Evaluation of pre- and posttransplant donor-specific transfusion/cyclosporine A in non-HLA identical living donor kidney transplant recipients. Cooperative Clinical Trials in Transplantation Research Group

Challenges, highlights, and opportunities in cellular transplantation: A white paper of the current landscape

Although cellular transplantation remains a relatively small field compared to solid organ transplantation, the prospects for advancement in basic science and clinical care remain bountiful. In this review, notable historical events and the current landscape of the field of cellular transplantation are reviewed with an emphasis on islets (allo- and xeno-), hepatocytes (including bioartificial liver), adoptive regulatory immunotherapy, and stem cells (SCs, specifically endogenous organ-specific and mesenchymal). Also, the nascent but rapidly evolving field of three-dimensional bioprinting is highlighted, including its major processing steps and latest achievements. To reach its full potential where cellular transplants are a more viable alternative than solid organ transplants, fundamental change in how the field is regulated and advanced is needed. Greater public and private investment in the development of cellular transplantation is required. Furthermore, consistent with the call of multiple national transplant societies for allo-islet transplants, the oversight of cellular transplants should mirror that of solid organ transplants and not be classified under the unsustainable, outdated model that requires licensing as a drug with the Food and Drug Administration. Cellular transplantation has the potential to bring profound benefit through progress in bioengineering and regenerative medicine, limiting immunosuppression-related toxicity, and providing markedly reduced surgical morbidity.

Is clinical tolerance realistic in the next decade?

Tolerance to allografts would mean a better quality of life and prognosis for transplant patients. Despite the first descriptions of tolerance to alloantigens over 50 years ago, deliberately induced tolerance in the clinic on a wide scale remains a goal that is not quite in reach. However, much progress has been made in understanding tolerance in rodent models and in the few reports of induced or spontaneously occurring tolerance in humans. Here, we review this progress made in the quest to achieve clinical tolerance.

Effect of donor-specific transfusions on the outcome of renal allografts in the cyclosporine era

Despite the introduction of new immunosuppressive agents, a steady decline of functioning renal allografts after living donation is observed. Thus nonpharmacological strategies to prevent graft loss have to be reconsidered, including donor-specific transfusions (DST). We introduced a cyclosporine-based DST protocol for renal allograft recipients from living-related/unrelated donation. From 1993 to 2003, 200 ml of whole blood, or the respective mononuclear cells from the potential living donor were administered twice to all of our 61 recipient candidates. The transplanted subjects were compared with three groups of patients without DST from the Collaborative Transplant Study (Heidelberg, Germany) during a 6-year period. Six patients were sensitized without delay for a subsequent cadaveric kidney. DST patients had less often treatment for rejection and graft survival was superior compared with subjects from the other Swiss transplant centers (n = 513) or from Western Europe (n = 7024). To diminish the probability that superior results reflect patient selection rather than effects of DST, a 'matched-pair' analysis controlling for relevant factors of transplant outcome was performed. Again, this analysis indicated that recipients with DST had better outcome. Thus, our observation suggests that DST improve the outcome of living kidney transplants even when modern immunosuppressive drugs are prescribed.

The critical role of Fas-Fas ligand interaction in donor-specific transfusion-induced tolerance to H-Y antigen

BACKGROUND

Donor-specific transfusion (DST) has been clinically used to enhance the survival of transplanted organs, and it has been shown in mice to induce tolerance to male (H-Y) antigen (Ag). Although the biologic mechanisms that initiate and maintain DST-induced tolerance involve clonal deletion, induction of anergy, and generation of regulatory cells, the molecules essential to tolerance induction are still unclear. In this study, we investigated the role of Fas-FasL interaction in DST-induced tolerance to H-Y Ag.

METHODS

C57BL/6 (B6) or B6-Fas(lpr) (lpr) female mice were intravenously injected with B6, lpr, or B6-FasL(gld) (gld) male spleen cells (SC). B6 male skin grafts, mixed lymphocyte reaction (MLR) assay, and cytotoxicity assay (CTL) were performed 7 days after DST. In some experiments, purified B-cells were used as transfused cells.

