Impact of total body irradiation on successful neutrophil engraftment in unrelated bone marrow or cord blood transplantation

Total body irradiation (TBI) has been thought to promote donor cell engraftment in allogeneic hematopoietic cell transplantation (HCT) from alternative donors. However, recent progress in HCT strategies may affect the clinical significance of TBI on neutrophil engraftment. With the use of a Japanese transplant registry database, we analyzed 3933 adult recipients (>15 y.o.) who underwent HCT between 2006 and 2013 from an 8/8 HLA‐matched unrelated bone marrow donor (MUD, n = 1367), an HLA‐mismatched unrelated bone marrow donor (MMUD, n = 1102), or unrelated cord blood (CBT, n = 1464). Conditioning regimens were divided into five groups: High‐TBI‐(>8Gy), Low‐TBI‐ (≤8Gy), and no‐TBI‐myeloablative conditioning (MAC), and Low‐TBI‐ and no‐TBI‐reduced‐intensity conditioning (RIC). In both MUD and MMUD, neutrophil engraftment rate was >90% in each of the five conditioning groups, and TBI was not associated with prompt neutrophil engraftment in multivariate analyses. Conversely, in CBT, TBI regimens had a higher rate of day‐30 neutrophil engraftment than no‐TBI‐regimens: 78% in High‐TBI‐MAC, 83% in Low‐TBI‐MAC, and 76% in Low‐TBI‐RIC versus 65% in No‐TBI‐MAC, and 68% in No‐TBI‐RIC (P < .001). Multivariate analyses in CBT demonstrated that TBI‐regimens were significantly associated with a higher rate of neutrophil engraftment. Subsequently focusing on CBT patients alone, TBI‐regimens were significantly associated with a higher rate of neutrophil engraftment in patients who received CBT with a 4/6 or less HLA allele‐match, or who had anti‐HLA antibodies. In summary, TBI‐regimens had no impact on neutrophil engraftment in the current practice of unrelated bone marrow transplantation. However, in CBT, TBI is still necessary to enhance engraftment.     

Cord blood transplantation using minimum conditioning regimens for patients with hematologic malignancies complicated by severe infections

Patients with severe infections are thought to be ineligible for cord blood stem cell transplantation (CBT) because the conventional 5–6 day-conditioning regimens potentially makes them susceptible to fatal infections by the time neutrophil engraftment occurs. Two patients were treated with minimum conditioning regimens consisting of 30 mg/m² fludarabin (Flu) and 2 g/m² cyclophosphamide (CY) on day-1 and total body irradiation (TBI) of 2 or 4 Gy on day −1 or 0 followed by single unit CBT. The reasons for adopting such weak regimen were febrile neutropenia due to the rejection of the first cord blood (CB) graft given to a patient with follicular lymphoma resistant to chemotherapy and pulmonary aspergillosis in another patient with AML who relapsed after CBT. The AML patient received 40 mg/m² of melphalan on day-2 to reduce the leukemia burden. Both patients achieved 100% donor chimerism by day 19 and day 20 after CBT without an apparent exacerbation of the infections and remained in remission at 23 and 18 months after the CBT. These findings suggest that the 1–2 day regimens excluding antihuman thymocyte globulin may be sufficiently potent to ensure engraftment of CB in immunocompromised patients and safely administered even when patients are complicated by active infections. An erratum to this article can be found at     

Rapid and complete donor chimerism in adult recipients of unrelated donor umbilical cord blood transplantation after reduced-intensity conditioning

Reduced-intensity conditioning may reduce transplantation-related mortality in high-risk adults undergoing hematopoietic transplantation. We investigated unrelated donor umbilical cord blood (UCB) transplantation after such conditioning in 43 patients (median age, 49.5 years; range, 22-65 years) with a primary end point of donor engraftment. The first 21 patients received busulfan 8 mg/kg, fludarabine 200 mg/m2, and 200 cGy of total body irradiation (Bu/Flu/TBI). Subsequent patients (n = 22) received cyclophosphamide 50 mg/kg, fludarabine 200 mg/m2, and 200 cGy TBI (Cy/Flu/TBI). UCB grafts (93%) were 1-2 HLA antigen-mismatched with the recipient and contained a median cryopreserved cell dose of 3.7 x 107 (range, 1.6 x 107-6.0 x 107) nucleated cells per kilogram of recipient body weight (NC/kg). Graft versus host disease (GVHD) prophylaxis was cyclosporin A to day 180 plus mycophenolate mofetil to day 30. The cumulative incidence of sustained donor engraftment was 76% (95% confidence interval [CI], 56%-96%) for Bu/Flu/TBI recipients and 94% (95% CI, 84%-100%) for Cy/Flu/TBI recipients. The median day of neutrophil recovery (at least 0.5 x 109/L) for engrafting Bu/Flu/TBI recipients was 26 days (range, 12-30 days) and for Cy/Flu/TBI recipients was 9.5 days (range, 5-28 days). Incidence of grades III-IV acute GVHD was 9% (95% CI, 1%-17%), and survival at 1 year was 39% (95% CI, 23%-56%). These data demonstrate that 0-2 antigen mismatched UCB is sufficient to engraft most adults after reduced-intensity conditioning and is associated with a low incidence of severe acute GVHD.     

