bluuebunny/crossref_metadata_2025 huggingface dataset:
Pomalidomide Therapy for Myelofibrosis: Analysis of Results From Three Consecutive Clinical Trials
Authors: Begna Kebede , Pardanani Animesh , Mesa Ruben A. , Hogan William J , Litzow Mark R. , Tefferi Ayalew
Published: October 2019

Abstract 1759

Background:

Pomalidomide is a second generation IMiDsÒ immunomodulatory drug that has been shown to be active in the treatment of myelofibrosis (MF)-associated anemia (J Clin Oncol 2009; 27: 4563; Leukemia 2011;25: 301). In the current sponsor-independent analysis, we report long-term follow up data on patients from the Mayo Clinic who had participated in three consecutive clinical trials using single agent pomalidomide for MF.

Methods:

From May 2007 to January 2010, 94 patients with MF (including primary and post-polycythemia/essential thrombocythemia) were enrolled in three consecutive phase I and II clinical trials involving pomalidomide with or without prednisone. Eight two patients who received only single agent pomalidomide constitute the study population for the current study. Follow up information was updated in July, 2011.

Results:

Among the 82 study patients, 19 were included in a phase I dose escalation study (2.5-3.5 mg/day), 58 in a phase II low-dose single agent pomalidomide study (0.5 mg/day), and 5 in a phase II randomized study (2 mg/day). Median age was 67 years and 63 (77 %) patients were red blood cell transfusion dependent at study entry. Forty-five (55%), 24 (29%), 7 (9%), and 2 (2%) patients remained on pomalidomide therapy for at least 6, 12, 24, and 36 months, respectively (Table 1). The overall anemia response rate per IWG-MRT criteria was 27% (22/82). Response occurred in the first 6 months in 21 (96%) of the 22 responders. The median time for response was 2.3 months (range, 1–10). The median response duration was 16.5 months (2–40). The anemia response rate in patients with spleen size palpable at less than 10 cm below the costal margin was 44 % (17/39) vs. 10 % (4/39) in those whose spleen was palpable at or above 10 cm (p=0.002). The anemia response rate was twice as likely in JAK2 mutated versus non-mutated cases (30% vs 15% p=0.2). Anemia response rate was also higher in patients with at least 50% increase in absolute basophil count during the first month of therapy: 39% (19/49) vs 6% (2/32) p=0.001). The anemia response rate was not significantly affected by karyotype, transfusion need or leukocyte count. Among the anemia responders (n=22), 3 (14%) relapsed in the first 12 months; relapse was more likely in the presence of baseline leukocytosis (p=0.006). Among the 24 patients who took pomalidomide for at lease 12 months, grade 1 sensory neuropathy developed in 4 (16%) patients.

Conclusion:

Anemia response to pomalidomide therapy in myelofibrosis often occurs in the first 6 months of treatment and is more likely to occur in the presence of JAK2V617F and absence of marked splenomegaly. Long-term treatment with pomalidomide might be associated with sensory peripheral neuropathy in a subset of treated patients.

Disclosures:

No relevant conflicts of interest to declare.
Phenotypic Analysis and Single-Cell Gene Profiling of Human Regulatory T Cell Subsets in Human Graft-Versus-Host Disease
Authors: Xhaard Alienor , Dong Shen , Maiella Sylvie , Pang Yuanyu , Benecke Arndt , Bianchi Elisabetta , Socie Gerard , Rogge Lars
Published: October 2019

Abstract 1975

Acute graft versus host disease (aGVHD) is an important cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (alloHSCT). CD4+FOXP3+ regulatory T cells (Treg) are a population with potent immunosuppressive properties and may offer a new way to prevent or treat aGVHD. Treg therapy has demonstrated high efficacy in mouse models; however, translation to human has been hampered by the identification of different subsets of human Treg and doubt about in vivo conversion of Treg into effector Th17 cells. Based on the expression of CD45RA and HLA-DR, we identified 3 different subsets of human FOXP3+ Treg in healthy subjects' peripheral blood as well as in cord blood. All 3 subsets were suppressive in vitro. Gene expression profiling combined with global pathway analysis revealed clearly distinct immune signatures for each subset, which were validated by analysis at the single-cell level. Single-cell gene profiling also uncovered a striking heterogeneity of gene expression within these Treg subpopulations and revealed that cytokine-expressing Treg did not downregulate FOXP3 and other Treg markers.

We prospectively studied Treg subsets in 18 consecutive alloHSCT recipients' peripheral blood. Median age was 47 years (range: 26 to 65). Analysis was performed before steroid initiation in patients with aGVHD (n=7) and at hematopoietic recovery in the control group (n=11). First sample was analyzed a median of 20 days after alloHSCT (range: 11 to 36) with no difference between the 2 groups. Percentages of FOXP3+ cells in CD4+ cells were not significantly different in aGVHD patients and in the control group (10.4 and 12.6%, p=0.53). However, we observed in the aGVHD group a strong alteration of Treg subsets compared to the control group, with a pronounced bias towards an activated phenotype. RA-DR+ cells were significantly more represented among FOXP3+ T cells in aGVHD patients than in the control group (80.8 versus 53%, p=0.003). Conversely, RA-DR- and RA+DR- cells were more frequent in the control group than in patients with aGVHD (26.8 versus 10.6% and 13.5 versus 2.1%, p=0.014 and p=0.0012, respectively).

Our data suggest that frequencies of specific Treg subpopulations, rather than the frequency of the total pool of CD4+FOXP3+ Treg, is altered in aGVHD and may serve as a biomarker for this condition.

Current work addresses the molecular and functional characteristics of Treg subsets in aGVHD patients. Since Treg have been suggested to convert into effector T cells in pro-inflammatory and lymphopenic conditions, we will also assess the potential “plasticity” of the three Treg subsets.

