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Gadd45b is a member of Gadd45 stress sensor protein family that also includes Gadd45a & Gadd45g. To investigate the effect of Gadd45b in bcr-abl oncogene driven chronic myeloid leukemia (CML) development, syngeneic wild type lethally irradiated mice were reconstituted with either wild type or Gadd45b null myeloid progenitors transduced with a retroviral vector expressing BCR-ABL. Loss of Gadd45b was observed to accelerate BCR-ABL driven CML development with shortened median mouse survival time. BCR-ABL Gadd45b deficient CML progenitors exhibited increased proliferation and decreased apoptosis, associated with hyper-activation of c-Jun NH2-terminal kinase and Stat5. These results provide novel evidence that gadd45b, like gadd45a, functions as a suppressor of BCR-ABL driven leukemia, albeit via a different mechanism. Disclosures No relevant conflicts of interest to declare.

Background and objective: Peroxisome proliferator-activated receptor (PPAR)-gamma(γ) is a member of superfamily of nuclear hormone receptors and involved in the lipids metabolism, adipocyte differentiation, atherosclerosis and anti-inflammation. The role of PPARγ in acute graft versus host disease (aGVHD ) remains unclear. In this study, we aimed to investigate the role of PPARγ during aGVHD after allogenic hematopoietic stem cell transplantation (allo-HSCT ). Methods: 50 patients undering allo-HSCT and 20 healthy controls were enrolled in study. Peripheral blood (PB) of patients 30 days, 60 days, and 90 days were collected after allo-HSCT. We also collected PB samples at aGVHD onset and after aGVHD remission. Peripheral blood mononuclear cells (PBMCs) were isolated for real-time PCR to detect the mRNA expression of PPARγ, IFNγ, IL4, T-bet, GATA3, Foxp3, RORγt . Results: Expression of PPARγmRNA in healthy controls were significant lower than that in patients after allo-HSCT(P Conclusion: Our findings suggest that low expression of PPARγ is associated with aGVHD occurrence. PPARγ may be a useful indicator to predict aGVHD and follow-up. Disclosures No relevant conflicts of interest to declare.

Background Isolated thrombocytopenia is a common complication of hematopoietic stem-cell transplantation (HSCT), which was defined as consistent low platelet counts with recovery of the other two cell lines after transplantation. This status leads to an increased risk of life-threatening hemorrhage, frequent requirements of platelet transfusion and extended hospital stays, representing a challenging clinical problem. Previous studies have demonstrated that decitabine, a hypomethylating agent, may increase platelet counts by promoting megakaryocyte maturation and platelet release in mouse model. Here, we conduct a clinical trial to validate this effect in post-HSCT setting. Methods We performed a prospective open-label study to evaluate the treatment of low-dose decitabine in patients with hematological malignancies who received allogeneic HSCT and suffered from isolated thrombocytopenia. The inclusion criteria were: (1) Platelet count ≤ 30 × 109/L persistently at day 60 post-HSCT or later; (2) Recovered neutrophil and hemoglobin; (3) Full donor chimerism; and (4) No response to conventional treatments for a duration of at least 4 weeks. Patients with malignancy relapse, active infections, uncontrolled graft-versus-host disease, severe organ damage or transplant-related thrombosis were excluded. From July 2013 to July 2016, 38 patients were randomly assigned into either the control group to receive conventional treatment only, or the test group to receive additional decitabine (15mg/m2, intravenously daily for 3 consecutive days). Results Major response was observed in 16 out of 19 patients (84.2%) in decitabine group, with a median time of 22 days to achieve platelet transfusion-independence. Two patients (10.5%) showed a minor response and 1 patient (5.3%) failed. In contrast, 3 out of 19 patients in the control group (15.8%) showed a major response, 2 patients (10.5%) showed a minor response, 14 patients (73.7%) did not show any improvement, of which 1 patient died of severe hemorrhage in week 5. For bone marrw morpholocial analysis, all 38 patients showed low levels of megakaryocytes at week 0. However, the megakaryocyte counts in decitabine group were significantly increased at week 4, while no significant difference was recorded in control group. After decitabine treatment, we did not observe a change in anti-platelet antibodies levels and T cell subsets ratios. However, reactive oxygen species (ROS) and megakaryocyte counts increased in the test group. No considerable myelosuppression, febrile neutropenia, and nonhematologic toxicities associated with the treatment were observed. Conclusions Our data showed an encouraging efficacy of decitabine in patients after HSCT suffering from isolated thrombocytopenia owing to remarkably increased megakaryocyte counts. Decitabine may improve isolated thrombocytopenia via regulating ROS and megakaryocyte reconstitution. Disclosures No relevant conflicts of interest to declare.

