a major complication after kidney transplantation. The cause of CHR is currently unknown. Autoantibodies have often been reported in kidney transplant recipients alongside antidonor human leukocyte antigen antibodies. Yet, the lack of comprehensive studies has limited our understanding of this autoimmune component in the pathophysiology of CHR. Methods. By using a series of ELISA and immunocytochemistry assays, we assessed the development of autoantibodies in 25 kidney transplant recipients with CHR and 25 patients with stable graft function. We also compared the reactivity of five CHR and five non-CHR patient sera with 8027 recombinant human proteins using protein microarrays. Results. We observed that a majority of CHR patients, but not non-CHR control patients, had developed antibody responses to one or several autoantigens at the time of rejection. Protein microarray assays revealed a burst of autoimmunity at the time of CHR. Remarkably, microarray analysis showed minimal overlap between profiles, indicating that each CHR patient had developed autoantibodies to a unique set of antigenic targets. Conclusion. The breadth of autoantibody responses, together with the absence of consensual targets, suggests that these antibody responses result from systemic B-cell deregulation.