Academic literature on the topic 'QE 3.5 UL 2007'

Abstract Abstract 3088 Background: Despite the use of modern immunochemotherapy (R-CHOP) regimens, almost 50% of patients with diffuse large-B-cell lymphoma (DLBCL) will relapse. Current prognostic models, most notably the International Prognostic Index, are comprised of patient and tumor characteristics and are unable to identify patients with less than a 50% chance of long-term survival. However, recent observations demonstrate that factors related to host adaptive immunity and the tumor microenvironment are powerful prognostic variables in non-Hodgkin lymphoma Methods: We retrospectively examined the absolute neutrophil count (ANC), monocyte count (AMC) and lymphocyte count (ALC), obtained from an automated complete blood count with differential, as prognostic variables in a cohort of 255 consecutive DLBCL patients that were uniformly treated with R-CHOP between 2000 and 2007 at a single institution. The primary study objective was to assess if ANC, AMC, and ALC at diagnosis were predictors of overall survival (OS) in DLBCL. Results: At diagnosis, the median ANC was 4720/uL (range 1190–17690), the median AMC was 610/uL (range 30–4040), and the median ALC was 1220/uL (range 140–5410). The median follow-up for these patients was 48 months. In the univariate analysis, each of these variables predicted OS as continuous variables. As dichotomized variables, an elevated ANC (≥5500/μL; hazard ratio 1.75, 95% confidence interval 1.14–2.60, p=0.01) and AMC (≥610/μL; hazard ratio 3.36, 95% confidence interval 2.10–5.59, p<0.0001) were each associated with inferior OS. In contrast, the presence of lymphopenia, defined as an ALC ≤1000/uL, was associated with inferior OS (hazard ratio 2.21, 95% confidence interval 1.43–3.39, p=0.0004). When components of the IPI were included on multivariate analysis only the AMC and ALC were independently significant prognostic factors for OS, with hazard ratios of 3.37 (95% confidence interval 2.05–5.74, p<0.0001) and 2.19 (95% confidence interval 1.38–3.44, p=0.0009), respectively. The dichotomized AMC and ALC generated the AMC/ALC prognostic index (PI) and stratified patients into 3 risk groups: very good (AMC <610/uL and ALC >1000/uL), good (AMC ≥610/uL or ALC ≤1000/uL), and poor-risk (AMC ≥610/uL and ALC ≤1000/uL) populations. For both the very good (n=79) and good-risk (n=134) groups median OS has not been reached with estimated 5-year overall survival of 88% and 69%, respectively. Median OS for poor-risk (n=42) patients was 1.7 years (95% confidence interval 1.1–2.7 years) with an estimated 5-year overall survival of 28% (p<0.0001). By comparison, the R-IPI was unable to identify a group of patients with a median survival less than 8 years. The estimated 5-year OS was 93%, 71% and 53% for very good, good and poor-risk patients, respectively. We sought to determine whether the AMC/ALC PI may provide additional prognostic information when combined with the R-IPI. To test this possibility, the 171 very good/good risk and 84 poor risk patients identified by the R-IPI were subsequently risk stratified using the AMC/ALC PI. Among R-IPI very good/good risk patients a subset of poor risk patients (n=21) with a median OS of 2.2 years (95% confidence interval 1.1–6.6 years) and 35% 5-year OS could be identified with the AMC/ALC PI. In contrast, 5-year OS ranged from 75%-88% among very good and good risk patients. Similarly, stratification of R-IPI poor risk patients by the AMC/ALC PI identified subsets of very good (n=19) and good risk (n=44) patients with median OS that had not been reached and 86% and 55% 5-year OS, respectively. High risk (n=21) patients had a median OS of 1.4 years (95% confidence interval 0.9–2.2 years) and an estimated 5-year OS of less than 25%. Conclusions: Measurement of AMC and ALC at diagnosis is widely applicable, cost effective, predicts OS, and identifies high-risk patients with DLBCL. Disclosures: No relevant conflicts of interest to declare.

