不同干细胞骨髓腔内输注对移植物抗宿主病和免疫耐受的影响

观察不同来源的造血干细胞经髓腔内输注能否在减轻移植物抗宿主病(GVHD)的同时诱导稳定的免疫耐受。雌性C57BL/6小鼠接受全身照射(TBI)预处理后,输注雄性BABL/c小鼠来源的骨髓细胞或经rhG-CSF动员后的外周造血干细胞,2 d后腹腔注射环磷酰胺(CTX)。观察各组GVHD发生情况,并通过皮肤移植对受者耐受状态进行检测。结果显示,髓腔内骨髓移植组(IBM-BMT)的受鼠无1例发生GVHD,而髓腔内外周造血干细胞移植组(IBM-PBSCT)的受鼠GVHD发生率较尾静脉组(IV)明显减低(P<0.05);IBM-BMT和IBM-PBSCT组受鼠对供鼠皮肤移植物的存活时间均超过120 d,较IV组明显延长(P<0.01)。实验表明髓腔内输注在降低GVHD发生率的同时,有利于稳定的免疫耐受状态的形成。     

髓腔内骨髓移植诱导异基因小鼠皮肤移植耐受的研究

探讨髓腔内骨髓移植(IBM-BMT)对异基因小鼠皮肤移植耐受的诱导效果。受鼠为雌性C57BL/6(H-2b,B6)小鼠,于第0天接受60Coγ射线全身照射(TBI),4 h内输注雄性BALB/c(H-2d)小鼠来源的骨髓细胞(BMC),2 d后腹腔注射环磷酰胺(CTX)。通过皮肤移植、混合淋巴细胞反应(MLR)检测耐受状态,并通过骨髓染色体分析了解BMC的植入程度。结果显示,接受IBM-BMT的B6小鼠对BALB/c小鼠的皮肤移植物平均存活时间(MST)超过300 d,显著长于其余两组(P<0.001);MLR结果证明,实验组B6小鼠获得供体特异性耐受,在耐受小鼠骨髓中可检测到一定比例的Y染色体存在。以上表明髓腔内骨髓移植可以保证异基因骨髓细胞的植入并形成混合嵌合状态,从而有效地诱导免疫耐受。     

CTLA-4Ig联合髓腔内骨髓移植诱导小鼠同种异体皮肤移植耐受的研究

目的探讨细胞毒性T淋巴细胞相关抗原4免疫球蛋白(Cytotoxic T Lymphocyte Antigen4-immunoglobulin,CTLA4-Ig)与髓腔内骨髓移植(IBM-BMT)联合应用对诱导供体小鼠皮肤移植免疫耐受的促进bd作用。方法受鼠为C57BL/6(H-2,B6)雌性小鼠,于第0天输注雄性BALB/c(2)小鼠来源的骨髓细胞(BMC),同时腹腔注射CTLA4-Ig;第6天进行皮肤移植,并于移植术后第2天再进行一次腹腔注射CTLA4-Ig,观察皮肤移植物存活时间。通过皮肤移植物的组织学分析,以及混合淋巴细胞反应(MLR)检测耐受状态,并通过骨髓染色体分析了解BMT的植入程度。结果联合治疗组B6小鼠的皮肤移植物平均存活时间(MST)显著长于其它各组(P<0.05);MLR结果证明,联合组B6小鼠获得供体特异性耐受,在耐受小鼠骨髓中可检测到一定比例的Y染色体存在。结论 CTLA4-Ig与髓腔内骨髓移植可保证异基因的骨髓细胞形成嵌合体,显著延长了移植物存活时间,诱导免疫耐受。     

人骨髓造血细胞经腹腔内和尾静脉注射移植SCID鼠的研究

目的 :比较腹腔内与尾静脉注射对SCID鼠进行异种骨髓移植的体内植入能力及GVHD的发生情况 ,为异种骨髓移植构建银屑病动物模型奠定基础。方法 :密度梯度离心法分离正常人骨髓单个核细胞 (BMMNC) ,以 4× 10 7的剂量分别经尾静脉和腹腔注射移植于经γ射线预照射的SCID鼠 ,移植后观察GVHD反应及外周血白细胞恢复动力学 ,并采用流式细胞术检测小鼠外周血及骨髓中人源性CD4 5 + 细胞比例 ,观察嵌合状态。结果 :单纯尾静脉注射移植组 ,在移植后 2周即出现明显GVHD症状 ,12周仅存活 1例 ;尾静脉注射结合CsA +MTX处理组 ,个别小鼠出现轻度GVHD表现 ,12周存活率 80 % (8 10 ) ;而经腹腔内注射者移植后出现轻度GVHD症状 ,之后逐渐恢复正常 ,12周存活率 70 % (7 10 )。移植后外周血白细胞动力学恢复情况、外周血及骨髓中人CD4 5 + 细胞比例 ,尾静脉注射结合CsA +MTX处理者与经腹膜腔内注射者二组间比较无显著性差异。结论 :人骨髓造血细胞可以顺利地由SCID鼠腹腔归巢到骨髓造血组织 ,并能重建骨髓造血 ,腹腔内注射的移植方式不影响植入能力 ,既可达到骨髓移植的目的 ,又可减少GVHD的发生及反应强度     