Myeloid and lymphoid chimerism after T-cell-depleted bone marrow transplantation: evaluation of conditioning regimens using the polymerase chain reaction to amplify human minisatellite regions of genomic DNA.

Determining both myeloid and lymphoid chimerism after T-cell-depleted allogeneic bone marrow transplantation (BMT) could be helpful in the understanding of the biology of engraftment and could provide a rational method of assessing the ability of different conditioning regimens to promote engraftment. We prospectively investigated the role of different pretransplant conditioning regimens in 29 leukemic patients post-BMT by assessing myeloid and T-cell chimerism using a rapid and sensitive polymerase chain reaction (PCR) method. Minisatellites are hypervariable regions of DNA consisting of tandem repeats of a core nucleotide sequence, and allelic polymorphism results from differences in the number of the repeats. We used this variation to distinguish between donor and recipient cells post-BMT. Seventeen patients (9 sibling and 8 unrelated donors) received conditioning with hyperfractionated total body irradiation (TBI), thiotepa, and cyclophosphamide (Cy). Of the other 12 patients (all sibling donors), 11 received TBI plus Cy plus another agent: VP16, carboplatinum, or AZQ. One patient received TBI plus thiotepa plus VP16. All but one of the patients studied received marrow from HLA-identical donors. PCR analysis confirmed donor lymphoid engraftment within 8 days of transplant in six of six patients studied. All granulocyte DNA was of donor origin within the first 4 weeks of transplant, regardless of the conditioning regimen. The day +28 T cells were exclusively of donor origin in 14 of 17 patients who received TBI plus thiotepa plus Cy, but were mixed chimeric in 10 of 12 patients who received other conditioning regimens (P < .001). Early graft rejection was seen in one unrelated transplant recipient conditioned with TBI plus thiotepa plus Cy. Late graft failure was observed in 3 of 12 patients with mixed T-cell chimerism and in none of 16 patients with full donor chimerism at day +28. However, 5 of 16 patients who had complete T-cell chimerism at day +28 developed acute graft-versus-host disease (GVHD), whereas no patient with mixed chimerism had acute GVHD. Our results indicate that minisatellite PCR is a rapid and sensitive method for assessing chimerism post-BMT, that the donor T cells are important for consistent durable engraftment, and that TBI plus thiotepa plus Cy may be superior to the other regimens studied in inducing full donor chimerism. Larger numbers and longer follow-up are necessary to confirm these data and also to assess the relationship between complete donor T-cell chimerism and leukemia-free survival.     

Influence of the conditioning regimen on erythrocyte chimerism, graft-versus-host disease and relapse after allogeneic transplantation with lymphocyte depleted marrow.

Three different conditioning regimens were applied to 144 patients undergoing allogeneic bone marrow transplantation (BMT) with HLA identical sibling marrow, depleted of lymphocytes by counterflow centrifugation. All regimens consisted of cyclophosphamide and fractionated total body irradiation (TBI). In 49 patients treated with regimen A the total TBI dose was 9 Gy. In regimen B the dose rate of TBI was increased and anthracyclines were added (n = 65). Thirty patients received regimen C with a total TBI dose of 12 Gy but no anthracyclines. The different conditioning regimens did not influence the percentage of patients with detectable recipient CFU-GM prior to infusion of donor marrow. The incidences of mixed erythrocyte chimerism at 6 months after BMT were 73, 33 and 20% for regimens A, B and C respectively. The conditioning regimen influenced significantly mixed erythrocyte chimerism from 6 to 24 months after BMT. Both age and the conditioning regimen influenced significantly the incidence of acute graft-versus-host disease (GVHD) (p = 0.017 and 0.0001 respectively). Acute GVHD greater than or equal to I occurred in 15, 29 and 77% of the patients treated with regimens A, B and C respectively. The incidence of acute and chronic GVHD was significantly higher in complete donor chimeras than in mixed chimeras (p less than 0.001 and p less than 0.01). The probability of relapse was 43% in 32 and 18% in 43 good risk patients treated with regimens A and B respectively (p = 0.07). Longer follow-up is needed to draw conclusions about relapse in regimen C.(ABSTRACT TRUNCATED AT 250 WORDS)     