Abstract Hematopoiesis of the host is a primary target organ of the graft-versus-host reaction. However histological analyses of the bone marrow are rarely reported. Here we report histological changes in the bone marrow of patients (pts) with and without chronic graft-versus-host disease (cGvHD). Bone marrow biopsies were obtained between 101 days and 4623 days (median:419 days) after transplantation as part of a controlled prospective phase ll study of patients with osteopenia/osteoporosis after allogeneic hematopoietic stem cell transplantation (HCT). Previously we reported an increased density of microvessels using an antibody against v. Willebrand factor (vW) (Hill W. et al Blood110, abstract No 1963; 2007). Here we report additional immunohistological and immunocytological findings in marrow and blood. We analyzed the number of CD34+ and vW+ microvessels as well as CD8+ suppressor/cytotoxic T-cells/mm² (T-S) in sequential biopsies of pts with (n=9) or without (n=6) cGvHD after median 2 years apart. Biopsies of 3 pts without HCT and without lymphoma involvement served as controls. Simultaneously lymphocyte subpopulations were evaluated in peripheral blood samples of pts with (n=16) or without (n=8) cGvHD. The pts were divided in 5 groups: neither aGvHD nor cGvHD; no cGvHD but acute GvHD before entry; cGvHD limited; cGvHD extensive without immunosuppression; cGvHD extensive with immunosuppression. Results: In the first biopsies the content of CD34+, vW+ microvessels and T-S cells were significantly higher in pts with cGvHD (group 3–5) than in those without cGvHD (group 1–2) (21,3 vs 8,2 p=0,03; 22,0 vs 9,2 p=0,002 respectively 106,2 vs 32,1 p=0,04). In the second biopsies these parameters were also increased in cGvHD: CD34+ (18,3 vs 11,2 p=0,02), vW+ (17,3 vs 9,0 p=0,08) microvessels and T-S cells (63,2 vs 37,8 p=0,27). The increased density of CD34+ and vW+ microvessels correlated with the number of T-S cells (p=0,05). As compared to normal controls we observed a significantly higher content of vW+ microvessels in all groups of transplanted pts (16,9 vs 4,2 p=0,03). In pts with cGvHD (group 3–5) CD34+ and vW+ microvessels were further increased (p=0,02 respectively p=0,002). At the time of the first biopsy the absolute T-S cell content in peripheral blood was moderately increased in group 5 (1124/ul) and minimally increased in group 2 (993/ul) (normal 270 – 880), whereas the overall T cell (CD3) content was normal in all groups. The percentage of activated T-S (HLA-DR+) cells was increased in all groups of transplanted pts (61,8% vs normal =33%; p=0,05). After two years T-S cells content was reduced in pts under immunosuppressive therapy (group 5) (1415 vs 900/ul; p=0.000) but remained increased over the norm. In group 4 T-S cell content was increased over the norm (800 vs 920/ul; p=0,043). In conclusion, sequential immunohistology and immunocytology analyses on bone marrow biopsies and peripheral blood provide evidence for the existence of a chronic graft-versus-host reaction of the bone marrow in pts with cGvHD. This is characterized by an increased content of CD34+ and vW+ microvessels and an increased content of T-S cells at least initially. However this reaction does not lead to a generalized hematopoietic insufficiency.

Abstract Abstract 4863 Introduction: Cytogenetic studies are an important prognostic tool in the management of hematologic malignancies such as myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). While a nonrandom structural gain of 1q may be seen in MDS and AML, it is most commonly due to an unbalanced translocation usually in association with other chromosomal abnormalities. Duplication of the long arm of chromosome 1 [dup(1)(q21q32)] as the sole abnormality in nonlymphoid hematologic malignancies has only rarely been reported. As a result, very little is known about the clinical significance of this chromosomal abnormality. However, it has been suggested that this single aberration is predictive of an increased risk of clonal evolution and poor overall prognosis. Case Presentation: A then 55 year old male presented in June, 2002 with a CBC showing: WBC 36,300/ul (74% blasts with Auer rods), Hgb 7.0 gm/dl, MCV 98fl, platelets 61,000/ul. Bone marrow biopsy was 90% cellular with sheets of blasts. The blasts were positive for CD34, CD117, HLA-DR, CD13, MPO, CD56, and Tdt. A diagnosis of AML M2 was made. Cytogenetics showed 45,X,-Y, t(8;21)(q22;q22). He underwent successful standard induction with “7+3” followed by consolidation with “5+2” and 4 cycles of high dose cytarabine. Subsequent bone marrows after induction and during consolidation showed no evidence of AML. The karyotype was 46,XY with no evidence of t(8;21) by FISH. He has had complete recovery of his blood counts, except for intermittent neutropenia. In May, 2004, G-banding of his bone marrow revealed the presence of a dup(1)(q21q32) as an isolated cytogenetic aberration for the first time. This finding was again seen on follow up studies in 2006, 2007, and 2009. His most recent evaluation in May 2010 showed WBC 5,500/ul (neutrophils 2,200/ul), Hgb 14.0 gm/dl, MCV 92fl, platelets 299,000/ul. Bone marrow biopsy was 40% cellular with trilineage hematopoiesis. The aspirate showed erythroid hyperplasia with megaloblastoid features. No dysplastic RBC or ring sideroblasts were seen. Cytogenetics showed 46,XY,dup(1)(q21q32)[15]/46,XY[5]. FISH for AML1/ETO t(8;21) and for abnormalities of chromosomes 5, 7, 8, and 20 were negative. Discussion: Dup(1q) has been reported as an isolated cytogenetic abnormality in a variety of MDS subtypes. It may be either a primary or secondary chromosomal aberration. It has been suggested that isolated dup(1q) in MDS is a harbinger of disease progression. Recent reports of MDS with either inverted dup(1)(q32 q21) or dup(1)(q21q32) of both chromosome 1 homologs showed no disease progression but had very short follow-up. Conclusion: To our knowledge, this case is the first report of an acquired duplication dup(1)(q21q32) as the sole abnormality in a patient previously treated for AML. This duplication developed approximately 2 years after induction and consolidation chemotherapy. The involved clone is not the original leukemic clone since there is no evidence for t(8;21) or -Y. Six years later, there has been no evidence of progression to MDS or sAML. It is not known why our patient has shown such long survivorship after discovery of dup(1)(q21q32), nor is it known if this chromosomal finding is a treatment related phenomenon. This case suggests that dup(1q) may not be exclusively associated with a poor prognosis. FISH analysis with a 1q21 probe is planned to confirm our G-banding observation. Disclosures: Lachant: sanofi-aventis: Speakers Bureau; glaxosmithkline: Speakers Bureau.