Introduction: Stenotrophomonas maltophilia is an important nosocomial pathogen, particularly in immunocompromised patients, especially in patients with hematologic diseases. Methods: We reviewed the clinical characteristics and prognosis of patients with S. maltophilia bacteremia over a five-year period from January 2010 to December 2014. Species identification was performed using the automated Vitek 2 compact system (bioMe rieux). Results: The incidence of S. maltophilia bacteremia was 25.1 per 10 000 admissions in our study. Thirty-four patients (median age: 34 years; 64.7% males) with S. maltophilia bacteremia were analyzed. The S. maltophilia bacteremia related 30-day mortality was 44.1%. Risk factors associated with mortality in patients with S. maltophilia infection in the univariate and multivariate analysis were represented in Tables I and II. In the univariate analysis, risk factors included T>39.0¡æ, septic shock, respiratory failure and non-remission after treatment for primary hematological diseases (P Conclusion: Combination regimens with ciprofloxacin and ceftazidime, or sulbactam and cefoperazone could be alternative treatment. Novel antibiotics are required for treatment of S. maltophilia infection, as well as infection control practices of environmental reserves, rapid detection of pathogens, risk stratification strategy and appropriate treatment for primary hematologic malignancies, which might conjointly contribute to better survival outcome of S. maltophilia bacteremia. Univariate analysis of prognostic factors associated with mortality from S. maltophilia bacteremia Table 1. Factor Mortality HR 95%CI P-value Withfactor Withoutfactor T>39.0¡æ 75% 16.7% 2.490 1.318-4.704 0.005 Septic shock 90.0% 25.0% 2.544 1.473-4.393 0.001 Respiratory failure 100% 20.8% 4.672 2.366-9.225 0.000 Treatment outcome for hematological diseases Remission 10.0% 85.7% 0.247 0.116-0.526 0.000 HR, hazard ratio; CI, confidence interval; HSCT, Hematopoietic stem cell transplantation Table 2. Multivariate analysis of prognostic factors associated with mortality from S. maltophilia bacteremia Factor HR 95%CI P-value Respiratory failure 2.688 1.297-5.569 0.008 Remission after treatment for hematological diseases 0.367 0.153-0.879 0.025 HR, hazard ratio; CI, confidence interval Table 3. Susceptibility pattern of the 34 patients with Stenotrophomonas maltophilia bacteremia Antimicrobial agents S (%) I (%) Ceftazidime 24(70.6%) 1(2.9%) Cefoperazone 19(44.1%) 6(17.6%) Sulbactam and Cefoperazone 20(58.8%) 5(14.7%) Piperacillin 7(20.6%) 6(17.6%) Piperacillin-Tazobactam 11(32.3%) 7(20.6%) Amikacin 6(17.6%) 0(0%) Ciprofloxacin 28(82.4%) 1(2.9%) S, susceptible; I, intermediately susceptible. Disclosures No relevant conflicts of interest to declare.

Objective To expolore the association of KIR2DS4 and its variant KIR1D with cytomegalovirus(CMV) infection after HLA-matched sibling hematopoietic stem cell transplantation. Methods Polymerase chain reaction with sequence-specific primers (PCR-SSP) method was used to genotype KIR genes in 267 donor-recipient pairs from Oct 2005 to Apr 2014. Posttransplant monitoring for CMV infection was performed by immune histochemically assays .165 donor-recipient pairs who belong to KIR gene haplotype AA were analyzed for the presence of KIR2DS4 and its variant KIR1D and then further subdivided into the following groups: 2DS4-/1D+ (homozygous for the deletion variant KIR1D), 2DS4+/1D+ (heterozygous), 2DS4+/1D- (two intact KIR2DS4 alleles). Furthermore, we investigated the influence of the KIR2DS4 variants on CMV infection of 165 patients receiving Sibling related HLA matched transplantation. Results There were no significant differences in frequency of KIR2DS4 or KIR1D between donors and recipients in the haplotype AA group. The ratio of 2DS4+ and KIR1D in haplotype AA group was 2:1.There was no difference on neutrophil engraftment and platelet recovery among the three groups after hematopoietic stem cell transplantation. The CMV infection rate was significantly higher in 2DS4+/1D- group compared with 2DS4+/1D+ group (44.0% vs 19.0%，P=0.002)．In 2DS4-/1D+ group ，the CMV infection rate was higer than that in 2DS4+KIR1D+ group (50.0% vs 19%，P=0.028). However，there was no difference in CMV infection rate between 2DS4+/1D-group and 2DS4-/1D+ group. Conclusion KIR2DS4 and its variant KIR1D are associated with CMV infection after HLA-matched sibling hematopoietic stem cell transplantation Disclosures No relevant conflicts of interest to declare.

