“RUNX1-IRES-GFP Knock-in” Mice Lack Expression of Runx1a: A Versatile Tool for Hematopoietic Stem Cell Analysis

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2329-2329
Author(s):  
Yukiko Komeno ◽  
Ming Yan ◽  
Shinobu Matsuura ◽  
Miao-Chia Lo ◽  
James R. Downing ◽  
...  
Keyword(s):  
Body Weight ◽  
Conflicts Of Interest ◽  
Lymphoid Cells ◽  
Hematopoietic Stem ◽  
Blood Indices ◽  
Cell Counts ◽  
Significant Difference ◽  
Versatile Tool ◽  
Exon 4 ◽  
Runx1 Expression

Abstract Abstract 2329 Previously reported “RUNX1-IRES-GFP knock-in mice” (Blood 2004;103:2522) (KI mice) were generated by replacing exon 4 of runx1 gene with cDNA of Runx1b/c from exon 4 to exon 8 followed by IRES-GFP, aiming to evaluate Runx1 expression in specific lineages and developmental stages during adult hematopoiesis. They are phenotypically normal, fertile, and blood indices are normal. GFP intensity correlates with Runx1 expression level, and shows lineage-specific changes during maturation in myeloid, erythroid, and lymphoid cells. However, the behavior in the hematopoietic stem cells (HSCs) had not been carefully examined. Interestingly, we discovered that this knock-in strategy eliminated Runx1a expression. Since Runx1a expression is relatively higher in HSCs than in differentiated cells, we analyzed HSCs in these mice to evaluate its roles in stable and stress hematopoiesis. We found that LSK fraction in bone marrow (BM) was significantly decreased in KI mice compared to wild type (WT) mice (0.043% vs 0.085%, p = 0.001). Among subpopulations in LSK, short-term HSC and multipotent progenitor fractions were significantly decreased (0.024% vs 0.046%, p = 0.003, 0.0021% vs 0.0026%, p = 0.001, respectively). SLAM marker staining using CD150 and CD48 showed similar results. Competitive repopulation assay showed less functional HSCs in KI mice. However, there was no significant difference in recovery of cell counts after single-dose 5-FU intraperitoneal injection (150 mg/kg body weight) or sublethal irradiation (5 Gy), or survival after weekly 5-FU injection. After G-CSF subcutaneous injection (125 μg/kg body weight, twice daily for 5 days), mobilized WBC or neutrophil in PB showed no difference. However, LSK and long-term HSC in PB were significantly less in KI mice (0.078% vs 0.135%, p = 0.010, 0.043% vs 0.092%, p = 0.029, respectively) while those in BM did not show significant difference (increased to 0.295% and 0.346% in KI and WT mice, respectively). In conclusion, Runx1a plays some non-redundant roles in stable hematopoiesis, while it is dispensable for tested stress hematopoiesis. RUNX1-GFP KI mice are a versatile tool to evaluate roles of Runx1a in normal hematopoiesis and leukemogenesis when combined with other genetic modifications. Disclosures: No relevant conflicts of interest to declare.

Hhex Is a Critical Gene In The Development Of Normal and Malignant Lymphoid Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3788-3788
Author(s):  
Charnise Goodings ◽  
Stephen B. Smith ◽  
Elizabeth Mathias ◽  
Elizabeth Smith ◽  
Rati Tripathi ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cell ◽  
Transgenic Mice ◽  
Conflicts Of Interest ◽  
Lymphoid Cells ◽  
Conditional Knockout ◽  
Hematopoietic Stem ◽  
Direct Transcriptional Target ◽  
Cell Counts ◽  
Transcriptional Target

Abstract Hematopoietically expressed homeobox (Hhex) is a T-cell oncogene. It is frequently deregulated in murine retroviral insertional mutagenesis screens and its enforced expression induces T-cell leukemia in bone marrow transduction and transplantation experiments. We discovered that HHEX is a direct transcriptional target of an LIM domain Only-2 (LMO2)-associated protein complex. HHEX clusters with LMO2-overexpressing T-ALLs and is especially overexpressed in Early T-cell Precursor (ETP) – ALL where it is a direct transcriptional target of LMO2. To further understand Hhex's function, we induced a conditional knockout in floxed Hhex mice with the Vav-iCre transgene. Mice were viable and showed normal blood cell counts with highly efficient deletion of Hhex in all hematopoietic tissues. Thymocytes from conditional knockouts showed a normal pattern of development. Most impressively, Hhex conditional knockout markedly prolonged the latency of T-ALL onset in CD2-Lmo2 transgenic mice (figure 1). Hhex conditional knockouts (Hhex cKOs) also had a significant decrease in mature B cells in the spleen and bone marrow. Interestingly, hematopoietic stem and progenitor cells plated on OP9-GFP or OP9-DL1 stromal cells showed proliferative defects and incomplete differentiation towards both B and T lineage. Also under stress conditions such as sublethal irradiation and competitive bone marrow transplants, Hhex conditional knockouts show a marked defect in both B and T lineages but an increase in early progenitor populations. Our experiments show that Hhex is a critical transcription factor in lymphoid development and in LMO2-induced T-ALL.Figure 1Hhex conditional knockout markedly prolonged the latency of T-ALL onset in CD2-Lmo2 transgenic miceFigure 1. Hhex conditional knockout markedly prolonged the latency of T-ALL onset in CD2-Lmo2 transgenic mice Disclosures: No relevant conflicts of interest to declare.