Abstract Backgrounds and Aims Hepatic veno-occlusive disease (VOD) associated with hematopoietic stem cell transplantation (HSCT) is characterized by a clinical triad of jaundice (total bilirubin, >2 mg/mL), hepatomegaly with right upper quadrant pain, and ascites and/or unexplained body weight gain (>5% of baseline) within 30 days after operation. Although the pathogenesis of hepatic VOD has not been fully elucidated, the common pathological features are thrombi formed in hepatic central vein. We previously reported that a significant decrease of plasma ADAMTS13 activity was noted in patients undergoing HSCT, who subsequently developed VOD (Park et al, BMT 2002). Then, we showed that plasma antigen levels of von Willebrand factor (VWF) has been kept higher in HSCT-patients with VOD than in those without, and in fact prophylactic infusions of fresh frozen plasma (FFP) with a dose of 10 ml/kg body weight 3 times per week were effective to reduce the frequency of VOD occurrence in high risk patients (Matsumoto et al, BMT 2007). However, more recent studies by ours indicate that FFP infusion alone is not enough to totally eliminate the occurrence (unpublished). Recently, it has been shown that the treatment with recombinant soluble thrombomodulin (rTM) is sometimes highly efficient to reverse VOD progression. But its pharmacokinetics and regimen for the treatment has not been established. As a first step to elucidate a possible combination regimen of FFP and rTM to VOD patients, here we have analyzed the transitional changes of unusually large VWF multimers (UL-VWFMs). The UL-VWFMs are released from damaged endothelial cells and induce platelet hyperagglutination under high shear stress generated in microvasculatures, and are often observed in patient plasmas undergoing HSCT. Patients and Methods During 2011-2012, 45 patients were received allogenic HSCT in the second internal medicine department of our university hospital. None of these patients ,however, were received planned prophylactic FFP infusions, and as a result six patients undergoing allogenic cord blood transplantation (CBT) developed VOD. Clinical features of these 6 patients are shown in Table 1. Under approval of Ethics Committee of Nara Medical University, we consecutively collected patient's citrated plasmas (ca 2.5 ml) and stored at -80°C until use. Using these deep-frozen plasma samples, we here extensively analyzed plasma levels of ADAMTS13 activity (ADAMTS13:AC), VWF antigen (VWF:Ag), and VWF collagen binding activity (VWF: CBA), together with VWF multimer analysis. More importantly, we also measured the corrected platelet count increment (CCI) to evaluate the efficiency of Platelet trsnsfusions. Then, we comprehensively evaluated these data with routine clinical and laboratory findings. Results and Discussion 1) Plasma levels of ADAMTS13:AC were moderately but consistently decreased during two months after HSCT, whereas those of VWF:Ag were kept high, usually more than 200% and often 500% of the normal. 2) The UL-VWFMs appeared soon after HSCT, and continued at least until absolute neutrophil count (ANC) increased to >500 (usually 20-30 days after HSCT). 3) Until platelet engraftment (usually 40-60 days after HSCT), platelet transfusions (every 2-3 days interval) are usually performed to prevent the bleeding complications. During that period, the CCI values were consistently low, but those values were significantly increased during the administration of rTM. 4) Excess platelet transfusions before platelet engraftment induced the consumption of larger VWFMs in patient's plasmas, and often almost simultaneously hepatic VOD developed. Thus, platelet transfusions during the appearance of UL-VWFMs in patient's plasmas may induce platelet clumping in microvasculatures, and lead to the development of thrombotic complications including hepatic VOD. 5) The measurement of plasma levels of VWF:CB activity appeared to well predict the presence of UL-VWFMs. A representative case is shown in Figure. Thus, a combination regimen of FFP and rTM might be advisable when the patients show the early clinical signs of hepatic VOD and the laboratory data such as VWF:CBA suggest the presence of UL-VWFMs in patient's plasmas. Disclosures: Matsumoto: Alexion Pharma: Membership on an entity’s Board of Directors or advisory committees. Fujimura:Alexion Pharma: Membership on an entity’s Board of Directors or advisory committees; Baxter International Inc: Membership on an entity’s Board of Directors or advisory committees.