Marrow transplantation for Fanconi anemia with or without leukemic transformation: an update of the Seattle experience.

Between March 1973 and August 1990, 17 patients with Fanconi anemia (FA) underwent bone marrow transplantation in Seattle. Marrow donors were HLA identical siblings (n = 14), phenotypically HLA identical parents (n = 2) and a one antigen mismatched parent (n = 1). Patients with no evidence of leukemic transformation (n = 12) were conditioned with 140-200 mg/kg cyclophosphamide (CY). Of five patients with leukemic transformation, four received CY (120 mg/kg) plus 12 Gy fractionated total body irradiation and one patient received busulfan (14 mg/kg) and CY (100 mg/kg). All patients engrafted; however, one patient whose sibling donor's cells showed variable results when assayed for chromosome instability required two additional marrow infusions. Toxicity associated with the conditioning regimen included severe oral mucositis (n = 14), hemorrhagic cystitis (n = 11) and diffuse erythroderma (n = 3). Seven of the 12 patients without leukemic transformation are surviving 1-17 years (median = 5 years) after transplant, with an estimated survival probability at 5 years of 65% (95% CI 0.31; 0.85). Two patients developed squamous cell carcinoma of the tongue greater than 10 years post-transplant. One of these patients died at 10.3 years as a result of the malignant process, and the other is disease free more than 12 years post-transplant. Of the five patients with leukemic transformation, one is alive at 8 years. These data demonstrate that marrow transplantation can offer long-term survival for patients with FA, engraftment can be achieved with reduced doses of CY in FA patients, and less toxic preparative regimens are needed for FA patients who have developed leukemic transformation.     

Allogeneic hematopoietic stem cell transplantation for aplastic anemia with pre-transplant conditioning using fludarabine,reduced-dose cyclophosphamide,and low-dose thymoglobulin: A KSGCT prospective study

The optimal pre-transplant conditioning for aplastic anemia (AA) remains unclear. We performed a prospective study on allogeneic transplantation from a related or unrelated donor for adult patients with AA. We assessed whether reduced-dose cyclophosphamide (CY) could decrease toxicity while maintaining engraftment, and low-dose thymoglobulin could safely prevent graft-vs-host disease (GVHD). The pre-transplant conditioning regimen consisted of fludarabine 120 mg/m², CY 100 mg/kg, and thymoglobulin 2.5 mg/kg with or without 2 Gy of total body irradiation. Twenty-seven patients with a median age of 36 years were analyzed. Sixteen patients received graft from related donors. The stem cell source was bone marrow in 26 patients. All of the patients but one, who died early, achieved neutrophil engraftment at a median of 19 days. Mixed chimerism was observed in six and five patients at days 30 and 90, respectively. Only one patient experienced secondary engraftment failure with complete donor-type chimerism. None of the patients developed severe acute GVHD. The cumulative incidence of chronic GVHD was 37.7% at 1 year. The overall survival rate was 96.3% at 1 year and 3 years. A high EB virus-DNA load was detected in one patient at days 60. No one developed EBV-lymphoproliferative disorder within a year. The results suggest that the conditioning regimen in this study was safe and effective. However, relatively high incidence of chronic GVHD needs further improvement.     