骨髓腔内途径脐血与间质干细胞共移植对造血重建的实验研究

目的：探讨骨髓腔内输注（IBM）脐血与间质干细胞（MSCs）对大鼠造血重建、骨髓MSCs恢复的影响，并研究供体MSCs植入状态以探讨MSCs的作用机制。方法：BrdU标记F344大鼠骨髓MSCs通过双侧胫骨IBM或尾静脉注射（IV）与胎鼠及新生大鼠外周血（FNPB）共移植Wistar雌鼠。监测受鼠存活状况、造血免疫重建、HSCs植入水平及骨髓MSCs恢复情况，并以免疫荧光法检测受鼠骨髓MSCs的来源。结果：(1)2个共移植组60 d存活率均为100%，单纯FNPB移植组仅为66.7%。(2)共移植组的外周血象、骨髓造血干祖细胞集落产率明显高于单纯FNPB移植组，尤以骨髓腔共移植组最佳。(3)2个共移植组的HSCs植入水平无统计学差异，而骨髓腔共移植组明显高于单纯FNPB移植组（P＜0.05）。(4)30 d时各移植组MSCs的增殖能力未达正常水平，但仍以骨髓腔共移植组的恢复情况最佳（P＜0.05）。(5)仅少部分受体可发现供、受体源性MSCs嵌合。 结论：脐血与MSCs共移植可促进受体骨髓MSCs恢复和造血重建，提高HSCs植入率；IBM途径应用安全，促进造血恢复的作用优于IV途径。     

人胎盘源间充质干细胞与人脐血单个核细胞联合移植促进SCID鼠早期造血重建

目的:利用骨髓腔内注射(IBMI)技术初步探讨人胎盘源间充质干细胞(PMSC)联合脐血单个核细胞(MNC)共移植入SCID鼠体内后的早期造血重建效应。方法:将人胎盘组织经胶原酶消化、贴壁和传代培养获得人PMSC,运用流式细胞仪术(FCM)检测其表面标志,并将其诱导分化为成骨细胞和脂肪细胞,继而对其进行成骨分化、脂肪分化鉴定;以人PMSC和脐血MNC为供体,通过IBMI方法或结合静脉注射(IV)方法,将两种细胞联合或单独移植入经亚致死量辐照预处理的SCID受鼠体内,50只受鼠随机分为5组:联合移植A组(PMSC+脐血MNC,IBMI)、单独移植B组(脐血MNC,IBMI)、联合移植C组(PMSC经IBMI,脐血MNC经IV)、生理盐水对照D组(辐照后仅注射生理盐水,IBMI)、空白对照E组(不辐照仅注射生理盐水,IBMI),每组10只。在移植后14 d取各组SCID小鼠注射侧和对侧胫骨腔内骨髓细胞,并用FCM检测分析人CD34+、CD45+细胞的植入水平。结果:从人胎盘组织中成功分离和培养PMSC,FCM检测其表型正常,并成功向成骨和成脂肪细胞诱导分化;SCID小鼠移植后14 d,照射对照组小鼠仅剩4只存活,其他组小鼠全部存活,B组注射侧及对侧胫骨骨髓腔内的人CD34+、CD45+细胞的百分比均明显低于A组小鼠的注射侧和对侧。结论:人PM-SC可以提高脐血MNC的植入率,促进早期造血重建。     