RESULTS

B6 female mice treated with B6 male SC permanently accepted B6 male skins, whereas untreated B6 or lpr female mice rejected B6 male skins. On the other hand, B6 female mice treated with gld male SC acceleratingly rejected male skin, as did lpr female mice treated with B6 or gld male SC. The recipient mice in the experimental groups, in which DST resulted in the accelerated rejection of the skin grafts, had strong allo-responses to H-Y Ag in MLR and CTL. Further, B6 female mice treated with gld male B-cells acceleratingly rejected male skins, whereas B6 female mice treated with B6 or lpr male B-cells from mice accepted male skins.

CONCLUSIONS

These findings suggest that the interaction between FasL upon infused SC, especially upon B-cells and Fas in a recipient, is essential in DST-induced tolerance to H-Y Ag.

Tolerance induction in clinical transplantation

Introduction of modern immunosuppressive agents has led to great success of allotransplantation in humans, and survival rates for all solid organs have been dramatically improved. However, a constant proportion of organs is lost every year due to chronic allograft rejection and immunosuppressive drug toxicity. This has led to a situation where, despite the of donor organ shortage, about one third of the patients on the kidney transplant waiting list are listed for a retransplant. The induction of donor-specific tolerance has the potential of at least partially resolving this problem, since it might prevent chronic rejection and drug toxicity at the same time. For a variety of protocols, successful tolerance induction has been demonstrated in rodent models. However, translation of such protocols to large animal models and on clinical trials has turned out to be very difficult. This review briefly describes mechanisms and barriers to transplantation tolerance, and then focuses on pre-clinical and clinical studies in non-human primates and humans. We have divided the strategies into two groups, based on the principle mechanisms of tolerance induction: the first group are protocols not using hematopoietic stem cell transplantation (HCT) as part of there regimen. They rely mainly on intensive T cell depletion (either by total body irradiation, total lymphoid irradiation or treatment with T cell-depleting agents such as anti-thymocyte globulin, anti-CD52 antibody or CD3 immunotoxin), which have been combined with costimulatory blockade, signaling blockade or donor antigen infusion. The second group are HCT-based protocols combining HCT with T cell-depleting agents and cytoreductive treatment. So far, only two protocols (one with total lymphoid irradiation and anti-thymocyte globulin, but no HCT; one with HCT, cyclophosphamide, anti-thymocyte globulin and thymic irradiation) have been translated into successful human studies. We summarize and discuss the results of these trials and suggest goals for further studies for the development tolerance protocols applicable for a broad population of allograft recipients.

Amelioration of hyperglycemia in streptozotocin-induced diabetic mice with fetal pancreatic allografts: prevention of rejection by donor specific transfusion in conjunction with CTLA4Ig

INTRODUCTION

Fetal pancreas has been considered as an alternative donor source for islet transplantation since it has potent capacity for beta cell differentiation and proliferation. However, prevention of fetal pancreatic allograft rejection can be hardly achieved compared with adult islet allografts.

AIMS

The aim of the study is to determine whether donor specific transfusion (DST) in conjunction with CTLA4Ig has any favorable effect on prevention of fetal pancreatic allograft rejection in mice.

METHODS

BALB/c splenocytes (SPC, 1 x 10) were injected iv into C57BL/6 mice in conjunction with CTLA4Ig (ip, 50 microgram, day 0, 2, and 4). Fourteen days later, the mice were made diabetic with streptozotocin (STZ, iv) and donor specific or third party pancreatic allografts were transplanted beneath the kidney capsule.

RESULTS

Morphologically, it was found that rejection of fetal pancreatic allografts can be prevented at 30 days after transplantation only when donor specific allografts were grafted into the mice treated with DST in conjunction with CTLA4Ig. Functionally, 3 out of 9 diabetic mice became normoglycemic by 120 days after transplantation of fetal pancreatic allografts.

CONCLUSION

DST in conjunction with CTLA4Ig can have a favorable effect on prevention of fetal pancreatic allograft rejection resulting in amelioration of STZ-induced diabetes in mice.

Prophylactic deoxyspergualin treatment in living-related renal-transplant recipients transfused with donor-specific blood

BACKGROUND

Deoxyspergualin (DSG) prophylaxis has improved long-term graft survival in living-related renal-transplant recipients transfused with donor-specific blood (DST). We examined the influence of acute rejection (AR) on graft survival in these patients.