Enhancement by dimethyl myleran of donor type chimerism in murine recipients of bone marrow allografts

A major problem in using murine models for studies of bone marrow allograft rejection in leukemia patients is the narrow margin in which graft rejection can be analyzed. In mice irradiated with greater than 9 Gy total body irradiation (TBI) rejection is minimal, whereas after administration of 8 Gy TBI, which spares a significant number of clonable T cells, a substantial frequency of host stem cells can also be detected. In current murine models, unlike in humans, bone marrow allograft rejection is generally associated with full autologous hematopoietic reconstitution. In the present study, we investigated the effect of the myeloablative drug dimethyl myleran (DMM) on chimerism status following transplantation of T cell-depleted allogenic bone marrow (using C57BL/6 donors and C3H/HeJ recipients, conditioned with 8 Gy TBI). Donor type chimerism 1 to 2 months post-transplant of 1 to 3 x 10(6) bone marrow cells was markedly enhanced by using DMM one day after TBI and prior to transplantation. Conditioning with cyclophosphamide instead of DMM, in combination with 8 Gy TBI, did not enhance engraftment of donor type cells. Artificial reconstitution of T cells, after conditioning with TBI plus DMM, by adding mature thymocytes, or presensitization with irradiated donor type spleen cells 1 week before TBI and DMM, led to strong graft rejection and consequently to severe anemia. The anti-donor responses in these models were proportional to the number of added T cells and to the number of cells used for presensitization, and they could be neutralized by increasing the bone marrow inoculum. These results demonstrate the potential of DMM to facilitate engraftment in unsensitized mice in which the host stem cells may compete with donor type cells; the use of DMM to create models in which mechanisms of immune rejection can be studied without interference due to stem cell competition; and that bone marrow allograft rejection may be overcome by increasing the bone marrow inoculum in these stringent models.     

feasibility and Results of Bone Marrow Transplantation from an HLA-Mismatched Unrelated Donor for Children and Young Adults with Acquired Severe Aplastic Anemia

Treating patients with severe aplastic anemia (SAA) who fail to respond to immunosuppressive therapy (IST) and do not have an HLA-matched donor is challenging. We report favorable outcomes in 11 patients who underwent bone marrow transplantation (BMT) from an HLA-mismatched unrelated donor. The median age was 11 years (range, 3-20 years). The conditioning regimen consisted of cyclophosphamide (200 mg/kg), antithymocyte globulin (10 mg/kg), and total body irradiation (5 Gy). Patients received tacrolimus and methotrexate for prophylaxis against graft-versus-host disease (GVHD). Donorrecipient pairs were mismatched for the HLA-DR antigen in 8 patients by serologic typing. HLA-A and HLA-B antigens were mismatched in 1 and 2 patients, respectively. Ten patients achieved engraftment. One patient who failed to engraft was rescued by a second transplantation from her mother, who was mismatched at 2 HLA antigens. Acute GVHD of grades II to IV occurred in 2 patients. Three patients developed limited chronic GVHD, and 1 patient developed extensive chronic GVHD of the lung. All patients are alive at 9 to 56 months after transplantation (median, 33 months). Considering our encouraging results, HLA-mismatched unrelated-donor BMT for SAA is feasible as a salvage therapy for nonresponders to IST.     

Conditioning-related toxicity and acute graft-versus-host disease in patients given methotrexate/cyclosporine prophylaxis

Intensive chemoradiotherapy conditioning regimens and acute graft-versus-host disease (GVHD) are both associated with significant morbidity and mortality after bone marrow transplantation. In this study, we investigated whether the conditioning regimen affected the development of acute GVHD. Thirty-four patients, four with severe aplastic anemia and 30 with a lymphohemopoietic malignancy, were prepared for transplantation either with cyclophosphamide (CY) alone, with CY combined with total body irradiation (TBI) or CY combined with etoposide and either TBI or busulfan. GVHD prophylaxis included methotrexate (MTX 10 mg/m2) given on days 1, 3 and 6, and daily cyclosporine (CSP) on days--1 through 180. The overall incidence of acute GVHD was 36% (15% for HLA identical, 87% for HLA non-identical recipients). However, when assessed by the severity of conditioning regimen-related toxicity, the incidence of GVHD grades II-IV (HLA identical; HLA non-identical) was 0% (0%; 0%), 37% (20%; 67%) and 50% (22%; 100%) for patients with mild, moderate and severe toxicity, respectively. Compliance with GVHD prophylaxis declined with increasing intensity and toxicity of the conditioning regimen. These data suggest that a regimen of three doses of MTX and daily CSP is as effective as four doses of MTX/CSP for GVHD prophylaxis in patients given HLA identical marrow grafts. However, GVHD regimen compliance and efficacy of GVHD prevention are inversely related to the intensity of the conditioning regimen.     