The BCR-ABL fusion oncogene which encodes a fused deregulated tyrosine kinase causes chronic myelogenous leukemia (CML) in humans. Imatinib, a small molecule ABL kinase inhibitor has been highly effective in treating chronic phase (CP) CML patients. However, a substantial number of patients undergo relapse due to development of resistance to imatinib therapy that leads to blast crisis (BC-CML), which is invariably fatal within weeks to months. Additional genetic aberrations assist in progression and identification of key players that are responsible for transformation is of utmost importance from a therapeutic point of view. Growth arrest DNA damage 45a (Gadd45a) gene, a member in the gadd45 family of genes including Gadd45b & Gadd45g, was identified as a myeloid differentiation primary response gene. There is evidence consistent with it’s involvement in G2/M cell cycle arrest and apoptosis in response to multiple stressors, including genotoxic and oncogenic stress. To investigate the effect of Gadd45a in the development of CML, adaptive bone marrow transplantation experiments with either wild type or Gadd45a null myeloid progenitors expressing 210-kD BCR-ABL fusion oncoprotein revealed that loss of Gadd45a accelerated BCR-ABL driven CML resulting in the development of a more aggressive AML/BC like disease. Recent newly obtained data indicate that number of Gadd45a deficient Leukemic stem cells (LSC) harboring BCR-ABL increased as disease progressed confirming Gadd45a as a crucial tumor suppressor in CML. Recent data also indicate, that transformed Gadd45a deficient progenitors exhibit increased proliferation and decreased apoptosis, associated with enhanced PI3K-AKT-mTOR-4E-BP1 signaling and upregulated oncogenic p30C/EBPα. More importantly, newly obtained data indicate that Gadd45a transcript levels in peripheral blood of human blast crisis (BC-CML) samples was found to be reduced compared to accelerated phase (AP-CML), chronic phase (CP-CML) and normal controls, assessed by Quantitative real time PCR analysis. Collectivly these data strongly suggest that Gadd45a expression is a novel prognostic indicator of CML progression, implicating Gadd45a as a downregulated target of BCR-ABL associated with progression to more aggressive stages. To conclude, our findings provide novel evidence that Gadd45a functions as a suppressor of BCR/ABL driven myeloid leukemogenesis, & that suppresion of Gadd45a is associated with CML progression. These data provide the impetus to further elucidate the role Gadd45a plays in suppressing the development of CML, and explore how its loss contributes to the progression of CML to more aggressive leukemic phenotypes. Disclosures: No relevant conflicts of interest to declare.

Abstract 5197 It remains unknown whether newly identified anti-inflammatory/immunosuppressive cytokine interleukin-35 (IL-35) is different from other anti-inflammatory cytokines such as IL-10 and transforming growth factor (TGF)-β in terms of inhibition of inflammation initiation and suppression of full-blown inflammation. Using experimental database mining and statistical analysis methods we developed, we examined the tissue expression profiles and regulatory mechanisms of IL-35 in comparison to other anti-inflammatory cytokines. Our results suggest that in contrast to TGF-β, IL-35 is not constitutively expressed in human tissues but it is inducible in response to inflammatory stimuli. We also provide structural evidence that AU-rich element (ARE) binding proteins and microRNAs target IL-35 subunit transcripts, by which IL-35 may achieve non-constitutive expression status. Furthermore, we propose a new system to categorize anti-inflammatory cytokines into two groups: (1) the house-keeping cytokines, such as TGF-β, inhibit the initiation of inflammation whereas (2) the responsive cytokines including IL-35 suppress inflammation in full-blown stage. Our in-depth analyses of molecular events that regulate the production of IL-35 as well as the new categorization system of anti-inflammatory cytokines are important for the design of new strategies of immune therapies. Disclosures: No relevant conflicts of interest to declare.

Abstract 3310 Our previous reports showed that survival/apoptosis of CD4+CD25+Foxp3+ regulatory T cells (Tregs) modulates vascular inflammation even though the mode of Tregs inhibition was unknown. Interleukin-35 (IL-35), consisting of two subunits Epstein-Barr virus–induced gene 3 (EBI3) and p35, is a novel anti-inflammatory cytokine, which is a member of the interleukin-12 (IL-12) cytokine family. IL-35 is produced by Tregs. It has been shown that IL-35 suppresses chronic inflammatory diseases such as asthma and inflammatory bowel diseases. However, an important question of whether IL-35 can carry out Tregs suppression and inhibit endothelial cell (EC) activation in acute inflammation remained unknown. Here we found that IL-35 significantly inhibits lung neutrophil infiltration into the surrounding areas of bronchioles and alveolar space when induced by intraperitoneal injection of lipopolysaccharide (LPS) in wild type mice and EBI3-deficient mice. Furthermore, cremaster microvasculature study using intravital microscopy showed IL-35 significantly suppresses leukocyte adhesion to the vascular wall as well, suggesting IL-35 inhibition of endothelial activation. Mechanistically, IL-35 inhibited LPS-induced upregulation of adhesion molecules on human aortic endothelial cells, a marker of endothelial activation, including vascular cell adhesion molecule 1 (VCAM-1). IL-35 acted through new IL-35 dimeric receptors gp130 and IL-12Rβ2, and inhibited VCAM-1 promoter transcription in mitogen-activated protein kinase (MAPK)-mediated pathway. These results provide a novel insight on Tregs and IL-35 inhibition of vascular inflammation. Disclosures: No relevant conflicts of interest to declare.

