bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stat3 Activation in Donor CD4 T-Cells Is Critical for Acute Gvhd
Authors: Ozaki Katsutoshi , Matsu Haruko , Hatanaka Keiko , Meguro Akiko , Oh Iekuni , Tatara Raine , Suzuki Takahiro , Mori Masaki , Nagai Tadashi , Muroi Kazuo , Ozawa Keiya 
Published: October 2019

Abstract
Abstract 1906
Stat3-deficient (Stat3KO) T-cells reportedly are less proliferative due to accelerated apoptosis in the presence of IL-6, and have suppressed IL-2Ra expression. There are conflicting mouse model results concerning Stat3 in graft-versus-host disease (GVHD). Previously, we demonstrated IL-21 signaling is essential for GVHD. As Stat3 is a downstream signaling molecule, clarifying its role in GVHD T-cells is important.
After co-transplantation of bone marrow and wild-type or Stat3KO CD4+ T-cells, recipients of the latter developed attenuated GVHD with longer survival than recipients of the former, and their splenic CD4+ T-cells exhibited a profound proliferation defect in the mixed lymphocyte reaction (MLR). In contrast to IL-21R-deficient CD4+ T-cells, pre-transplantation Stat3KO CD4+ T-cells showed similar MLR impairment, suggesting an intrinsic defect. Consistently, proliferation in low-dose anti-CD3 stimulation was defective, but MLR apoptosis was not increased. Neutralizing antibody against IL-2, but not IL-6R, suppressed MLR wild-type CD4 T-cell proliferation, suggesting Stat3KO CD4+ T-cells' MLR apoptosis might be attributed to lack of IL-6 contribution.
Pallandre et al. reported Stat3 ablation in CD4 exacerbated GVHD, speculating Stat3 depletion suppressed regulatory T-cell function, leading to accelerated GVHD. Lu et al. analyzed T-cell phosphorylated proteins during allo-activation, demonstrating Stat3 and Erk1/2 are important for this and GVHD. Radojcic et al. showed Stat3KO T-cells cannot induce chronic cutaneous GVHD because of repressed CD4 proliferation and loss of Th17 differentiation. Reasons for differing conclusions are unknown. One possibility is enhanced innate immunity induced by Stat3-siRNA-transduced stem and progenitor cells, consistent with several reports. Our use of Stat3KO T-cells overcame this problem. The latter two reports are consistent with our results. To our knowledge, we report the first direct evidence Stat3 activation in donor CD4+ T-cells is critical for acute GVHD. Durant et al. delineated detailed gene regulation in Stat3KO CD4+ T-cells, and one of their conclusions—Stat3 is important for CD4+ T-cell proliferation—is consistent with our results.

Disclosures:
No relevant conflicts of interest to declare.
Use of the G-CSF Biosimilar Ratiograstim® to Mobilize Peripheral Stem Cells in Healthy Donors for Allogeneic Stem Cell Transplantation
Authors: Schmitt Michael , Lena Diestel , Schneider Catarina , Xu Xun , Borchert Kersten , Gläser Dietrich , Hilgendorf Inken , Scheuerlein Robert , Freund Mathias , Schmitt Anita 
Published: October 2019

Abstract
Abstract 1928

INTRODUCTION:
There is limited experience in the application of the biosimilar Ratiograstim® for mobilization of peripheral stem cells and especially in healthy donors (HD). The G-CSF biosimilar Ratiograstim® was approved by the EMA for mobilization of peripheral stem cells. Here, we investigated on two cohorts the efficacy and safety of peripheral stem cell mobilization by either the biosimilar or the reference G-CSF.
MATERIAL AND METHODS: 22 patients and their related donors were investigated for: 1. leukocyte-count in the peripheral blood of healthy donors, 2. number of collected CD34+ stem cells, 3. number of apheresis procedures, 4. CD34+ cell count per kg body weight of the patients, 5. time till regeneration, 6. side effects.