混合骨髓移植后过继免疫治疗小鼠白血病

背景：急性白血病自体造血干细胞移植后复发率高,异基因造血干细胞移植后移植相关病死率高,混合造血干细胞移植及移植后过继免疫治疗有可能取长补短,提高疗效。 目的：观察自体骨髓混合H-2半相合异体骨髓移植后供体淋巴细胞输注+白细胞介素2治疗对小鼠白血病的疗效。 方法：将Balb/c小鼠经直线加速器照射3 Gy后分为白血病模型组、白血病模型照射组、混合移植组、自体骨髓移植组,均尾静脉注射5×10⁵ K562(GFP+/NeoR+)或K562(GFP-/NeoR-)细胞。7 d后6 Gy照射,自体骨髓移植组移植自体骨髓细胞或联合白细胞介素2治疗;混合移植组移植小鼠自体骨髓细胞混合1/10的H-2半相合异体骨髓细胞后应用白细胞介素2或联合供体淋巴细胞输注治疗。4周后行小鼠外周血及骨髓细胞形态检查,外周血细胞亚群、GFP及NeoR基因测定,肝、脾匀浆细胞GFP和NeoR基因测定。 结果与结论：白血病模型组小鼠因骨髓造血功能衰竭于20 d内全部死亡,白血病模型照射组小鼠因造血功能衰竭于14 d内全部死亡;自体骨髓移植组、混合移植组均有多少不等小鼠无白血病存活超过28 d,且混合骨髓移植后及自体骨髓移植后应用白细胞介素2治疗可提高白血病小鼠长期无病生存率,在此基础上联合供体淋巴细胞输注可更进一步提高白血病小鼠长期无病生存率。     

不同途径的供者淋巴细胞输注对移植物抗宿主病的影响

目的:观察髓腔内供者淋巴细胞输注(IBM-DLI)对异基因小鼠外周造血干细胞移植(allo-PBSCT)后移植物抗宿主病(GVHD)的影响.方法:雌性C57BL/6小鼠为受鼠,接受全身照射(TBI)预处理后,输注雄性BALB/c小鼠来源的经rhG-CSF动员后的外周造血干细胞,分别经尾静脉(IV)和髓腔内进行DLI,建立异基因GVHD模型,观察移植后小鼠的生存状态和GVHD发生情况,应用流式细胞仪检测受鼠体内嵌合体形成和CD4~+CD25~+调节性T细胞(Tregs)比例,酶联免疫吸附实验(ELISA)检测白细胞介素4(IL-4)、γ干扰素(IFN-γ)水平.结果:IBM-DLI组的受鼠GVHD发生比例和严重程度较IV-DLI组明显降低(P＜0.01);移植后第7天各组受鼠骨髓中供鼠来源的细胞比例均在95%以上;与IV-DLI组比较,脾细胞中Tregs比例在IBM-DLI组明显升高(P＜0.01),IBM-DLI组IL-4分泌增多,IFN-γ分泌减少 (P＜0.01).结论:与IV-DLI相比,IBM-DLI有利于减轻GVHD的发生,其机制可能与受鼠体内Tregs细胞比例增高以及Th细胞向Th2细胞分化有关.     

骨髓腔内输注脐带血及间充质干细胞对大鼠免疫重建影响

目的探讨骨髓腔内（IBM）输注脐带血及骨髓间充质干细胞（BMSC）对移植后大鼠免疫重建的影响。方法雌性F344胎鼠及新生鼠外周血（FNPB）及雄性F344大鼠BMSC共移植经致死量60Coγ射线辐照的雌性Wistar大鼠,其中FNPB均由IBM输注,BMSC则通过IBM或尾静脉（IV）注射。观察受鼠存活状况、供体造血干细胞（HSC）植入水平、免疫细胞及功能恢复、移植物抗宿主病（GVHD）表现,并用PCR检测受鼠供体BMSC来源Y染色体。结果两共移植组60d均100%存活,生存率和供体HSC植入水平差异无统计学意义,但明显优于单纯FNPB移植组;骨髓腔共移植组外周血白细胞及粒单系细胞集落形成单位（CFU-GM）、混合集落形成单位（CFU-GEMM）集落产率恢复较快,14d显著高于其他组（P〈0.05）。而单纯FNPB移植组各检测时点集落计数均明显低于共移植组（P〈0.05）,30dCD19＋细胞比例亦明显低于正常;30d各移植组PHA、LPS诱导淋巴细胞增殖实验及单向混合淋巴细胞培养无明显差异;60d两共移植组存活受鼠均检测到供体BMSC来源Y染色体。结论 HSC与BMSC联合输注可促进受者免疫重建,尤以IBM输注为佳。     