Disclosures:

No relevant conflicts of interest to declare.
Absence of the Wnt Antagonist Sclerostin Adversely Affects B Cell Development in the Bone Marrow Niche
Authors: Cain Corey J , Rueda Randell , McLelland Bryce T , Collette Nicole , Loots Gabriela , Manilay Jennifer O
Published: October 2019

Abstract 220

Hematopoietic cell fate decisions are dependent on their localized microenvironmental niche. In the bone, endosteal osteoblasts have been shown to support hematopoietic stem cells (HSC) self-renewal, as demonstrated by transgenic and knockout mouse models in which osteoblast populations were increased or decreased. In addition, Wnt signaling and the Wnt antagonist Dkk-1 have been implicated in various aspects of hematopoiesis and HSC self-renewal. Sclerostin (Sost) is a secreted protein that is primarily expressed by fully mature osteocytes and acts on osteoblasts as a negative regulator of bone growth, by antagonizing Wnt signaling by its binding to the Wnt co-receptors Lrp4, Lrp5, and/or Lrp6. Here, we investigated the role of Sost on hematopoiesis in the bone marrow niche. Increased osteoblast activity in sclerostin-knockout (Sost−/−) mice results in hypermineralized bones with small bone marrow cavities. As such, Sost−/− mice contain markedly reduced numbers of CD45+hematopoietic cells in the bone marrow. Since hematopoietic stem cell activity is dependent on osteoblast function, we examined whether the hyperactive osteoblast activity in Sost−/− mice influences the numbers of hematopoietic stem cells, lymphoid progenitor cells and myeloid progenitor cells in the bone marrow. Surprisingly, no differences were observed in hematopoietic stem and progenitor cell frequency and cell number. However, we found the bone marrow of Sost−/− mice to be depleted of B cells, and this reduction can be attributed to premature apoptosis beginning at the pre-pro-B cell stage. Examination of Sost expression showed that no hematopoietic cells expressed Sost, however, pre-pro, immature and recirculating B cells expressed Lrp5 and Lrp6. These gene expression patterns suggested that the defect in B cell development in Sost−/− mice is non-cell autonomous and that absence of Sost could affect Wnt signaling in these populations. We observed that the expression of Wnt target genes CCND1 and Lef-1 were not affected by the absence of Sost, but c-Myc was significantly upregulated in recirculating B cells in the bone marrow. We also observed a significant decrease in CXCL12 expression in the bone marrow stroma in Sost−/− mice, consistent with their inability to adequately support B cell development. Taken together, our results indicate that the B cell developmental defects in Sost−/− mice are non-cell autonomous, and we are currently performing reciprocal bone marrow transplantation experiments to further support this hypothesis. Our studies demonstrate a novel role for Sost in the regulation of B cell development in the bone marrow, and demonstrate that distinct Wnt antagonists play specific roles in the regulation of hematopoiesis.

Disclosures:

No relevant conflicts of interest to declare.
Risk of Acute Myeloid Leukemia Among Solid Organ Transplant Recipients
Authors: Morton Lindsay M , Clarke Christina A , Chang Ellen T , Hall Erin C , Lynch Charles F , Pfieffer Ruth , Weisenburger Dennis D , Engels Eric A
Published: October 2019

Abstract 2559

Background.

Patients receiving solid organ transplants experience increased risk of subsequent hematologic malignancies, particularly post-transplant lymphoproliferative disorder and non-Hodgkin lymphoma, likely in relation to infection with oncogenic viruses and pharmacologic immunosuppression to prevent graft rejection. However, less is known about the risks for myeloid neoplasms such as acute myeloid leukemia (AML).

Methods.

We linked data from the US Scientific Registry of Transplant Recipients, a national database of solid organ transplantation, with 13 state and regional cancer registries to obtain cancer occurrence among 175,732 solid organ transplants during 1987–2008. The observed number of patients developing AML was compared to that expected in the general population of the 13 registry areas using standardized incidence ratios (SIRs).

Results.

AML was identified in 107 solid organ transplant recipients (13.8 cases/100,000 person-years), a rate that was nearly three times higher than expected in the general population [SIR=2.9, 95% confidence interval (CI) 2.4–3.5]. Excess risks were highest among children and young adults but remained significantly elevated among individuals receiving a solid organ transplant prior to age 65 years (SIR, 95%CI: <20 years=9.3, 3.4–20.2; 20–34 years=6.3, 3.2–11.3; 35–49 years=3.9, 2.6–5.6; 50–64 years=2.5, 1.9–3.3; 65+years=1.7, 0.9–2.9). Patients receiving liver or heart and/or lung transplants had higher risks than patients receiving kidney transplants (liver=4.1, 2.9–5.7; heart and/or lung=4.0, 2.7–5.7; kidney=2.0, 1.4–2.7). Risks also were higher among individuals receiving a second solid organ transplant than those receiving their first (second=6.8, 3.5–11.9; first=2.7, 2.2–3.3). Excess risks persisted throughout the 22-year period and showed no trend over time.

Conclusions.

In the largest population-based study of transplant-related malignancies conducted to date, we demonstrate that patients receiving solid organ transplants have substantially elevated risk for subsequent AML. Future investigations should evaluate the possible role of specific immunosuppressive medications in the etiology of post-transplant AML.