RESULTS:
In HD receiving subcutaneously Ratiograstim®, WBC counts in the peripheral blood ranged from 29.9 G/L to 64.6 G/L (mean 48.9 G/L) and the CD34 cell counts from 19.3/μl to 114.6/μl (mean 67.6/μl). In a mean of 1.45 apheresis procedures 172.5×106 up to 494×106 CD34+ cells (mean 354.7×106) were collected. This resulted in CD34+ cell numbers of 2.28×106 up to 1×107 (mean 5.17×106) per kg body weight of the patients. In HD receiving subcutaneously the reference G-CSF, WBC counts ranged from 27.1 G/L up to 62.5 G/L (mean 43.3 G/L) and the CD34+ cell counts from 13.55/μl up to 122.4/μl (mean 57.3/μl). A mean of 1.27 apheresis procedures were necessary to collect 181.74×106 up to 598.00×106 CD34+ cells (mean 370.49×106) absolutely. This translates into 2.33×106 up to 7.9×106 (mean 4.95×106) CD34+ cells per kg body weight of the patients. Patients regenerated >0.5 G/L neutrophils/μl within 15 days in the Ratiograstim® cohort versus 17 days in the reference group.

SUMMARY:
In total we analyzed two cohorts, one cohort of 22 patients and donors receiving the biosimilar Ratiograstim® versus another cohort receiving reference G-CSF. No unexpected side effects and no increased frequencies in side effects as flu-like symptoms, allergic reactions and alterations in kidney and liver function were observed. In comparison to the reference group we did not see significant differences in 1. WBC count in the peripheral blood after mobilisation, 2. CD34+ cell count after mobilisation, 3. CD34+ cell count absolute numbers, 4. CD34+ cells per kg body weight of the patients, 5. engraftment, 6. regeneration of WBC, neutrophils and platelets. All patients engrafted. Therefore, the efficacy of the biosimilar Ratiograstim® when compared to the reference G-CSF was comparable in our cohort of patients in the context of allogeneic stem cell transplantation.

Disclosures:
Schmitt: ratiopharm: Honoraria, Research Funding. Freund:Medac: Honoraria, Research Funding.
Carboxyl-Terminal Thrombospondin-Type 1 (TSP-1) Repeats of ADAMTS13 Inhibits Platelet Adhesion to Collagen-Coated Surface Under Shear Stress, Independent of Proteolytic Activity
Authors: Xiao Juan (Jenny) , Zheng X. Long 
Published: October 2019

Abstract
Abstract 195
ADAMTS13 contains multiple free thiols on its surface, which may form disulfide bonds with surface-exposed free thiols on plasma-derived von Willebrand factor (VWF). This interaction may prevent lateral association of apposed VWF under arterial shear stress. However, the functional consequence of ADAMTS13-VWF interaction without proteolysis is not known. We hypothesize that the interaction between the C-terminus of ADAMTS13 and the C-terminus of VWF inhibits thrombus formation under shear stress. Using a BioFlux microfluidic system, we showed that under arterial shear stress, 10 dyn/cm2, fluorescein-labeled platelets from PPACK (thrombin inhibitor) anti-coagulated human whole blood adhered to collagen (type I)-coated surface in a time-dependent manner. Addition of human recombinant full-length ADAMTS13 (10 nM) into whole blood dramatically reduced the surface coverage of fluorescein-labeled platelets. Conversely, addition of an inhibitory polyclonal anti-ADAMTS13 IgGs (150 ug/ml) to whole blood dramatically accelerated the accumulation of fluorescein-labeled platelets. These results suggest that this microfluidic system is highly sensitive for the assessment of anti-thrombotic function of ADAMTS13. Under the same conditions, we were able to further show that addition of recombinant C-terminal fragment of ADAMTS13 comprising of the 5th to 8th thrombospondin type 1 (TSP1) repeats and two CUB domains (T5C) or the 2nd to 8th TSP1 repeats and two CUB domains (T2C) into whole blood also inhibited the surface coverage of fluorescein-labeled platelets on collagen-coated surface in a concentration-dependent manner. In the presence of 0.1 μM and 0.5 μM of recombinant T2C or T5C, the surface coverage of fluorescein-labeled platelets was reduced by ∼40% and ∼60%, respectively. The inhibitory activity of these recombinant C-terminal fragments was nearly abolished if pre-treated with 40 mM of N-ethylmaleimide which blocked surface-exposed free thiols. Moreover, recombinant CUB domains at the highest concentration tested (1.0 μM) did not appear to alter the surface coverage of fluorecein-labeled platelets under the same conditions. These results suggest that the C-terminal TSP1 repeats of ADAMTS13 inhibit platelet adhesion and aggretion or thrombus formation through thiol-thiol interactions between ADAMTS13 and VWF (or other proteins). We conclude that the C-terminal TSP1 repeats may modulate thrombus formation independent of proteolytic activity.