Human-Leukocyte-Histocompatibility Antigens Predict Response to Rituximab and Donor Lymphocyte Infusion (DLI) After Non-Myeloablative Allogeneic Stem Transplantation (NST) for Chronic Lymphocytic Leukemia (CLL)

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2548-2548
Author(s):  
Issa F. Khouri ◽  
Roland Bassett ◽  
Pedro Cano ◽  
Susan O'Brien ◽  
Yvonne Hsu ◽  
...  
Keyword(s):  
T Cell ◽  
Conflicts Of Interest ◽  
Chronic Gvhd ◽  
Hla Class I ◽  
Median Number ◽  
Class I ◽  
Hematopoietic Stem ◽  
Hla Alleles ◽  
Cell Counts ◽  
Significant Difference

Abstract Abstract 2548 Background: The effectiveness of allogeneic NST in CLL has been attributed to a graft-versus-leukemia effect due to elimination of tumor cells by alloimmune effector lymphocytes. In a previous study (Khouri et al, Exp Hematol 2004), we found that when patients with CLL develop relapse after NST, immunomanipulation (IMM) via withdrawal of immunosuppression and DLI with rituximab can induce sustained remissions in some patients. The underlying mechanism of this GVL effect is unknown. The simultaneous presence of the killer-immunoglobulin-like receptor (KIR) 3DL1 and its corresponding human leucocyte antigen (HLA) class I ligands bearing the Bw4 epitope has been described in CLL (Verheyden S, Leukemia 2006). Purpose: Considering that the HLA class I molecules may act as restriction elements for GVL targets after NST in CLL, we investigated the potential association of certain common class I HLA alleles and response to IMM. Methods: We studied all 43 CLL pts who required IMM after NST in sequential phase II protocols at the U.T. MD Anderson Cancer Center from February 1996 to August 2007 because of persistent disease or because of progression. In our analysis, we examined the most common alleles and serotypes expressed in the patients studied. This included HLA-A1, A2, A3, A24, B7, B8, B35, B44, B60, B62, BW4, BW6, CW7. These allele groups are known to be common in most world populations. Rituximab was given at a dose of 375 mg/m2 intravenously followed by 3 weekly doses of 1000 mg/m2. A DLI of 1 × 107 CD3-positive T cells/kg was given after the first two doses of rituximab if no GVHD occurred. An escalated DLI dose was given at 6-week intervals if there was persistent active disease and no GVHD. Results: Median age (range) was 55 years (39-73) and the median Hematopoietic Stem Cell Comorbidity Index was 3 (range, 0–8). The median number of prior chemotherapies was 3. At their transplant, 48% of pts had refractory disease, 90% had Binet stage B/C, and 60% had a beta-2 microglobulin of =/> 3. P53 deletion was detected in 11 of 35 pts (31%) tested. Mixed T-cell chimerism was observed in 60 % of pts at day 90. The median number of DLI infused was 2 (range, 1–6); their median maximal dose was 43.6 (range, 1–200) × 106 CD3+/Kg. In these 43 pts, 20 (47%) experienced complete remission (CR), by CT scans, marrow and flow analysis. Pts characteristics at time of study entry (described above) for NST, and at the time of initiation of IMM (this included white blood cell counts, LDH, % lymphocyte in marrow, % CD5-CD19, lymph node size by computed tomography, maximum dose DLI, number of DLIs, GVHD prior IMM and grade, T-cell chimerism), as well as HLA subtypes were assessed. The major determinants to achieve CR following IMM included receipt of a PBSC graft and achievement of a good (> 90%) donor T-cell chimerism at day 90 (p = 0.035), and having a combination of HLA-A1-positive, HLA-A2-negative, and HLA-B44-negative (p= 0.0009). The rate of CR to IMM was 9%, 36%, 50%, 91% respectively in patients who had none of the HLA factors described, I, 2, and all 3 respectively. There was no statistically significant difference in pts and disease characteristics between HLA-A1-positive or negative, HLA-A2 positive or negative nor between HLA-B44-positive or negative pts. In addition the risks of acute II-IV [Cumulative incidence (CI)=23%) and chronic GVHD (CI=69%) were not different between the respective subtypes. With a median follow-up in surviving pts of 37.2 months (range, 11.4–131.1), the progression-free survival rates at 5-year for patients with HLA-A1+/A2-/B44- vs those who had none of those HLA types were 68% vs 15%, respectively, (p<0.0001). Conclusions: Our results represent the first report showing certain HLA alleles might be predictive for response to GVL and achieving long-term remission in CLL. Verification of our findings in a larger cohort of pts is highly warranted for better selecting pts for IMM for the treatment of recurrent malignancy in CLL. Disclosures: No relevant conflicts of interest to declare.

