bluuebunny/crossref_metadata_2025_split huggingface dataset:
Downregulation of Mir-22 in ALL Cells Is Associated with the Accumulation of Histone Modification but Independent of DNA Methylation.
Authors: Li Xiaoqing , Liu Jun , Zhou Rui , Huang Shi , Chen Xian-Ming , Huang Shiang 
Published: October 2019

Abstract
Abstract 3464
Poster Board III-352
MicroRNA-22 is one of the miRNAs frequently downregulated in human ALL cells and may play an important anti-tumor role in normal hematopoiesis. Histone modification and DNA methylation can have different roles in gene silencing in cancer. To investigate whether histone modifications would contribute to the dysregulation of miRNA-22 in acute lymphoblastic leukemia (ALL), the effect of a histone deacetylase inhibitor, trichostatin A (TSA), on miRNA-22 expression of primary ALL cells was analyzed by real-time PCR. The total number of patients included to this study is 33, including 26 samples of leukemia (18 of ALL and 8 of acute myeloid leukemia) and 7 normal controls. All patient blood samples were collected at the time of diagnosis. We detected a lower expression of pri-miR-22 in PMBCs from ALL patients compared with that from the health volunteers. Treatment with TSA significantly increased pri-miR-22 expression in PMBCs from ALL patients, but not in cells from the health volunteers. Whereas PMBCs from ALL patients and AML patients showed comparable levels of pri-miR-22. TSA treatment had no effect on pri-miR-22 expression in PMBCs from AML patients, suggesting TSA-mediated upregulation of miR-22 transcription in ALL but not AML malignant cells. Moreover, we used MPS assay to analyze the methylation status at the promoter element of miR-22 gene in primary human specimens. No DNA hypermethylation was detected in PMBCs from the health volunteers and patients with either ALL or AML. These data provide further evidence that miR-22 silencing in ALL cells may be DNA methylation-independent. In contrast, accumulation of the repressive histone marker H3K27 trimethylation (H3K27triM) was indentified around the transcriptional start point of the gene, which reduced by TSA treatment.
In conclusion, we showed that histone modification is involved in miRNA dysregulation in human ALL cells. Specifically, the silencing of miR-22 in ALL cells is associated with the accumulation of histone modification in its promoter element of miR-22 gene but independent of DNA methylation. The accumulation of H3K27triM may be a novel epigenetic mechanism for miR-22 silencing in ALL.

Disclosures
No relevant conflicts of interest to declare.
A Comparison of the Sex-Specific Incidence of Immune Thrombocytopenia in Children, Teenagers, and Adults in the General Practice Research Database.
Authors: Yong Mellissa , Schoonen W. Marieke , Li Lin , Kaye James A. 
Published: October 2019

Abstract
Abstract 3502
Poster Board III-439

Background
Immune thrombocytopenia (ITP) is an autoimmune condition characterized by low blood platelet counts. It has been reported that the epidemiology of ITP in the pediatric population (<18 years old) is different from that in adults. We therefore assessed the incidence of ITP in the pediatric population as compared to the adult population in a large UK-based primary care database – the General Practice Research Database (GPRD).

Methods
We identified all patients with a first-time diagnosis of ITP recorded in the GPRD during the period from 1990 to 2005. Age- and sex-specific incidences of ITP were estimated as the number of patients with a first-time recorded diagnosis of ITP divided by the person-time contributed by all subjects in the database who did not have a diagnosis of ITP.

Results
Of the total of 1,146 incident cases of ITP among 29.2 million person-years (PY) of observation from 1990 to 2005, we observed 257 incident cases of pediatric ITP (<18 years old) in 6.1 million PY, of whom 197 were children (aged less than 10 years) and 60 were teenagers (10 – 17 years old) at diagnosis. The age-specific incidence estimate for ITP in children was 5.7 per 100,000 PY [95% confidence interval (CI): 5.0 – 6.6 per 100,000 PY], with a statistically significantly 60% higher incidence in boys compared to girls. By contrast, among teenagers the overall incidence was lower [2.2 (95% CI: 1.7 – 2.9) per 100,000 PY] with a suggestion of a 50% higher incidence rate in girls compared to boys. The overall incidence in the adult population was 3.8 (95% CI: 3.6 – 4.1) per 100,000 PY, with women having a statistically significantly 48% higher incidence compared to men.