Abstract BACKGROUND: Reconstitution of adaptive immunity is critical for long term survival following hematopoietic cell transplantation. Antigen presenting dendritic cells (DC) and CD4+ T cells are critical for attaining immunity. Unrelated umbilical cord blood transplantation (UCBT) is a suitable option for those who lack HLA-matched sibling donors. However, opportunistic infections remain the major cause of non-relapse mortality. Analysis of the COBLT trial reported that successful recovery of antiviral immunity is associated with a reduced rate of relapse (BBMT. 2006;12:1335). METHODS: Between July, 2005 and December, 2007, 95 children with successful donor cell engraftment were assessed for reconstitution of DC subsets along with CD4+ T cells to analyze their impact on overall survival (OS) following myeloablative conditioning and a single cord blood transplant at Duke University. Utilizing Trucount™ methodology 4-color surface FACS was employed to enumerate absolute cell numbers at 3, 6, 12, 24, 36 months after transplant. RESULTS: 52 (55%) of patients were transplanted for non-malignant diseases while 43 (45%) had malignancies. The median age was 2.7 years (range, 0.1–18.0). 55 (59%) of patients were male and 74 (78%) were white. 38 (40%) were 4/6 HLA match, 39 (41%) were 5/6 and 18 (19%) were 6/6. The median infused TNC was 7.2 x 107/kg (range, 0.8–31.6), median infused CD34+ was 1.9 x 105/kg (range, 0.0–11.0), and median infused CD3+ T cells was 11.7 x 106/kg (range, 0.0–90.3). Of the 95 patients considered in this analysis, 6 patients died before day 180 with a day 180 survival probability of 93.7% (95% CI 86.5%–97.1%), 11 patients died between day 180 and 365 with a 1-year survival probability of 81.7% (95% CI 72.2%–88.2%) and 8 patients died between day 365 and 730 with a 2-year survival probability of 69.1% (95% CI 57.1%–78.3%). In an univariate analysis of OS post-transplant, HLA match of 5/6 or 6/6 (HR=0.41, p=0.02), absolute number of CD123+ “plasmacytoid” dendritic cells (pDC) &gt;8 cells/ul and a non-malignant diagnosis (HR=0.25, p=0.001) were associated with a decreased risk of death, while CD4+ T cell and CD11c+ “myeloid” DC recovery had no statistical impact, Table 1. In this cohort, where all studied patients have successfully engrafted with relatively high cell dose; gender, race, CMV serology, TNC, CD34+ cell dose, TBI had no discernible impact. There were two prognostic factors that maintained statistical significance in a multivariate model; Absolute number of CD123+ DC &gt;8 cells/ul (HR=0.44, p=0.05) and non-malignant disease (HR=0.27, p=0.002), while HLA was not statistically significant (HR=0.53, p=0.10), Table I. Importantly, non-malignant patients do not get TBI, do not die due to relapse, tend to be younger and such receive higher cell doses. CONCLUSION: This is the first analysis to our knowledge to suggests that the absolute number of CD123+ pDC &gt;8 Cells/ul is an independent predictor of survival after UCBT. These cells are the most potent APC providing interferon-alpha mediated activation of the immune system besides presentation of antigenic peptides. There is a need for better understanding of the factors that may impact pDC reconstitution so novel therapeutic approaches may improve survival after UCBT. Univariate Modeling of OS HR (95% CI) p-value Interpretation Gender Female 1.52 (0.72–3.21) 0.27 NS Male 1.00 Disease Non-Malignant 0.25 (0.11–0.58) 0.001 Non-Malignant patients have a 75% decreased risk of dieing as compared to malignant Malignant 1.00 TNC/kg 1.03 (0.97–1.10) 0.35 NS CD34+/kg 1.01 (0.86–1.19) 0.87 NS CD3+/kg 1.01 (0.98–1.04) 0.68 NS HLA Match 5/6 or 6/6 0.41 (0.20–0.88) 0.02 59% decreased risk of dieing with a HLA match of 5/6 or 6/6 4/6 1.00 41% decreased risk Abs CD4+ T cells Time-dependent 0.59 (0.23–1.52) 0.28 of dieing if you get 200 abs CD4+ T-cell Absolute Number of CD123+ DC (pDC/ul) Time-Dependent 0.42 (0.18–0.95) 0.04 