Anti-NK cell treatment induces stable mixed chimerism in MHC-mismatched, T cell-depleted, nonmyeloablative bone marrow transplantation

OBJECTIVE: To clarify natural killer (NK) cell-mediated resistance under cytoreductive conditioning and T cell-depleted bone marrow transplantation, we investigated the effects of host NK cell depletion on engraftment and induction of stable mixed chimerism. METHODS: BALB/c mice (H-2kd) were injected intraperitoneally with anti-asialoGM1 antibody (anti-NK Ab) on day -1. On day 0, they received total body irradiation (TBI) at a dose of 500 cGy, followed by intravenous infusion of 2 x 10(7) T cell-depleted (TCD) bone marrow cells from C57BL/6 mice (H-2kb). Early engraftment and chimerism were determined by the relative ratio of peripheral blood (PB) lymphocytes expressing either H-2kd or H-2kb on day +21. Long-term engraftment and chimerism were evaluated on PB and spleen by multicolor flow cytometry. RESULTS: Although no recipients treated with TBI alone showed engraftment, all the recipients conditioned with anti-NK Ab and TBI showed successful engraftment as well as a donor-dominant pattern of mixed chimerism in both PB and spleen. Spleen cells from recipients with mixed chimerism showed specific tolerance to both host and donor strains, but not to a third party (C3H/He). None of the reconstituted mice showed signs of graft vs host disease, and all survived up to day +330. CONCLUSION: These observations indicate that host NK cell depletion may be used to reduce the intensity of conditioning regimens for engraftment of TCD grafts, and can contribute to establishment of stable mixed chimerism in major histocompatibility complex-mismatched nonmyeloablative transplantation.     

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.     

T cell non-depleted bone marrow transplantation for primary refractory erythroleukemia using a partially HLA-mismatched related donor]

We performed an HLA-mismatched T cell non-depleted bone marrow transplant on a 53-year-old man with acute erythroleukemia that was highly resistant to conventional remission-induction chemotherapy. After conditioning that included total body irradiation, the patient received a two-HLA-antigen-mismatched bone marrow graft harvested from his sister using tacrolimus and methotrexate for graft-versus-host disease (GVHD) prophylaxis. He successfully established rapid engraftment accompanied by steroid-responsive GVHD localized to the skin. Although bone marrow samples on day 31 and day 66 disclosed a complete remission with full donor chimerism, the patient relapsed and died of pulmonary infection on day 154. There is evidence that tacrolimus is effective in alleviating GVHD. Selected patients who have partially mismatched related donors with less HLA disparity may benefit from tacrolimus-based T cell non-depleted bone marrow transplants because of the more potent graft-versus-leukemia effect that can be expected compared to transplants using T cell depleted inoculum.     

配型不合造血干细胞移植治疗重型再生障碍性贫血的疗效及安全性

目的 研究人类白细胞抗原(HLA)配型不合造血干细胞移植治疗重型再生障碍性贫血(SAA)的疗效和安全性.方法 从2006年1月至2010年5月共入选17例SAA患者接受配型不合造血干细胞移植治疗,供受者间HLA 2个位点不合8例,3个位点不合9例,以改良马利兰/环磷酰胺+抗人胸腺细胞免疫球蛋白(BU/CY+ATG)为预处理方案,进行骨髓加外周血干细胞移植.结果 所有病例均达到完全供者植入.发生Ⅲ～Ⅳ度急性移植物抗宿主病(GVHD)3例,14例可评估病例中,广泛型慢性GVHD 1例;中位随访285(60～1670)d,11例患者生存,9例血象恢复正常,另2例脱离输血.6例患者死于移植相关合并症.结论 当无HLA配型相合同胞供者时,SAA患者采用HLA配型不合移植是可行的治疗选择.

Abstract：

Objective To study the efficacy and safety of human leukocyte antigen (HLA)mismatched hematopoietic stem cell transplantation (HSCT) on severe aplastic anemia(SAA). Methods From January 2006 to May 2010, 17 patients received mismatched HSCT. HLA antigens were 3-locimismatched in 9 patients, 2-loci-mismatched in 8. All patients received recombinant human granulocyte colony-stimulating factor (rhG-CSF) primed bone marrow cells plus peripheral blood stem cells after modified busulfan/cyclophosphamide + antithymocyte immunoglobulin (BU/CY + ATG ) conditioning regimen. Results All patients achieved full donor type engraftment. Grade Ⅲ-Ⅳ graft versus host disease (GVHD) occurred in 3 patients and extensive chronic GVHD in 1. With a median following-up time of 285(60-1670) d, 11 patients were alive, 9 of them had normal blood counts and the other 2 were blood transfusion independent. Six patients died of transplant-related complications. Conclusion Mismatched HSCT is a feasible and safe option for SAA patients without sibling identical donors.     

