Donor lymphocyte infusion-mediated graft-versus-leukemia effects in mixed chimeras established with a nonmyeloablative conditioning regimen: extinction of graft-versus-leukemia effects after conversion to full donor chimerism

BACKGROUND: We investigated an approach to separating graft-versus-lymphoma (GVL) effects from graft-versus-host disease (GVHD) in mice receiving a nonmyeloablative conditioning regimen allowing establishment of mixed hematopoietic chimerism. METHODS: We evaluated the ability of donor lymphocyte infusions (DLI) to mediate GVL effects without GVHD in mixed chimeras prepared with cyclophosphamide, anti-T-cell antibodies, and thymic irradiation. To examine the fate of GVH-reactive donor CD8+ T cells, we used the 2C T-cell receptor (TCR) transgenic mouse strain, which carries an Ld-specific transgenic TCR on the B6 background. RESULTS: Administration of DLI on day 35 post-BMT led to conversion from mixed to full donor chimerism and mediated a powerful GVL effect with complete protection (100% survival) against mortality induced by a host-type lymphoma (EL4) administered 7 days later (100% mortality in non-DLI controls; P<0.001). No GVHD occurred in DLI recipients. Rechallenging the surviving DLI recipients, which had converted to full chimerism, with the same tumor dose 17 weeks later led to rapid tumor mortality. Long-term DLI recipients had anti-host proliferative responses, but not CTL responses in vitro. When given as DLI together with wild-type spleen cells, marked expansion of GVH-reactive 2C CD8+ T cells was observed on day 10, followed by a marked decline in their numbers by week 10 post-DLI. CONCLUSIONS: Nonmyeloablative induction of mixed chimerism followed by administration of DLI can mediate powerful GVL effects. The late loss of DLI-mediated GVL effects may reflect the eventual loss of donor-derived GVH-reactive CTL, which occurs in association with conversion to full donor chimerism.     

基因工程Treg细胞对小鼠异基因骨髓移植后GVHD和GVL效应的影响

目的 探讨输注慢病毒载体介导的小鼠基因工程调节性T淋巴细胞(Treg细胞)对小鼠异基因骨髓移植后移植物抗宿主病(GVHD)及移植物抗白血病(GVL)效应的影响.方法 利用慢病毒载体介导,将小鼠叉状头螺旋转录因子(Foxp3)基因转导入Balb/c小鼠的CD4+CD25-T淋巴细胞,即为基因工程Treg细胞.以Balb/c小鼠为供者.C57BL/6小鼠为受者,进行异基因骨髓移植,移植当天受者接受X线直线加速器全身照射.用随机数字表法将受者分为5组,每组10只.(1)单纯照射组:经受者尾静脉输注RPMI 1640培养液0.2 ml;(2)白血病对照组:经受者尾静脉输注供者骨髓细胞5×106个+C57BL/6小鼠T淋巴细胞白血病/淋巴瘤细胞株(EL4细胞)500个;(3)移植对照组:经受者尾静脉输注供者骨髓细胞5×106个+脾细胞5×106个+EL4细胞500个;(4)工程Treg组:经受者尾静脉输注供者骨髓细胞5×106个+脾细胞5×106个+EL4细胞500个+基因工程Treg细胞5×106个;(5)空载体对照组:经受者尾静脉输注供者骨髓细胞5×106个+脾细胞5×106个+EL4细胞500个+空载体转导的CD4+CD25-T淋巴细胞5×106个.每天观察受者存活情况;记录GVHD及白血病的发生情况;各组均于小鼠濒死前取其肝脏、小肠、皮肤、脾脏等组织,进行病理学观察;取长期存活(超过60 d)受者的骨髓细胞,检测嵌合情况.结果 单纯照射组、白血病对照组、移植对照组、工程Treg组和空载体对照组小鼠存活时间分别为(10.3±1.5)d、(20.7±1.9)d、(26.0±4.3)d、(49.0±17.7)d和(24.4±4.1)d,工程Treg组小鼠存活时间明显长于其他各组,差异有统计学意义(P＜0.05).白血病对照组小鼠肝、脾组织病理切片均存在白血病细胞浸润表现,移植对照组及空载体对照组小鼠肝脏、皮肤和小肠病理切片存在GVHD病理改变,而工程Treg组长期存活小鼠各组织病理切片结构基本正常,未见GVHD及白血病细胞浸润病理表现,该组GVHD评分明显低于移植对照组及空载体对照组.结论 小鼠异基因骨髓移植时联合输注基因工程Treg细胞可有效减少GVHD的发生并保留GVL效应.     