58% decreased risk of dieing if you get &gt;8 Absolute Number of CD11c+ (Myeloid DC/ul) Time-dependent ( 1.05 (0.44–2.47) 0.92 NS CD4+ (%CD4+) Time-dependent 2.12 (0.80–5.62) 0.13 NS Multivariate Model HR (95% CI) p-value Interpretation HLA Match 5/6 or 6/6 0.53 (0.25–1.14) 0.10 47% decreased risk of dieing with a HLA match of 5/6 or 6/6 4/6 1.00 Absolute Number of CD123+ (Plasmacytoid DC/ul) Time-Dependent 0.44 (0.20–1.00) 0.05 56% decreased risk of dieing if you get &gt;8/ul Disease Non-Malignant 0.27 (0.12–0.63) 0.002 Non-Malignant patients have a 75% decreased risk of dieing as compared to malignant Malignant 1.00

Objective: Chronic myeloid leukemia (CML) is a rare disease among children. It comprises 3% of childhood leukemias. CML in children is different from CML in adult. Here we analyzed the clinical features and prognosis of pediatric CML in a single institute from China. Methods: A retrospective study was performed by reviewing clinical records of pediatric CML from 2002 to 2019. Results: A total of 48 pediatric CML cases were included in the study, with 35 males and 13 females (M: F=2.7:1). Four cases were diagnosed during 2002~2007, 12 cases during 2008~2013 and 32 cases during 2014~2019. Two (4.2%) patients were in accelerate phase (AP) and other 46 patients were in chronic phase (CP) at diagnosis. Median age of onset was 9y (range 1~17y). The most common symptoms were fever (21.6%), fatigue (14.9%) and cough (10.8%). Median size of spleen under left costal margin was 5cm (range 0~21cm). Median WBC count was 15.7/ul, hemoglobin 9.5g/dL, platelet count 58/ul, neutrophils percentage 56% (range 21~74%), basophils percentage 3% (range 1~16%) and median eosinophil percentage was 2% (range 0~19%). Thirty-five patients had done karyotype examination, and 28 cases (80%) with classical Philadelphia chromosome (Ph+). Other 13 patients without Ph chromosome but with BCR/ABL1 fusion gene. In our study, there were 4 patients treated by hydroxyurea and α-interferon, other 44 patients have been used imatinib (IM) 240-340mg/m2 per day. Median time from onset to diagnosis was 0.7 months (range 1 day~12 months). Median follow-up time was 52 months (range 1~200 months), while the 5-year overall survival (OS) and event-free survival (EFS) are 100% and 89.1%, respectively. Different gender, age at diagnosis, WBC count, platelet count, karyotype show no difference in OS and EFS. Four patients suffered from blast crisis (BC) (2 patients progressed after using hydroxyurea for 1 and 33 months, 2 patients progressed after using IM for 36 and 6 months, respectively). One patient's BCR/ABL1 transcript level was increased in 36 months after first administration of IM and recovered at 48 months by adding IM dosage from 200mg to 300mg per day. According to the European LeukemiaNet (ELN) criteria, 95.5% patients achieved complete hematologic response (CHR), 90.5% patients achieved complete cytogenetic response (CCyR) and 66.7% patients achieved major molecular response (MMR) at 3, 12, 18 months after IM administration, respectively. There was obvious correlation between WBC count at diagnosis and early molecular response (EMR). Median WBC count was 4.8/ul in patients with EMR and 38.1/ul in patients without EMR. Other clinical features, such as gender, age at diagnosis, hemoglobin count, platelet count and size of spleen, make no difference in EMR. Conclusion: This is a retrospective study on pediatric CML. The median age at diagnosis is 9 years old. Most of all patients are CML-CP. 5y OS and EFS are 100% and 89.1%. The CHR, CCyR, MMR at 3,12,18 months after IM therapy are 95.5%, 90.5% and 66.7% separately. Until now there is no sufficient data on efficiency and safety specific to pediatric CML patients. Further clinical investigations through international collaboration are need to help more and more patients to achieve treatment-free remission. Disclosures No relevant conflicts of interest to declare.