Disclosures:
No relevant conflicts of interest to declare.
Formation of Procoagulant Platelets in Heparin-Induced Thrombocytopenia (HIT) Follows a Unique Signaling Pathway
Authors: Andre Pierrette , Stolla Moritz , Woulfe Donna , Chavez Massiel , Bergmeier Wolfgang , Rauova Lubica , Cines Douglas B. , Poncz Mortimer , McKenzie Steven 
Published: October 2019

Abstract
Abstract 197
HIT is a drug-induced, immune-mediated thrombocytopenia and thrombosis disorder associated with considerable morbidity and mortality. HIT is associated with generation of procoagulant platelet microparticles (Warkentin et al., Blood 1994; 84:3691), one of the cardinal features of procoagulant platelets, along with a phosphatidylserine-positive (PS+) external plasma membrane and surface retention of procoagulant proteins from plasma or released from platelet γ-granules. Other names for procoagulant platelets include COAT, or coated, platelets (Dale, J Thromb Haemostas 2005; 3:2185). To date, virtually all of the work on procoagulant platelets has used collagen or convulxin signaling via ITAM-associated GPVI, combined with thrombin signaling via GPCRs PAR1/PAR4. Batar and Dale reported the formation of coated platelets as a result of dual platelet FcγRIIa and thrombin stimulation; they used crosslinking of an anti-FcγRIIa antibody or anti-platelet glycoprotein antibodies which also engaged FcγRIIa (J Lab Clin Med 2001; 138:393). We report here the procoagulant activation of human and FcγRIIa transgenic (tg) mouse platelets stimulated by the HIT immune complex (IC) and thrombin (thr). HIT IC consist of ultralarge complexes of heparin and platelet factor 4 (hep/PF4) bound by HIT-like monoclonal antibody KKO. Washed human platelets, wild-type mouse platelets, or FcγRIIa tg mouse platelets were stimulated with the HIT IC + thr. Controls include convulxin (100 ng/ml) + thr, HIT IC alone, or thr alone as the stimulus. Human platelets and FcγRIIa-tg platelets, but not wild-type mouse platelets, develop a 40 to 60% PS+ population in response to HIT IC (100 ug/ml KKO)+ thr (0.5 U/ml), but not to either alone, as assessed by flow cytometry using labeled Annexin V. Unlike cvx + thr, which consistently shows a broad distribution of PS+ platelets in our hands and in the literature, HIT IC-stimulated platelets reproducibly show one discrete PS+ subpopulation (n = 6 per group). Preincubation of platelets with novel specific Syk inhibitor PRT318 (Reilly et al., Blood 2011; 117:2241) completely prevented PS+ platelet formation. FcγRIIa-tg platelets null for Akt2 showed a ∼50% reduction in the formation of PS+ platelets. Studies with FcγRIIa-tg mice null for Cal-DAG GEFI are ongoing. Understanding the unique pattern of procoagulant platelets generated by HIT IC + thr and the signals which produce it may lead to new diagnostic tests and therapeutic interventions.