Graft-versus-leukemia effect in minor antigen mismatched chimeras given delayed donor leucocyte infusion: immunoregulatory aspects and role of donor T and ASGM1-positive cells

BACKGROUND: Previous studies have demonstrated that delayed donor leukocyte infusion (DLI) can increase graft-versus-leukemia (GVL) without increasing graft-versus-host-disease (GVHD) in MHC mismatched bone marrow (BM) chimeras. In our report, the immune status of minor antigen mismatched BM chimeras given DLI was studied. Particularly the role of donor ASGM1 positive or T cells in the graft-versus-leukemia effect (GVL) was investigated. METHODS: AKR mice (H2k, Mls1a, Thy1.1) received TBI (9,5 Gy) and T cell-depleted (TCD) C3H (H2k, Mls2a, Thy1.2) BM alone (BM chimeras), or TCD BM together with immunocompetent C3H spleen cells at the time of BM transplantation (BM+SP chimeras), or TCD BM and 3 weeks later C3H spleen cells (DLI chimeras). Chimerism and T lymphocyte subsets were scored using FACS and anti-Thy, anti-Vbeta6, anti-IL2-beta receptor, anti-CD4, anti-CD3, and anti-CD8 mAbs. Leukemia challenge consisted of 5 x 10(6) AKR T cell lymphoma (BW4157) cells injected i.v. ASGM1 positive (ASGM1+) cells and T cells were depleted using anti-ASGM1 or anti-Thy1.2 antibodies, respectively. Immune tolerance was studied using MLR and CML tests. RESULTS: BM + SP chimeras developed acute and lethal GVHD, whereas DLI chimeras were totally free from GVHD. In DLI chimeras, host-reactive cytotoxic T cells (CTL) could not be induced and host-reactive CD8Vbeta6 cells were deleted whereas CD4Vbeta6 cells and MLR reactivity persisted temporarily. In contrast, in BM+SP chimeras, anti-host CTL were easily generated and an expansion of both host-reactive CD8Vbeta6 and CD4Vbeta6 T cells was found as well as high anti-host MLR reactivity. Depletion of either ASGM1 + cells or T cells from the DLI inoculum resulted in an abrogation of GVL reactivity, suggesting that both cell populations were involved in the protection against BW4157 leukemia. Three weeks after DLI, the GVL effect waned which correlated with the disappearance of host-reactive CD4 cells and MLR reactivity. CONCLUSION: In minor antigen mismatched BM chimeras, anti-host reactivity after DLI is characterized by (1) an absence of clinical GVHD, (2) clonal deletion of host-reactive CD8 cells, (3) an absence of anti-host CTL induction, and ( 4) a temporary persistence of host-reactive CD4 T cells and of MLR reactivity. In addition, either donor ASGM1+ cells or an interaction between these cells and T cells contribute to the GVL effect.     

A decrease in graft-vs.-host disease without loss of graft-vs.-leukemia reactivity after MHC-matched bone marrow transplantation by selective depletion of donor NK cells in vivo.

It is thought that natural killer cells may play a role in graft-vs.-host reactions after allogeneic bone marrow transplantation, but the use of NK cell-specific reagents has been limited. In this report, an NK allele-specific monoclonal antibody, anti-NK 1.1, was used to study the impact of in vivo donor NK cell depletion on GVH disease, graft-vs.-leukemia (GVL) reactivity and donor T cell chimerism after allogeneic murine BMT. AKR/J (H-2k) recipient mice were preconditioned with suboptimal irradiation (9 Gy = LD50) and transplanted with major histocompatibility complex-matched B10.BR (H-2k) BM cells with or without added spleen cells as a source of T cells. The addition of increasing numbers of spleen cells to the BM inoculum produced GVHD of varying intensities. The beneficial effect of NK depletion on GVHD was dependent on the intensity of the GVH reaction. Donor NK cell depletion had no effect on the survival of mice with severe GVHD after MHC-matched BMT (B10.BR into AKR) or after MHC-mismatched BMT (B10.BR into DBA/2; H-2k into H-2d). However, donor NK depletion increased survival of AKR hosts given sufficient B10.BR splenic T cells to induce mild-to-moderate GVHD. Ex vivo depletion of donor CD8+ T cells also reduced GVH-associated mortality, but the use of both CD8 and NK depletion offered no improvement over either alone, suggesting an interaction between CD8+ and NK 1.1+ cells. In contrast to CD8 depletion, donor NK depletion did not compromise the rapid and complete establishment of donor T cell chimerism nor the ability of chimeras to mount an effective GVL reaction. Thus, elimination of donor NK cells provides an alternate strategy for reducing GVHD without loss of GVL reactivity following MHC-matched allogeneic BMT.     

