ALBERT

Description: Background Allogeneic hematopoietic stem cell transplantation is an effective method for treatment of hematological malignancies, while GVHD and graft rejection are main complications, which seriously affect patients' survival rates and quality of life. Aim Establishing allo-transplantation mice model with mRFP and GFP transgenic mice, to simulate clinical hematopoietic stem cell transplantation and explore the mechanism of stem cell homing and GVHD. Methods 1) Thirteen C57BL/6 GFP transgenic mice, used as recipients, were irradiated with 7 Gy. Each mouse was injected through caudal vein with 2*106 bone marrow cells isolated from FVB mRFP transgenic mice. 2) Symptoms like weight loss, depilation, diarrhea were observed as GVHD manifestation while survival rates were evaluated. Routine blood test and FACS were performed at different time points to confirm hematopoiesis reconstitution. 3) Mice were perfused with paraformaldehyde under anesthesia to fix the tissue, while pathological examination and real-time PCR were performed for studying donor and recipient cells interactions in different organs. 4) Semi-solid decalcification was used to treat the femora before observing under confocal microscope directly or after making frozen section, three-dimensional reconstruction were made to observe the cellular interaction, especially for cells within the bone marrow. Result 1) Depilation, wrinkled skin, hunchback and sharp decline of weight were observed in 8/13 mice. Routine blood test implicated hematopoietic reconstitution. FACS showed 86.1%±7.8% mRFP+ cells in peripheral blood of recipients. 2) mRFP+ cells were found distributing throughout the body's organs. mRFP+ Lymphocyte infiltration and inflammatory exudate were seen especially in the small intestine, lung, liver and skin (Fig.1). GFP+ cells were found surrounding mRFP+ cells in the bone marrow of the femora decalcified with semi-solid decalcification. Their interactions can be further observed clearly in bone marrow microenvironment in three-dimensional reconstruction by confocal microscope (Fig.2). Discussion Owing to RFP on donors' cells and GFP on recipients' cells, together with our novel protocol named semi-solid decalcification, we can visually observe the donor and recipient cells' location, ratio and cellular interaction, as well as morphological changes. Within various tissues especially for such tissues as bone marrow and lung, the details between cells can be studied lively by fluorescence microscope and confocal microscope. In recipient mice with GVHD, donor cells can be found in various target tissues such as intestine, lung, liver and skin. Gene marked cells with fluorescence protein can benefit morphological, immunological, cytogenetic and molecular studies in recipients after HSCT. Conclusion The allo-transplantation model with mRFP and GFP transgenic mice is powerful in study of Stem Cell Homing and Donor-Recipient Cellular Interaction. The cellular interaction can be easily observed by three-dimensional reconstruction after semi-solid decalcification, especially for bone marrow and lung. Disclosures: No relevant conflicts of interest to declare.

Description: Key Points Haploidentical transplant achieves outcomes similar to those of identical-sibling transplant for AML patients in first remission. Haploidentical transplant is a valid postremission treatment of intermediate- or high-risk AML patients lacking an identical donor.

Description: Background The best donor for a haematopoietic cell transplant in a person with acute myeloid leukaemia (AML) in 1st remission is controversial. Prior data indicate similar outcomes after transplants from HLA-haplotype-matched relatives, HLA-identical siblings and HLA-matched unrelated donors. Methods We analyzed data from persons with intermediate- or high-risk AML in 1st complete remission (CR1) treated in a prospective, multi-centre study. Results 602 consecutive subjects received a transplant from an HLA-haplotype-matched relative (N=328) or an HLA-identical sibling (N=274). 4 year leukaemia-free survivals were 78% (95% confidence interval [CI], 73, 83%) and 80% (75, 85%; P=0.39). In multivariate analyses younger donor/recipient age (donor