Abstract Background: Deficiency of ADAMTS13 results in an increase of the plasma unusually large von Willebrand factor multimer (UL-VWFM) and finally causes microcirculatory disturbance. We demonstrated that the imbalance of increased UL-VWFM over decreased ADAMTS13 activity may contribute to the development of multiorgan failure (MOF) in patients with alcoholic hepatitis (AH)(Alcohol Clin Exp Res, 2007, 31: 27S–35S). Endotoxemia has been considered to trigger the enhancement of pro-inflammatory cytokines, which may cause systemic inflammatory response syndrome together with microcirculatory disturbance leading to MOF in severe alcoholic hepatitis (SAH). The aim of this study was to determine the plasma cytokine levels, plasma endotoxin concentration and the inhibitor against the ADAMTS13, and tried to explore potential mechanism to reduce the activity of plasma ADAMTS13 in patients with AH and SAH. Methods: Subjects studied were 28 patients with AH and 5 patients with SAH, who were admitted into our hospital between June 2001 and January 2006. All patients with AH survived, and 3 of 5 patients with SAH died of hepatic failure and MOF. Plasma ADAMTS13 activity and its inhibitor were determined by a sensitive chromogenic ELISA (ADAMTS13-act-ELISA: Kainos Inc.). Plasma VWF antigen (VWF:Ag), interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor-α (TNF-α) were measured by ELISA. Plasma UL-VWFM was analyzed by SDS-0.9% agarose gel electrophoresis. Plasma endotoxin concentration was determined by a chromogenic substrate assay (Toxicolor LS-M Set, Seikagaku Kogyo Co.) with kinetic analysis after pretreatment with detergent, Triton X-100, and heating at 70 °C for 10 min. Results: The concentrations of IL-6, IL-8, and TNF-α on admission were significantly higher in patients with SAH than in those with AH and healthy normal controls. The ADAMTS13 activity concomitantly decreased with increasing concentrations of cytokines on admission (IL-6 & IL-8; normal range (N) mean 68 % & 70 %, N ~ 100 pg/ml 37 % & 37 %, &gt;100 pg/ml 13 % & 9%, TNFα; N 57 %, &gt;N 22 %, respectively). In contrast, the VWF:Ag progressively elevated with increasing concentrations of these cytokines (IL-6 & IL-8; N 298 % & 309 %, N ~ 100 pg/ml 509 % & 425 %, &gt;100 pg/ml 624 % & 880 %, TNFα; N 352 %, &gt;N 609 %, respectively). Plasma endotoxin concentration was markedly higher in patients with SAH (means 52.3 pg/ml) and AH (21.7 pg/ml) than in controls (7.9 pg/ml). The endotoxin concentration inversely correlated with ADAMTS13 activity (r= − 0.474, p&lt;0.01), and was higher in patients with UL-VWFM than those without (47.6 pg/ml vs. 18.5 pg/ml, p&lt;0.001). The inhibitor was detected in 4 patients with SAH (0.9 ~ 2.1 BU/ml) and 6 patients with AH (0.5 ~ 1.6 BU/ml). Patients with the inhibitor showed lower serum albumin level (3.3 g/dl vs. 4.2 g/dl, p&lt;0.05) and higher levels of serum total bilirubin (11.1 mg/dl vs. 2.5 mg/dl, p&lt;0.01), polymorphonuclear neutrophil count (8762/mm3 vs. 4093/mm3, p&lt;0.001), CRP (4.6 mg/dl vs. 1.1 mg/dl, p&lt;0.05) and plasma endotoxin concentration (39.4 pg/ml vs. 17.3 pg/ml, p&lt;0.01) than those without. At the recovery stage, the ADAMTS13 activity increased to normal range, the VWF:Ag decreased, and the UL-VWFM disappeared with the decrease in the concentrations of cytokines and endotoxin, and the disappearance of the inhibitor. Conclusion: Decreased ADAMTS13 activity and increased VWF:Ag could be induced not only by enhanced cytokinemia including IL-6, IL-8, and TNFα, but also by the inhibitor against ADAMTS13:AC. Both cytokinemia and the inhibitor are closely related to enhanced endotoxemia, which may cause the imbalance of the enzyme to substrate leading to MOF especially in patients with SAH.