非清髓性外周血干细胞移植后白血病复发的防治

目的探讨非清髓性造血干细胞移植后白血病复发的防治。方法7例合并有其它系统疾病的白血病患者接受非清髓性外周血干细胞移植,移植后采用环孢素A及短程甲氨蝶呤预防移植物抗宿主病(GVHD),造血细胞植入后,动态检测骨髓单个核细胞嵌合体的变化,根据嵌合体状态,采用供者淋巴细胞输注(DLI),并配合环孢素A用量的调整来防治白血病复发。结果7例患者移植后造血功能得到恢复,3例移植前合并的疾病有所加重,经处理缓解,移植早期相关并发症少而轻。移植后有3例嵌合体由混合嵌合体(MC)转为完全供者型嵌合体(CC),再转为MC,伴Ph染色体阳性,DLI5~6次后Ph染色体转为阴性,嵌合体状态又转为CC,其中2例发生广泛皮肤慢性GVHD;3例的嵌合体持续为CC,无复发,其中2例接受了1次DLI,此2例在环孢素A减量过程中发生GVHD;1例的嵌合体持续为MC,虽经3次DLI,但无效,患者死于白血病复发。结论非清髓性造血干细胞移植后应动态监测嵌合体状态,采用供者淋巴细胞输注,并配合环孢素A用量的调整,对白血病的复发有一定的效果。     

Allospecific Rejection of MHC Class I‐Deficient Bone Marrow by CD8 T Cells

Avoidance of long‐term immunosuppression is a desired goal in organ transplantation. Mixed chimerism offers a promising approach to tolerance induction, and we have aimed to develop low‐toxicity, nonimmunodepleting approaches to achieve this outcome. In a mouse model achieving fully MHC‐mismatched allogeneic bone marrow engraftment with minimal conditioning (3 Gy total body irradiation followed by anti‐CD154 and T cell–depleted allogeneic bone marrow cells), CD4 T cells in the recipient are required to promote tolerance of preexisting alloreactive recipient CD8 T cells and thereby permit chimerism induction. We now demonstrate that mice devoid of CD4 T cells and NK cells reject MHC Class I‐deficient and Class I/Class II‐deficient marrow in a CD8 T cell–dependent manner. This rejection is specific for donor alloantigens, since recipient hematopoiesis is not affected by donor marrow rejection and MHC Class I‐deficient bone marrow that is syngeneic to the recipient is not rejected. Recipient CD8 T cells are activated and develop cytotoxicity against MHC Class I‐deficient donor cells in association with rejection. These data implicate a novel CD8 T cell–dependent bone marrow rejection pathway, wherein recipient CD8 T cells indirectly activated by donor alloantigens promote direct killing, in a T cell receptor–independent manner, of Class I‐deficient donor cells.     

Mixed hematopoietic chimerism allows cure of autoimmune diabetes through allogeneic tolerance and reversal of autoimmunity

Bone marrow transplantation from diabetes-resistant strains with complete replacement of the recipient immune system by the allogeneic donor has led to tolerance to donor islets and cure of diabetes in a mouse model of type 1 diabetes. However, the ability to tolerize host T-cells of diabetic NOD mice is unknown. We demonstrate that nonmyeloablative conditioning achieves mixed hematopoietic chimerism across major histocompatibility complex (MHC) barriers in spontaneously diabetic NOD mice. This conditioning preserves alloreactive and autoreactive diabetogenic host NOD T-cells, but when mixed chimerism was established, diabetic NOD mice accepted donor-type allogeneic islet grafts and were cured of diabetes, despite a significant recipient T-cell contribution. Furthermore, induction of mixed chimerism permitted acceptance of NOD islet grafts, demonstrating reversal of autoimmunity. Allogeneic bone marrow transplantation was critical for tolerization of diabetogenic and alloreactive host T-cells. Thus, mixed hematopoietic chimerism induces tolerance to donor islets and reverses established autoimmunity in diabetic NOD mice.     

Addition of cyclophosphamide to T-cell depletion-based nonmyeloablative conditioning allows donor T-cell engraftment and clonal deletion of alloreactive host T-cells after bone marrow transplantation

BACKGROUND: Bone marrow (BM) chimerism has been shown to have a beneficial effect on allograft survival. We recently found that production of donor T-cells was highly correlated with induction of tolerance in minimally conditioned chimeras. In the present studies, we demonstrate that nonmyeloablative conditioning and BM cell infusion modulate innate and adaptive host immune responses. METHODS: Chimeras were generated by bone marrow transplantation (B10.BR to B10). Recipients were preconditioned with T-cell depleting antibodies and total body irradiation with or without cyclophosphamide. Donor-specific tolerance was tested by skin grafting. RESULTS: Transfer of tolerant splenocytes to immunocompetent secondary recipients did not transfer tolerance, nor did infusion of tolerant CD4+/CD25+ T-cells into chimeras without donor T-cell production, demonstrating that linked suppression is an unlikely mechanism in tolerance induction in the context of BM cell infusion. The addition of a single dose of cyclophosphamide to the conditioning enhanced engraftment and tolerance. This was associated with production of donor T-cells and effective clonal deletion, and a significant reduction in activated recipient plasmacytoid dendritic cells (pDC) and natural killer (NK) cells. Chimeras without donor T-cell production that eventually lost their chimerism did not generate an antidonor humoral response, whereas unconditioned controls infused with similar numbers of BM cells did, indicating that infusion of donor BM cells into conditioned recipients induced immune deviation for adaptive B-cell immunity, preventing sensitization to major histocompatibility complex (MHC) alloantigens. CONCLUSIONS: These results demonstrate that recipient T-cells, pDC, and NK cells contribute to the host barrier for establishing chimerism, implicate deletional tolerance as the mechanism for total body irradiation-based nonmyeloablative conditioning for BM transplantation, and show a beneficial effect of BM cells in preventing sensitization to MHC alloantigens.     