Incidence of graft vs host disease in allogeneic bone marrow transplantation in a single center study from Turkey

Graft versus host disease (GVHD) is one of the obstacles encountered in allogeneic bone marrow transplantation (alloBMT) and has a direct impact on the transplant outcome and survival. In this report, we summarized the incidence of acute and chronic GVHD among 71 HLA matched and 9 HLA mismatched sibling alloBMTs performed for various hematological malig-nancies, mainly leukemias seen at Ibn-i Sina Hospital. Fifty-five were male and 25 were female Turkish patients. Median age was 29 (12-48). Cyclophosphamide(CY) + total body irradiation (TBI)(12), CY + total lymphatic irradiation (TLI)(6), busulfan (BU) + CY(58) and ALG/ATG + CY(4) were the regimens used for conditioning. Cyclosporin A (CsA) + short term methotrexate were given for GVHD prophylaxis except for two syngeneic transplants who both received only CsA. In 22 of the patients ABO and in 30 patients sex mismatched bone marrow was given. Thirty-one (38.8%) patients showed acute GVHD (grade I-II: 22, grade III-IV: 9) and 8 (11.6%) showed chronic GVHD. In HLA matched and mismatched patients acute GVHD incidence were 33.7% and 44.4% respectively. All of the HLA mismatched patients that showed acute GVHD were in advanced stage. Of the patients with acute GVHD, 28 (96.5%) disclosed skin, 22 (75.9%) hepatic and 14 (48.3%) gut involvement. In the chronic form three patients had mild limited, two limited, two moderate and one advanced GVHD. Seven of the patients were lost due to GVHD. To determine the graft versus leukemia effect of alloBMT, we compared the disease free survival (DFS) of the 68 leukemia patients. Although the patients who had grade I-II acute GVHD showed a better DFS than the patients who did not have acute GVHD, it did not reach to a significance (15.9 vs 13.6 months: p=0.43).     

Conditioning regimen of melphalan, fludarabine and total body irradiation in unmanipulated HLA haploidentical stem cell transplantation based on feto-maternal tolerance

Unmanipulated hematopoietic stem cell transplantation from haploidentical family donors is frequently associated with graft failure and severe graft-versus-host disease (GVHD). We employed a myeloablative conditioning regimen consisting of 125 mg/m2 of fludarabine, 140 mg/m2 of melphalan and TBI of 10 to 12 Gy for three patients. The donor in each case was a haploidentical two-loci HLA mismatch mother or son. Engraftment failure was observed in one patient. In the other two patients, engraftment was confirmed within 15 days after transplantation. Acute and chronic GVHD was observed, but was controllable in both cases. HLA mismatched transplantation based on feto-maternal tolerance may provide an alternative option for patients who do not have HLA-matched donors.     

Allogeneic hematopoietic cell transplantation for paroxysmal nocturnal hemoglobinuria

BACKGROUND: Although allogeneic hematopoietic cell transplantation (HCT) has a potential to cure patients with paroxysmal nocturnal hemoglobinuria (PNH), appropriate indication and conditioning regimen for HCT have not been established. PATIENTS AND METHODS: Between July 1999 and December 2001, five patients with PNH underwent allogeneic HCT: three for refractory hemolysis and two for aggravating cytopenia. Four patients with hypercellular marrow received Bu-Fludara-ATG (busulfan 4 mg/kg/d for 2 d, fludarabine 30 mg/m2/d for 6 d, and ATG 20 mg/kg/d for 4 d) for conditioning therapy and one patient with hypocellular marrow was conditioned with Cy-ATG (cyclophosphamide 50 mg/kg/d for 4 d and ATG 30 mg/kg/d for 3 d). Three patients received stem cell graft from matched sibling donor and two patients from 1-antigen mismatched unrelated donor. RESULTS: One patient who was conditioned with Bu-Fludara-ATG failed to engraft and died at post-transplant day 62. The other four patients showed three lineage engraftment and normal expression of CD55 and CD59 antigens by flow cytometric analysis. They are alive with stable engraftment and full donor chimerism between post-transplant day 510 and 1116. Acute graft vs. host disease (GVHD) of grade II or more occurred in two patients and extensive chronic GVHD in four. CONCLUSION: HCT using related or unrelated donor could eradicate PNH clones and may cure patients with the disease. Further studies are needed to establish the role of allogeneic HCT, especially with reduced intensity conditioning therapy, in the treatment of PNH.     

