bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of Treatment Patterns and Consequences of Immune Thrombocytopenic Purpura (ITP).
Authors: Fisher Maxine D. , Yang Grace , Burawski Lauren P. , Grotzinger Kelly M. , Provan Andrew B. , Barron John J. 
Published: April 2020

Abstract
Standard treatment strategies for chronic immune thrombocytopenic purpura (ITP) in adults include oral steroids, high dose IVIG (intravenous immunoglobulin), Anti-D, or splenectomy (in refractory cases). Although guidelines have been developed, optimal and most frequently applied treatment strategies remain uncertain.
In this retrospective administrative claims database study, patient demographics, comorbidities, and treatment characteristics were captured to assist in determining burden of illness on patients with chronic ITP. Patients from five US health plans with medical claims for ITP (ICD-9CM codes 287.3 or 287.5) between 1/1/00 – 2/29/04 were included if they had continuous health plan enrollment 6 months prior to and 12 months after an index diagnosis of ITP. To be considered as chronic, patients also were required to have ≥1 additional drug claims or ITP diagnoses claim(s) six months after the index. Patients with codes for HIV, hepatitis, chemotherapy, or HIT were excluded.
A total of 3,743 patients met the study criteria; 53% were females (n=1,969). Mean age was 57 ± 16.9. Patients had a mean follow-up duration of 976 ± 441 days. Mean Deyo-Charlson Comorbidity Indices were 1.2 ± 1.9 pre-index, 2.0 ± 2.4 post-index of a maximum score of 21. Hypertension (62% pre-index; 51% post-index) and coronary heart disease (38% pre-index; 28% post-index) were common comorbidities. Of concomitant medications, most patients were taking antibiotics pre-index (n=3,008) as well as post-index (n=3,316). Twenty-nine percent of patients were hospitalized during follow-up with ITP recorded during the inpatient stay. The mean number of days to drug treatment was 378 ± 376. Among patients who received pharmacological treatment (n=1,834), the most frequently used first-line and second-line therapies were oral corticosteroids (n=1,742) and cyclosporine (n=75), respectively. Among patients treated with oral corticosteroids with ≥1 year follow up, the average time on treatment was 95 days. Further evaluation of the period between the index ITP diagnosis and drug therapy, and pharmacologic interventions for ITP during hospitalizations are underway.
Dyrk-3 Kinase Is an Erythroid Cell-Intrinsic Attenuator of Stress Erythropoiesis.
Authors: Bogacheva Olga , Bogachev Oleg , Menon Madhu , Valoret Elizabeth , Karur Vinit , Prosser H. , Creasy Caretha , Erickson-Miller Connie , Wojchowski Don 
Published: April 2020

Abstract
During anemia, red cell production depends critically upon erythropoietin and is also supported by Gas-6, oncostatin-M, and BMP4/Madh5 as recently characterized stress erythropoietic factors. Considerably less is understood concerning factors that limit this process. Via gene disruption, and as studied in four functional paradigms, stress erythropoiesis presently is shown to be attenuated by Dyrk-3 kinase. Tissue-wide RT-PCR analyses confirmed Dyrk-3 expression selectively in erythroid progenitor cells, and testes. In Dyrk-3−/− mice, reproductive capacity and steady-state hematopoiesis were normal (with the exception of modest decreases in splenic BFUe). In response to phenylhydrazine- induced anemia, however, reticulocyte production in the absence of Dyrk-3 was sustained, and was elevated to 270% of wild-type controls. Reticulocyte levels (and hematocrits) in Dyrk-3−/− mice also were elevated significantly over controls following 5′-fluorouracil- induced anemia, and a two-fold advantage for Dyrk-3−/− CD71highTer119pos cell formation was observed in short-term bone marrow transplant experiments. These outcomes indicated enhanced rates of Dyrk-3−/− erythroblast development, and using a unique medullary erythroblast expansion system, accelerated development of Dyrk-3−/− Kitpos proerythroblasts to maturing CD71high Ter119pos cells was observed. Given these data, Dyrk-3 is proposed to selectively limit (and possibly apportion) red cell production during stress erythropoiesis.
A Human Antibody, Cloned from a Patient with Heparin-Induced Thrombocytopenia, That Binds Heparin/Platelet Factor 4 Complexes.
Authors: Dessain Scott K. , Rybinski Katherine E. , Adekar Sharad P. , Rauova Lubica , Sachais Bruce S. , McKenzie Steven E. , Reilly Michael P. 
Published: April 2020