Abstract Abstract 266 Neonatal alloimmune thrombocytopenia (NAIT) is caused by maternal antibodies specific for fetal platelet antigens and is the most common cause of intracranial hemorrhage in full term infants. The antigen HPA-1a, carried on beta 3 integrin (GPIIIa), is the most common trigger for NAIT and the 2% of women who are HPA-1a-negative are at risk to produce such antibodies. Most HPA-1a antibodies causing NAIT can be easily detected but it is not rare for an HPA-1a negative mother who lacks detectable antibodies to give birth to an infant with thrombocytopenia. Several recent reports suggest that low avidity HPA-1a antibodies not detected by conventional serologic methods are responsible for some of these cases (Socher 2009, Bakchoul 2011). To examine this question, we retroactively analyzed a cohort of 3478 suspected NAIT cases referred for laboratory diagnosis. Among 677 HPA-1a-negative mothers, we identified 61 in whom HPA-1a-specific antibodies were not detected by conventional methods. Surface plasmon resonance (SPR) analysis enables ligand-receptor interaction to be studied in real time without washing the target. Using this approach, we studied reactions of IgG from the 61 archived serum samples against purified GPIIb/IIIa isolated from group O platelets and identified 18 samples that reacted preferentially with the HPA-1a-positive version of the integrin in comparison with HPA-1a-negative integrin. Information defining clinical status was obtained on 13 of these cases by follow-up communication. Seven cases had been referred because of neonatal thrombocytopenia. Platelet nadirs ranged from 8,000/ul to 141,000/ul (median 38,000/ul). Five of the 7 infants had bleeding and were given maternal platelet transfusions and/or IVIgG. Normal platelet counts were achieved after 4 to 70 days (median 7 days). One infant had a normal platelet count, however IVIgG had been given to its mother throughout pregnancy. The remaining 5 cases were referred in mid-pregnancy because an HPA-1a-negative sister previously gave birth to an infant with NAIT. Four of these infants had normal platelets at birth; one had mild TP (platelets 125,000/ul). Only 3 of 12 mothers typed for HLA were positive for HLA-DRB3*0101, a marker found in >95% of women who make “conventional” HPA-1a antibodies during pregnancy (p < 0.001). The ability of human antibodies to cause destruction of human platelets in vivo can be studied in the NOD/SCID mouse, which lacks xenoantibodies normally found in other species (Newman 2007). Serum from 4 mothers was available in quantities sufficient for mouse studies; three of the four maternal sera caused accelerated destruction of HPA-1a-positive, but not HPA-1a-negative platelets. These findings indicate that low-avidity HPA-1a antibodies not detectable by conventional serologic methods are made by a subset of women exposed to the HPA-1a antigen during pregnancy and that some, but not all of these antibodies are capable of causing NAIT, which is usually mild, but can be severe. Women negative for HLA-DRB3*0101 may be especially prone to produce antibodies of this type. Maternal-fetal incompatibility for platelet antigens other than HPA-1a is very common and many apparent NAIT cases not involving HPA-1a go unresolved. The possibility that low avidity antibodies specific for antigens other than HPA-1a are responsible for some of these cases deserves study. Disclosures: No relevant conflicts of interest to declare.

Abstract Hydroxyurea therapy is associated with reduced morbidity among patients with sickle cell disease (SCD). Avascular necrosis of the femoral head (AVN) is one potentially debilitating complication of SCD. In this study, we examined the relationship between hydroxyurea use and the prevalence of AVN among children with SCD. We performed a retrospective chart review of 202 children with SCD, aged 10–21 years, followed in the pediatric hematology program at the Children’s Hospital at Montefiore (Bronx, NY) between July 2007 and 2008. Abstracted data included age, ethnicity, SCD genotype, frequency of hospitalization, hip radiograph results, laboratory data and hydroxyurea use. Hip radiographs were performed prospectively as part of SCD health maintenance from 2005–2008. Forty-four patients were excluded because they did not have a screening hip radiograph. Descriptive statistics were calculated for independent variables. T-tests and chi-square tests were used to compare clinical and demographic characteristics of children with and without AVN. Multivariate logistic regressions were used to estimate the odds ratio of having AVN among SCD patients. Our final sample consisted of 158 patients whose demographic characteristics are listed in Table 1. The prevalence of AVN was 16.5% (n=26). Of the clinical variables analyzed, we identified significant associations between the presence of AVN and hydroxyurea use (p=.005), as well as older age (p=.013) (Table 1.) Children with AVN had significantly lower mean lactic dehydrogenase levels (LDH) (p=.04) and higher mean corpuscular volumes (MCV) (p=.012). (Table 2.) After controlling for gender, ethnicity, sickle cell genotype, and frequency of hospitalizations, age was also found to be associated with AVN (OR 1.15, 95% confidence interval (CI): 1.01,1.31, p=0.033). SCD patients on hydroxyurea had higher odds of having AVN compared to non-users (OR 3.51, 95% CI: 1.31, 9.38, p= 0.013). Laboratory values (MCV, Hemoglobin, LDH and Hematocrit) had a high degree of collinearity and were removed from the final model. In summary, the prevalence of AVN in our sample was 16.5%. This is substantially higher than the prevalence of approximately 6% reported by the Cooperative Study of Sickle Cell Disease for comparative age groups in a prospective