骨髓移植与1型糖尿病

自体和同种异体骨髓移植治疗难治性自身免疫性疾病是近年来研究的热点。1型糖尿病是最常见的器官特异性自身免疫性疾病之一,自体骨髓移植能够缓解自身免疫性胰岛炎,重建相对正常的免疫系统;而同种异体骨髓移植则不仅能纠正自身免疫状态,而且能对供者的胰岛产生特异性免疫耐受。因此,骨髓移植对1型糖尿病的防治以及胰岛移植等都具有重要的价值。     

Bone marrow cavity: a supportive environment for islet engraftment

An important goal in advancing islet transplantation for the treatment for type 1 diabetes, is to discover transplantation sites that promote long-term islet engraftment. Here, we investigate the bone marrow cavity in rats as a potential site for islet transplantation. Dark agouti streptozotocin diabetic recipients received DA islets to one of three sites: to the renal subcapsular, intrahepatic or bone marrow cavity site. Assessment of graft function was made by measuring blood glucose concentrations using a wireless continuous glucose monitoring system (CGM), performing a glucose tolerance test (GTT), and histological analysis. To determine if bone tissue secretes factors supportive to islet function and survival, human islets were cultured in the presence of osteoblast conditioned medium. Gene expression, insulin secretion and content were assessed in islets after culture. All transplant recipients with islets transplanted to the bone marrow cavity site had reversal of hyperglycemia and remained diabetes free until the end of the experiment at four months. Mean blood glucose concentrations, glucose variability and GTT, using CGM in recipients, yielded similar results between all transplantation sites. Histological assessments at four months after transplantation showed viable islets within the bone marrow space. Incubation of human islets in the presence of osteoblast conditioned medium resulted in positive changes in gene expression, insulin secretion and content. These positive changes were mediated by osteocalcin which was present in the conditioned medium. In summary, islets transplanted to the bone marrow cavity in diabetic rats showed good engraftment. In addition, the bone marrow cavity may provide an environment that is protective against post-transplant cellular stress thus increasing the chances of long-term islet function and survival.     

Bone marrow cavity: A supportive environment for islet engraftment

An important goal in advancing islet transplantation for the treatment for type 1 diabetes, is to discover transplantation sites that promote long-term islet engraftment. Here, we investigate the bone marrow cavity in rats as a potential site for islet transplantation. Dark agouti streptozotocin diabetic recipients received DA islets to one of three sites: to the renal subcapsular, intrahepatic or bone marrow cavity site. Assessment of graft function was made by measuring blood glucose concentrations using a wireless continuous glucose monitoring system (CGM), performing a glucose tolerance test (GTT), and histological analysis. To determine if bone tissue secretes factors supportive to islet function and survival, human islets were cultured in the presence of osteoblast conditioned medium. Gene expression, insulin secretion and content were assessed in islets after culture. All transplant recipients with islets transplanted to the bone marrow cavity site had reversal of hyperglycemia and remained diabetes free until the end of the experiment at four months. Mean blood glucose concentrations, glucose variability and GTT, using CGM in recipients, yielded similar results between all transplantation sites. Histological assessments at four months after transplantation showed viable islets within the bone marrow space. Incubation of human islets in the presence of osteoblast conditioned medium resulted in positive changes in gene expression, insulin secretion and content. These positive changes were mediated by osteocalcin which was present in the conditioned medium. In summary, islets transplanted to the bone marrow cavity in diabetic rats showed good engraftment. In addition, the bone marrow cavity may provide an environment that is protective against post-transplant cellular stress thus increasing the chances of long-term islet function and survival.     