Hematopoietic Stem Cell Engraftment and Seeding Permits Multi-Lymphoid Chimerism in Vascularized Bone Marrow Transplants

Vascularized bone marrow transplantation (VBMT) across a MHC barrier under a 7-day αβ-TCR mAb and CsA protocol facilitated multiple hematolymphoid chimerism via trafficking of the immature (CD90) bone marrow cells (BMC) between donor and recipient compartments. Early engraftment of donor BMC [BN(RT1ⁿ)] into the recipient BM compartment [LEW(RT1^l)] was achieved at 1 week posttransplant and this was associated with active hematopoiesis within allografted bone and correlated with high chimerism in the hematolymphoid organs. Two-way trafficking between donor and recipient BM compartments was confirmed by the presence of recipient MHC class I cells (RT1^l) within the allografted bone up to 3 weeks posttransplant. At 10 weeks posttransplant, decline of BMC viability in allografted bone corresponded with bone fibrosis and lack of hematopoiesis. In contrast, active hematopoiesis was present in the recipient bone as evidenced by the presence of donor-specific immature (CD90/RT1ⁿ) cells, which correlated with chimerism maintenance. Clonogenic activity of donor-origin cells (RT1ⁿ) engrafted into the host BM compartment was confirmed by colony-forming units (CFU) assay. These results confirm that hematolymphoid chimerism is developed early post-VBMT by T-cell lineage and despite allografted bone fibrosis chimerism maintenance is supported by B-cell linage and active hematopoiesis of donor-origin cells in the host BM compartment.     

非清髓性造血干细胞移植后移植物抗宿主病的临床观察

目的 观察非清髓性造血干细胞移植（NST）后移植物抗宿主病（GVHD）的发生情况。方法 将18例患者分为3组：A组为6例重型再生障碍性贫血（SAA）成人患者，行无关供者脐血造血干细胞移植；B组为5例SAA患者，行同胞供者骨髓联合外周血造血干细胞移植；C组为7例肿瘤性血液病患者，其中3例行同胞供者骨髓移植，4例行外周血造血干细胞移植。均采用以抗胸腺细胞球蛋白或抗淋巴细胞球蛋白为基础的预处理方案。A组和B组应用环孢素A（CsA）和甲泼尼龙预防GVHD，C组应用CsA和甲氨蝶呤预防GVHD。C组形成混合性嵌合体后行供者淋巴细胞输注（DLI）。结果 A组有4例形成并维持混合性嵌合体状态，1例死于真菌性败血症，1例自动出院。移植后早期，B组有3例供者型嵌合体占94％以上，并在短期内转变并维持完全供者嵌合体状态，获得无病存活，其中1例在移植后8个月发生慢性GVHD；另2例行供者千细胞输注后，1例6个月后死于继发性纵隔淋巴瘤，1例造血功能恢复。C组患者早期均形成混合性嵌合体，获得血液学部分缓解，患者DLI前无急性GVHD发生，1例于2次DLI后死于严重感染，1例失访；另5例分别经过4、3、7、5、4次DLI，全部转为完全供者型嵌合体，并获得血液学完全缓解，4例并发慢性GVHD，2例并发急性GVHD。结论 对于SAA患者，NST的临床效果较好，GVHD的发生率较低；而对于肿瘤性血液病，NST后患者的早期死亡率低，急性GVHD发生率下降，但慢性GVHD和感染的发生率较高。     

Treatment of streptozotocin-induced diabetes mellitus in rats by transplantation of islet cells from two major histocompatibility complex disparate rats in combination with intra bone marrow injection of allogeneic bone marrow cells