study1. SCD patients exposed to hydroxyurea were three times more likely to have AVN than those not exposed to this drug. Vaso-occlusive pain crisis is a recognized risk factor for AVN, thus we could expect a higher rate of AVN among patients on hydroxyurea. However, the odds ratio of 3.5 is unexpectedly high and warrants further investigation into the role of hydroxyurea as a risk factor for AVN. Nonetheless, these preliminary results suggest that more stringent screening regimens for AVN may be indicated among this subset of patients. Table 1. Clinical characteristics of patients with and without avn *p&lt;0.05 **p&lt;0.01 No AVN (N =132) AVN (N = 26) Age * 15.7 years 17.4 years Sex Male 64 (49%) 17 (65%) Ethnicity Black 110 (83%) 23 (88%) Hispanic 22 (17%) 3 (12%) HgbSS 84 (64%) 20 (77%) HgbSC 38 (29%) 4 (15%) HgbSBthal0 5(3.8%) 2 (8%) Hgb SC HgbSBthal+ 5 (3.8%) 0 On Hydroxyurea** 38 (29%) 15 (58%) # Hospitalizations 0 60 (45%) 10 (38%) 1–5 64 (49%) 14 (54%) &gt;5 8 (6%) 2 (8%) Table 2. Mean Laboratory Values for Patients With And Without AVN No AVN AVN *p&lt;0.05 (N =132) (N = 26) WBC 10.7 k/uL 10.5 k/uL Hgb 9.4 gm/dL 9.6 gm/dL MCV* 83 fL 89 fL Platelets 381 k/uL 376 k/uL Reticulocyte 7.70% 8.10% Ferritin 369.8 ng/mL 438.7 ng/mL LDH* 471.6 U/L 389 U/L Creatinine 0.6 mg/dL 0.6 mg/dL Hgb F 9.80% 11.30%

Abstract Cerebral malaria (CM) is a major cause of death in young children in sub-Saharan Africa. Although the pathogenesis of this condition remains poorly understood, Plasmodium falciparum infection results in adhesion of infected erythrocytes (IE) to microvascular endothelium, and acute endothelial cell (EC) activation. Recent studies have shown that plasma VWF:Ag and VWF propeptide levels are markedly elevated in children with severe falciparum malaria. Moreover elevated VWF:Ag levels inversely correlate with clinical outcomes. In addition, circulating ultra-large VWF multimers have also been observed in children with severe malaria. Importantly, platelet-decorated UL-VWF strings have been shown to recruit trophozoite-stage falciparum-IE to EC surfaces in shear-based assays. Collectively, these emerging data suggest that VWF may play a novel role in the pathogenesis of CM. To further investigate this hypothesis, we utilized an established murine model of experimental CM which involves wild type (WT) C57BL/6J mice infected with Plasmodium berghei ANKA. In brief, WT C57Bl/6J mice were inoculated with 2x106P. berghei ANKA via I.P. injection. These mice typically developed CM and died within 6-8 days. In keeping with findings in children with falciparum malaria, acute EC activation was also an early and consistent feature in the murine model of CM. Mean plasma VWF:Ag levels were significantly elevated from Day+3 in infected mice compared to controls (Day +3 1.8 fold increase; Day +5 2.5 fold increase; p<0.01). In addition, plasma angiopoietin-2 and osteoprotegerin levels were also both significantly elevated from Day +3 and Day +5 respectively in mice infected with P. berghei. Interestingly, despite the fact that murine plasma ADAMTS13 activity levels were not significantly reduced, pathological ultra-large VWF multimers (UL-VWF) were also observed in murine plasma from Day +3 following P. berghei inoculation. Cumulatively these findings suggest that early marked elevation in VWF:Ag levels, and the appearance of pathological UL-VWF multimers in the plasma, represent hallmarks of both human and murine severe malaria infection. To determine whether VWF plays a direct role in modulating the pathogenesis of CM in vivo, we further investigated P. berghei infection in VWF-/- C57BL/6J mice. Importantly, although there was no difference in blood parasitaemia levels, overall survival was significantly prolonged in VWF-/- mice compared to wild type mice (6 versus 7.25 days; p=0.0106). Moreover, a significant delay in malaria clinical progression in the VWF-/- mice was also observed using a previously validated clinical scoring algorithm for experimental cerebral malaria. (Amante et al, Am J Path 2007). Recent studies have demonstrated that platelets may play a direct role in modulating malaria parasite killing. Consequently, to investigate potential mechanisms through which VWF-/- mice are protected against experimental CM, daily platelet counts were determined in WT and VWF-/- mice following infection. In keeping with observations in human patients infected with falciparum malaria, significant thrombocytopenia was also a consistent feature in the murine model. For example, by Day +4 following inoculation of WT mice mean platelet count had fallen by 71.6 ± 26 %. Interestingly however, significant thrombocytopenia was also observed in VWF-/- mice infected with P. berghei (84.2 ± 9 %). Despite the significant differences in clinical progression and overall survival no significant differences in platelet counts were observed between VWF-/- and WT mice at any time point. These findings suggest that VWF-/-mice are protected against CM through a platelet-independent mechanism. In conclusion, we demonstrate that early and consistent EC activation is a feature of the murine model of experimental CM similar to previous findings of children infected with P. falciparum. In addition, our findings show that marked elevation of VWF:Ag, and the appearance of pathological UL-VWF multimers in the plasma, both represent hallmarks of human and murine severe malaria infection. Finally, we report that VWF-/- mice exhibit significantly prolonged survival against CM, and that this effect is mediated through a platelet-independent mechanism. Given the significant morbidity and mortality associated with CM, these novel data have direct translational significance. Disclosures No relevant conflicts of interest to declare.