Abstract 5217 Objective: Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare and distinct type of T-cell lymphoma. The objective of this study was to explore the clinical presentation, treatment, and prognosis of patients with SPTCL. Methods: Twelve cases of SCPTCL, treated in our hospital between June 2005 and June 2010, were included in this study. Their clinicopathological data were reviewed and analyzed retrospectively. Results: The median age at diagnosis was 41 years (range 25–69 years) and 7 (58%) were women. 9 cases had a CD3+, CD4-, CD8- phenotype; 2 cases, a CD3+, CD4-, CD8+ phenotype; and 1 case, a CD3+, CD4+, CD8- T-cell phenotype. In all cases, strong expression of cytotoxic proteins (granzyme B, TIA-1, perforin) was observed. CD56 was expressed in 8 of 12 cases. 4 patients had presented with solitary or localized skin lesions. Ulceration was observed in 3 patients. B symptoms, such as fever, chills, night sweats, and weight loss, had been recorded in 7 of 12 patients. Laboratory abnormalities, mainly anemia, leucopenia, thrombocytopenia or combined cytopenias, and elevated liver function tests and lactate dehydrogenase, were reported in 4 patients. Bone marrow examination showed histiocytic hyperplasia, hemophagocytosis, or decreased cellularity in 3 cases, but no evidence of lymphoma. A HPS was diagnosed in 4 of 12 patients (33%), and was fatal in 2 of them. Four patients presenting with solitary or localized skin lesions had been treated with radiotherapy (2 cases) or surgery (2 cases). All 4 patients reached complete remission and only 1 of them showed a skin relapse, which was treated successfully with radiotherapy again. Eight patients with diffused lesions were treated with chemotherapy (CHOP or CHOP-like courses). After initial treatment 5 (63%) of 8 patients had developed new skin lesions, and 2 of them had developed extracutaneous localizations. Then the 3 of the relapsed patients were treated with autologous stem cell transplantation, all of whom obtained complete remission. At the time of last follow-up (median follow-up: 34 months; range: 10–60 months), 5 patients are in complete remission, 4 patients have ongoing skin disease, while 3 patients have died, 2 of the complications of HPS or therapy-related side effects and 1 of unrelated disease. The 3-year OS and DSS of the patients were 75% and 42%, respectively. Patients without HPS had a significantly better 3-year OS (88%) than patients with HPS (50%; P Conclusion: SPTCL seems to be a kind of heterogeneity disease. The factors associated with an unfavorable disease course were: diffuse lesions, a low white blood cell count, elevated lactate dehydrogenase, and combine with HPS. Autologous stem cell transplantation may improve the overall survival of high risk patients. Disclosures: No relevant conflicts of interest to declare.

Abstract 1668 The bcr-abl fusion oncogene causes chronic myelogenous leukemia (CML) in human. Growth arrest DNA damage 45a (Gadd45a) gene, a member in the gadd45 family of genes including Gadd45b & Gadd45g, is upregulated during myeloid lineage terminal differentiation. It is involved in G2/M cell cycle arrest and apoptosis in response to multiple stressors, including genotoxic and oncogenic stress. To investigate the effect of GADD45A in the development of CML, syngeneic wild type lethally irradiated mice were reconstituted with either wild type or gadd45a null myeloid progenitors transduced with a retrovirally expressed 210-kD BCR-ABL fusion oncoprotein. It was observed that loss of gadd45a accelerates BCR-ABL driven CML resulting in the development of a more aggressive AML like disease. BCR-ABL transformed GADD45A deficient progenitors exhibit increased proliferation and decreased apoptosis, associated with enhanced PI3K-AKT-mTOR-4E-BP1 signaling and upregulation of p30C/EBPα and MCL-1 expression. Since Gadd45a functions as a tumor suppressor in murine BCR-Abl driven leukemia, the status of Gadd45a mRNA expression levels was also investigated in human CML samples by utilizing real time PCR analysis. It was found that Gadd45a transcript levels were significantly upregulated in chronic phase CML samples. However in accelerated and blast phase samples, expression was significantly downregulated relative to normal controls. Thus, Gadd45a expression was observed to be altered in human CML samples correlating with disease progression. These results provide novel evidence that gadd45a functions as a suppressor of BCR/ABL driven myeloid leukemogenesis. These data also provide the impetus to further elucidate the role Gadd45a plays in suppressing the development of CML, and explore how its loss contributes to the progression of CML to a more aggressive leukemic phenotype. Disclosures: No relevant conflicts of interest to declare.