Abstract
In heparin-induced thrombocytopenia (HIT), patients receiving heparin develop IgG antibodies that bind complexes formed between heparin and platelet factor 4 (PF4). Most patients are asymptomatic, but some develop life- and limb-threatening arterial or venous thrombosis. We previously described a transgenic mouse model of HIT that demonstrated four factors are necessary and sufficient to recapitulate the clinical manifestations of HIT with thrombosis: heparin, human PF4, a heparin/PF4 antibody, and platelet activation via FcγRIIA. We hypothesize that specific quantitative and qualitative characteristics of heparin/PF4 antibodies determine which patients with HIT will develop thrombosis. Because heparin/PF4 antibodies isolated from patients with HIT are generally polyclonal and heterogeneous, it has been impossible to directly test this hypothesis. We recently developed a novel means of cloning human antibodies, in which we fuse primary human B-cells to a murine cell line that ectopically expresses human telomerase (hTERT) and murine interleukin-6 (mIL-6). This method readily generates heterohybridoma cells that stably secrete human antibodies. We have used this method to clone human heparin/PF4 antibodies from patients with HIT and thrombosis. We identified a patient with clinical HIT, exhibiting a heparin-dependent drop in platelet counts, plasma heparin/PF4 IgG antibodies by ELISA, and a deep venous thrombosis. We fused peripheral blood lymphocytes from this patient to our novel fusion partner cell line, and isolated 2 independent hybridomas that express IgM antibodies that strongly bind heparin/PF4 complexes. We assayed the specificity of the cloned antibodies by testing serial dilutions for heparin/PF4 binding activity by ELISA. Each cloned antibody bound heparin/PF4 with an absorbance &gt;2X background at dilutions that ranged from 1:32–1:64, whereas three negative control antibodies gave no detectable binding at dilutions of 1:2 or greater. cDNA sequencing indicated that both antibodies have the same heavy chain sequences, including a novel CDR3 region, suggesting that the antibodies were derived from post-germinal center memory B-cells rather than from naive B-cells. Using recombinant DNA techniques and ectopic expression in CHO cells, we produced an IgG1 version of one of these antibodies (8E5). By ELISA, the 8E5 IgG1 antibody binds human PF4 at optimal ratio of 10 μg/ml to 0.4 U/ml of heparin (see Figure). We are currently exploring the nature of the 8E5 IgG/heparin/PF4 complex and its platelet activating/thrombotic potential.
Figure Figure
Prevention of Acute Graft-Versus-Host Disease Despite Compensatory Function of Lymphoid Organs In Vivo.
Authors: Beilhack Andreas , Schulz Stephan , Baker Jeanette , Beilhack Georg F. , Nishimura Ryosei , Landan Gilad , Baker Enosh M. , Herman Edward I. , Butcher Eugene C. , Contag Christopher H. , Negrin Robert S. 
Published: April 2020