BACKGROUND: We have established a new method for the transplantation of allogeneic pancreatic islets obtained from two different rat strains in combination with a newly developed bone marrow transplantation (BMT) method in which bone marrow cells (BMCs) are directly injected into the bone marrow cavity (intra bone marrow BMT [IBM-BMT]). METHODS: Streptozotocin-induced diabetic Brown Norway (BN: RT1A(n)) rats were injected with fludarabine, irradiated with 5.0 Gy x 2, and BMCs from two allogeneic rat strains, Fischer 344 (F344: RT1A(1)) and PVG (PVG: RT1A(c)), were then directly injected into the bone marrow cavity (IBM-BMT). Simultaneously, approximately 600 pancreatic islets (PIs) from F344 and PVG rats were mixed and transplanted into the liver by way of the portal vein. RESULTS: All the recipients thus treated showed normoglycemia 30 days after the treatment. Hematolymphoid cells were completely reconstituted with the two donor-type cells, and immunologic tolerance to F344 and PVG major histocompatibility complex (MHC) determinants were induced. CONCLUSIONS: The transplantation of PIs from two MHC-disparate donors was completely achieved in combination with IBM-BMT, resulting in the improvement of blood glucose levels and the amelioration of diabetes mellitus.     

Bone marrow transplantation depleted of T cells followed by repletion with incremental doses of donor lymphocytes for relapsing patients with chronic myeloid leukemia: a therapeutic strategy

BACKGROUND: For patients with chronic myeloid leukemia (CML), long-term survival after stem cell transplantation requires adequate control of graft-versus-host disease (GVHD) and disease recurrence. Relapsing patients respond to donor lymphocyte infusion (DLI) but develop life-threatening complications. METHODS: Patients with CML in first chronic phase received bone marrow (n = 14) or peripheral blood progenitor cell transplants (n = 4) from HLA-identical siblings. GVHD prophylaxis was by ex vivo T-cell depletion with CAMPATH 1G. If disease recurred, donors' mononuclear cells were collected by apheresis, the CD3 samples commencing at 10(6)/kg were aliquoted at half-log increment intervals, cryopreserved, and infused until disease clearance. RESULTS: Eighteen patients (median age: 32.5 years) received transplants. All engrafted without procedure-related mortality. Fourteen patients relapsed, and 13 entered the DLI program. Two developed extensive GVHD after single schedule infusions ranging from 89x10(6) to 670x10(6) mononuclear cells/kg, and one survives in complete remission (CR). The rest, treated with incremental dose DLI, experienced no acute toxicities. One, who had developed grade III steroid-responsive GVHD, died in CR2 from opportunistic infections. Steroids reversed limited cutaneous GVHD and elevated liver enzymes in five patients. Three others developed pancytopenia, and two restored blood counts only after donor peripheral blood progenitor cell infusions. Molecular CR2 was established in 12/13 patients, occurring in 10/11 (91%) on the incremental program at a median accumulation of 67 (range: 5-166) x10(6) CD3 cells/kg. Sixteen of 18 (89%) survive at median of 854.5 days from bone marrow transplantation, 4 in CR1 and 10 in CR2 at a median disease-free survival (for remission 2) duration of 341 days. The median combined disease-free survival of the 14 patients in CR 1+2 is 660 days, with 99% average performance status. CONCLUSIONS: Escalating DLI leads to safe new molecular CR in most CML relapse patients. These results raise the possibility of using "safe" transplantation programs of T-cell depletion, that include graded DLI as prevention against disease recurrence.     

Detection of chimerism following vascularized bone allotransplantation by polymerase chain reaction using a Y-chromosome specific primer.

Chimerism following allogeneic organ transplantation is a phenomenon known to occur and be associated with development of immunologic tolerance in allotransplantation. However, little is known about graft cell migration following vascularized bone allografting. In this study, chimerism was assessed following vascularized tibia transplantation from male DA or PVG donors to female PVG rat recipients using a semi-quantitative polymerase chain reaction for the Y-chromosome. FK-506 (Tacrolimus) was administered after transplantation for immunosuppression. All immunosuppresssed PVG rat recipients of PVG bone grafts showed a high level of chimerism (1%) in the thymus, spleen, liver and cervical lymph nodes at 18 weeks post-transplant. Donor cells were also detected in the contralateral tibia and humerus. In non-immunosuppressed PVG rat recipients of DA bone grafts, donor cells were detected in the spleen in three of five rats within 2 weeks post-transplant. In these animals the bone grafts were severely rejected. In immunosuppressed PVG rat recipients of DA bone grafts, two of five, four of eight and eight of 10 rats showed low level chimerism (0.1%) in peripheral blood at 1, 12, and 18 weeks post-transplant. Six rats showed a high level of chimerism in the spleen and thymus. Histological studies revealed no rejection findings through 18 weeks post-transplant. Our results indicate that chimerism, or the presence of graft cells in host tissue, may occur in the face of acute rejection and be demonstrable following vascularized isograft and allograft living bone transplantation when chronic immunosuppression is maintained. Graft vascular patency during the short-term likely allows cellular migration, even in the face of acute rejection. Long-term survival and proliferation of graft marrow elements in host tissue may be possible with adequate immunosuppression.     