Abstract 3076 Background: Hemostatic disorders are common and potentially fatal complications in patients undergoing hematopoietic stem-cell transplantation (HSCT). Limited data exist on early diagnosis and prevention of these complications. In this study, we retrospectively investigated the outcome and risk factors associated with thrombotic and bleeding complications in HSCT recipients. Methods: From April 2004 to December 2010, 527 hematologic patients receiving HSCT (126 Auto-HSCT and 401 Allo-HSCT) were enrolled in the study, and their clinical manifestation and laboratory parameters were analyzed for evaluating the outcome of hemostatic complications and related risk factors. All analyses were carried out using the SAS program (version 8.1). Results: Overall incidence of thrombotic complication, which included 9 veno-occlusive diseases (VOD), 1 transplantation related thrombotic microangiopathy (TA-TMA), 1 pulmonary embolism (PE) and 1 deep vein thrombosis (DVT), was 2.3% (12 cases), and occurred in 11 patients who received allogeneic HSCT, and 1 patient who received autologous HSCT. The overall mortality after thrombotic events was 75% (9 cases) in all HSCT recipients with thrombotic complications. A total of 382 HSCT recipients (72.5%) developed bleeding events, including minor bleeding of 67.1% (210 cases), moderate bleeding of 28.4% (89 cases), and severe bleeding of 4.5% (14 cases) of all bleeding patients. By bleeding sites, 183 patients developed hemorrhagic cystitis (34.7% of all HSCT recipients). Other organs of hemorrhage involved skin or mucosa (46.5% of all HSCT recipients), gastrointestinal tract (21.1%), vagina (9.3%), and respiratory tract (1.3%). By risk factors analysis, CD33 mAb use and preparative regimen containing total body irradiation were significantly associated with the occurrence of thrombotic disorders (P0.05). Survival rate was correlated with the bleeding site and intensity of bleeding disorders (P Conclusions: Our study suggested that HSCT patients with thrombotic complications experienced high mortality while the HSCT recipients with bleeding disorders had high morbidity. Hence, early diagnosis and therapy of hemostatic complications are crucial to improve the prognosis of HSCT recipients. Disclosures: No relevant conflicts of interest to declare.

Abstract 1671 Chronic Myelogenous Leukemia (CML) is a disease resulting from the neoplastic transformation of hematopoietic stem cells (HSC) by the translocated tyrosine kinase BCR/ABL. The BCR-ABL protein product is a constitutively active tyrosine kinase, which promotes cell survival and proliferation by means of diverse intracellular signaling pathways, thereby being the culprit for malignant transformation. The early growth response (Egr)-1 gene, a member of the Egr family of genes encoding for zinc-finger transcription factors, has been shown to be an early response gene, to mediate cellular responses to growth factors and to be a stress response gene. Both growth factor stimulation and stress in most cells causes rapid induction of Egr-1 within minutes that leads to the activation of downstream growth pathways in normal cells. Egr-1 regulates the expression of multiple genes, either directly or indirectly, that impact on cell cycle arrest, survival and/or apoptosis, which can interface with BCR-ABL signaling. Included among these genes are p53, TGFbeta, PTEN, gadd45a, gadd45b, Foxo3a, p21, FasL, and Trail. There is a large body of evidence consistent with Egr-1 behaving as a tumor suppressor in hematopoietic cells, both in vivo & in vitro, in both humans & mice. This laboratory has shown that Egr-1 abrogates the block in M1 terminal differentiation imparted by either oncogenic c-Myc or E2F-1, suppressing their leukemia promoting function in nude mice. Since Egr-1 can be a tumor suppressor and its down-stream effectors cross-talk with BCR-ABL signaling it was asked if Egr-1 can act as a suppressor of BCR-ABL driven leukemogenesis. To assess the effect of Egr-1 on BCR-ABL driven leukemia, syngeneic wild type lethally irradiated mice were reconstituted with wild type or Egr-1 null myeloid progenitors transduced with a 210-kD BCR-ABL-expressing MSCV-retrovirus. It was observed that loss of Egr-1 accelerated the development of BCR-ABL driven leukemia in recipient mice. In vitro proliferation assays have shown enhanced proliferation capacity for BCR-ABL transduced Egr-1 null myeloid progenitors compared to wild type counterparts. In addition, flow cytometric analysis of Egr-1 null myeloid progenitors from bone marrow (BM) has shown a slightly smaller stem cell (Lineage- Sca+ and c-Kit+ [LSK]) population as compared to wild type progenitors from BM. Therefore, the accelerated induction of BCR/ABL-mediated leukemia using Egr-1 null progenitors cannot be accounted for by increased numbers of stem cells. Taken together, these results indicate that Egr-1 functions as a suppressor of BCR-ABL driven CML. Further elucidating the role of Egr-1 in the murine model of BCR-ABL driven leukemia and analysis of Egr-1 expression in human CML peripheral blood and BM could result in novel targets for diagnosis and prognosis, as well as for targeted therapeutics. Disclosures: No relevant conflicts of interest to declare.