Disclosures:

No relevant conflicts of interest to declare.
DNMT3B Expression Delays Leukemogenesis,
Authors: Tschanter Petra , Schulze Isabell , Bäumer Nicole , Surmann Beate , Agelopoulos Konstantin , Krug Utz , Berdel Wolfgang E. , Linhart Heinz , Müller-Tidow Carsten
Published: October 2019

Abstract 3446

Acute myeloid leukaemia (AML) is a malignant disease with poor prognosis, which is, among other biological features, characterized by epigenetic changes including alterations in DNA methylation. DNA methyltransferases (DNMT) play an important role in regulation of DNA methylation and mutations of DNMT3A are frequently found in AML. We analyzed the effects of DNMT overexpression on leukemogenesis using an inducible DNMT3B mouse model (Linhart et al., 2007). To analyse the impact of DNMT3B overexpression on leukemia we retrovirally co-transduced lineage-negative bone marrow cells of wildtype and DNMT3Btg mice with a MSCV-cMyc-bcl2 and a MSCV-tTA-GFP containing vector. Under these conditions, doxycycline suppressed DNMT3B expression whereas absence of doxycycline led to overexpression of DNMT3B on the mRNA and protein level. DNMT3B overexpression was not toxic since colony formation in vitro did not differ between DNMT3B expressing and physiologically expressing cells. To analyze leukemogenesis, 5 × 104 sorted GFP-positive cells were transplanted into sublethally irradiated wildtype recipients. Both recipients of transduced wildtype cells and recipients of transduced DNMT3Btg cells developed leukemia with a tendency of delayed leukemogenesis in DNMT3B overexpressing mice. GFP positive leukemic cells were sorted and doxycycline regulated DNMT3B expression was verified by Western blot analysis in vitro. To determine the repopulation capacity of the leukemic cells we performed transplantation of GFP-positive primary leukemia cells into secondary wildtype recipients. Leukemia of both, wildtype and DNMT3B-overexpressing donors was transplantable and lethal. However, DNMT3Btg leukemic cells were severely impaired in leukemia development in secondary recipients. Secondary recipients of leukemic DNMT3Btg cells died significantly later (p= 0.02). Taken together, these findings demonstrate that DNMT3B expression impairs leukemia maintenance. Loss of DNMT activity might contribute to the pool size of leukemia initiating cells.

Disclosures:

Krug: Boehringer Ingelheim: Research Funding.
Re-Evaluation of CD37 As Target for Radioimmunotherapy of Non-Hodgkin Lymphoma,
Authors: Dahle Jostein , Repetto Ada , Mollatt Camilla Sivertsen , Melhus Katrine Brustad , Bruland Øyvind Sverre , Kolstad Arne , Larsen Roy Hartvig
Published: October 2019

Abstract 3732

The monoclonal anti-CD20 antibody rituximab alone or as part of combination therapy, is considered standard therapy for non-Hodgkin's B-cell lymphomas. However, significantly better clinical results have been obtained for beta-emitting anti –CD20 radioimmunoconjugates (RICs) than for rituximab. RICs targeting CD20 may be problematic because of antigenic drift and antigen blocking caused by previous treatments with rituximab. Therefore, novel therapeutic approaches targeting other B cell antigens might be more effective after rituximab treatment failure than a new anti-CD20 treatment. In the present study, we have compared the therapeutic effect of the novel anti-CD37 RIC 177Lu-DOTA-HH1 with the anti-CD20 RIC 177Lu-DOTA-rituximab against Daudi human lymphoma cells in vitro and in vivo. At the same antibody concentration 177Lu-DOTA-HH1 was significantly more effective in inhibiting cell growth in vitro than 177Lu-DOTA-rituximab. SCID mice were intravenously injected with 10 million Daudi cells one week before RIC treatment. A significantly increased survival of mice treated with 177Lu-DOTA-HH1 as compared with 177Lu-DOTA-rituximab treatment was observed. Furthermore, the toxicity of the 177Lu-DOTA-HH1 treatment was significantly lower than for 177Lu-DOTA-rituximab. In addition, we have compared binding properties and biodistribution of HH1 with rituximab. The affinity of HH1 to CD37 was similar to the affinity of rituximab to CD20. The CD37-HH1 complex was internalized 10 times faster than CD20-rituximab. Both antibodies had a relevant biodistribution and low uptake in bone. This work warrants further preclinical and clinical studies with 177Lu-HH1.

Disclosures:

Dahle: Nordic Nanovector: Employment. Bruland:Nordic Nanovector: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Larsen:Nordic Nanovector: Equity Ownership, Membership on an entity's Board of Directors or advisory committees.
The Toll-Like Receptor-Like Molecule CD180 and Soluble CD14 Transmit Survival Signals in B-Cell Chronic Lymphocytic Leukemia Cells Presumably by Acting As Co-Receptors,
Authors: Seiffert Martina , Schulz Angela , Stilgenbauer Stephan , Lichter Peter
Published: October 2019

Abstract 3883

Survival and proliferation of B-cell chronic lymphocytic leukemia (CLL) cells strongly depend on external factors. When removed from their natural microenvironment CLL cells rapidly undergo spontaneous apoptosis in vitro unless cocultured with stromal cells or non-malignant leukocytes. Recently, we could show that monocytes effectively support long-term survival of CLL cells in vitro. Our results from cytokine antibody arrays and extensive transcriptome analyses of primary CLL cell cocultures suggested a functional role of several soluble factors as well as signaling pathways of innate immunity, like Toll-like receptor-, TREM1- and NRF2-mediated signaling. The most interesting soluble factors are currently quantified in serum samples of the german CLL8 study cohort of CLL patients by cytometric bead arrays. So far, our data show that two of these candidates, CCL2 and soluble CD14, are significantly increased in the serum of CLL patients. In vitro studies using recombinant soluble CD14 demonstrated that CLL cell survival was significantly increased in the presence of this factor. CD14 which is expressed in particular by monocytes and macrophages is an important mediator of innate immunity. Along with TLR-4, CD14 acts as a co-receptor for the detection of bacterial lipopolysaccharide (LPS). Alternatively, LPS can also bind to the toll-like receptor-like molecule CD180, which shows strong homology to TLR-4, but does not harbor an intracellular signaling domain. Since TLR-4 is not expressed in CLL cells, we investigated the potential role of CD180 in CD14-mediated cell survival. Flow cytometry analysis revealed an upregulation of CD180 surface expression in CLL cells under survival-inducing culture conditions. Stimulation of CD180 with a cross-linking antibody resulted in activation of CLL cells measured by increased cell size and upregulation of the activation marker CD86, and significantly increased survival rates of CLL cells. Both CD14- and CD180-mediated survival signals lead to an increase in NF-κB activity and up-regulation of its target gene BCL-2. Depletion of CD180 surface expression in CLL cells abolished the pro-survival effect of soluble CD14, suggesting that this factor mediates its signals via binding to CD180. In summary, our data demonstrate that both, soluble CD14 and the toll-like receptor-like molecule CD180 transmit pro-survival signals in CLL cells, most likely by acting as co-receptors. Currently, we characterize the intracellular signaling machinery which is involved in these processes.