Conclusions
Our results showed an interaction between age and sex with ITP incidence, suggesting that patterns of disease burden differ among children, teenagers, and the adult population. Further investigation into these differences, including comorbidities and treatment practices is warranted.

Financial disclosure
This study was supported by Amgen Inc.

Disclosures:
Yong: Amgen Inc.: Employment, Equity Ownership. Schoonen:Amgen Inc.: Employment, Equity Ownership. Kaye:Amgen Inc.: Research Funding.
Bone Marrow Cell Rejection by Innate Immune Pathways Is Exclusively Dependent On the TRIF Pathway.
Authors: Xu Hong , Yan Jun , Zhu Ziqiang , Hussain Lala-Rukh , Huang Yiming , Wen Yujie , Ildstad Suzanne T 
Published: October 2019

Abstract
Abstract 3526
Poster Board III-463
Research on transplantation rejection, tolerance, and immunosuppressive agents has been directed toward the adaptive immune response as, until now, it has been believed to be the dominant mechanism for alloreactivity. The role of innate immunity in transplantation has not been fully defined. Despite the sentinel role of innate immunity in driving and shaping adaptive immunity, the contribution of innate immunity to bone narrow cells has only recently been identified. TLR4-driven MyD88-dependent immunity has been demonstrated to be critical for allogeneic innate immune responses to solid organ transplants. Whether innate immunity plays a role in BMC rejection has not been defined. In the present studies we tested whether the absence of MyD88 would enhance allogeneic engraftment in bone marrow transplantation (BMT). The core component of TLR signaling is activation of an IL-1-like pathway dependent upon the adapter MyD88. MyD88−/− B6 mice (n=6) were used to study the role of MyD88 signaling in allogeneic BMC rejection. As TRIF is another crucial adapter for TLR3 signaling and responsible for induction of signaling via type 1 IFNs, B6 TRIF−/− mice (n=6) were also investigated. Wild-type B6 (H2b, n=6) mice were used as controls. In the present study, MHC plus minor antigen-disparate BALB/c (H2d) mice served as allogeneic bone marrow donors. Recipients were nonmyeloablatively conditioned with anti-CD154 mAb (day0 and +3) to block CD40:CD154 co-stimulatory pathway and sirolimus (day0 to +4) to block late-stage T cell activation by inhibiting IL-2 responsiveness. Recipients were transplanted with 15 × 106 allogeneic (BALB/c; H2d) marrow cells 4-6 hours following conditioning with 100 cGy total body irradiation (TBI). Allogeneic engraftment was achieved in 33.3% of MyD88−/− recipients at 1 mo after BMT, a percentage similar to that for wild-type B6 mice. Surprisingly, 100% of TRIF−/− mice engrafted. The level of donor chimerism in TRIF−/− mice was 5.1 ± 0.6% at one month after BMT, which was significantly higher than in MyD88−/− (1.8 ± 1.0%; P < 0.0001) or in wild-type B6 mice (1.3 ± 0.8%; P < 0.005) and thereafter through all time points tested (2, 4 and 5 months, P < 0.05). The levels of donor chimerism increased with time and the level of donor chimerism reached 14.7 ± 7.1% TRIF−/− at five months. These results suggest that allogeneic BMC rejection is uniquely independent of the MyD88 pathway but rather involves TRIF signaling. These data suggest that the innate immune response to BMC differs from that for solid organs and may reflect the specificity of BMT compared with other transplants. These findings demonstrate for the first time that BMC elicit an innate immune response via the TRIF pathway and may open the door to novel approaches for immune-based conditioning to promote engraftment.