Abstract 4601 Peripheral T-cell lymphoma (PTCL) is generally characterized by poor prognosis. To determine the role of Hyper-CVAD chemotherapy and autologous stem cell transplantation (ASCT) in PTCL, we retrospectively analyzed the outcomes of 31 patients with PTCL between 1999 and 2009. 15 patients received Hyper-CVAD chemotherapy with 3-year overall survival (OS) of 52.4% and 3-year progression free survival (PFS) of 25.7%. 16 patients received ASCT with 3-year OS of 76.2% and 3-year PFS of 61.3%. There was significant difference in 3-year PFS between the two treatments (P=0.012). Additionally, patients underwent ASCT with elevated LDH, ≥ 2 IPI points and extranodal involvement had a favorable outcome comparing with the ones received Hyper-CVAD chemotherapy. These findings might suggest that ASCT likely offer a durable survival benefit for patients with aggressive peripheral T cell lymphoma. Disclosures: No relevant conflicts of interest to declare.

Abstract 4505 Background F Thrombotic and bleeding events are common and potentially fatal complications in patients receiving hematopoietic stem-cell transplantation (HSCT), which is profoundly associated with the survival of HSCT recipients. The hemostatic imbalance and endothelial injury are main manifestations in the course of HSCT, leading to thrombotic or bleeding disorders; however, there is still a lack of information on early differential diagnosis and prevention of those complications. In this study, we retrospectively investigated the outcomes and the risk factors of thrombotic and bleeding complications in HSCT recipients, and determined the clinical significance of hemostatic factors in thrombotic and bleeding events after HSCT. Methods F 423 hematologic patients receiving HSCT (113 auto-HSCT and 310 allo-HSCT recipients) were enrolled in the study, and their clinical manifestation and laboratory parameters were analyzed for evaluating the outcomes of hemostatic complications and related risk factors. Results: The overall incidence of bleeding disorders in 423 HSCT recipients was 65% (275 cases), in which 211 cases (76.8%) are allo-HSCT recipients. Bleeding was identified and evaluated based on a daily score of intensity. Minor bleeding was seen in 74.9% (206 cases), moderate bleeding was seen in 21.8% (60 cases), and severe bleeding was seen in 3.3% (9 cases) of all bleeding patients. The organs of hemorrhage involve skin or mucosa (36% in all HSCT recipients), gastrointestinal tract (36%), lung (1.2%), brain (0.4%), and urinary (39%). In regards to thrombotic complications, 12 recipients (2.8% in all HSCT recipients) developed thrombotic events, including 9 veno-occlusive diseases (VOD), 1 transplantation related thrombotic microangiopathy (TA-TMA), 1 pulmonary embolism (PE) and 1 deep vein thrombosis (DVT). The overall mortality after thrombotic events was 66.7% (8 cases) in all HSCT recipients with thrombotic complications. Both thrombotic and bleeding disorders were significantly correlated with age, disease category and pretreatment regimen (P0.05). No difference was found in the reconstruction time required for haematogenesis between recipients with or without bleeding disorders (P>0.05), but the survival rate was correlated with the site and intensity of bleeding disorders (P Conclusion: Our study showed that the HSCT patients with bleeding disorders presented high morbidity while the HSCT recipients with the thrombotic complications had high mortality. Some of the risk factors and hemostatic parameteters were correlated with thrombotic or bleeding complications. Therefore, our observations suggest the necessity to diagnose and treat hemostatic complications early to improve the prognosis of HSCT recipients. Disclosures: No relevant conflicts of interest to declare.