大鼠骨髓间质干细胞对同种骨髓移植后造血重建和免疫重建的作用

目的：探讨大鼠骨髓间质干细胞（MSC）对 同种异体骨髓移植造血重建和免疫重建的影响。方法:建立大鼠同种异 体骨髓移植模型，通过生存率分析、外周血象检测、免疫细胞计数和受体免疫功能检测，综 合评价MSC对骨髓移植(bone marrow transplantation,BMT)后造血重建和免疫重建的作用。 结果：(1) MSC可促进BMT后造血重建：移植后30 d，共移植组外周血白 细胞、淋巴细胞和血小板数均高于单纯骨髓移植组；共移植组骨髓细胞数也高于对照组。(2 )MSC可促进BMT后免疫重建：移植后30 d，共移植组胸腺细胞数、脾细胞总数均高于骨髓单 纯移植组；共移植组对ConA、LPS 刺激的淋巴细胞增殖反应以及对第三体来源的同种混合淋 巴细胞反应均强于单纯BMT组。结论：大鼠MSC与骨髓共移植对同种异体 骨髓移植造血重建和免疫重建有一定促进作用。     

Intra-bone marrow-bone marrow transplantation facilitates hemopoietic recovery including dendritic cells

In this report, we provide evidence using a serial bone marrow transplantation (BMT) protocol that intra-bone marrow (IBM)-BMT (IBM-BMT) can efficiently reconstitute the hemopoietic system with cells of donor origin, in contrast to conventional intravenous (IV)-BMT (IV-BMT). Furthermore, the hematolymphoid system of secondary recipients that had received bone marrow cells (BMCs) from primary recipients treated with IBM-BMT recovered earlier than that of the secondary recipients of BMCs from primary recipients treated with IV-BMT. This was the case when the Lin-/c-kit+ progenitor cells of the secondary and tertiary recipients were examined. These findings indicate that IBM-BMT can facilitate the development of not only cells of various lineages but also the effective generation and, more importantly, the maintenance of the progenitor cells. Furthermore, we show that IBM-BMT can reconstitute the dendritic cell (DC) subsets (myeloid and lymphoid DCs), which are critical for the initiation of both adaptive and innate immune responses. The frequency of both myeloid and lymphoid DC subsets was approximately equal to that of normal age-matched untreated controls and, after second and third BMT, this ratio was close to that observed in the normal controls. However, the lymphoid DCs were clearly reduced in the secondary and tertiary recipients of BMCs from mice that had received IV-BMT. Therefore, the development of DC subsets is also normally maintained in the IBM-BMT group.     

Allogeneic intra-bone marrow transplantation prevents rheumatoidarthritis in SKG/Jcl mice

The treatment of autoimmune diseases by allogeneic bone marrow transplantation remains a promising therapeutic avenue. However, more intensive studies on murine models are essential before application to a large number of human patients. In particular, the use of bone marrow transplantation to treat rheumatoid arthritis has been problematic. We have taken advantage of the SKG/Jcl mouse that develops a chronic T cell-mediated autoimmune disease that mimics rheumatoid arthritis which attempted to prevent the development of immunopathology in these mice by allogeneic bone marrow transplantation (BMT). In particular, we utilized our unique technology in which bone marrow cells (BMCs) of control C57BL/6J mice are directly injected into the bone marrow cavity in the tibia of SKG mice (intra-bone marrow [IBM]-BMT). As controls, SKG/Jcl mice were transplanted with whole BMCs from syngeneic SKG mice. Importantly, 12 months after IBM-BMT [B6 → SKG] demonstrated no evidence of arthritis, whereas the control [SKG → SKG] mice demonstrated, the expected immunopathology of a rheumatoid arthritis-like condition. Further, hematolymphoid cells in [B6 → SKG] mice were reconstituted by donor-derived cells and the percentages of Treg (Foxp3⁺/CD4⁺) cells, the percentages of receptor activator of nuclear factor-κB ligand (RANKL)⁺ cells on the CD4⁺T cells and the serum levels of tumor necrosis factor-α, interleukin-1 and interleukin-6 were normalized in the [B6 → SKG] mice. These data suggest that IBM-BMT is a viable method of immunological manipulation that suppresses the severe joint destruction and bone absorption in SKG/Jcl mice and lends further credence to the use of this methodology in humans with intractable rheumatoid arthritis.     

