Donor-specific allograft tolerance by administration of recipient-derived immature dendritic cells and suboptimal immunosuppression

We recently showed that injection of recipient-type immature bone marrow-derived dendritic cells (iBMDCs) the day before transplantation induced a significant prolongation of allograft survival. This study aimed at improving the administration protocol to induce allograft tolerance. Various amounts of iBMDCs were administered to syngeneic LEW.1A rats before and after transplantation of an allogeneic LEW.1W heart, with or without additional suboptimal immunosuppression. Allograft survival was not improved by repeated injections of syngeneic iBMDCs or by additional treatment with low-dose rapamycin. Combining injections of iBMDCs and LF 15-0195 showed a striking synergistic effect and induced definitive allograft acceptance in 92% of recipients. Tolerant recipients accepted donor-type, but not third-party type skin grafts, suggesting the development of regulatory mechanisms capable of maintaining donor-specific tolerance. The reported findings may contribute to the development of new therapeutic strategies to induce transplantation tolerance in humans.     

骨髓输注减轻大鼠肺移植急性排斥反应的研究

目的 研究供体骨髓细胞输注减轻大鼠肺移植急性排斥反应。方法 应用Cuff技术改进大鼠原位单肺移植模型，同时输注供体骨髓细胞，采集受体鼠外周血动态监测嵌合；存活4周大鼠杀死后切取移植肺进行排斥反应分级，切取脾应用免疫组织化学方法检测组织嵌合。结果 流式细胞术在骨髓输注组外周血中检测到明显的嵌合，在脾脏中得到组织嵌合。骨髓输注组移植肺急性排斥反应明显减轻。结论 肺移植同时输注供体骨髓细胞，可以产生显著的供体细胞与受体细胞嵌合，有效地抑制大鼠肺移植急性排斥反应。     

转染IKK2dn的受者树突状细胞回输延长同种异体肾移植大鼠的存活时间

目的 探讨IKK2dn基因转染并负载供者抗原的受者未成熟树突状细胞(imDC)延长同种异体肾移植大鼠的存活时间及其机制.方法 获取和培养Lewis大鼠骨髓源性DC,转染IKK2dn并负载BN大鼠可溶性抗原进行体外实验,检测CD86和主要组织相容性复合物(MHC)Ⅱ的表达及DC刺激T淋巴细胞增殖的能力.肾移植受者为Lewis大鼠,用随即数字表法分DC组、空转染组、转染组、对照组,术前7d分别输注1×10~7个D、Adv-0-DC、负载BN抗原的Adv-IKK2dn-DC和等量生理盐水,供者均为BN大鼠.另设第三方供者组,术前处理同转染组,供者为Wistar大鼠.移植后检测各组受者T淋巴细胞的增殖能力及血清白细胞介素2(IL-2)和γ干扰素(IFN-γ)的表达水平,观察各组大鼠的存活时间和发生排斥反应情况.结果 DC的体外实验结果显示:与转染IKK2dn前相比,转染后DC仍能低水平表达CD86和MHC Ⅱ,负载供者抗原后CD86和MHCⅡ表达均增加,而转染IKK2dn后再负载供者抗原,CD86和MHC Ⅱ的表达未发生明显变化;DC负载供者抗原后,刺激T淋巴细胞增殖的能力明显增强(P<0.05),而转染IKK2dn并负载供者抗原后不能有效刺激T淋巴细胞增殖.肾移植术后的检测结果显示:转染组T淋巴细胞的增殖能力明显低于其他4组(P<0.05或P相似文献   

Ex vivo expansion of canine dendritic cells from CD34+ bone marrow progenitor cells

BACKGROUND: The aims of this study were to ex vivo expand canine dendritic cells and determine their phenotype and functional characteristics. METHODS: CD34+-selected cells and CD34+-depleted canine bone marrow (BM) cells were cultured in Iscove's modified medium for 14 days. Cytokines added to the cultures included human granylocyte/macrophage colony-stimulating factor 5 ng/ml, hFlt3 ligand 200 ng/ml, and human tumor necrosis factor-alpha 10 ng/ml. Cultured cells and purified subpopulations were assessed for cell surface antigen expression, morphology, and function by flow cytometric analysis, electron microscopy, and an allogeneic mixed lymphocyte reaction at day 14. RESULTS: Two main cell populations were identified, DR++(bright)/CD14- and DR+(dim)/CD14+. Ex vivo expanded CD34+-selected cells showed increased allostimulatory activity compared to both cultured CD34+-depleted cells and mononuclear cells. In contrast, ex vivo expansion from CD34+-depleted cells was unsuccessful. After sorting cells from the ex vivo expanded CD34+-selected bone marrow to enrich for DR++/CD14- cells, a 42-fold increase (median) of allostimulatory activity was observed as compared with sorted DR+/CD14+ cells (P=0.02). CONCLUSIONS: Cells with dentric cell-like phenotypes and functions can be cultured from canine CD34+-selected bone marrow cells. Future studies will address the roles of these cells in engraftment, graft versus host reactions and graft-host tolerance in a canine hematogoietic stem cell transplantaton model.     