Allogeneic stem cell transplantation with fludarabine/melphalan (non-TBI and non-BU/CY) for patients aged 50 or more

Since 1999, we started to modify the conditioning regimen in allogeneic stem cell transplantation for middle-aged to elderly patients (> = 50), and experimented with 3 conditioning regimens. The clinical outcome was compared between fludarabine/melphalan (FLU/MEL) conditioning and two other conditioning regimens (reduced TBI (7.5 Gy) and BU/CY). From 1999 through 2005, a total of 33 patients aged 50 or more with a hematological malignancy received allogeneic transplantation in our institute. Seventeen received FLU/MEL conditioning and 16 received the other conditioning regimens. The FLU/MEL group included more patients receiving unrelated bone marrow transplantation. There were no differences in primary disease, risk, HLA disparity, GVHD prophylaxis and stem cell source. Sustained engraftment was achieved in all evaluable patients in both groups. Regimen-related toxicities were the same in both groups. Transplant-related-mortality (TRM), relapse rate and disease-free survival were 22% and 25%, 25% and 47%, 59% and 37% in the FLU/MEL group and in the other group, respectively. The incidence of grade II-IV acute GVHD was 25% and 13%, respectively, and that of chronic GVHD was 38% and 56%, respectively. FLU/MEL conditioning achieved satisfactory engraftment. Although the relapse rate showed a lower tendency with FLU/MEL conditioning, there were no differences as far as TRM was concerned. FLU/MEL conditioning could be a novel conditioning regimen for middle-aged to elderly patients.     

Addition of high-dose Ara-C to the BMT conditioning regimen reduces leukemia relapse without an increase in toxicity.

The optimal conditioning regimen for allogeneic BMT for hematological malignancies is still to be determined. We used a conditioning regimen including high-dose Ara-C (HDAC)/CY/TBI for patients at high risk for leukemic relapse (regimen A, Ara-C 3 g/m2 every 12 h for six doses followed by CY 45 mg/kg for 2 days and TBI 13.2 Gy in eight fractions) and a standard CY/TBI conditioning regimen for patients at low risk (regimen B, CY 60 mg/kg for 2 days and TBI 13.2 Gy in eight fractions). We analyzed 55 patients treated with regimen A (group A) and 36 patients with regimen B (group B). Relapse rates (10.9% in group A, 2.9% in group B, P = 0.23), 5-year overall (53.2% in group A and 60.8% in group B, P = 0.26) and disease-free (47.7% in group A and 60.8% in group B, P = 0.11) survival rates were not significantly different between these groups, although group A consisted of high-risk patients. Regimen-related toxicities were not significantly different between the two groups. This result suggests that adding HDAC to CY/TBI conditioning regimen may reduce leukemic relapse and improve survival without increasing regimen-related toxicities.     

Anti LFA1 monoclonal antibody for the prevention of graft rejection after T cell-depleted HLA-matched bone marrow transplantation for leukemia in adults

A mouse IgG monoclonal antibody (MoAb) directed against the human LFA1 molecule (25.3 MoAb) was used in nine adult leukemic patients to prevent graft rejection after T cell-depleted HLA matched bone marrow transplantation. Based on the results of a previous study in children 0.1 mg/kg of 25.3 was given on days -3, -1, +1, +3, +5 in addition to a standard conditioning regimen with cyclophosphamide (120 mg/kg) and fractionated total body irradiation. The marrow transplant was T cell-depleted using T101 Fab immunotoxin ricin A chain. Seven patients received post-graft immunosuppression with methotrexate and cyclosporine A; two patients received no immunosuppression post-graft. A mean T cell depletion of 98.3% (80-100%) was achieved. Tolerance to the infusions of 25.3 MoAb was excellent. No patient developed any form of graft-versus-host disease. However two patients failed to engraft and three patients had delayed graft failures. These results show that this regimen of anti LFA1 MoAb, which was extremely good at permitting engraftment of HLA mismatched T cell-depleted transplant in children with constitutional diseases, is not able to prevent graft failure and rejection of T cell-depleted HLA matched transplants in adults with leukemia. Further efforts are needed to overcome graft failures in this clinical situation.