Bone marrow chimerism and tolerance induced by single-dose cyclophosphamide

BACKGROUND: Establishment of hematopoietic chimerism is the most stable strategy for donor-specific tolerance. Safer pretreatment regimens are needed for clinical application. We evaluated the efficacy of a simple protocol using cyclophosphamide (CYP) on induction of chimerism and organ transplant tolerance across major histocompatibility complex (MHC) barriers in the rat. MATERIALS AND METHODS: Bone marrow cells from BN (RT1(n)) donors were infused to LEW (RT1(l)) recipients on day 0 after a single injection of CYP at various doses on day -1. Donor-derived hematopoietic chimerism was evaluated by flowcytometry. The recipients received BN or third party (BUF) heart allografts on day 100. RESULTS: While pretreatment with 200 mg/kg of CYP induced high levels of hematopoietic chimerism, six of eight recipients died of severe graft-versus-host-disease (GVHD). CYP at dose of 150 mg/kg induced 36.5 +/- 24.1% of donor-derived chimerism on day 10, and sustained macrochimerism was seen until day 100 without GVHD. Pretreatment with 100 mg/kg of CYP resulted in only transient chimerism (4.8 +/- 5.2%) which disappeared by day 20. In the recipients with 50 mg/kg of CYP, donor bone marrow cells were rapidly rejected and no chimerism was observed. The recipients with 150 mg/kg of CYP accepted BN heart allografts (>100 days x 5), while rejecting BUF allografts by day 12 (n = 4). BN heart allografts were rejected in the recipients with 100 (MST: 57 days, n = 5) and 50 mg/kg (MST: 7 days, n = 5) of CYP. CONCLUSIONS: A single dose of CYP can induce hematopoietic chimerism across MHC-barriers. The dose of 150 mg/kg seems to be optimal to induce organ transplant tolerance without developing GVHD.     

Manipulation of graft-versus-host disease for a graft-versus-leukemia effect after allogeneic bone marrow transplantation in AKR mice with spontaneous leukemia/lymphoma

Graft-versus-host (GVH) disease can result in a beneficial graft-versus leukemia (GVL) effect after bone marrow transplantation in patients with malignant disease. In this report, we used bacteria-free AKR (H-2k) mice bearing advanced spontaneous T cell leukemia/lymphoma as a moel to evaluate the GVH and GVL effects of bone marrow transplantation using fully incompatible SJL (H-2s) donors. A therapeutic GVL effect, accompanied by increased leukemia-free survival, was obtained only when 0.5 X 10(6) allogeneic lymphocytes (lymph node cells) were added to the marrow inoculum. Transplantation of allogeneic bone marrow without added lymph node cells (or use of syngeneic cells) resulted in a significant increase in leukemia relapse; increasing the dose of allogeneic lymph node cells to 2.0 X 10(6) resulted in significantly higher GVH-associated mortality. Survival and therapeutic benefits were obtained only when the intensity of the GVH reaction was carefully controlled by manipulation of alloreactive lymphocytes present in the marrow. These results suggest, indirectly, that T cell depletion may abolish any GVL effect of marrow transplantation, even if the donor is mismatched with the host at the major histocompatibility complex. The frequency in the spleen of cytotoxic T lymphocytes (CTL) reactive against host alloantigens was estimated using limiting-dilution microcytotoxicity assays at various times after transplantation of allogeneic bone marrow with and without added lymph node cells. The average frequency of CTL was highest in mice that were given marrow plus lymph node cells and tested within the first four weeks after transplantation. The level of CTL activity measured in vitro was dependent on the dose of lymphocytes injected and correlated with both the GVL and GVH effects in vivo. Down-regulation of CTL activity against host, but not third-party, alloantigens in vitro was observed under limiting dilution assay conditions, leading to the suggestion that host-specific regulatory cells may be present in these allogeneic bone marrow chimeras.     

Successful allogeneic leg transplantation in rats in conjunction with intra-bone marrow injection of donor bone marrow cells