Isolation ad infusion of donor CD34+ bone marrow cells in cadaver kidney transplantation

Background: Infusion of donor bone marrow cells induces tolerance in allograft models. CD34⁺ stem cells present in human bone marrow could be endowed with tolerogenic properties. Methods: CD34⁺ stem cells were isolated from bone marrow extracted from vertebral bodies of cadaveric donors. Donor CD34⁺ cells (0.6-3.7 x 10⁶/kg) were infused during surgery in 10 kidney transplant recipients receiving OKT3 as induction therapy. Chimerism was investigated using nested PCR for donor-specific HLA alleles. Results: The infusion of CD34⁺ stem cells was perfectly tolerated. Five patients remained free of acute rejection at follow-up, 47-325 days post-operatively. The five other patients underwent a single episode of corticosensitive acute rejection. Long-term chimerism was not induced in the seven patients investigated for the persistence of donor DNA. Conclusions: Infusion of donor CD34⁺ stem cells in kidney transplantation is safe. The clinical usefulness of the procedure remains to be established.     

Effects of donor bone marrow infusion in clinical lung transplantation

BACKGROUND: We have demonstrated that donor cell chimerism is associated with a lower incidence of obliterative bronchiolitis (OB) in lung recipients, and that donor chimerism is augmented by the infusion of donor bone marrow (BM). We herein report the intermediate results of a trial combining the infusion of donor BM and lung transplantation. METHODS: Clinical and in vitro data of 26 lung recipients receiving concurrent infusion of donor bone marrow (3.0 to 6.0 x 10(8) cells/kg) were compared with those of 13 patients receiving lung transplant alone. RESULTS: Patient survival and freedom from acute rejection were similar between groups. Of the patients whose graft survived greater than 4 months, 5% (1 of 22) of BM and 33% (4 of 12) of control patients, developed histologic evidence of OB (p = 0.04). A higher proportion (but not statistically significant) of BM recipients (7 of 10, 70%) exhibited donor-specific hyporeactivity by mixed lymphocyte reaction assays as compared with the controls (2 of 7, 28%). CONCLUSIONS: Infusion of donor BM at the time of lung transplantation is safe, and is associated with recipients' immune modulation and a lower rate of obliterative bronchiolitis.     

Sublethal fractionated total-body irradiation and donor bone marrow infusion for induction of allograft tolerance

Tolerance to skin allografts across the strong histocompatibility barrier H-2b to H-2d was achieved with sublethal fractionated total-body irradiation, FTBI, delivered to H-2d mice in 3 doses of 250 rads within 24 hr, followed by transfusion of 3 X 10(7) H-2b donor bone marrow (BM) cells. H-2b skin allografts were applied within 48 hr after the initial radiation. 70% of the mice became long-term (greater than 180-day) survivors with fur-bearing grafts. Marked interexperiment variability in survival rates suggested that infection was the major cause of death in this model and lower weight gain and survival rates for allogenic BM vs. media-treated controls suggested that graft-versus-host disease (GVHD) was also a factor. The observation, however, that long-term survivors (70% of all mice) gained weight and appeared healthy suggested that the GVHD might be self-limiting. Chimeric analysis revealed that approximately 25% of spleen cells were of donor origin, both at short-term (6 weeks) and long-term (greater than 1 year) intervals after tolerance induction. In spite of hematopoietic chimerism, a low incidence of spontaneous tumors, less than 1%, occurred in the long-term survivors.     