Disclosures:

No relevant conflicts of interest to declare.
Outcome of Patients with Multiple Myeloma (MM) After 1st Relapse Following Front-Line Treatment with Autologous Stem Cell Transplantation (ASCT): Impact of Early Reduced Intensity Allogeneic Transplantation (RICALLO)
Authors: Tabrizi Reza , Vigouroux Stephane , Marit Gerald , Pigneux Arnaud , Melot Cyril , Leguay Thibaut , Bouabdallah Krimo , Dilhuydy Marie-Sarah , Schmitt Anna , Milpied Noel
Published: October 2019

Abstract 4533

The aim of this single center study was to assess the outcome of pts with MM following the first relapse after autologous transplantation, according to whether or not a RICALLO was performed early in 2d response.

Records of the patients were reviewed and the criteria for entering the study were: Symptomatic MM treated frontline with a program including single or double ASCT, relapse at any time following ASCT, response (CR, VGPR or PR) to a second line treatment. RICALLO was proposed to pts with no significant co-morbidities, having a suitable donor (either sibling or 10/10 MUD) and who gave their consent after precise information on the risk of the RICALLO.

One hundred and seven pts treated between 01/2004 and 02/2011 fulfilling the inclusion criteria were identified. The initial treatment for relapse consisted of VD (37 pts), RD (29 pts), TD (36 pts), VTD (4 pts) or autologous SCT (1 pt). 22 pts received a RICALLO (allo group) while in 2d response, a median 7.7 months (2–36) after relapse. The RIC consisted of fludarabine plus either 2Gy ICT or busulfan and ATG (according to ongoing available protocols in the centre). The graft was PBSC from sibling (N: 8) or MUD (N: 14). 85 pts (CT group) received therapies according to ongoing protocols or available standard of cares. Following further relapses, 11 pts received a RICALLO while in ≥ 3d response in the CT group. The main characteristics of the patients in each group: age, MM prognostic factors at diagnosis, type of 1st line therapy (VAD or bortezomib containing regimens), single or double ASCT, time to relapse after ASCT and 2d line treatment were similar between the 2 groups. The response achieved with 2d line treatment was different between 2 groups (CR + VGPR/other: 8/14 and 7/76 in allo and CT group respectively, p= 0.01)

The 3y OS from the time of relapse for the entire cohort was: 47% (CI95%, 41–53). It was of 45% (CI95% 34–56) and of 48% (CI95% 41–55) for the allo group and the CT group respectively (p= ns). The median time from 1st relapse to death was 31 mo in the entire cohort and 20 and 34 mo in the allo group and CT group respectively (p= ns). The causes of death were, relapse in 5 and 33 pts, or treatment toxicity in 8 and 3 pts in the allo group and CT group respectively.

Three 3 y EFS (event = 2d relapse or death) was 16% (CI95%, 11–21) for the whole cohort and 16% (CI95%, 6–26) and 19% (CI95%, 13–25) for the allo group and CT group respectively (p= ns).

Conclusion:

In conclusion, we did not observe any difference in survival or PFS between allo-SCT and CT in patients at first relapse following an auto SCT.

Disclosures:

No relevant conflicts of interest to declare.
Long Term Follow up of Patients with Immune Thrombocytopenia Receiving Rituximab
Authors: Al-Habsi Khalid , Al-Khabori Murtadha K. , Al-Muslahi Muhanna , Pathare Anil , Farsi Khalil Al , Huneini Mohammed Al , Lamki Sulayma Al , Alkindi Salam
Published: October 2019

Abstract 4675

Introduction:

Rituximab has been used in the management of chronic immune thrombocytopenia (ITP) with promising results. The risk of losing response, however, is yet to be determined with long term follow up.

Method:

We retrospectively analyzed 32 consecutive patients (20 females, 12 males) with ITP (including 6 patients with secondary ITP) treated with rituximab in two tertiary care hospitals in Oman between May 2006 and May 2011. Response criteria were based on the International Consensus report (Rodeghiero F et al. Blood 2009).

Result:

The median age at diagnosis was 25 years (range, 4 – 58). Clinical presentation ranged from mild echymosis to more severe central nervous system bleeding. Patients received a median of one line of therapy before rituximab (range, 1–4), including 3 patients who failed splenectomy. Patients received intravenous rituximab using 375 mg/m2 once weekly for 4 weeks. The median time from diagnosis to receiving rituximab was 21 months (range, 1– 177). Only one patient was positive for Hepatitis C virus, but no hepatitis B or HIV positive in this cohort. Anti nuclear antibody was positive in 34% (10/29) of patients. The median hemoglobin and platelet counts at diagnosis were 12 g/dl (range, 5–16) and 11×109/L (range, 1–60) respectively. The median follow up time after rituximab was 26 months (95% confidence interval: 11–40). The overall cumulative response rate was 59% (partial response of 15% and complete response of 44%). The median time to respond was 30 days (Standard error [SE] 49) with a response rate of 44% at 4 weeks (95% Confidence interval: 29–62%). The multivariable Cox model analysis (variables include: age at diagnosis, gender, number of previous therapies and primary vs. secondary) revealed none of the variables included to be statistically significant. The cumulative rate of loss of response was 32% (6/19) with a median time to lose response of 54 months (SE, 0.03). In patients who lost response, the median time to lose response was 17 months (SE, 14). Of the 6 patients who lost response, 4 received a second course of rituximab and all 4 achieved a full response. No major side effects to rituximab were reported during the follow up.