Allogeneic hematopoietic chimerism in mice treated with sublethal myeloablation and anti-CD154 antibody: absence of graft-versus-host disease, induction of skin allograft tolerance, and prevention of recurrent autoimmunity in islet-allografted NOD/Lt mice

We describe a tolerance-based stem cell transplantation protocol that combines sublethal radiation with transient blockade of the CD40-CD154 costimulatory pathway using an anti-CD154 antibody. With this protocol, we established hematopoietic chimerism in BALB/c mice transplanted with fully allogeneic C57BL/6 bone marrow. The percentage of donor-origin mononuclear cells in recipients was more than 99%. In addition, all chimeric mice treated with anti-CD154 antibody remained free of graft-versus-host disease (GVHD) and accepted donor-origin but not third-party skin allografts. It was similarly possible to create allogeneic hematopoietic chimerism in NOD/Lt mice with spontaneous autoimmune diabetes. Pancreatic islet allografts transplanted into chimeric NOD/Lt mice were resistant not only to allorejection but also to recurrence of autoimmunity. We conclude that it is possible to establish robust allogeneic hematopoietic chimerism in sublethally irradiated mice without subsequent GVHD by blocking the CD40-CD154 costimulatory pathway using as few as 2 injections of anti-CD154 antibody. We also conclude that chimerism created in this way generates donor-specific allograft tolerance and reverses the predisposition to recurrent autoimmune diabetes in NOD/Lt mice, enabling them to accept curative islet allografts. (Blood. 2000;95:2175-2182)     

Bone marrow-derived stem cell transplantation for the treatment of insulin-dependent diabetes

The bone marrow is an invaluable source of adult pluripotent stem cells, as it gives rise to hematopoietic stem cells, endothelial progenitor cells, and mesenchymal cells, amongst others. The use of bone marrow-derived stem cell (BMC) transplantation (BMT) may be of assistance in achieving tissue repair and regeneration, as well as in modulating immune responses in the context of autoimmunity and transplantation. Ongoing clinical trials are evaluating the effects of BMC to preserve functional beta-cell mass in subjects with type 1 and type 2 diabetes, and to favor engraftment and survival of transplanted islets. Additional trials are evaluating the impact of BMT (i.e., mesenchymal stem cells) on the progression of diabetes complications. This article reviews the progress in the field of BMC for the treatment of subjects with insulin-dependent diabetes, and summarizes clinical data of pilot studies performed over the last two decades at our research center by combining allogeneic islet transplantation with donor-specific BMC. Clinical data is summarized from pilot studies performed at our research center over the last two decades.     

Depletion of alloantigen-primed lymphocytes overcomes resistance to allogeneic bone marrow in mildly conditioned recipients

OBJECTIVE: Successful implantation of allogeneic bone marrow (BM) cells after nonmyeloablative conditioning would allow to compensate for the inadequate supply of compatible grafts and to reduce mortality of graft-vs.-host disease (GVHD). Recently, we proposed to facilitate engraftment of mismatched BM by conditioning for alloantigen-primed lymphocyte depletion (APLD) with cyclophosphamide (CY). Here we summarize the experimental results obtained by this approach. MATERIALS AND METHODS: Naive or mildly irradiated BALB/c mice were primed with C57BL/6 BM cells (day 0), treated with CY (day 1) to deplete alloantigen-primed lymphocytes, and given a second C57BL/6 BM transplant (day 2) for engraftment. Recipients were repeatedly tested for chimerism in the blood and followed for GVHD and survival. The protocol was also tested for inducing tolerance to donor tissue and organ allografts, and for treatment of leukemia, breast cancer, and autoimmune diabetes in NOD mice. RESULTS: APLD by 200 mg/kg CY provided engraftment of allogeneic BM from the same donor in 100% mildly irradiated recipients. Eighty percent chimeras remained GVHD-free more 200 days. All chimeras accepted permanently donor skin grafts and donor hematopoietic stromal progenitors. Allogeneic BM transplantation (BMT) after APLD had a strong therapeutic potential in BALB/c mice harboring malignant cells and in autoimmune NOD recipients. Tolerance-inducing CY dose could be reduced to 100 mg/kg. Conditioning for APLD resulted in engraftment of allogeneic BM after a significantly lower radiation dose than treatment with radiation and CY alone. CONCLUSION: Our results demonstrate that conditioning for APLD has a definite advantage over general immunosuppression with CY and radiation therapy.     