METHODS

The study groups consisted of either historic control recipients without DSG (group A, n=64, 1985-1989) and recipients with DSG as the initial immunosuppressive agent (group B, n=76, 1989-1995). Both groups received DST from a one-haplotype identical donor and were treated with cyclosporine-based immunosuppression. Rejection was classified into accelerated rejection (Acc, within 5 days), AR (from 6 days-3 months), and late AR (LAR, from 4 months-1 year).

RESULTS

Overall 5-year graft survival rates were significantly higher in group B than group A (89.5 vs. 73.4%, P=0.0070). Each group was then subdivided on the basis of whether or not they had an episode of Acc, AR, or LAR. In group A, 5-year graft survival rate was not affected the presence or absence of Acc (75.0 vs. 73.1%), and it was influenced significantly by the presence or absence of AR (50.0 vs. 85.7%, P=0.0012) or LAR (46.7 vs. 81.6%, P<0.0001). In group B, 5-year graft survival did not change significantly by the presence or absence of Acc (100 vs. 88.7%), AR (81.8 vs. 92.6%), or LAR (81.0 vs. 92.7%).

CONCLUSIONS

Prophylactic use of DSG in living-related renal-transplant recipients treated with DST improves long-term graft survival, even in patients with AR episodes.

Bone marrow transfusions in cadaver renal allografts: pilot trials with concurrent controls

BACKGROUND

The safety and immune tolerance potential of donor marrow infusion with cadaveric source renal transplants was evaluated in a series of non-randomized multicenter pilot trials by the NIH Cooperative Clinical Trials in Transplantation (CCTT) Group.

PATIENTS AND METHODS

Three strategies were tested: (1) immunosuppression with cyclosporin, azathioprine and prednisone with a single post-transplant day 1 infusion of 5 x 107 viable cells/kg, (2) OKT3 induction with triple drug therapy and marrow transfusion on day 1, or (3) same therapy as (2) but with an additional marrow transfusion on day 10-12.

RESULTS

Thirty-eight marrow recipients and 35 contemporaneous controls were entered with a mean follow-up of over 5 yr. Graft survival was initially better in the marrow recipients than the controls but was similar after 5 yr. Microchimerism rates were similar for the marrow infusion and control groups throughout the follow-up period, regardless of the immunosuppression strategies.

DISCUSSION

Bone marrow infusions were well tolerated by a group of cadaver renal allograft recipients. There were no complications from the infusion(s), no episodes of graft-vs.-host disease (GVHD) and no increase in infections or other complications. There was a trend toward early improved graft survival in marrow recipients. Decreased rejection rates were observed in black recipients.

Long-term graft survival with or without donor-specific transfusion in cyclosporine era in one haplo-identical living-related renal transplant recipients beyond the first year: a 19-year experience

With improvement in immunosuppressive drugs, the beneficial role of donor-specific blood transfusion (DST) in the preconditioning of renal allograft recipients has been diminished. This retrospective study was conducted to investigate the influence of DST on long-term graft survival in successful one haplotype-mismatched kidney transplantation in the cyclosporine (CsA) era at Iwate Medical University. Between August 1983 and October 1996, 52 one haplotype-mismatched living related first renal transplants were performed. Fifty grafts survived beyond the first year after transplantation. These 50 patients were divided into two groups according to maintenance immunosuppression, 12 kidney graft recipients received azathioprine (AZA), prednisolone (PSL), CsA, and DST, and 38 recipients received AZA, PSL and CsA. Our DST protocol consisted of three transfusions of 30 ml of donor-specific buffy-coat at 4-week intervals, without immunosuppressive coverage. In recipients receiving DST and CsA, the 5-, 10-, and 13-year graft survival rates were 100%, 83%, and 67%, respectively. In recipients without DST, the 5-, 10-, and 13-year graft survival rates were 95%, 74%, and 69%, respectively. There was no significant difference between the two groups in long-term graft survival. In conclusion, DST and CsA combination treatment in our protocol may not induce long standing donor-specific immunologic hyporesponsiveness. Other strategies are expected to induce immunotolerance.