Intra-bone marrow injection of donor bone marrow cells suspended in collagen gel retains injected cells in bone marrow, resulting in rapid hemopoietic recovery in mice

We have recently developed an innovative bone marrow transplantation (BMT) method, intra-bone marrow (IBM)-BMT, in which donor bone marrow cells (BMCs) are injected directly into the recipient bone marrow (BM), resulting in the rapid recovery of donor hemopoiesis and permitting a reduction in radiation doses as a pretreatment for BMT. However, even with this IBM injection, some of the injected BMCs were found to enter into circulation. Therefore, we attempted to modify the method to allow the efficient retention of injected BMCs in the donor BM. The BMCs of enhanced green fluorescent protein transgenic mice (C57BL/6 background) were suspended in collagen gel (CG) or phosphate-buffered saline (PBS), and these cells were then injected into the BM of irradiated C57BL/6 mice. The numbers of retained donor cells in the injected BM, the day 12 colony-forming units of spleen (CFU-S) counts, and the reconstitution of donor cells after IBM-BMT were compared between the CG and PBS groups. The number of transplanted cells detected in the injected BM in the CG group was significantly higher than that in the PBS group. We next carried out CFU-S assays. The spleens of mice in the CG group showed heavier spleen weight and considerably higher CFU-S counts than in the PBS group. Excellent reconstitution of donor hemopoietic cells in the CG group was observed in the long term (>100 days). These results suggest that the IBM injection of BMCs suspended in CG is superior to the injection of BMCs suspended in PBS.     

Long-term maintenance of donor-derived hematopoiesis by intra-bone marrow-bone marrow transplantation

The long-term maintenance of hematopoietic stem cells (HSCs) is assessed by serial bone marrow transplantation (BMT), in which HSCs are injected intravenously. Recently, we have found that intra-bone marrow (IBM)-BMT can efficiently reconstitute the hematopoietic system with cells of donor origin, in contrast to conventional intravenous (i.v.) BMT. In the present study, we have compared the long-term maintenance of HSCs using multiple rounds of serial i.v.-BMT and IBM-BMT. The frequencies of donor-derived progenitor cells (Lin(-)/c-kit(+) cells) and more primitive progenitors (Lin(-)/c-kit(+)/CD34(+)/Sca-1(+) cells) were higher in the tertiary recipients by serial IBM-BMT than in those that had received bone marrow cells by serial i.v.-BMT. Furthermore, neither donor-derived progenitor cells nor mature hematolymphoid cells were detected in approximately 25% of the tertiary recipients after serial i.v.-BMT, indicating that progenitor cells can be efficiently maintained by IBM-BMT but not by i.v.-BMT. Finally, we confirmed that the recipients treated with the primary IBM-BMT (without carrying out serial BMT) showed a significantly higher survival rate than those treated with i.v.-BMT. These findings clearly show that IBM-BMT efficiently promotes the longterm maintenance of donor-derived hematopoiesis.     

Combination of intra-bone marrow-bone marrow transplantation and subcutaneous donor splenocyte injection diminishes risk of graft-versus-host disease and enhances survival rate

The combination of allogeneic bone marrow transplantation (allo-BMT) and donor lymphocyte infusion (DLI) is a useful method for establishing donor chimerism and preventing a relapse of leukemia/lymphoma. However, there is a risk of inducing uncontrollable fatal graft-versus-host disease (GVHD). In fact, allo-BMT plus intravenous (IV)-DLI using donor splenocytes induces fatal GVHD in recipient mice. In this study, we examined the effects of the combination of intra-bone marrow (IBM)-BMT and the subcutaneous injection of donor splenocytes (SC-DLI) on the allo-BMT system. Recipient BALB/c mice were conditioned by sublethal irradiation (5 Gy), followed by IBM-BMT plus IV-DLI or SC-DLI in C57BL/6 mice. The IV-DLI group showed better engraftment of donor hemopoietic cells than the control group (without DLI) but showed fatal GVHD. The SC-DLI group, however, showed good reconstitution and mild GVHD. These results suggest that the combination of SC-DLI and IBM-BMT promotes the reconstitution of hemopoiesis and helps reduce the risk of GVHD.     

Adult thymus transplantation with allogeneic intra-bone marrow-bone marrow transplantation from same donor induces high thymopoiesis, mild graft-versus-host reaction and strong graft-versus-tumour effects