Abstract
Acute graft-versus-host disease (aGVHD) results from alloreactive donor derived T cells attacking targets in the gastrointestinal tract, liver and skin. We observed the initiation and rapid kinetics of aGVHD in a murine model [FVB/N (H-2q) into irradiated Balb/c (H-2d)] using in vivo bioluminescence imaging. The transition from the initiation to the effector phase of aGVHD (day 3–4) was characterized by rapid T cell proliferation and upregulation of gut homing receptors alpha4beta7, alphaEbeta7 and CCR9 on alloreactive T cells in Peyer’s patches (PP), mesenteric lymph nodes (LN) and spleen, but not peripheral LNs. Therefore we asked whether the lack of specific lymphoid priming sites would lead to decreased alloreactive T cell infiltration in the gut compared to the liver and skin. Using PP deficient mice, we observed that mesenteric LN and spleen compensate for the lack of PP as alloreactive priming sites. Transplantation of PP and LN deficient mice (TNFalpha-/-) showed that the spleen alone was sufficient to cause the complete profile of aGVHD with a time course similar to that of wildtype mice. Splenectomized mice with intact secondary lymphoid organs also developed aGVHD. Strikingly, treatment of splenectomized recipients with blocking antibodies against the lymphoid homing receptors L-selectin and MAdCAM-1 prevented GVHD with 100% survival (&gt;120 d, p&lt;0.0001). Our study shows that multiple priming sites are involved in GVHD initiation, the spleen compensating for the lack of PP and mesenteric LN, and vice versa. In contrast, splenectomy and antibody blocking resulted in a clear survival benefit for all recipients.
The Role of Annexin II in Stem Cell Homing to Endosteal Osteoblasts - Molecular Dissection of the Hematopoietic Stem Cell Niche.
Authors: Taichman Russell S. , Jung Younghun , Wang Jingcheng , Song Junhui , Wang Jianhua H. , Havens Aaron , Sun Yanxi X. , Krebsbach Paul H. 
Published: April 2020

Abstract
HSC differentiation occurs in direct proximity to osteoblasts (OBs) with in the bone marrow cavity. Using a novel cell blotting system in which OB membranes were run on non-denaturing discontinuous gels and blotted with labeled HSC cell lines, two major adhesive bands were identified. The two proteins were identified as annexin II monomers and multimers.
Immunohistochemistry and laser capture and microarray studies demonstrated that annexin II is preferentially expressed at endosteal surfaces and endothelial cells. Antibody studies against annexin II blocked the adhesion of HSC to OB in vitro. siRNA knockdown and over-expression studies of annexin II resulted in either reduced or enhanced binding characteristics, respectively, as expected. These findings were verified using primary human CD34+ bone marrow cells and human OBs where the binding of the progenitor cells and CFU-activities were linked with annexin II. Peptide mapping demonstrated that the majority of the HSC binding activity resides in the N-terminal aspect of the peptide.
To assess the role of annexin II in hematopoietic reconstitution, lethally irradiated mice were transplanted with bone marrow cells in the presence or absence of antibody to annexin II, antibody to the p11 annexin II binding partner, or isotype matched controls. Additional groups included use of the N-terminal p1-12 annexin II synthetic peptide or control. Animals that did not receive any marrow cells died within 14 days. Of the mice transplanted with 2x10^5 bone marrow cells, 1/8 animals died at day 11, representing an 80% survival rate. In contrast, when mice were transfused with the same number of marrow cells together with antibody to annexin II, none of the mice survived; the control treated animals survived (n = 8). Equivalent antibody doses against the annexin II binding partner p11 decreased the survival rate of the treated animals compared to IgG controls. However this treatment was less effective in inhibiting survival compared to the antibody to annexin II. Like wise, the survival of mice treated with two different doses of the p1-12 peptides at two different cell concentrations was significantly relative to the groups treated with a scrambled peptide control. These data suggest that the N-terminal twelve amino acids of annexin II facilitate stem cell homing to the marrow. Together these in vitro and in vivo data suggest a novel role for annexin II in the marrow microenvironment.
Bortezomib Induces Selective Depletion of Activated T Lymphocytes and Modifies the Cytokine’s Production Pattern.
Authors: Blanco Belen , Perez-Simon Jose A. , Sanchez-Abarca Luis I. , Carvajal-Vergara Xonia , Mateos Juan , Vidriales Belen , Lopez-Holgado Natalia , Alberca Mercedes , Villaron Eva , Schenkein D. , Canizo Consuelo , Pandiella Atanasio , San Miguel Jesus F. 
Published: April 2020