Disclosures:
Ildstad: Regenerex: Equity Ownership.
NK Cell-Mediated Rejection of Bone Marrow Cells- In Vivo Evidence of NK Cell Subset Licensing.
Authors: Sun Kai , Barao Isabel , Redelman Doug , Murphy William 
Published: October 2019

Abstract
Abstract 3537
Poster Board III-474
Natural killer (NK) cells have been shown to attack virally-infected and transformed cells as well allogeneic bone marrow cells (BMC) but not normal self-tissues. The mechanism of missing self recognition and self tolerance of NK cells is poorly understood. NK cells exist as subsets based on expression of inhibitory receptors (Ly49 in mouse, KIR in man) that bind MHC class molecules. In vitro data have shown that murine NK cell subsets bearing Ly49 receptors for self MHC class I molecules have intrinsically higher effector function, supporting the hypothesis that NK cells undergo a host MHC class I-dependent functional education, allowing the NK cells bearing the appropriate Ly49 receptors to preferentially mediate effector function. Thus far, no in vivo evidence for this preferential licensing or arming has been shown. We assessed the intrinsic response potential of the different Ly49+ NK cell subsets in BMC rejection without having the complicating effects of binding MHC on the target cell (which delivers potent inhibitory signals to the NK cell) by using β2-microglobulin deficient (β2m−/−) mice as donors which totally lack class I MHC molecules. Using syngeneic, congenic, and allogeneic strains of mice as recipients and depleting the different Ly49 subsets, we found that NK cell subsets whose Ly49 molecules have been shown to bind “self-MHC Class I” (ie Ly49G2 in H2d and Ly49C in H2b haplotypes) were found to be the dominant subset responsible for mediating the rejection of the β2m−/− BMC. This provides the first in vivo evidence for host MHC class I-dependent functional education (licensing or arming). Importantly, we also demonstrated that prior activation of the NK cells in vivo could override this licensing effect and allow the “non-licensed subset” to mediate rejection. The pattern of NK mediated rejection ability by Ly49 subsets was observed in B10D2 allogeneic H2d strain mice but not observed in BALB/c allogeneic H2d strain mice indicating that licensing ability was not solely dependent on host MHC expression and supporting the role of MHC class I–independent system for NK-cell self-tolerance. Interestingly, all H2d strain mice (B10.D2, BALB/c, and B6D2F1) were able to resist significantly greater amounts of B2m-/- BMC than H2b strain mice indicating that the rheostat hypothesis regarding Ly49 affinities for MHC and NK cell function impacts BMC rejection capability. These results demonstrate that both MHC and non-MHC genes on the host has multiple effects on NK cell subset-mediated BMC rejection and that licensing or arming of Ly49 NK cell subsets can be observed in vivo.

Disclosures:
No relevant conflicts of interest to declare.
Study On the Mechanism of Enhancing Immune Reconstitution of Keratinocyte Growth Factor in Murine Allogeneic Umbilical Cord Blood Cell Transplantation.
Authors: Chen Guanghua , Wang Yi , Depei Wu , Huang Haiwen , Wang Ying , Xu Yang , Sun Aining , Chang Weirong 
Published: October 2019

Abstract
Abstract 3544
Poster Board III-481

Objective
To explore the impact and mechanism of keratinocyte growth factor (KGF) infusion on immune reconstitution post murine allogeneic umbilical cord blood cell transplantation (UCBT).

Methods
Mix cord blood was obtained at E19.5 from several litters of B6 females and was used as umbilical cord blood (UCB) graft. Thirty-two BALB/c mice were randomly assigned to 4 groups with 8 mice per group in the first cohort UCBT, mice were reconstituted with PBS or 1×106, 2×106, 3×106 UCB mononuclear cells (MNCs). Twenty-four BALB/c mice were randomly assigned to 3 groups with 8 mice per group in the second cohort UCBT, mice were injected with 1×106, 2×106 or 3×106 MNCs. All mice received platelet transfusion on +8d. Sixteen BALB/c mice were randomly assigned to 2 groups with 8 mice per group in the third cohort UCBT, mice were injected s.c. with KGF or PBS before TBI. All mice were injected with 2×106 MNCs and were supported with platelet transfusion on +8d. We studied survival, splenic lymphoid cell subsets, sjTREC assay after UCBT.