Correction of infantile agranulocytosis (Kostmann's syndrome) by allogeneic bone marrow transplantation

Allogeneic bone marrow transplantation has been unsuccessful as therapy for genetically determined bone marrow disorders. In patients prepared for transplantation with drugs alone long-term hematopoietic engraftment is not achieved due to the overgrowth of the infused donor bone marrow cells by residual recipient hematopoietic stem cells. Utilizing a combination of total body irradiation and antihuman thymocyte serum, the successful eradication of the abnormal hematopoietic stem cells of patients with the Wiskott-Aldrich syndrome and now infantile agranulocytosis has been achieved. Following preparation with total body irradiation and antihuman thymocyte serum a 20 month old patient with infantile agranulocytosis has complete donor hematopoietic and lymphoid engraftment one year after a histocompatible allogeneic bone marrow transplant. Prior to transplantation, this patient had no circulating or bone marrow granulocytes; following transplantation he has normal numbers of circulating granulocytes with normal in vivo and in vitro function. This therapeutic result demonstrates that genetic disorders of myeloid function can be corrected by allogeneic bone marrow transplantation following preparation with total body irradiation and antihuman thymocyte serum, and suggests that infantile agranulocytosis is due to an intrinsic defect of the pluripotent hematopoietic stem cell and not to a micro-environmental defect.     

CD26 inhibition enhances allogeneic donor-cell homing and engraftment after in utero hematopoietic-cell transplantation

In utero hematopoietic-cell transplantation (IUHCT) can induce donor-specific tolerance to facilitate postnatal transplantation. Induction of tolerance requires a threshold level of mixed hematopoietic chimerism. CD26 is a peptidase whose inhibition increases homing and engraftment of hematopoietic cells in postnatal transplantation. We hypothesized that CD26 inhibition would increase donor-cell homing to the fetal liver (FL) and improve allogeneic engraftment following IUHCT. To evaluate this hypothesis, B6GFP bone marrow (BM) or enriched hematopoietic stem cells (HSCs) were transplanted into allogeneic fetal mice with or without CD26 inhibition. Recipients were analyzed for FL homing and peripheral-blood chimerism from 4 to 28 weeks of life. We found that CD26 inhibition of donor cells results in (1) increased homing of allogeneic BM and HSCs to the FL, (2) an increased number of injected animals with evidence of postnatal engraftment, (3) increased donor chimerism levels following IUHCT, and (4) a competitive engraftment advantage over noninhibited congenic donor cells. This study supports CD26 inhibition as a potential method to increase the level of FL homing and engraftment following IUHCT. The resulting increased donor chimerism suggests that CD26 inhibition may in the future be used as a method of increasing donor-specific tolerance following IUHCT.     

Bone marrow transplantation stimulates pancreatic β−cell replication after tissue damage

Bone marrow transplantation has been shown to normalize hyperglycemia but the mechanisms underlying pancreatic β-cell regeneration remain elusive. Here, we investigate the capacity of transplanted bone marrow cells to engraft into the pancreas, to adopt an endothelial cell phenotype and to stimulate β-cell regeneration after islet damage. Genetically marked whole bone marrow from Tie2-Cre/ZEG mice was transplanted into lethally irradiated wild-type mice. The fate of the transplanted cells, as well as blood glucose levels and β-cell mass dynamics, was investigated in normal and hyperglycemic recipient mice. Bone marrow transplantation significantly increased β-cell mass and reduced the hyperglycemia of mice subjected to β-cell damage by streptozotocin (STZ). This was associated with enhanced replication of pre-existing β-cells, proportional to the degree of β-cell damage, whereas no evidence was obtained for islet neogenesis. The engrafted bone marrow-derived cells in the pancreas showed little capacity to differentiate into blood vessel endothelium but retained a myeloid cell fate. By contrast, the transplantation evoked pronounced proliferation of recipient endothelial cells. These findings illuminate an important adjuvant function of transplanted bone marrow cells in both angiogenesis and β-cell regeneration. This may have interesting clinical implications, not least for human islet transplantation endeavours, where co-transplantation of islets with bone marrow cells might represent a simple means to improve islet survival and function.     