Abstract 1217 The bcr/abl oncogene causes chronic myelogenous leukemia (CML) in humans. BCR/ABL is known to localize to the cytoskeleton and to display a constitutively active tyrosine kinase activity that leads to the recruitment of downstream effectors of cell proliferation and survival. This is accomplished via several adapter proteins and signaling pathways, including Ras, PI3K-AKT, PkD2-NFkB and JAK-STAT5, all of which are believed to participate in the pathogenesis of CML. The complex nature of these signaling pathways and how they contribute to the initiation and progression of CML is only partially understood. The Gadd45 family of genes (Gadd45a, Gadd45b & Gadd45g) encode for small (18 kd) nuclear proteins that are rapidly induced by multiple stressors, including genotoxic and oncogenic stress. They are involved in G2/M cell cycle arrest and apoptosis in response to exogenous stress stimuli through MAPK and JNK/SAPK pathways. Furthermore Gadd45a has been identified as a mediator of oncogenic Ras signaling. GADD45 proteins are upregulated during myeloid lineage terminal differentiation. To investigate if and how GADD45A and GADD45B play a role in the development of CML, syngeneic wild type lethally irradiated mice were reconstituted with wild type, gadd45a or gadd45b null myeloid progenitors transduced with a retrovirally expressed 210-kD BCR/ABL fusion oncoprotein. It was observed that loss of gadd45a or gadd45b accelerates the development of BCR/ABL driven leukemia in wild type recipients. BCR/ABL transformed gadd45a or gadd45b deficient progenitor recipients exhibited significantly accelerated kinetics of increase in the number of WBC and percentage of myeloid blasts in blood compared to mice reconstituted with the same number of wild type bone marrow cells transduced with BCR/ABL. There was also increase in the rate of accumulation of CD11b+Gr1+ cells in the bone marrow and spleen. Using in vitro and in vivo BrdU assays, enhanced proliferation capacity was observed for BCR/ABL transduced gadd45a, but not gadd45b, deficient myeloid progenitors. However, impaired apoptosis was observed both in BCR/ABL transduced gadd45a and gadd45b deficient myeloid progenitors. These results indicate that both gadd45a and gadd45b function as suppressors of the development of BCR/ABL driven CML, where gadd45a appears to suppress CML via a mechanism involving both inhibition of cell proliferation and enhancement of apoptosis, whereas gadd45b appears to effect only apoptosis. Enhanced JNK signaling was observed in both gadd45a and gadd45b deficient progenitors, whereas enhanced p38 and AKT signaling was observed only in gadd45a deficient myeloid progenitors. Taken together, these data indicate that loss of either gadd45a or gadd45b accelerates BCR-ABL driven CML via distinct signaling and cellular pathways. Further elucidating the role Gadd45 stress sensors play in suppressing the development of leukemia should increase understanding of the molecular/cellular pathology BCR/ABL mediated leukemogenesis, and has the potential to lead to the development of new/improved modalities for treatment of leukemia. Disclosures: No relevant conflicts of interest to declare.

3264 Poster Board III-1 The bcr/abl oncogene causes chronic myelogenous leukemia (CML) in human. BCR/ABL induces the transformation of myeloid lineage through MAPK, JNK/SAPK, PI3K signaling pathways. Growth arrest DNA damage 45A (GADD45A) and GADD45B are upregulated during myeloid lineage terminal differentiation. They are involved in G2/M cell cycle arrest and apoptosis in response to exogenous stress stimuli through MAPK and JNK/SAPK pathways. To investigate the effect of GADD45A and GADD45B in the development of CML, syngeneic wild type lethally irradiated mice were reconstituted with wild type, gadd45a or gadd45b null myeloid progenitors transduced with a retrovirally expressed 210-kD BCR/ABL fusion oncoprotein. We found that loss of gadd45a or gadd45b accelerated the development of CML-like disease in wild type recipients. BCR/ABL transformed gadd45a or gadd45b deficient progenitor recipients exhibited a significantly accelerated kinetics of increase in the number of WBC and percentage of myeloid blasts in blood compared to mice reconstituted with the same number of wild type bone marrow cells transduced with BCR/ABL. There was also increase in the rate of accumulation of CD11b+Gr1+ cells in the bone marrow and spleen. Using in vitro and in vivo BrdU assays, enhanced proliferation capacity was observed for both BCR/ABL transduced gadd45a and gadd45b deficient myeloid progenitors. BCR/ABL transduced gadd45a and gadd45b deficient primary myeloid progenitors formed more and bigger colonies compared to BCR/ABL transformed wild type progenitors. Impaired apoptosis was showed in BCR/ABL transduced gadd45a deficient myeloid progenitors. These results indicate that both gadd45a and gadd45b function as suppressors of the development of BCR/ABL driven CML, where gadd45a appears to suppress CML via mechanism involving inhibition of cell proliferation enhancement of apoptosis, whereas gadd45b appears to only inhibit cellular proliferation. Dissecting the molecular nature of signaling paths involved in the suppressive function of gadd45a and gadd45b in BCR/ABL driven CML, as well as analysis of Gadd45 in CML patients, is underway. Disclosures: No relevant conflicts of interest to declare.