Results
The survival rates at +100d of mice resconstituted with allogeneic 1×106, 2×106, 3×106 UCB MNCs were 25%, 37.5% and 37.5% in the first cohort UCBT,respectively. The survival rates at +100d of mice injected with 1×106, 2×106, 3×106 MNCs and with platelet support were 87.5%, 100.0% and 100.0%, respectively. The splenic T, NKT, NK and B cell counts in PBS treated control mice on +35d were (9.57±0.74)×106, (0.64±0.06)×106, (1.43±0.10)×106 and (19.13±1.50)×106, respectively. While in KGF treated mice on +35d were (13.47±0.74)×106, (0.89±0.03)×106, (1.79±0.04)×106 and (20.50±0.91)×106, respectively. The level of sjTREC in control mice was 182.2±10.7copies per 105 cells Gwhile that of KGF treated mice was 224.2±9.6 copied per 105 cells and was higher than that of control mice (P=0.019).

Conclusion
Peripheral blood abtained from E19.5d fetus is rich in hematopoietic stem cells. We established a murine allogeneic UCBT model with platelet support on +8d. KGF treatment could enhance immune reconstitution after UCBT.

Disclosures:
No relevant conflicts of interest to declare.
Predicting Disease Progression to Multiple Myeloma (MM) From MGUS/SMM In SWOG-0120 Observational Trial
Authors: Dhodapkar Madhav , Shaughnessy John , Hoering Antje , Nair Bijay , Bolejack Vanessa , van Rhee Frits , Crowley John , Barlogie Bart 
Published: October 2019

Abstract
Abstract 1932

Background:
Most MM develops through an asymptomatic precursor stage. Current analyses understanding the risk of progression to clinical MM are based on limited set of variables. In 2002, South West Oncology Group (SWOG) began a prospective observational clinical trial of patients with asymptomatic plasmaproliferative disorders (PCD) to evaluate clinical, imaging, genetic and immunologic features predictive of disease progression.

Patients and Methods:
All patients with asymptomatic PCD underwent detailed staging evaluation at study entry and were prospectively followed at 3–6 month intervals until disease progression requiring therapy. Data from clinical features at baseline were evaluated to assess the risk for progression to clinical MM (P-MM).

Results:
Between 11/2002 and 4/2010, 230 patients have been enrolled, of whom 140 were deemed to have smoldering MM (SMM) and 90 monoclonal gammopathy of undetermined significance (MGUS), based on international myeloma working group criteria. The two groups differed in terms of abnormal serum free light chain ratio (FLCR; SMM: 79%, MGUS: 52%; p<0.001) and low levels of uninvolved Ig (SMM: 77%, MGUS; 53%; p<0.001), while no significant differences were noted in the proportion of patients with elevated beta 2 microglobulin (B2M) >=3.5mg/L, albumin <3.5 g/dL, elevated C-reactive protein >8mg/L or lactate dehydrogenase (LDH). Among 13 variables potentially linked to P-MM, baseline B2M >=3.5mg/L, baseline serum albumin <3.5g/dL, serum M-spike and bone marrow plasmacytosis (as continuous variables), serum calcium >8 mg/dL, abnormal FLCR and low levels of uninvolved Ig were all associated with greater propensity of P-MM on univariate analysis. However upon multivariate analysis, abnormal serum FLCR and SMM disease type were the only surviving adverse variables predictive of disease progression.

Conclusions:
These data demonstrate in the context of a large prospective multicenter trial that abnormal FLCR is a dominant predictor of clinical malignancy in asymptomatic PCD. These findings support the need to understand the biology of abnormal FLCR and incorporate novel criteria based on imaging, genetics and host response.

Disclosures:
No relevant conflicts of interest to declare.
Could the Increased Prevalence of Thrombotic Complications at High Altitude In Polycythemia Vera (PV) Be Contributed by Hypoxia?
Authors: Lee# Jasmine CH , Zangari# Maurizio , Stein Brady L , Hickman Kimberly , Wilson Andrew , Moliterno Alison , Spivak Jerry L , Gordeuk Victor R. , Prchal Josef T. 
Published: October 2019