Abstract
The NF-kB family has emerged as a key transducer of inflammatory signals involved in dendritic cell maturation and T lymphocyte activation. Accordingly, the diverse signaling pathways downstream of TCR/CD3 converge on several transcription factors including NFAT, AP-1 and NF-kB. We explored the ability of the proteosome inhibitor bortezomib, which prevents Nuclear Factor kB (NF-kB) activation, to block T-cell activation, proliferation and survival within alloreactive as compared to resting T-cells. For this purpose, T-cells were stimulated with PHA, aCD3/aCD28, allogeneic dendritic cells (APC) or through mixed lymphocyte cultures. NF-kB expression increased in activated T-lymphocytes as compared to resting T-cells. Interestingly, the higher the NF-kB expression, the more intense the proliferative blockade induced by bortezomib. This effect on proliferation was due to a selective induction of apoptosis among activated T-cells. Thus, after mixed lymphocyte reaction (MLR) cultures, alloreactive T-cells were 2 logs more sensitive to bortezomib-induced apoptosis than the resting T-cell counterpart as assessed by annexin / 7AAD staining. This effect of bortezomib was partially blocked by adding the caspase inhibitor Z-VAD to the culture. The addition of bortezomib not only decreased the proliferation and viability of activated T-lymphocytes but also the levels of IFN-g and IL-2, which were significantly decreased among activated T-cells cultured with bortezomib at doses ranging from 10 to 100 nM. Secondary mixed lymphocyte cultures demonstrated a selective loss of alloreactive T-cells while activation and proliferation against third party donor was partially preserved.
In conclusion, at concentrations reached in the clinical setting, bortezomib induces selective apoptosis and decreases Th1 response among alloreactive T-lymphocytes while it barely affects unstimulated T-cells. These results establish the basis for the clinical use of bortezomib in the management of GVHD
Enhanced Immune Reconstitution and Function by CD4+CD25+ Regulatory T Cells Following Allogeneic Hematopoietic Cell Transplantation.
Authors: Nguyen Vu H. , Shashidhar Sumana , Zeiser Robert , Ho Lena , Brown Janice M.Y. , Negrin Robert S. 
Published: April 2020

Abstract
Regulatory T cells (Treg), defined phenotypically by CD4+CD25+ expression, reduce the incidence and severity of acute graft-versus-host disease (GvHD) in murine models of major-MHC mismatched hematopoietic cell transplantation (HCT), presumably by dampening the proliferation and activation of mature effector T cells. It is unclear whether the effect of Treg on effector T cells is a selective or nonselective process or if Treg regulate the process of intrathymic and peripheral T cell maturation and selection following HCT, particularly given the intrinsic link of GvHD and immune reconstitution. The current study assessed the impact of Treg on the quantitative and functional lymphoid reconstitution in a murine model of major-MHC mismatched HCT. Treg (5x105) from the spleen and lymph nodes of FVB/N (H2q) mice were co-transplanted into lethally irradiated Balb/c (H2d) host along with wild-type FVB/N T-cell depleted bone marrow (TCD-BM) cells (5x106) and splenocytes (1.25x106) (Tcon), the latter to induce GvHD. Chimerism studies were performed on day 14 and 40 post-transplantation to measure the level of donor immune reconstitution. At both time points, total lymphoid reconstitution was delayed in the GvHD control group and enhanced in the recipients transplanted with Treg (p-values=0.0005 on day 14, &lt;0.0001 on day 40). T cell reconstitution, particularly CD4+ cells, was enhanced in the Treg group at both time points and reached statistical significance on day 40 (p-value=0.003). The number of donor natural killer cells was particularly enhanced on day 14 in the Treg recipients (p-value=0.0003). B-cell reconstitution, as measured by percentage of CD19+ cells, was minimal for all groups at day 14, but was enhanced at day 40 in recipient animals that received Treg (p-value=0.006). The T cell repertoire assessed by V-beta TCR screening with FACS analysis showed a polyclonal distribution. To determine if the improved and diverse lymphoid reconstitution is associated with increased immune function, mice were challenged with murine CMV (5x10e5 pfu/mouse) intraperitoneally at day 14 post-transplantation. Two weeks after infection, 66% of animals which received Treg in addition to Tcon, and 11% of animals which received Tcon alone were alive (p-value=0.05). Uninfected mice in the respective groups served as controls to separate the effect of CMV infection and GvHD on survival. Compared to infected animals, no deaths were observed in the respective uninfected groups at this time point (Tcon alone, p-value=0.0004; Treg+Tcon, p-value=0.21). In both infected and control uninfected animals, Treg treated animals had no evidence of significant clinical GvHD while animals that received Tcon alone had severe GvHD. These findings indicate that Treg enhance both the quantitative and functional recovery of the lymphoid cell populations while providing protection against GvHD.
Complete Absence of the Lineage-Determining Transcription Factor C/EBPα Results in Loss of Myeloid Identity in Bcr/abl Induced Malignancy.
Authors: Wagner Katharina , Zhang Pu , Rosenbauer Frank , Drescher Bettina , Kobayashi Susumu , Radomska Hanna S. , Kutok Jeffery L. , Krauter Jürgen , Tenen Daniel G. 
Published: April 2020