Conclusion:

Rituximab is an effective and a well tolerated second line therapy for ITP. The response to rituximab can be maintained for a long duration with a high rate of response after retreatment. None of the pretreatment variables studied carried a significant predictive value for response. The study was limited by the small sample size and further larger prospective studies are recommended.

Disclosures:

Off Label Use: Rituximab was used in our study as a second line for the management of chronic immune thrombocytopenia.
Consistent Activation of Flt3 Promotes Hematopoietic Progenitors Toward Dendritic Cell Development in Mouse
Authors: Zhu Xuejun , Yang Zhongfa , Wang Junling , Rosmarin Alan G.
Published: October 2019

Abstract 4789

Dendritic cells (DCs) play key roles in mediating innate and acquired immune responses. DCs have a short half life in peripheral organs and are derived constitutively from bone marrow hematopoietic stem cells (HSCs) and Flt3+ progenitors. Cytokine signaling from Flt3 is crucial for stimulation of DC development. Previous studies demonstrated that injection of Flt3 ligand (Flt3L) in mouse caused a transient, but substantial increase in DC development. The effects of long-term activation of Flt3 signaling with physiological levels of Flt3L, however, have not yet been defined. Transgenic mice with constitutively activated Flt3 signaling were generated by replacing the Flt3 alleles with a mutant version Flt3ITD. Both mature DCs and DC progenitors increased modestly in Flt3ITD mice; both lymphoid and myeloid derived DCs were increased compared with wild type mice. Although the level of DCs in Flt3ITD mice did not reach the high levels in mice injected with Flt3L, the effect of Flt3ITD on DC development was consistent and long-lasting. Thus, activation of Flt3 signaling by different mechanisms led to distinct responses of bone marrow stem and progenitor cells for DC development. Flt3ITD mice provide a unique model to analyze DC differentiation from bone marrow stem and progenitor cells at physiological levels of Flt3L.

Disclosures:

No relevant conflicts of interest to declare.
Dendritic Cells Loaded with Treating Myeloma Cells with Combination of JSI-124 and Bortezomib Can Generate Potent Myeloma-Specific CTLs Through Recovering Dysfunction of Dendritic Cells in Myeloma Patients
Authors: Lee Youn-Kyung , Kim Mi-Hyun , Hong Cheol Yi , Lim Mi-Hyun , Nguyen-Pham Thanh-Nhan , Jin Chun-Ji , Lee Hyun Ju , Yang Deok-Hwan , Jung Sung-Hoon , Ahn Jae-Sook , Bae Soo-Young , Kim Yeo-Kyeoung , Chung Ik-Joo , Hwang Tai Ju , Kim Hyeoung-Joon , Lee Je-Jung
Published: October 2019

Abstract 4926

Signal transducers and activators of transcription 3 (STAT3) is highly activated in multiple myeloma triggered by IL-6. Although DC vaccine can induce antitumor immune response, DCs are faced with dysfunction after loading of tumor antigen. Here we show that the dysfunction of DCs from antigen loading can be recovered by treating JSI-124 and bortezomib on myeloma cells. Treatment of combination JSI-124 and bortezomib induced high expression of heat shock protein 90 (Hsp90) on the surface of dying myeloma cells, DCs loaded these myeloma cells showed low expression of p-STAT3 and reduced IL-10, IL-6 and IL-23 production without any effect on IL-12p70. Also DCs loaded with dying myeloma cells treated by JSI-124 and bortezomib combination could generate the most potent myeloma-specific CTLs targeting to myeloma cells. Our data suggested that treatment of myeloma cells with combination JSI-124 and bortezomib can recover the dying myeloma cells-loaded DC dysfunction through the highly expressed Hsp90 on tumor cells, down-regulated p-STAT3 and inhibitory cytokines, and these DCs can generate to potent myeloma-specific CTLs for obtaining better immunotherapeutic method in multiple myeloma.

Disclosures:

Lee: Vaxcell-Bio therapeutics Co.: Employment. Kim:Vaxcell-Bio therapeutics Co.: Employment. Lim:Vaxcell-Bio therapeutics Co.: Employment. Lee:Vaxcell-Bio therapeutics Co.: Employment.
An Electrophoretic Study of the Abnormal Proteins in Urine, Peripheral Venous and Bone Marrow Sera in Multiple Myeloma
Authors: JIM ROBERT T. S.
Published: October 2019

1. Abnormal and distinct homogeneous globulins of different electrophoretic mobilities have been found in a high percentage of concentrated whole urines from patients with multiple myeloma, occurring either as a single isolated globulin or as the dominant globulin in combination with smaller amounts of albumin and other globulin components. In contrast, the electrophoretic pattern of non-Bence Jones protein observed in a wide variety of diseases is dominated by albumin in association with smaller amounts of various globulin components usually more heterogeneous in nature.

2. The abnormal dominant globulins were found in 21 out of 35 or 60 per cent of the myeloma urines studies, while only 28.5 per cent were positive for Bence Jones protein by the conventional heat test.

3. Electrophoresis of concentrated whole urines in multiple myeloma appears to be a more sensitive technic for the detection of the abnormal urinary protein than the conventional heat test and may be a useful additional diagnostic procedure when the latter reactions cannot be elicited.