Abstract
Abstract 1988

# Both authors contributed equally.
Thrombotic complications are a major cause of morbidity and mortality in polycythemia vera (PV). While the risk of PV thrombotic complications is significantly higher in patients with a previous history of thrombosis or transient ischemic attacks, advanced age (> 60 years), leukocytosis and possibly a high JAK2 V617F allelic burden, other contributing etiologies have not been excluded. It is unclear whether environmental variations including hypoxia could modify thrombosis risk. Chronic hypoxia induces many phenotypic changes, including increased erythropoietin production resulting in secondary erythrocytosis and pulmonary hypertension. Moreover, a congenital disorder of augmented hypoxia sensing at ambient oxygen tension, Chuvash polycythemia, is associated with a marked, yet unexplained, increased rate of thrombotic complications.
Salt Lake City, UT is located in a valley at ~5,000 feet of altitude and the surrounding areas from which PV patients are referred ranges from 4,300 to 6,900 feet in altitude. In this area, the average hemoglobin concentration is 0.6–1.3 gm/dL higher than the average US value, indicating a physiological response to this level of hypoxia.
To analyze the possible effect of moderate hypoxia on PV thrombotic complications, we retrospectively compared the history of thrombotic complications in PV patients from Salt Lake City and Baltimore, MD, a city with a referral area in which the elevation is <500 feet. A total of 237 PV patients were analyzed in this study; 166 were treated in Baltimore and 71 were treated in Salt Lake City, Their demographics are presented in the Table.
Patients from Salt Lake City were older than the Baltimore patients, more often male, and had longer disease duration. A history of thrombosis was present in 58% of the Salt Lake City patients compared to 27% of the Baltimore patients (P <0.0001). After adjusting for age, sex and disease duration, Salt Lake City patients had an estimated 3.9-fold increase in the odds of history of thrombosis compared to Baltimore patients (95% confidence interval of 1.9 to 7.8; P = 0.0002).
The analysis suggests that hypoxia may modify the PV phenotype. The degree of HIF-1 and HIF-2 augmentation and altered regulation of their target genes, and the potential for increased thrombotic risk due to environmental hypoxia should be evaluated prospectively in PV patients living at different altitudes.

Disclosures:
No relevant conflicts of interest to declare.
Pegylated Interferon-Alfa-2a In Clinical Responders Often Decreases JAK2 V617F Allelic Burden and/or Reverses Clonal Hematopoiesis, but These Are Not Always Parallel In PV and ET Females
Authors: Swierczek Sabina , Verstovsek Srdan , Agarwal Archana , Manshouri Taghi , Hickman Kimberly , Prchal Josef T. 
Published: October 2019

Abstract
Abstract 1990

Polycythemia vera (PV) and essential thrombocythemia (ET) are hematological malignancies due to clonal proliferation arising from a multilineage stem cell. Pegylated interferon-alfa-2a is a better-tolerated form of interferon shown to be effective in inducing clinical remission and reducing the JAK2V617F allelic burden in PV and ET patients. However, while the somatic JAK2V617F mutation, which is seen in the majority of PV patients, is not the PV-initiating mutation, it appears to have prognostic significance. Conventional preparations of interferon alfa have been shown in isolated instances to convert clonal to polyclonal hematopoiesis in PV patients. Our study involved 6 PV patients and 3 ET patients who achieved complete clinical remission after peg-IFN-α-2a therapy. We evaluated both the allelic burden of JAK2V617F mutation, as well as clonality of hematopoiesis by our previously developed quantitative X-chromosome-based transcriptional clonality assay.
All of the PV and ET patients had variable allelic burdens of JAK2V617F before starting the peg-IFN-α-2a therapy. The baseline allelic burden ranged from 11.8% to 93.6%, with a mean percentage of 50.9%. Peg-IFN-α-2a was administered for at least 18 months. Following peg-IFN-α-2a treatment, the allelic burden of JAK2V617F mutation decreased in all patients, with a mean of 11.37% and a range of 2.4% -31.8% (see Table); however, clonal hematopoiesis persisted in some responding patients (see Table, these results in italics). In one ET patient (not in Table), prolonged peg-IFN-α-2a therapy induced clinical remission and resumption of polyclonal hematopoiesis, with a JAK2V617F allelic burden of <1%; however, after discontinuation of peg-IFN-α-2a, the patient relapsed and her hematopoiesis reverted to clonality, yet her JAK2V617F remained at <1%.
In summary, pegylated interferon-alfa-2a induces clinical remission in a large proportion of PV and ET patients. However, at the cellular level, improvement in JAK2V617F allelic burden and resumption of normal hematopoiesis are not always parallel.

Disclosures:
Verstovsek: Incyte Corporation: Research Funding.