Cotransplantation of human stromal cell progenitors into preimmune fetal sheep results in early appearance of human donor cells in circulation and boosts cell levels in bone marrow at later time points after transplantation

Both in utero and postnatal hematopoietic stem cell (HSC) transplantation would benefit from the development of approaches that produce increased levels of engraftment or a reduction in the period of time required for reconstitution. We used the in utero model of human-sheep HSC transplantation to investigate ways of improving engraftment and differentiation of donor cells after transplantation. We hypothesized that providing a more suitable microenvironment in the form of human stromal cell progenitors simultaneously with the transplanted human HSC would result in higher rates of engraftment or differentiation of the human cells in this xenogeneic model. The results presented here demonstrate that the cotransplantation of both autologous and allogeneic human bone marrow-derived stromal cell progenitors resulted in an enhancement of long-term engraftment of human cells in the bone marrow of the chimeric animals and in earlier and higher levels of donor cells in circulation both during gestation and after birth. By using marked stromal cells, we have also demonstrated that injected stromal cells alone engraft and remain functional within the sheep hematopoietic microenvironment. Application of this method to clinical HSC transplantation could potentially lead to increased levels of long-term engraftment, a reduction in the time for hematopoietic reconstitution, and a means of delivery of foreign genes to the hematopoietic system.     

Busulfan-conditioned bone marrow transplantation results in high-level allogeneic chimerism in mice made tolerant by in utero hematopoietic cell transplantation

OBJECTIVE: In utero hematopoietic cell transplantation (IUHCT) is a non-ablative approach that achieves mixed allogeneic chimerism and donor-specific tolerance. However, clinical application of IUHCT has been limited by minimal engraftment. We have previously demonstrated in the murine model that low-level allogeneic chimerism achieved by IUHCT can be enhanced to near-complete donor chimerism by postnatal minimally myeloablative total body irradiation (TBI) followed by same-donor bone marrow transplantation. Because of concerns of toxicity related to even low-dose TBI in early life, we wondered if a potentially less toxic strategy utilizing a single myelosuppressive agent, Busulfan (BU), would provide similar enhancement of engraftment. METHODS: In this study, mixed chimerism was created by IUHCT in a fully allogeneic strain combination. After birth, chimeric mice were conditioned with BU followed by transplantation of bone marrow cells congenic to the prenatal donor. RESULTS: We demonstrate that: 1) low-level chimerism after IUHCT can be converted to high-level chimerism by this protocol; 2) enhancement of chimerism is BU dose-dependent; and 3) BU reduces the proliferative potential of hematopoietic progenitor cells thus conferring a competitive advantage to the non-BU-treated postnatal donor cells. CONCLUSION: This study confirms the potential of IUHCT for facilitation of minimally toxic postnatal regimens to achieve therapeutic levels of allogeneic engraftment.     

Bone marrow-derived mesenchymal stem cells remain host-derived despite successful hematopoietic engraftment after allogeneic transplantation in patients with lysosomal and peroxisomal storage diseases

Human bone marrow contains mesenchymal stem cells (MSCs) that can differentiate into various cells of mesenchymal origin. We developed an efficient method of isolating and culture expanding a homogenous population of MSCs from bone marrow and determined that MSCs express alpha-L-iduronidase, arylsulfatase-A and B, glucocerebrosidase, and adrenoleukodystrophy protein. These findings raised the possibility that MSCs may be useful in the treatment of storage disorders. To determine if donor derived MSCs are transferred to the recipients with lysosomal or peroxisomal storage diseases by allogeneic hematopoietic stem cell (HSC) transplantation, we investigated bone marrow derived MSCs of 13 patients 1-14 years after allogeneic transplantation. Highly purified MSCs were genotyped either by fluorescence in situ hybridization using probes for X and Y-chromosomes in gender mis-matched recipients or by radiolabeled PCR amplification of polymorphic simple sequence repeats. Phenotype was determined by the measurement of disease specific protein/enzyme activity in purified MSCs. We found that MSCs isolated from recipients of allogeneic HSC transplantation are not of donor genotype and have persistent phenotypic defects despite successful donor type hematopoietic engraftment. Whether culture expanded normal MSCs can be successfully transplanted into patients with storage diseases and provide therapeutic benefit needs to be determined.     