4. In patients with multiple myeloma the electrophoretic pattern of the protein in bone marrow serum does not appear to differ significantly from the corresponding protein pattern of peripheral venous serum.
Clinical and Necropsy Findings in Hemoglobin C Disease
Authors: JENSEN WALLACE N. , SCHOEFIELD R. ALAN , AGNER ROY
Published: October 2019

A patient with homozygous hemoglobin C disease was observed during a five month period of time. Estimates of the rates of red cell synthesis were made prior to and during the administration of compound E. The post mortem findings and results of paper electrophoresis of myoglobin are presented.
The Lutheran Blood Groups: A Second Example of Anti-Lub and Three Further Examples of Anti-Lua
Authors: GREENWALT TIBOR J. , SASAKI THOMAS
Published: October 2019

1. An example of the blood group antibody, anti-Lub, was found in a patient who had a mild hemolytic transfusion reaction. It was shown to possess the characteristics of an immune antibody and to be able to distinguish between a single dose and a double dose of the Lub gene.

2. Three new examples of the antibody, anti-Lua, are presented. All of them were found in normal blood donors and have properties which indicate that they are naturally occurring antibodies.

Dr. R. R. Race and Dr. R. Sanger confirmed the presence of anti-Lub in Mrs. S.’s serum, and studied other members of her family and the three anti-Lua sera. We are grateful to them for many favors and their kind encouragement.

We are obligated to Miss Marie Cutbush for making available the LuaLua cells from Mrs. R. and her sister, and for a supply of anti-Lub serum.

Thanks are due to Dr. A. E. Mourant who furnished our original supply of anti-Lua serum and to Dr. Philip Levine for the anti-Tja and anti-Vel sera.

We are indebted to Dr. J. M. Fine of Milwaukee for permission to study Mrs. S. and to the patient and her family for their cooperation.

The sera from 18,613 blood donors were studied by Betty McCarthy, Rosemary Polka, Pearl Lemke, Agnes Molnar, Jeannette Flagstadt and Betty Hutter.
Leukocyte Changes During Acute Cross-Circulation Experiments Between Leukemic and Normal or Irradiated Rats
Authors: HOLLINGSWORTH J. W. , FINCH S. C. , CHALTAS MARY
Published: October 2019

1. Normnal and irradiated rats underwent periods of cross-circulation with Shay granulocytic chloroleukemic rats.

2. The leukemic white blood cells disappeared rapidly from the arterial blood of the irradiated rat at a rate approximately identical with that of the removal of cross-transfused normal leukocytes.

3. Many leukemic cells remained in the arterial blood of normal recipent rats during the 90 miniute observation time after cross-circulation.

4. It was postulated that leukocytes transfused its rats by this method remain viable. In the irradiated leukopenic recipient, the rapid arterial blood removal rate of transfused cells may represent distribution in a depleted total body leukocyte "pool." Similarly, distribution may occur more slowly in normal animals with normally saturated tissue stores of leukocytes.

5. There was no indication that a large dose of total body irradiation increased the capacity of the reticulo-endothelial system to remove transfused leukocytes from circulation.
Immunologic Features of Erythrocyte Sensitization
Authors: VAUGHAN JOHN H. , WALLER MARION V.
Published: October 2019

In the January 1957 issue of BLOOD, the top line of text on page 34 belongs on page 35, top.
Radioactive Vitamin B12 Absorption Studies: Results of Direct Measurement of Radioactivity in the Blood
Authors: DOSCHERHOLMEN ALFRED , HAGEN PAUL S. , LIU MARGARET
Published: October 2019

A new method for the determination of the absorption of vitamin B12 has been described using measurement of radioactivity in the blood or plasma after the ingestion of physiologic test doses of Co60 labeled vitamin B12.

Although doses of 1.0 µc. (0.92 µg. vitamin B12) gave higher counts, equally reliable results were obtained with 0.5 µc. (0.46 µg. vitamin B12). The radioactivity was found in the plasma portion of the blood.

With this method it was possible to differentiate between all of nine patients with pernicious anemia and 36 control subjects.

In non-pernicious anemia subjects and in pernicious anemia patients given intrinsic factor, there was a relatively delayed rise in the blood or plasma radioactivity until a peak was reached in the 8 to 12 hour interval after the ingestion of the test dose. This absorption curve was quite different from the early rise observed by others after massive oral doses of vitamin B12, indicating a different mode of absorption.

Following the peak blood concentration the radioactivity gradually declined and small amounts usually persisted for as long as one week, quite different from the rapid disappearance after parenteral administration previously reported.

This method appears valuable in the diagnosis of pernicious anemia and other vitamin B12 malabsorptive states, in the evaluation of intrinsic factor activity, and in studies of various aspects of the metabolism of vitamin B12.
Studies on Thrombopoiesis
Authors: IZAK G. , NELKEN D. , GUREVITCH J. , HERZOG MISS A.
Published: October 2019

Thrombocyte production from megakaryocytes of healthy humans, dogs, guinea pigs and mice was observed continuously for one to six days in tissue culture.

Approximately 70 per cent of the explanted megakaryocytes broke down to give rise to numerous platelets, while the remaining 30 per cent of the cells remained unchanged.

The newly formed thrombocytes were separated from the rest of the bone marrow tissue, counted and their serotonin absorbing capacity determined.

There was invariably a gradual increase in both the number of thrombocytes and in their serotonin absorbing capacity during the one to six days of observation.

The results obtained were similar in human megakaryocytes and in those of experimental animals.
Studies on Hemoglobin E
Authors: NA-NAKORN SUPA , MINNICH VIRGINIA
Published: October 2019

The results of a study of ten members of an unusual family are presented; the mother and four children were found to have homozygous Hgb E disease, the father and three childrens either thalassemia-heterozygous Hgb E or thalassemia-homozygous Hgb E disease. It was impossible to make a definite diagnosis in one boy who might have had any one of the three conditions presented by the rest of the family.