Disclosures:
No relevant conflicts of interest to declare.
Hepatitis B and Hepatitis C Co-Infection in Patients with Hematological Malignancies
Authors: Garmaeva Tatyana Ts , Kulikov Sergey M. , Michailova Elena A , Sudarikov Andrei B , Filatov Felix P , Savchenko Valeryi G 
Published: October 2019

Abstract
Abstract 2090

BACKGROUND.
Coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV) in immunocompromised patients (pts) with hematological malignancies is not well-studied problem. Early recognition of HBV and HCV infectioning incidence in such pts is difficult due to influence of cytostatic and immunosuppressive therapy and possible mutual HBV or HCV inhibitions. Independence of HBV and HCV infection events has to be discussed.

AIM.
To determine the prevalence of HBV and HCV co-infection in pts with hematological malignancies to check the possible correlation between the incidence of the infections.

PATIENTS AND METHODS.
All 265 patients treated in hematology department during 2004–2006 years were prospectively continuously monitored and examined for markers HBV and HCV (HBsAg, anti-HCV, DNA HBV, RNA HCV, HBeAg, anti-HBs, anti-HBc, anti-HBe) in serum, plazma, blood cells, bone marrow, cerebrospinal fluid) and clinico-biochemical symptoms of liver dysfunction were registered approximately every 3 weeks until 2008 year. Liver biopsy was performed on 64 pts in 2004–2006 yy, 23 pts esch with HBV and HCV immunohistology. Approximately 80% of pts were with acute leukemias (AL) and aplastic anemias (AA). Male; 47% (n=125), female; 53% (n=140). The median age was 38 years (range, 15 to 79).

RESULTS.
At the beginning of treatment and monitoring 17 of 265 pts (6.4%) had positive markers of HCV and the number of pts with positive markers of HCV increased up to 70 (26%) to the end of monitoring, and for HBV markers increased from 23 pts (8.7%) to 174 pts (65.3%). We found, that many pts were co-infected with HBV and HCV, and their total number increased from 5 pts (1,9%) äî 37 pts (14%). Positive tests of HBV and HCV co-infection was found in 57 pts of 265, that is 32.8% of 174 HBV-positive pts and 81.4% of 70 HCV-positive pts, odds ratio (OR=2.9) (95%CI =1.5–5.7), xi square significance p=0.0012. More complicate longitude analysis did not show that the incidence rate of second infection is significantly higher than the first. That means that the correlation between first and second infections is still questionable. Coinfection with HBV and HCV resulted in clinical presentation of hepatitis B and/or hepatitis C in most cases and cumulative incidence rate rises up to 100% at 630 day after the first appearance of any positive marker.

CONCLUSION.
The high prevalence of HBV and HCV coinfection of pts with hematological malignancies is attributed to common risk factors for infection transmission after transfusions of blood components and parenteral medical procedures. For pts with hematological malignancies after first detection of positive test for single marker of HBV and/or HCV it is very reasonable to intensify the monitoring of HBV and HCV markers and to follow clinical signs.

Disclosures:
No relevant conflicts of interest to declare.
Efficacy and Safety of VTE Prophylaxis with Oral Rivaroxaban Compared to Fondaparinux or Low-Molecular Weight Heparin In a Large Cohort of Consecutive Patients Undergoing Major Orthopaedic Surgery
Authors: Beyer-Westendorf Jan , Donath Lars , Lützner Jörg , Werth Sebastian , Radke Oliver , Guenther Klaus-Peter , Weiss Norbert 
Published: October 2019

Abstract
Abstract 210
Efficacy and safety of VTE prophylaxis with oral rivaroxaban compared to fondaparinux or low-molecular weight heparin in a large cohort of consecutive patients undergoing major orthopaedic surgery.