BACKGROUND: We have recently established a new method for bone marrow transplantation (BMT) in mice: bone marrow cells are directly injected into the intra-bone marrow (IBM) cavity. IBM-BMT induces persistent donor-specific tolerance and enhances the rapid recovery or reconstitution of the hematolymphoid system of donor origin without any signs of graft-versus-host disease (GVHD) or graft failure. Furthermore, the prior injection of fludarabine can reduce the irradiation dose to the sublethal level (4.5 Gy x 2). Therefore, we hypothesize that IBM-BMT plus fludarabine is applicable to allogeneic leg transplantation in rats. METHODS: Brown Norway (BN; RT1An) rats were injected intravenously with 50 mg/kg of fludarabine phosphate, followed by sublethal fractionated irradiation (4.5 Gy x 2) 1 day before IBM-BMT. The hind limbs from Fischer 344 (F344; RT1Al) rats were transplanted on day 0, and bone marrow cells (3 x 10(7) cells/50 microL) obtained from the donor F344 rats were injected into the bone marrow cavity of the left tibias of the recipient BN rats. RESULTS: The hematolymphoid cells in the recipient BN rats were completely reconstituted by the cells of the donor F344 rats. The limbs transplanted from the donor F344 rats were accepted for >1 year without any clinical signs of rejection (10 of 10). The lymphocytes of the BN rats showed tolerance to both donor-type and recipient-type major histocompatibility complex determinants in mixed lymphocyte reaction, but showed a significant response to the third-party major histocompatibility complex determinants. CONCLUSIONS: Using a combination of the injection of fludarabine, low-dose irradiation, and IBM-BMT, we have succeeded in allogeneic limb transplantation without using any immunosuppressants after the operation. This strategy would be applicable to the transplantation of other vascularized organs in humans.     

Tolerance to composite tissue allografts across a major histocompatibility barrier in miniature swine

BACKGROUND: Tolerance to composite tissue allografts might allow the widespread clinical use of reconstructive allotransplantation if protocols to achieve this could be rendered sufficiently nontoxic. The authors investigated whether tolerance could be generated in miniature swine to composite tissue allografts across a major histocompatibility (MHC) barrier. A clinically relevant tolerance protocol involving hematopoietic cell transplantation without the need for irradiation or myelosuppressive drugs was tested. METHODS: Seven recipient animals were transiently T-cell depleted and a short course of cyclosporine was initiated. Twenty-four hours later, a donor hematopoietic cell transplant consisting of cytokine-mobilized peripheral blood mononuclear cells or bone marrow cells and a heterotopic limb transplant were performed. In vitro anti-donor responsiveness was assessed by mixed-lymphocyte reaction and cell-mediated lympholysis assays. Acceptance of the limb allografts was determined by gross and histologic appearance. Chimerism in the peripheral blood and lymphohematopoietic organs was assessed by flow cytometry. RESULTS: All seven experimental animals accepted the musculoskeletal elements but rejected the skin of the allografts. All but one of the animals displayed donor-specific unresponsiveness in vitro. The animals that received cytokine mobilized-peripheral blood mononuclear cells showed chimerism but had clinical evidence of graft-versus-host disease (GVHD). None of the animals that received bone marrow cells showed stable chimerism and none developed GVHD. CONCLUSIONS: This protocol can achieve tolerance to the musculoskeletal elements of composite tissue allografts across an MHC barrier in miniature swine. Stable chimerism does not appear to be necessary for tolerance and may not be desirable because of the risk of GVHD.     

The role of alphabeta- and gammadelta-T cells in allogenic donor marrow on engraftment, chimerism, and graft-versus-host disease.

BACKGROUND: We previously characterized a facilitating cell (FC) in mouse marrow that enables engraftment of allogeneic hematopoietic stem cells (HSCs) without causing graft-versus-host disease (GVHD). The FC shares some cell surface molecules with T cells (Thy1+, CD3epsilon+, CD8+, CD5+, and CD2+) but is T-cell receptor (TCR) negative. Historically, depletion of CD3+ or CD8+ cells from rat marrow was associated with an increased rate of failure of engraftment. In this study, we evaluated whether depletion of alphabeta- and gammadelta-TCR(+) T cells from donor marrow would retain engraftment potential yet avoid GVHD. METHODS: Wistar-Furth rats were conditioned with 950 cGy of total body irradiation and transplanted with ACI bone marrow processed to remove either alphabeta-TCR(+), gammadelta-TCR(+), or alphabeta- plus gammadelta-TCR(+) T cells. Recipients were typed for chimerism at 28 days and monthly thereafter. RESULTS: Recipients of marrow depleted of alphabeta- (group A), gammadelta- (group B), or alphabeta- and gammadelta-TCR(+) T cells (group C) engrafted and had an average chimerism level of 73.0+/-8.3%, 92.3+/-9.2%, and 46.3+/-32.8%, respectively. Aggressive T-cell depletion did not remove the FC population (CD8+/CD3+/TCR(-)). Group A and group B both developed GVHD, with a higher incidence of GVHD in group B compared to group A. None of the recipients in group C developed GVHD. CONCLUSIONS: These data demonstrate that depletion of T cells from rat marrow does not impair engraftment of HSCs, indirectly supporting the existence of FCs in rat marrow. Moreover, donor alphabeta- and gammadelta-TCR(+) T cells contribute to GVHD in a nonredundant fashion, although alphabeta-TCR(+) T cells are more potent as the effector cells. Finally, the level of donor chimerism is influenced by the composition of the graft, because recipients of marrow that contain alphabeta-TCR(+) T cells exhibited significantly higher donor chimerism compared to recipients of marrow depleted of both alphabeta- and gammadelta-TCR(+) T cells.     