It is not possible from the genetic, clinical and hematologic data to differentiate thalassemia-homozygous Hgb E from thalassemia-heterozygous Hgb E disease in the various members of the family.

The difficulty of differentiating mild thalassemia-heterozygous Hgb E from homozygous Hgb E is presented. Confusion arises in the overlapping of values obtained in the laboratory for the two conditions.

The presence of large numbers of target cells in the peripheral blood is a striking feature in the family. A consideration is made that the abnormality accompanying the Hgb E disease may be a hereditary defect in target cell production which may or may not be a variant of thalassemia.

Suggestive evidence is presented for a minimal hemolytic component in homozygous Hgb E disease manifested by a slightly shortened red cell survival time and a moderate increase in erythrocytic elements in the bone marrow.
Studies of Phagocytic Activity of Lymphocytes
Authors: KOSZEWSKI B. J. , EMERICK C. W. , DICUS D. R.
Published: October 2019

Eight subjects with chronic intractable disease were subjected to intravenous injections of India ink and the peripheral blood was studied for evidence of phagocytosis. Carbon particles were seen not only in the granulocytes and monocytes, but also in lymphocytes. Through these intravital studies, further proof is established for the theory that human lymphocytes are capable of phagocytosis.
In Vitro Effects of X-radiation on White Blood Cells and Blood Platelets
Authors: WAGNER RICHARD , MEYERRIECKS NORMA , BERMAN CARROLL Z.
Published: October 2019

1) Alkaline phosphatase activity of leukocytes is enhanced by radiation with 50,000 r. This disturbance accentuates the inherent aging process of white blood cells and may be explained by changes in the cell envelope.

2) X-radiation diminishes the endogenous oxygen uptake of leukocyte-platelet suspensions by approximately 20 per cent. This response to radiation is demonstrable at exposures of as little as 5,000 r. The decreasing effect is diminished when substrates such as sodium succinate or α-glycerophosphate are added, within a wide range of their concentration. With increasing substrate concentration the decrease due to radiation approaches that of the endogenous respiration and even exceeds it in some of the experiments.

3) In pure blood platelets a similar decreasing x-radiation effect occurs for endogenous respiration as well as succinic dehydrogenase activity; α-glycerophosphate dehydrogenase activity, on the other hand, is enhanced.

4) The oxygen uptake in leukocyte-platelet suspensions due only to leukocytes can be calculated. While the percentage radiation decrease of pure leukocytes is unchanged for endogenous and succinate activity, the decrease for α-glycerophosphate as substrate reaches considerably higher levels (68 per cent compared with 8.2 per cent in leukocyte-platelet suspensions). Thus α-glycerophosphate dehydrogenase activity seems to be most sensitive to x-radiation. It was shown in one of our previous studies that α-glycerophosphate dehydrogenase is one of the most important respiratory enzymes in leukocytes.

5) The glycolytic system in leukocytes remains intact following exposure to radiation with 50,000 r.
Therapeutic Results in Treatment of Hodgkin’s Disease with CB 1348 and R-48
Authors: ROTTINO ANTONIO
Published: October 2019

Forty patients with Hodgkin’s disease were treated with CB 1348 or R-48 or both. These drugs are useful and easy to administer. They have a therapeutic effect upon subjective symptoms and enlarged lymph nodes. The average remission lasts two months, shorter in some cases and longer in other cases. Toxicity is minimal. Hematologic depression occurs late as a rule and is reversible upon discontinuance of the drugs. Both drugs appeared to produce the same effect at about the same rate, and the effect lasted for about the same length of time. R-48 proved effective in some instances where CB 1348 had not been so, and CB 1348 sometimes induced a remission when T. E. M. had failed. In some cases radiation therapy caused recession of nodes when both drugs had been ineffective.
MLL-Rearranged ALL Cells Are Highly Dependent On the Expression of EP300-Interacting Inhibitor of Differentiation 1 (EID1)
Authors: van der Linden Marieke Hendrika , Schneider Pauline , Pieters Rob , Stam Ronald
Published: October 2019

Abstract 1462

MLL-rearranged acute lymphoblastic leukemia (ALL) remains a difficult to treat type of leukemia, for which alternative and more adequate treatment options are still urgently needed. Various genome-wide transcriptome studies, including ours, have shown that MLL-rearranged ALL patients display highly unique gene expression profiles. In search of new and valid therapeutic targets to which more adequate treatments could be developed, we constantly screen our gene expression profiling data for potential candidates. In the present study we set out to investigate EID1 (EP300-interacting inhibitor of differentiation 1), which we found highly and specifically expressed in MLL-rearranged ALL cells. Validating this observation, quantitative RT-PCR analysis confirmed that EID1 expression was significantly higher in MLL-rearranged ALL cells as compared with other ALL subtypes or healthy bone marrow samples. Next, we performed shRNA-mediated knockdown of EID1 in MLL-rearranged ALL cells, which resulted in a dramatic reduction of viable cells. Subsequently, flow cytometry analyses demonstrated that this rapid reduction of cell viability was due to massive induction of apoptosis as well as an abrupt cell cycle arrest. Consequently, it appeared difficult to study the actual function of EID1 over-expression in MLL-rearranged ALL cells. On the other hand, these features make EID1 an attractive target for therapeutic intervention in MLL-rearranged ALL. Hence, further studies on the function of EID1 in MLL-rearranged ALL and exploring the possibilities to inhibit it are warranted.