Although allogeneic bone marrow transplantation (BMT) plus donor lymphocyte infusion (DLI) is performed for solid tumours to enhance graft-versus-tumour (GVT) effects, a graft-versus-host reaction (GVHR) is also elicited. We carried out intra-bone marrow-bone marrow transplantation (IBM-BMT) plus adult thymus transplantation (ATT) from the same donor to supply alloreactive T cells continually. Normal mice treated with IBM-BMT + ATT survived for a long time with high donor-derived thymopoiesis and mild GVHR. The percentage of CD4(+) FoxP3(+) regulatory T cells in the spleen of the mice treated with IBM-BMT + ATT was lower than in normal B6 mice or mice treated with IBM-BMT alone, but higher than in mice treated with IBM-BMT + DLI; the mice treated with IBM-BMT + DLI showed severe GVHR. In tumour-bearing mice, tumour growth was more strongly inhibited by IBM-BMT + ATT than by IBM-BMT alone. Mice treated with IBM-BMT + a high dose of DLI also showed tumour regression comparable to that of mice treated with IBM-BMT + ATT but died early of GVHD. By contrast, mice treated with IBM-BMT + a low dose of DLI showed longer survival but less tumour regression than the mice treated with IBM-BMT + ATT. Histologically, significant numbers of CD8(+) T cells were found to have infiltrated the tumour in the mice treated with IBM-BMT + ATT. The number of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labelling (TUNEL)-positive apoptotic tumour cells also significantly increased in the mice treated with IBM-BMT + ATT. Allogeneic IBM-BMT + ATT thus can induce high thymopoiesis, preserving strong GVT effects without severe GVHR.     

Prevention of graft-versus-host disease by intrabone marrow injection of donor T cells: involvement of bone marrow stromal cells

We have developed a new and effective method for bone marrow transplantation (BMT): bone marrow cells (BMCs) are injected directly into the bone marrow (BM) cavity of recipient mice. The intrabone marrow injection of BMCs (IBM-BMT) greatly facilitates the engraftment of donor-derived cells, and IBM-BMT can attenuate graft-versus-host reaction (GVHR), in contrast to conventional intravenous BMT (i.v.-BMT). Here, we examine the mechanisms underlying the inhibitory effects of IBM-BMT on GVHR using animal models where GVHR is elicited. Recipient mice (C57BL/6) were irradiated and splenic T cells (as donor lymphocyte infusion: DLI) from major histocompatibility complex-disparate donors (BALB/c) were injected directly into the BM cavity (IBM-DLI) or injected intravenously (i.v.-DLI) along with IBM-BMT. The BM stromal cells (BMSCs) from these recipients were collected and related cytokines were examined. The recipient mice that had been treated with IBM-BMT + i.v.-DLI showed severe graft-versus-host disease (GVHD), in contrast to those treated with IBM-BMT + IBM-DLI. The suppressive activity of BMSCs in this GVHD model was determined. The cultured BMSCs from the recipients treated with IBM-BMT + IBM-DLI suppressed the proliferation of responder T cells remarkably when compared with those from the recipients of IBM-BMT + i.v.-DLI in mixed leucocyte reaction. Furthermore, the level of transforming growth factor-beta and hepatocyte growth factor in cultured BMSCs from IBM-BMT + IBM-DLI increased significantly when compared with those from the recipients of IBM-BMT + i.v.-DLI. Thus, the prevention of GVHD observed in the recipients of IBM-BMT + IBM-DLI was attributable to the increased production of immunosuppressive cytokines from BMSCs after interaction with host reactive T cells (in DLI).     

Administration of granulocyte colony-stimulating factor to recipients followed by intra-bone marrow-bone marrow transplantation accelerates acceptance of allogeneic bone marrow cells in mice

We have recently established a novel method for bone marrow transplantation: intra-bone marrow–bone marrow transplantation (IBM–BMT), by which the rapid recovery of donor-derived hematopoiesis can be expected even when reduced radiation doses are used. In this paper, we examine, using mice, whether the combination of pretreatment of recipients with granulocyte-colony-stimulating factor (G-CSF) and IBM–BMT can induce a more rapid recovery of donor-derived hematopoiesis than IBM–BMT alone.

We first pretreated recipients with recombinant human (rh) G-CSF (250 μg/kg/day) for 5 consecutive days (days −6 to −2). On day −1, the recipients were irradiated, and IBM–BMT was carried out on day 0. On day 12, we performed colony-forming units of spleen (CFU-S) assays. The combination of G-CSF pretreatment and IBM–BMT augmented the CFU-S counts, the weight of spleens, and the numbers of donor-derived hematopoietic cells. We next analyzed the mechanisms underlying these effects of G-CSF and found that (i) G-CSF induces Th2 polarization, which can prevent graft rejection, and (ii) G-CSF augments natural suppressor activity, which suppresses graft rejection. The combination of G-CSF pretreatment and IBM–BMT can produce the rapid recovery of donor-derived hematopoiesis and suppress graft rejection. This method would lighten the burden on patients in allogeneic BMT.