Description: Abstract 3015FN2 Objective: Acute hemorrhagic cystitis (HC), a severe complication of hematopoietic stem cell transplantation (HSCT), being considered mainly as a result of cyclophosphamide (CTX), seriously affects the quality of life of patients. Mesna, whose half-life is about 70min, is widely used to prevent HC. Aim of this research is to explore the effect of continuous intravenous injection of mesna on HC in HSCT. Methods: (1) 108 patients who underwent HSCT in Nanfang hospital from July 2008 to December 2010 were recruited into this study (70 male and 38 female, the median age is 35.00); 106 cases were allogenic HSCT, 2 cases were auto-HSCT. Conditioning regimens were BuCy or TBI-Cy, in which CTX were given 60mg/kg·d, d−3, −2. Intravenous injection of mesna was used to prevent HC continuously (continuous group, n=68) or intermittently (intermittent group, n=40). Graft versus host disease (GVHD) prevention regimen was cyclosporine A+MTX for HLA-matched sibling donors and cyclosporine A+MTX+ATG for unrelated donors or HLA partial-matched related donors. (2) Both groups received the same daily dose of mesna, which is about 150% of CTX daily dosage. In the intermittent group, 25% of mesna's daily dosage was injected at 0h, 3h, 6h and 9h after the use of CTX at each time-point; while in the continuous group, 25% of mesna's daily dosage was injected before the use of CTX, with the rest dosage being continuously injected intravenously for 24hs using micro-infusion pump (25% daily dosage of mesna dissolved in 40ml 0.9% sodium chloride lasting for 8h was given, q8h), from the first dose of CTX till 48hs after the last injection of CTX. Incidences and grades of HC in the two groups were followed up and analyzed. (3) The mesna concentration in urine of two groups was detected by HPLC, with the comparison of trough concentrations being presented by comparing the average peak concentration. Results: (1) Within 30d after transplantation, HC occurs in 13 of the 40 (32.5%) cases in the intermittent group (6 cases of II°, 4 cases of III°, 3 cases of IV°) with none (0%) in the continuous group. Within 60d after transplantation, HC occurs in 16 of 40 (40.0%) cases in the intermittent group (8 cases of II°, 5 cases of III°, 3 cases of IV°) with the mean occurrence time being +14.6d (-1d - +44d); while only 7 of 68 (10.3%) cases (5 cases of I°and 2 of II°) in the continuous group with the mean time of +43.0d (+33d–+54d). There were statistical significances of the incidence (P =0.000), grade/severity (P =0.007) and occurrence time (P =0.005) of HC between the two groups. (2) Logistic regression analysis shows that the HC occurrences relates with the way of using mesna(P =0.025), with continuous mesna injection being a protective factor(OR=0.114, 95% CI=0.017–0.764); while age, sex, 24h mean liquid intake, 24h mean excretion, 24h mean urinary volume (each P 〉0.1) and HLA matching (P =0.063) were unrelated factors. (3) The urine mesna trough concentration/average peak concentration was 0.219 (0.043–0.399) and 0.643 (0.153–0.868) in the intermittent group and the continuous group, respectively(P =0.031, n=4). Discussion: Early occurrence of HC is mostly related to high dose of cyclophosphamide, while late occurrence of HC can also be related with infection and GVHD, etc. The continuous injection of mesna seems to be a better way for the prevention of HC in HSCT patients, due to its short half-life of mesna. Injection with micro-infusion pump can reduce the liquid intake, especially suitable for those who have heart or kidney dysfunctions. More tests of mesna and acrolein concentration will help to reveal the mechanism. Conclusion: Continuous intravenous injection of mesna is a more efficient method in prevention of HC in hematopoietic stem cell transplantation than routine intermittent intravenous injection. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 4295 Syngeneic blood and marrow transplantation (BMT) has been applied in the treatment of many malignant or nonmalignant hematologic disorders with no or minimal and transient graft-versus-host disease (GVHD), much less transplant-related mortality (TRM) in contrast to allogeneic BMT, and lower relapse rate compared with autologous BMT. However, limited data in a single BMT center is not sufficient for statistical analysis. To evaluate the clinical outcomes of syngeneic BMT, CSBMT has performed a cooperative survey among BMT centers in mainland, Taiwan, and Hong Kong. From January 1964 to May 2009, 94 transplants from syngeneic donors have been performed in 32 BMT centers. The median age was 20 (1.5 to 51) years old. The diagnosis included AML (29 cases), SAA (26 cases), ALL (17 cases), CML (12 cases), lymphoma (3 cases), MDS (4 cases), neuroblastoma (2 cases), and large granular lymphocytosis (1 case). The main conditioning regimens were CYTBI or BUCY for malignant diseases, none or CY plus ATG for SAA. Bone marrow (BM, 34) or peripheral blood (PB, 49) or both BM and PB (11) as grafts were used. Five patients (SAA 2, AML 3) underwent the same donor's syngeneic BMT twice. One patient with large granular lymphocytosis and 1 case with SAA underwent the same donor's syngeneic BMT thrice. The median follow-up time was 28 months (1 month to 45 years). The median time for white blood cells 〉 1.0 × 109/L, and platelets 〉 20 × 109/L was 11 (2-30) days, 13 (0-122) days, respectively. Two patients (2.1%) had grade I acute GVHD (aGVHD), and 4 cases (4.3%) had grade II aGVHD. However, only one patient's specimen was consulted by pathologist. All aGVHD was controlled easily with low-dose steroid. No chronic GVHD was noted. Three-year disease-free survival (DFS) for the patients with nonmalignant disorders was 88.5%. Among them, the longest survivor was living and well for 45 years after transplant. Three-year DFS for the patients with malignant diseases was 62.9%. The overall survival rates at 3 years were 87.9%, and 69.5% for nonmalignant, and malignant diseases, respectively. 22 of 94 patients died after BMT (nonmalignant 3, malignant 19). The only cause of death for the patients with nonmalignant disorders was rejection. Relapse was the main cause of death in patients with malignancies (17/19). TRM was 2.1%. In conclusion, syngeneic BMT is a safe and effective therapeutic option for both nonmalignant and malignant hematologic disorders. Syngeneic donor, if available, should be the first choice in all cases of AA and hematological malignancies in general. The longest survivor of 45 years post-BMT is presented in this series. The good results and advantage of syngeneic BMT cast light on the potential utility of stored autologous placental-cord blood which is shared by the identical twin through the same placenta. Disclosures: No relevant conflicts of interest to declare.