Disclosures:

No relevant conflicts of interest to declare.
Bone Mineral Density At Diagnosis Determines Fracture Rate in Children Treated According to the DCOG-ALL9 Protocol
Authors: te Winkel Mariel L , Pieters Rob , Hop Wim C.J. , Roos Jan C. , van der Sluis Inge M. , Bökkerink Jos P.M. , Leeuw Jan A. , Bruin Marrie C. A. , Kollen Wouter J.W. , Veerman Anjo J.P. , de Groot-Kruseman Hester A. , van den Heuvel-Eibrink Marry M.
Published: October 2019

Abstract 1469

Purpose

As survival rates for pediatric acute lymphoblastic leukemia (ALL) have significantly improved, awareness of side effects such as skeletal toxicity becomes increasingly important. As BMD decrease over time might be associated with an increased risk of fractures, we performed repeated measurements of BMD in a large nation-wide study and studied the incidence of fractures in these children treated for ALL.

Methods

Prospectively, serial measurements (at diagnosis, after 32 weeks, after 2 years (at cessation of therapy) and after 3 years (1 year after cessation of therapy)) of bone mineral density of the lumbar spine (BMDLS) were performed in 399 ALL patients using dual energy X-ray absorptiometry (DXA). Using logistic multivariate regression, we evaluated the following putative risk factors for a low BMDLS:age at diagnosis, gender, risk group of ALL treatment, weight and height at diagnosis. Moreover, Kaplan-Meier survival analysis was used to assess the cumulative incidence of fractures in 672 patients treated with the dexamethasone-based DCOG-ALL9 protocol. All reported fractures were symptomatic, and confirmed by X-ray. Cumulative incidences of fractures for different subgroups were compared with the Log-Rank test.

Results

At diagnosis, mean BMDLS of ALL patients was lower than that of healthy peers (mean BMDLS= −1.10 SDS, P< 0.001), and this remained significant lower during and after treatment (8 months: BMDLS = −1.10 SDS, P< 0.001; 24 months: BMDLS = −1,27 SDS, P< 0.001; 36 months: BMDLS = −0.95 SDS, P< 0.001). Multivariate linear regression analysis showed that after correction for weight, height and gender, treatment according to the HR treatment arm and older age at diagnosis had a significant negative effect on the decline of BMDLS during treatment (high-risk group: b = −0.50, P<0.001 and age at diagnosis: b = −0.15, P<0.001). The cumulative incidence of fractures at 3 years was 17.8%. Cumulative incidences of fractures between risk groups and age groups were not significantly different (NHR 18.8% vs. HR 15.7%, P = 0.18 and <10 years 17.7% vs. ≥10 years 17.6%, P = 0.85). Patients who developed fractures had a lower BMDLS during treatment than those without fractures. Treatment-related bone loss was similar in patients without fractures and patients with fractures (respectively: Δ BMDLS = −0.12 SDS vs. Δ BMDLS= −0.36 SDS; interaction group time, P = 0.295).

Conclusion

This large prospective study shows that the low value of BMDLS both at diagnosis and during treatment, rather than the treatment-related decline of BMDLS, determines the markedly increased fracture risk of 17.8%.

Disclosures:

No relevant conflicts of interest to declare.
Baseline Metabolic Tumor Volume Is Predictive of Patient Outcome in Diffuse Large B Cell Lymphoma
Authors: Casasnovas Rene-Olivier , Sasanelli Myriam , Berriolo-Riedinger Alina , Morschhauser Franck , Itti Emmanuel , Huglo Damien , Versari Annibale , Coiffier Bertrand , Meignan Michel
Published: October 2019

Abstract 1598

Tumor bulk assessed by maximum tumor diameter was previously found to influence the outcome of young patients with low risk (aaIPI 0–1) DLBCL (Pfreundschuh et al Lancet Oncol, 2011; 12: 1013), but the prognostic impact of bulk and more generally tumor volume in high-risk DLBCL remains to be explored. Conversely, maximum SUV reduction calculated between baseline PET and PET performed after 4 cycles of immunochemotherapy (ΔSUVmax0–4) was recently shown to predict outcome in this population (Casasnovas et al Blood 2011; 118: 37).

In this study, we assessed the metabolic tumor volume (MTV) and the tumor bulk at baseline in 121 patients <60 years with an aaIPI2–3 DLBCL enrolled in the LNH07-3B trial (NCT00498043). We then compared the prognosis value of both parameters to that of ΔSUVmax0–4.

MTV was measured by FDG PET/CT with a semi automatic method using various volume shapes and systematic 41% SUVmax thresholding. Tumor mass with a maximum diameter > 10 cm assessed on CT scan was considered as bulky.

Median follow-up was 28 months. Median baseline MTV was 303 cc (17–1488). Baseline MTV (≥625 cc vs <625cc, on the basis of a ROC analysis) significantly predicts 2-year progression free survival (2y-PFS) (57 % vs 83%; p=0.0032) and 2-year overall survival (2y-OS) (60% vs 90%; p=0.002). By contrast bulk >10 cm was not predictive of outcome.

As previously published ΔSUVmax0–4 (> 70% vs ≤70%) found to predict 2y-PFS (88% vs 40%; p<10-4) and 2y-OS (94% vs 59%; p<10-4). Combining baseline MTV to early response assessed by ΔSUVmax0–4 allows to split the group of good responders patients defined on the basis of ΔSUVmax0–4 >70% after 4 cycles of immunochemotherapy (n=101, 88%) into 2 separated prognosis subsets (2y-PFS: 90% vs. 77%, p<10-4; 2y-OS: 96% vs. 77%, p<10-4). So far MTV could not significantly identify subgroups within the 15 patients with ΔSUVmax≤70% even if patients with higher MTV base line had lower PFS and OS.

In our series baseline MTV was predictive of PFS and OS in high risk DLBCL patients while bulk was not. MTV identified different risk categories of DLBCL patients within DLBCL patients with a good interim response (ΔSUVmax0–4 >70%) and may improve the negative predictive value of interim PET.

Disclosures:

No relevant conflicts of interest to declare.