伊马替尼联合供者淋巴细胞输注治疗造血干细胞移植后慢性粒细胞白血病复发

目的 探讨伊马替尼联合供者淋巴细胞输注(DLI)治疗异基因造血干细胞移植后慢性粒细胞白血病(CML)复发的效果.方法 3例CML(慢性期)患者,在接受预处理后,例1接受其胞妹外周血造血干细胞移植,例2接受其胞兄的骨髓移植,例3接受其胞弟的骨髓与外周血造血干细胞联合移植.例1移植后采用环孢素A(CsA)和霉酚酸酯(MMF)预防移植物抗宿主病(GVHD),例2采用CsA、短程甲氨蝶呤(MTX)、抗胸腺细胞球蛋白及抗CD25单克隆抗体预防GVHD,例3应用CsA、MTX和MMF预防GVHD.采用细胞遗传学及荧光原位杂交技术动态监测治疗效果.移植后发生血液学复发时,给予伊马替尼口服,并行DLI.结果 例1移植后30 d行DLI,输注CD3+T淋巴细胞0.5×107 /kg,移植后50 d和70 d,再次行DLI,分别输注CD3+ T淋巴细胞1.0 × 107 /kg和2.0×107 /kg,短串联重复序列(STR)检测提示为完全供者嵌合(DC).移植后120 d,疾病进展,给予伊马替尼400 mg/d,同时输注供者CD3+ T淋巴细胞2.5 × 107/kg.移植后180 d,STR检查提示仍为DC.患者最终于移植后17个月因髓外复发死亡.例2的染色体核型于移植后35 d转变为46,XY,XY为100%,BCR-ABL融合基因阴性.移植后100 d,原发病复发.停用免疫抑制剂,输入供者CD3+ T淋巴细胞3.9×107 /kg,同时口服伊马替尼500 mg/d.DLI联合伊马替尼治疗后30 d,患者的染色体核型为46,XY,XY为100%,BCR-ABL融合基因阴性,患者至今无病存活53个月.例3移植后5 d造血功能获得重建,移植后60 d,染色体核型为46,XY.移植后120 d,确诊CML复发,遂给予伊马替尼400 mg/d,并行DLI,共输注供者CD3+ T淋巴细胞8×107 /kg,1个月后,患者的染色体核型再次转为46,XY,患者至今无病存活50个月.结论 伊马替尼联合DLI对造血干细胞移植后CML复发具有一定的治疗效果.     

Donor hematopoietic progenitor cells in nonmyeloablated rat recipients of allogeneic bone marrow and liver grafts

BACKGROUND: Although the persistence of multilineage microchimerism in recipients of long-surviving organ transplants implies engraftment of migratory pluripotent donor stem cells, the ultimate localization in the recipient of these cells has not been determined in any species. METHODS: Progenitor cells were demonstrated in the bone marrow and nonparenchymal liver cells of naive rats and in Brown Norway (BN) recipients of Lewis (LEW) allografts by semiquantitative colony-forming unit in culture (CFU-C) assays. The LEW allografts of bone marrow cells (BMC) (2.5x10(8)), orthotopic livers, or heterotopic hearts (abdominal site) were transplanted under a 2-week course of daily tacrolimus, with additional single doses on days 20 and 27. Donor CFU-C colonies were distinguished from recipient colonies in the allografts and recipient bone marrow with a donor-specific MHC class II monoclonal antibody. The proportions of donor and recipient colonies were estimated from a standard curve created by LEW and BN bone marrow mixtures of known concentrations. RESULTS: After the BMC infusions, 5-10% of the CFU-C in the bone marrow of BN recipients were of the LEW phenotype at 14, 30, and 60 days after transplantation. At 100 days, however, donor CFU-C could no longer be found at this site. The pattern of LEW CFU-C in the bone marrow of BN liver recipients up to 60 days was similar to that in recipients of 2.5x10(8) BMC, although the donor colonies were only 1/20 to 1/200 as numerous. This was expected, because the progenitor cells in the passenger leukocytes of a single liver are equivalent to those in 1-5x10(6) BMC. Using a liquid CFU-C assay, donor progenitor cells were demonstrated among the nonparenchymal cells of liver allografts up to 100 days. In contrast, after heart transplantation, donor CFU-C could not be identified in the recipient bone marrow, even at 14 days. CONCLUSION: effective immunosuppression, allogeneic hematopoietic progenitors compete effectively with host cells for initial engraftment in the bone marrow of noncytoablated recipients, but disappear from this location between 60 and 100 days after transplantation, coincident with the shift of donor leukocyte chimerism from the lymphoid to the nonlymphoid compartment that we previously have observed in this model. It is possible that the syngeneic parenchymal environment of the liver allografts constitutes a privileged site for persistent progenitor donor cells.