Description: Key Points RUNX1/RUNX1T1-based MRD status at 1, 2, and 3 months after HSCT could discriminate patients at high risk of post-HSCT relapse. Rather than c-KIT mutations, MRD monitoring allows further rapid identification of patients at high risk of relapse after allo-HSCT.

Description: Chronic graft-versus-host disease (cGVHD) is the main cause of non-relapse mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Mesenchymal stem cells (MSCs) in bone marrow (BM) remain unclear in the pathophysiology of cGVHD. In this study, we analyzed BM-MSCs from 66 patients after allo-HSCT, including 33 with active cGVHD and 33 without cGVHD. BM-MSCs showed similar morphology, frequency, phenotype, and proliferation in patients with or without cGVHD. MSCs from the active cGVHD group showed a decreased apoptosis rate (P 

Description: Background The optimal dose of antithymocyte globulin (ATG) with respect to the prevention of graft-versus-host disease (GVHD) following haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is under investigation. In our previous single-center randomized study, as compared with 6 mg/kg ATG, 10 mg/kg ATG was found to be associated with better GVHD prevention and superior GRFS, but an increase in infection-related deaths. Later on, in our multi-center randomized trial, 7.5 mg/kg ATG for GVHD prophylaxis was associated with reduced EBV and CMV infections without increased incidence of GVHD in comparison with 10.0 mg/kg ATG in haplo-HSCT. Methods We reanalyzed and updated the prospective, randomized trial (clinicaltrials.gov, NCT01883180) identifying the influence of 7.5mg/kg versus 10.0 mg/kg of ATG on clinical outcomes in haplo-HSCT with extended follow-up (N=145. Seventy-six patients received 7.5 mg/kg ATG (ATG-7.5), whereas the remaining patients received 10 mg/kg ATG (ATG-10). Results The median follow-up period was 1702 days (range, 23-2036 days). The rate of infection-related deaths in ATG-10 arm was double that of the ATG-7.5 arm (20.0% vs 11.8%; P=0.024). The 5 year cumulative incidence of relapse was not significantly different between the ATG-7.5 and ATG-10 groups (16.8% vs. 5.7%, P = 0.053). The 5 year cumulative incidence of non-relapse mortality was comparable between the ATG-7.5 and ATG-10 groups (27.6% vs. 28.7%, P = 0.938). The 5 year cumulative incidence of chronic GVHD (46.7% vs. 48.3%, P = 0.913), moderate-to-severe chronic GVHD (32.8% vs. 25.3%, P = 0.248), and severe chronic GVHD (17.1% vs. 13.3%, P = 0.505) were comparable between the ATG-7.5 and ATG-10 groups. The 5 year probabilities of disease-free survival (DFS) in the ATG-7.5 and ATG-10 groups were 55.6% and 65.7%, respectively (P = 0.281). The 5 year probability of GVHD-free/relapse-free survival (GRFS) in the ATG-10 group was significantly higher than that in the ATG-7.5 group (48.1% vs. 29.5%, P = 0.020). The 5 year cumulative incidence of late effects of grades 1-5 (67.2% vs. 71.2%, P = 0.695) and multiple late effects (26.2% vs. 25.4%, P = 0.920) were comparable between the ATG-7.5 and ATG-10 groups. In multivariate analysis, ATG-7.5 was associated with a significantly lower GRFS compared to ATG-10 (hazard ratio, 1.819; 95% confidence interval, 1.106-2.994; p=0.019). Conclusion it appears that 10 mg/kg ATG was found to be associated with superior GRFS and comparable GVHD and late effects, but an increase in infection-related deaths as compared with 7.5 mg/kg ATG for haplo-HSCT. Figure Disclosures No relevant conflicts of interest to declare.