Aim:
Patients undergoing major orthopaedic surgery (MOS) have a high risk of postoperative venous thromboembolism (VTE). Several types of pharmacological thromboprophylaxis are approved for this indication. In phase III VTE prevention trials in MOS, the new oral facor Xa inhibitor rivaroxaban proved superior efficacy over LMWH in preventing VTE without increasing bleeding complications. However, study populations consist of selected patients screened for strict exclusion criteria before randomisation. Little is known about efficacy and safety of rivaroxaban prophylaxis in large unselected cohorts of patients undergoing MOS in daily practice.

Method:
We retrospectively evaluated 5346 consecutive patients undergoing MOS at our centre between January 2005 and June 2011 for the rate of VTE events, bleeding complications and surgical revisions by review of patient charts, complication and transfusion databases and autopsy reports. All events were analyzed according to the type of thromboprophylaxis used.

Results:
Of the 5346 patients, 1055 patients received thromboprophylaxis with rivaroxaban (R; hospital standard since 2010), 1683 patients received LMWH (hospital standard 2005–2007), 2069 received fondaparinux (F; hospital standard 2007–2009) and 539 patients received other prophylaxis. Symptomatic VTE event rates for patients receiving R, F or LMWH were 2.5%, 5.5% and 3.9%, respectively (table 1). R was significantly more effective to prevent symptomatic VTE compared to F or LMWH, mostly due to significantly lower rates of distal VTE.
Overall, the safety of VTE prophylaxis with R was superior over F or LMWH with significantly lower rates of surgical revisions (1.1%, 1.8% and 4.7%, respectively) and lower rates of severe bleeding complications (7.4%, 11.1% and 14.9%, respectively, which also was statistically significant.

Conclusion:
VTE prophylaxis with rivaroxaban is superior over prophylaxis with fondaparinux or LMWH with regard to the prevention of symptomatic VTE complications. Furthermore, rivaroxaban prophylaxis was also safer with regard to severe bleeding complications and surgical complications compared to fondaparinux or LMWH, which is in contrast to the results of large phase III trials and the current opinion, that superior efficacy of prophylaxis has the downside of higher bleeding complications. We conclude that real world patients undergoing MOS are different from study populations and may especially benefit from rivaroxaban prophylaxis with regard to both efficacy and safety.

Disclosures:
Beyer-Westendorf: Bayer Healthcare: Research Funding, Speakers Bureau.
Protein Disulfide Isomerase Regulates Sickle Erythrocyte Volume Via ET-1 Dependent Casein Kinase II Mechanism
Authors: Valentin-Berrios Shirley D , Romero Jose R , Rivera Alicia 
Published: October 2019