Donor T cells are not required for induction of allograft tolerance in mice treated with antilymphocyte serum, rapamycin, and donor bone marrow cells

BACKGROUND: Postgraft infusion of donor bone marrow cells (BMC) effectively induces tolerance to skin allografts in antilymphocyte serum- and rapamycin-treated recipients in fully major histocompatibility complex-mismatched mouse strain combinations. We used various gene knockout mice to examine the role of donor T cells and B cells in BMC-induced allograft tolerance. METHODS: All recipient mice received ALS on days -1 and 2 and rapamycin (6 mg/kg) on day 7 relative to fully major histocompatibility complex-mismatched skin grafting on day 0. Donor BMC prepared either from mice lacking CD4- and/or CD8a-, or CD3epsilon-expressing cells or B cells, or from corresponding wildtype mice, were given on day 7. The level and phenotypes of chimerism was determined by flow cytometry. RESULTS: All T cell- and B cell-deficient BMC were as effective as wild-type BMC in inducing prolongation of skin graft survival. A low degree of chimerism without donor type T cells was detected in tolerant mice given T cell-deficient BMC or wild-type BMC 60 days after transplantation. Chimeric cells were composed of B cells and macrophages/monocytes. Low level chimerism without donor T or B cells was also present in tolerant mice given B cell-deficient BMC. CONCLUSION: Donor type T cells and T cell chimerism are not required for induction of allograft tolerance by the antilymphocyte serum/rapamycin/donor BMC-infusion protocol. Donor B cells also do not participate in tolerance induction. Thus, infusion of T cell-depleted BMC in conjunction with conventional immunosuppressive regimens will be a simple, safe, and effective way to induce allograft tolerance in clinical organ transplantation.     

Donor skin allograft survival after bone marrow transplantation: Case report and systematic review of the literature☆

Background

We present a case of skin allograft survival in a patient who previously received a bone marrow transplant from the same HLA-matched donor. DNA fingerprinting of skin biopsies showed mixed cellularity originating from the donor and recipient (68% and 32% donor DNA in the allograft skin and the native recipient's skin, respectively). Histologic sections demonstrated both grade 3/4 rejection and graft-versus-host-disease. We have conducted a systematic review in search for other cases of donor skin allograft survival after a bone marrow or hematopoietic stem cell transplantation.

Importance of donor- and recipient-derived selectins in cardiac allograft rejection

The selectins expressed on activated endothelial cells (E- and P-selectin), leukocytes (L-selectin), and platelets (P-selectin) play crucial roles in the rolling and tethering of leukocytes. We explored the importance of donor and recipient selectins in acute and chronic cardiac allograft rejection using mice deficient in all three selectins (ELP-/-). In BALB/c recipients, survival of fully allomismatched hearts from ELP-/- C57BL/6 donors was almost double that of wild-type grafts. In ELP-/- cardiac allografts, mononuclear cell infiltration and vasculitis of intramyocardial coronary arteries were significantly reduced. Interestingly, ELP-/- grafts were rejected similarly in both the presence and the absence of recipient selectins, and both wild-type and ELP-/- recipients promptly rejected wild-type hearts. Alternative adhesive molecules such as alpha4beta7 integrin may compensate for the lack of selectins and may mediate rejection in ELP-/- recipients. Chronic rejection was evaluated in a major histocompatibility complex (MHC) class II mismatch model using C57BL/6.C-H2(bm12) mice. While lack of selectins in recipients did not offer protection against chronic rejection, luminal stenosis of coronary arteries in ELP-/- grafts was markedly diminished. In conclusion, donor-derived selectins contribute to the development of both acute and chronic cardiac allograft rejection, and targeting donor selectins may open novel therapeutic approaches in clinical transplantation.     

Immunosuppressive and trafficking properties of donor splenic and bone marrow dendritic cells

BACKGROUND: Infusion of donor dendritic cells (DC) has been shown to prolong allograft survival in a number of models. However, many regimens that utilize donor DC do not consistently produced tolerance or long-term allograft survival. We hypothesized that one factor limiting the therapeutic effect of donor DC is their relative inability to traffic to recipient peripheral lymph nodes and inhibit the function of resident alloreactive T cells. METHODS: Donor strain DC isolated from the spleens or bone marrow of Flt3L-treated mice were transferred intravenously into recipients at the time of skin grafting. Where indicated, recipients were treated with an anti-CD40L antibody and CTLA4-Ig. RESULTS: Infusion of donor DC together with costimulatory blockade promoted donor-specific prolongation of skin allograft survival in mice. Perhaps due to their more immature phenotype, bone marrow DC trafficked more effectively to the spleen, bone marrow, and thymus and were associated with significantly longer allograft survival than were splenic DC. Neither population of DC trafficked well to peripheral lymph nodes. Consistent with our hypothesis, splenic but not lymph node T cells from DC-treated recipients displayed donor-specific hyporesponsiveness in vitro. CONCLUSION: These data suggest that one factor contributing to rejection following treatment with donor DC plus costimulation blockade is the persistence of donor-reactive T cells within the recipient's secondary lymphoid structures. Strategies to improve DC trafficking to these structures may enhance their therapeutic effect.