Growth arrest DNA damage 45b (GADD45b) is upregulated during myeloid lineage terminal differentiation. It is also involved in G2/M cell cycle arrest and apoptosis in response to exogenous stress stimuli. To investigate the effect of GADD45b in the development of leukemia, lethally irradiated mice were reconstituted with either wildtype or gadd45b null myeloid progenitors which retrovirally expressed 210-kD BCR/ABL fusion oncoprotein. We found that both wildtype and gadd45b null myeloid progenitors expressing BCR/ABL induced chronic myelogenous leukemia (CML)-like disease between 11days to 22days after bone marrow transplantation in recipients. However, gadd45b null recipients had a shorter latency (11days–19days) compared to those of wildtypes (14days–22days). This result implies that GADD45b acts as a supressor of CML. Data will be presented on further analyzing the phenotypes of these mice.

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is a potential curative treatment for patients with malignant hematological disease. However Allo-HSCT limited by the availability of a suitably matched donor. With only 30–40% of patients having a matched-related donor available, haploidentical transplantation may increase the applicability of Allo-HSCT. The high incidence of severe GVHD is a barrier of the application of haploidentical HSCT. KIR ligand was HLA-Cw or HLA-Bw4.in our study, we detected HLA-Cw loci gene of donors and receipts with PCR-SSP who received haploidentical-HSCT. 21 patients with malignant hematologic disease, age 9–47 (median 24 year), who needed urgent transplant but neither HLA-identical sibling donors nor HLA-matched unrelated donors available, received non-T cell depleted haploidentic HSCT between July, 2002 to March 2006. patients were classified as follows AML 7 (standard risk 3, high risk 4), ALL6 (standard risk 2, high risk 4), CML 8 (4 in CP, 4 in AP or BP). All donors were HLA-haploidentical relatives who had at least two major histocompatibility complex antigen mismatched with the recipients including offspring, sibling and mother. All patients underwent haplo-HSCT with G-CSF primed BM or PB as stem cells. donors received G-CSF(300ug/12h×5d) from −5d, bone marrow cells were collected at −2d, PBSC were collected at −1d if CD34+ cells less than 4×106/kg of recipient’s body weight. The CD34+ cells in graft of HLA-Cw matched group were (5.43±1.59)×106/kg of recipient’s body weight. HLA-Cw mismatched group were (6.54±1.53)×106/kg of recipient’s body weight(P>0.05). CD3+T cells in graft of HLA-Cw matched group were (0.46±0.08)×108/kg of recipient’s body weight. HLA-Cw mismatched group were (1.89±1.15) ×108/kg(P

Objective: To study the distribution of CMV glycoprotein B (gB) genotypes in the patients with CMV infection after allo-HSCT Methods: Seventy-four patients undergoing allo-HSCT were enrolled in this study. After allo-HSCT, all the patients were detected for CMV gB DNA in peripheral blood by haplo-nested PCR methods;The CMV gB DNA positive samples were screened, which were sufficient for enzyme digestion. Glycoprotein B typing was performed through digesting PCR products with RsaIand HinfI;The sequences were mensurated with ABI PRISM 377 XL DNA Sequencer. Results: The PCR products of thirty-eight patients were digested with enzyme. the distribution of gB genotypes was as follows:I(gB1) 19/38 (50.0%), II(gB2) 3/38 (7.89%),III(gB3) 14/38 (36.84%), and unclassification 2/38 (5.27%). Conclusion: The distribution of gB genotypes was different in the patients with CMV infection after allo-HSCT; There may be exiting new genotype.

Objective: To compare the dendritic cells reconstitution after different allogeneic hematopoietic stem cell transplantation in early time Methods: From June 2004 to March 2005, Twenty-eight patients undergoing allo-HSCT were enrolled in this study. There were 16 patients who undergone normal HSCT, 8 patients who undergone Haploidentical HSCT and 4 patients who undergone Nonmyeloablative HSCT. Three-colour flow cytometry was applied to study the alteration of the percentage and number in circulating peripheral blood dendritic cells subsets on day 14,day 30,day 60 after transplantation among three distinct type HSCT. Results: The dendritic cells subsets number of myeloablative HSCT patients were very low. No difference was observed in the kinetics of DC1 (Lin−HLA-DR+CD11c+)and DC2 (Lin−HLA-DR+CD123+) reconstitution between the normal HSCT group and Haploidentical HSCT group patients(p Conclusion: The early reconstitution of dendritic cells in Nonmyeloablative HSCT patients is earlier than the patients who undergone myeloablative HSCT. The early reconstitution of dendritic cells in normal HSCT and Haploidentical HSCT patients were later than others.