Allogeneic transplantation of blood-derived, T cell-depleted hemopoietic stem cells after myeloablative treatment in a patient with acute lymphoblastic leukemia

This report describes an allogeneic peripheral blood stem cell transplant in a patient who had received marrow ablative therapy. The patient was an 18-year-old white male with acute lymphocytic leukemia in third remission for whom an allogeneic bone marrow transplant was recommended. His HLA-identical sibling preferred to donate peripheral blood stem cells rather than marrow. The donor cells were collected with 10 apheresis procedures and depleted of T lymphocytes to prevent excessive graft-versus-host disease. Nine collections were cryopreserved. The patient received high-dose cytosine arabinoside and 12 Gy of total body irradiation, followed by infusion of all cryopreserved donor cells. A portion of the tenth apheresis product collected on the day of transplant containing 1.8 x 10(9) T lymphocytes was infused without further processing to approximate the number of T lymphocytes given in an allogeneic bone marrow transplant; the remainder was T lymphocyte depleted and infused. More than 1 x 10(9)/l granulocytes were present on day +11. A bone marrow biopsy on day +27 showed trilineage engraftment. Cytogenetic studies demonstrated that the recipient's marrow and peripheral blood were populated exclusively with donor cells. Allogeneic peripheral stem cell transplantation produced an early hematopoietic engraftment. Since the patient died on day +32, sustained engraftment could not be evaluated.     

Bone marrow transplantation for the treatment of immune deficiency states

The first successful allogeneic bone marrow transplants were performed in children with severe combined immune deficiency (SCID). Bone marrow transplants for patients with SCID have been in the forefront of clinical bone marrow transplantation including the first successful use of T lymphocyte-depleted haploidentical bone marrow and matched unrelated donors. Successful bone marrow transplantation for most forms of SCID requires only the engraftment of donor lymphoid stem cells; donor hematopoietic stem cell engraftment is usually not required. The Wiskott-Aldrich syndrome was the first genetic disease involving the hematopoietic stem cell to be completely corrected by allogeneic bone marrow transplantation. The successful transplantation of Wiskott-Aldrich syndrome patients demonstrated that agents with adequate anti-lymphoid and hematopoietic stem cell activity were necessary in order to achieve complete donor lymphoid and hematopoietic stem cell engraftment. Initially, total body irradiation and now busulfan are used to ablate recipient hematopoietic stem cells, while cyclophosphamide is used to ablate recipient lymphoid stem cells. No single agent/drug is capable of eliminating both stem cell populations. Histocompatible bone marrow transplantation has a role in the treatment of patients with immune deficiency due to primary defects of the hematopoietic stem cell. The recent introduction of cytokines (gamma-interferon and granulocyte colony stimulating factor) may reduce the need for bone marrow transplantation for myeloid immune deficiency states. Initial attempts to treat patients with the acquired immune deficiency syndrome by bone marrow transplantation were limited by the lack of effective concomitant anti-viral therapy. Bone marrow transplantation for immune deficiency states continues to be in the forefront of human bone marrow transplantation.     

Donor CD4+CD25+ T cells promote engraftment and tolerance following MHC-mismatched hematopoietic cell transplantation

Allogeneic bone marrow transplantation (BMT) is a potentially curative treatment for both inherited and acquired diseases of the hematopoietic compartment; however, its wider use is limited by the frequent and severe outcome of graft-versus-host disease (GVHD). Unfortunately, efforts to reduce GVHD by removing donor T cells have resulted in poor engraftment and elevated disease recurrence. Alternative cell populations capable of supporting allogeneic hematopoietic stem/progenitor cell engraftment without inducing GVHD could increase numbers of potential recipients while broadening the pool of acceptable donors. Although unfractionated CD4(+) T cells have not been shown to be an efficient facilitating population, CD4(+)CD25(+) regulatory cells (T-reg's) were examined for their capacity to support allogeneic hematopoietic engraftment. In a murine fully major histocompatibility complex (MHC)-mismatched BMT model, cotransplantation of donor B6 T-reg's into sublethally conditioned BALB/c recipients supported significantly greater lineage-committed and multipotential donor progenitors in recipient spleens 1 week after transplantation and significantly increased long-term multilineage donor chimerism. Donor engraftment occurred without GVHD-related weight loss or lethality and was associated with tolerance to donor and host antigens by in vitro and in vivo analyses. Donor CD4(+)CD25(+) T cells may therefore represent a potential alternative to unfractionated T cells for promotion of allogeneic engraftment in clinical hematopoietic cell transplantation.     