Abstract
Abstract 2114
Disordered K+ efflux and osmotically induced water loss leads to red blood cell (RBC) dehydration and plays a role in the pathophysiology of Sickle Cell Disease. We previously reported that activation of endothelin-1 (ET-1) receptors in sickle erythrocyte was partially responsible for dense sickle cell formation. However, the mechanism by which ET-1 regulates RBC volume remains unclear. Serine/threonine kinases have been shown to regulate K+ transport in RBC. Casein Kinase II (CK2), a serine/threonine kinase, phosphorylates acidic proteins, regulates calmodulin activity and cytoskeletal proteins and is present in RBC. CK2 activity is blocked by apigenin, emodin, heparin, and ornithine decarboxylase. Previous reports have shown a role for flavonoids such as apigenin as substrates for erythrocyte plasma membrane oxidoreductases. We recently observed a role for Protein Disulfide Isomerase (PDI) in regulating cellular hydration and K+ efflux in human RBC. PDI catalyzes disulfide interchange reactions in the plasma membrane, mediates redox modifications and is up-regulated under hypoxic conditions. However the relationship between CK2 and PDI in the setting of cellular hydration status is un-explored. Our results indicate that erythrocyte membrane CK2 activity increases when sickle cells are incubated with 500 nM ET-1 for 30 min (2.8 ± 0.1 to 4.9 ± 0.01 nmol/min/mL * 106 cell) an event that is blunted by pre-incubation with the ET-1 B receptor blocker, BQ788 (2.5 ± 0.1 nmol/min/mL * 106 cell, n=3, p<0.04) and 20 μM apigenin (2.7 ± 0.4 nmol/min/mL * 106 cell, n=3, p<0.04). We examined the role of CK2 activation on cellular dehydration. We incubated sickle erythrocytes for 3 hours in deoxygenation-oxygenation cycles in the presence or absence of 20μM apigenin or 2μM 4,5,6,7-tetrabromobenzotriazole (TBB), a specific CK2 inhibitor, and measured the changes in erythrocyte density by phthalate oil density analysis. We observed that inhibition of CK2 led to reduced deoxygenation-stimulated cellular dehydration in sickle erythrocytes by apigenin (D50= 1.106 to 1.100 g/mL) or TBB (D50 =1.097 g/mL). We then studied the role of CK2 inhibitors on PDI activity by Insulin Turbidity Assay and observed that apigenin and TBB led to significant reductions in PDI activity in vitro (64% and 42% respectively). We also studied the effects of the flavonoids: naringenin, naringin, apigenin and rutin on PDI activity and observed reductions in PDI activity that were greater with apigenin>rutin>TBB>naringin>naringenin (n=2, P<0.05). Furthermore, we observed that K+ flux via Gardos channel activation is correlated with PDI activity in vitro in sickle erythrocytes. Taken together our results implicate CK2 and PDI as intermediate regulators of ET-1 stimulated cellular volume systems in red blood cells. Supported by NIH R01-HL09632 to AR.

Disclosures:
No relevant conflicts of interest to declare.
Single-Photon Emission CT to Access Outcomes in Children with Moyamoya Syndrome and Sickle Cell Disease Before and After Encephaloduroarteriosynagiosis
Authors: Sarnaik Sharada A. , Lancelot Moira M. 
Published: October 2019

Abstract
Abstract 2143

Background:
About 11% of patients with sickle cell disease (SCD) will develop and ischemic stroke by 20 years. Patients with SCD and Moyamoya Syndrome (MMS) are at an especially high risk for developing stroke. Encephaloduroarteriosynagiosis (EDAS) is emerging as a safe and effective method for the treatment of MMS in Pediatric patients with SCD since it provides improved revascularization. Single-photon emission CT (SPECT) has been used in pediatric MMS patients to demonstrate regions of decreased cerebral perfusion and cerebrovascular reserve. The use of SPECT in SCD patients with MMS undergoing EDAS has not been evaluated.

Methods:
Between 2001 and 2011 we had 45 patients with SCD who developed clinical evidence of cerebrovascular accident (CVA), transient ischemic attack (TIA), or seizure with radiologic evidence (magnetic resonance and or angiography) of MMS. 20 underwent surgical revascularization with EDAS. Vascular reserve and cerebral perfusion was assessed with SPECT before and after EDAS in 9 patients.

Results:
6/9 patients had bilateral EDAS while 3/9 had unilateral EDAS. The postoperative clinical outcome of each patient was assigned to one of the following 3 categories based on the SPECT reports: (1) improved if there was increased perfusion and vascular reserve after EDAS, (2) stable if there were no new areas of decreased perfusion or vascular reserve after EDAS and (3) worsened if there were new areas of decreased perfusion or vascular reserve with increased risk for future infarct after EDAS. 6/9 patients showed improvement, 2/9 patients showed stable cerebral perfusion and vascular reserve and 1 patient showed additional areas at risk for future infarct. SPECT was performed on average 5.7 (range 1.5–16.1) months before EDAS and 16.2 (range 1–47.1) months after EDAS.

Conclusions:
SPECT performed before and after EDAS of the involved cerebral hemispheres can assess effectiveness of revascularization surgery and may predict the further clinical outcomes of pediatric patients with SCD and MMS.

Disclosures:
No relevant conflicts of interest to declare.