Abstract
The lineage-determining transcription factor C/EBPα is required for myeloid differentiation. Decreased function or expression of C/EBPα is often found in human acute myeloid leukemia. However, the precise impact of C/EBPα deficiency on the maturation arrest in leukemogenesis is not well understood. To address this question, we used a murine transplantation model of a bcr/abl induced myeloproliferative disease. The expression of bcr/abl in C/EBPα+/+ and C/EBPα+/− fetal liver cells lead to a chronic myeloid leukemia-like disease. Surprisingly, bcr/abl expressing C/EBPα−/− fetal liver cells fail to induce a myeloid disease in transplanted mice, but instead cause a fatal, transplantable erythroleukemia. Accordingly, increased expression of SCL and GATA-1 in hematopoietic precursor cells of C/EBPα−/− fetal livers was found. The mechanism for the lineage shift from myeloid to erythroid leukemia was studied in a bcr/abl positive cell line. Consistent with findings of the transplant model, expression of C/EBPα and GATA-1 was inversely correlated. Id1, an inhibitor of erythroid differentiation, was upregulated upon C/EBPα expression. Chromatin immunoprecipitation was done and C/EBPα binding to a 3 prime enhancer of the Id1 gene was observed. Downregulation of Id1 by RNA interference impaired C/EBPα induced granulocytic differentiation. Thus, Id1 is a direct and critical target of C/EBPα. Taken together, our study provides the first evidence that myeloid lineage identity of malignant hematopoietic progenitor cells requires the residual expression of C/EBPα.
Telomerase Promotes the Self-Renewal of Human Hematopoietic Progenitor Cells but Does Not Maintain Telomere Length.
Authors: Wei Junping , Wunderlich Mark , Mulloy James C. 
Published: April 2020

Abstract
Telomerase is a reverse transcriptase that adds telomeric sequences onto chromosome ends. During hematopoiesis, telomerase activity is high in proliferating hematopoietic stem and progenitor cells, but decreases sharply as cells differentiate. Approximately 90% of all human cancers are telomerase positive, including samples from AML patients. To understand the role of telomerase in human hematopoietic stem and progenitor cell proliferation and differentiation, and in the development of leukemia, we established stable long-term cultures expressing high levels of telomerase by retrovirus-mediated transduction of the h-TERT (catalytic subunit of telomerase) gene into AML1-ETO-expressing CD34+ (AE) cells. We have previously shown that these AE cells maintain CD34 expression and proliferate for 7 months in culture but gradually lose telomere length and are not immortal, providing a good model for studying the molecular mechanisms involved in telomere shortening. Strikingly, telomerase expression enhanced the self-renewal ability of the human hematopoietic progenitor cells, as shown by continuous replating ability in methylcellulose assays. We also detected a pronounced delay in the differentiation of the progenitor cells upon telomerase expression, and an expansion of the progenitor pool. Telomerase expression promoted proliferation due to increased cell cycle progression as well as a survival advantage. At the same time, these cells demonstrated a progressive decline in telomere length, despite telomerase activity equivalent to that detected in leukemia cell lines. We conclude that expression of hTERT expands the pool of hematopoietic progenitors but does not maintain long telomeres in human CD34+ cells. hTERT plays a critical role not only in telomere homeostasis for genetic stability but also in cellular proliferation, differentiation, and self-renewal, functions that may be part of hTERT involvement in leukemogenesis. These data open an important debate regarding the specific contribution of telomerase expression to the leukemic phenotype and the potential timing of this essential hit in the progression of the disease.