Implanted islets in the anterior chamber of the eye are prone to autoimmune attack in a mouse model of diabetes

Aims/hypothesis

Type 1 diabetes is an autoimmune disease resulting from the destruction of insulin-producing beta cells. Along with advances in generating replacement beta cells for treating diabetes, there is also increasing demand for non-invasive tools to evaluate the recurrence of autoimmune attack on transplanted tissue. Here, we examined the anterior chamber of the eye as a potential islet transplant site, and also evaluated whether in vivo imaging of the islets transplanted in the eye could enable real-time visualisation of autoimmune processes underway in the pancreas.

Methods

Syngeneic islet equivalents were transplanted into the eye or kidney capsule of streptozotocin-induced diabetic C57BL/6 mice to compare islet dose (25–125 islet equivalents) and function across transplant sites. Autoimmune attack of syngeneic islets was evaluated in the pancreas and eye tissues of NOD and NOD-severe combined immunodeficient (SCID) mice given diabetogenic splenocytes.

Results

Islet transplantation in the eye decreased fasting plasma glucose levels and increased weight gain and survival in an islet-dose-dependent manner. Even 50 islets in the eye reduced blood glucose levels, whereas ≥200 islets were required in the kidney for a similar effect. Autoimmune destruction of pancreatic islets in the eye mirrored that in the pancreas and could be visualised in real time by non-invasive imaging.

Conclusions/interpretation

We found that far fewer islets were required to restore normoglycaemia when transplanted into the anterior chamber of the eye vs the kidney capsule. However, our results suggest that islets are not protected against autoimmune attack in the eye, making this a suitable site for visualising autoimmune processes against transplanted tissue.     

Bone marrow transplantation stimulates pancreatic β-cell replication after tissue damage

Bone marrow transplantation has been shown to normalize hyperglycemia but the mechanisms underlying pancreatic β-cell regeneration remain elusive. Here, we investigate the capacity of transplanted bone marrow cells to engraft into the pancreas, to adopt an endothelial cell phenotype and to stimulate β-cell regeneration after islet damage. Genetically marked whole bone marrow from Tie2-Cre/ZEG mice was transplanted into lethally irradiated wild-type mice. The fate of the transplanted cells, as well as blood glucose levels and β-cell mass dynamics, was investigated in normal and hyperglycemic recipient mice. Bone marrow transplantation significantly increased β-cell mass and reduced the hyperglycemia of mice subjected to β-cell damage by streptozotocin (STZ). This was associated with enhanced replication of pre-existing β-cells, proportional to the degree of β-cell damage, whereas no evidence was obtained for islet neogenesis. The engrafted bone marrow-derived cells in the pancreas showed little capacity to differentiate into blood vessel endothelium but retained a myeloid cell fate. By contrast, the transplantation evoked pronounced proliferation of recipient endothelial cells. These findings illuminate an important adjuvant function of transplanted bone marrow cells in both angiogenesis and β-cell regeneration. This may have interesting clinical implications, not least for human islet transplantation endeavours, where co-transplantation of islets with bone marrow cells might represent a simple means to improve islet survival and function.     

New strategies in allogeneic stem cell transplantation: immunotherapy using irradiated allogeneic T cells

Recipients of T cell-depleted allogeneic bone marrow transplants have increased risks of relapse and graft rejection. The addition of donor T cells to the TCD allograft will decrease the risk of graft rejection but will increase the risk of graft-versus-host disease (GVHD). Relapse of leukemia or lymphoma following allogeneic bone marrow transplantation can be successfully treated with post-transplant infusions of donor lymphocytes. A relatively small number of donor T cells can have a profound anti-tumor effect and facilitate engraftment, but has an unpredictable potential for severe GVHD. An alternative to using viable immunocompetent donor immune cells to facilitate engraftment and to treat relapsed patients are donor lymphocytes that have been treated to limit their ability to proliferate and cause GVHD. T cells treated with irradiation retain cytotoxic activity against tumor cells and host immune cells. We have tested the hypothesis that allogeneic donor T cells treated with low-dose irradiation will facilitate engraftment and mediate an anti-leukemia effect in a mouse model of bone marrow transplantation. Multiple infusions of irradiated allogeneic donor lymphocytes in the peri-transplant period had graft-enhancing activity without resulting in GVHD. Murine recipients of irradiated allogeneic splenocytes and allogeneic bone marrow had stable donor-derived hematopoiesis without a significant contribution of irradiated donor cells to the T cell compartment. Removing T cells from the allogeneic splenocytes prior to irradiation largely eliminated their graft facilitating activity. Based upon the promising results of the pre-clinical murine studies, we initiated a phase I clinical trial of multiple infusions of irradiated allogeneic lymphocytes in patients who had relapsed after allogeneic BMT. Of 12 patients treated to date on this study, three have shown objective responses of their leukemia or lymphoma to multiple infusions of irradiated donor lymphocytes. We have initiated a new phase I clinical study to test the efficacy of multiple infusions of irradiated allogeneic cytotoxic T cells to facilitate engraftment in allogeneic transplantation. Successive cohorts of patients will be transplanted with allogeneic stem cells alone, or a combination of allogeneic stem cells and increasing numbers of irradiated allogeneic T cells. Irradiated allogeneic lymphocytes that retain short-term allo-specific cytotoxicity and lack the potential for clonal expansion in vivo can be considered as a novel form of immunotherapy with defined pharmacokinetics.     

The effect of transgenic expression of TGF-beta1 on transplanted islet graft survival

BACKGROUND/AIMS: Transgenic mice expressing the active form of porcine TGF-beta1 (NOD- TGF-beta1 Tg) were completely protected from autoimmune diabetes in the NOD genetic background in our previous study. Here, we attempted to determine whether transgenic expression of TGF-beta1 in transplanted islets prevents autoimmune destruction in NOD mice. METHODOLOGY: We transplanted islets to the subcapsular region of the kidney using NOD-TGF-beta1 Tg and NOD mice as donor and recipient or vice versa. Cyclophosphamide was administered twice to streptozocin-induced diabetic females NOD-TGF-beta1 Tg or their female littermates after islet transplantation. RESULTS: All islets grafts of NOD-TGF-beta1 Tg in spontaneously diabetic NOD mice were rejected earlier than those of their littermates. Hyperglycemia was induced in all littermates, but three out of four NOD-TGF-beta1 Tg, which were STZ-induced diabetic female mice, remained normoglycemic in response to the administration of cyclophosphamide after islet transplantation. CONCLUSIONS: Our results lack direct evidence for the local paracrine TGF-beta1 to protect the transplanted islet grafts. We observed, however, prolonged survival of NOD islets grafts in diabetic NOD-TGF-beta1 Tg suggesting the protective role of transgenic TGF-beta1 to suppress the autoimmune process in our syngenic transplantation model. We are convinced that this data could help resolve many problems regarding islet transplantation for type 1 diabetes.     

同种异体胰岛移植免疫耐受的诱导

同种异体胰岛移植为1型糖尿病患者带来了治愈疾病的希望,临床应用的成功显示了胰岛移植良好的发展前景。但移植后患者需终身服用免疫抑制剂,使胰岛移植仅适合用药物难以控制的糖尿病或需进行肾移植的患者。显然,诱导免疫耐受无疑将大大扩展胰岛移植的指征,更多的1型糖尿病患者将从中得益,避免糖尿病远期并发症的发生并提高生活质量。本文综述了诱导免疫耐受、延长同种异体移植胰岛存活的最新实验进展,包括外周和中央型耐受的诱导。对一些细胞表面分子,如共刺激分子、黏附素及细胞因子受体等进行干预,均可延长移植于非自身免疫疾病背景小鼠的同种异体胰岛存活时间。去除同种异体反应性T细胞、诱导供体特异的调节性T细胞是建立外周耐受的重要途径,甚至对有抵抗耐受倾向的自身免疫性非肥胖糖尿病小鼠也有效。通过骨髓移植,结合无须清除原始粒细胞的方案,能获得造血细胞嵌合,使胰岛成功移植于自身免疫性糖尿病受体中,并尽可能减少移植物抗宿主疾病的发生。