Role of the Transcription Factor LYL-1 in the Adult and Fetal Hematopoietic Stem Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2775-2775
Author(s):  
Claude Capron ◽  
Catherine Lacout ◽  
Yann Lecluse ◽  
Isabelle Poullion ◽  
Fedor Svinarchouk ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Hematopoietic Stem Cells ◽  
Absolute Number ◽  
Binding Motif ◽  
Hematopoietic Stem ◽  
Cell Counts ◽  
Significant Difference ◽  
The Absolute

Abstract The hematopoietic stem cells (HSC) have the ability to self-renew and to give rise to all blood lineages. These processes occur via a hierarchy of progenitors with progressively more limited differentiation and self-renewal potential and are orchestrated by specialized protein such as transcription factors. LYL-1 protein contains a basic helix-loop-helix DNA binding motif also found in several proteins involved in the control of cellular proliferation and differentiation such as SCL/TAL-1. As LYL-1 shares an 80% homology at the protein level with SCL/TAL-1, we wanted to determine the function of LYL-1 in hematopoiesis and particularly on HSC. For this study, we used knock in lyl-1−/− mice in which exon 4 was replaced by LacZ/Neo cassette. Lyl−/− mice are viable and have normal blood cell counts as well as a normal marrow cellularity. In addition, using a hematopoietic colony forming cells (CFCs) assay, no significant difference was seen in the myeloid CFCs of either lyl-1−/− or lyl-1+/+ BM and FL cells except a 2-fold increase in the absolute number of BFU-E in lyl-1−/− FL as compared to lyl-1+/+ FL. We analyzed more primitive progenitors in details because using Fluorecein Di-beta Galactopyranoside (FDG)-staining assay, we showed that lyl-1 is mainly expressed in primitive Lin− Sca-1+ c-Kit+ cells (LSK) cells from either BM or FL (91 ± 7% and 78 ± 5% of FDG positive cells in lyl-1−/− BM and FL LSK cells, respectively). In addition, analysis of lyl-1−/− and lyl-1+/+ cells revealed a 1.8-fold and 2-fold decrease in the percentage of primitive LSK in BM and FL, respectively, as compared to wild type cells. Furthermore, using the Hoechst 33342 efflux assay, we noticed a significant decrease in the absolute number of more primitive LSK-SP (side population) cells in lyl-1−/− BM as compared to lyl-1+/+ BM cells (52800 ± 5412 cells/femur versus 91080 ± 8475 cells/femur, respectively) suggesting an important role of LYL-1 in the HSC function. In order to confirm this hypothesis, in vivo assays were performed. We observed a 1.5-fold decrease in the lyl-1−/− BM and FL day 12 CFU-S content as compared to lyl-1+/+ cells. Adoptive transfer experiments were subsequently performed using lethally irradiated Ly5.1 mice. Data showed that lyl-1−/− cells from either BM or FL displayed a hematopoietic reconstitution defect in competitive repopulation assays. Indeed, Ly5.1 recipients were injected with a mixture of 5x106 (5:1), 106 (1:1) or 0.5x106 (0.5:1) lyl-1−/− or lyl-1+/+ Ly5.2 expressing cells and 106 competitive BM Ly5.1 expressing cells. All hosts engrafted with lyl-1−/− BM cells shown a significant reduced levels of chimerism (% of circulating Ly5.2+ cells) as compared to hosts engrafted with lyl-1+/+ BM donors (4.3 ± 2.8% (5:1); 7.5 ± 5.5% (1:1); 0.6 ± 0.3% (0.5:1) in lyl-1−/− BM cells versus 66 ± 8% (5:1); 52 ± 9% (1:1); 53 ± 10% (0.5:1) in lyl-1+/+ BM cells) and similar difference was observed with FL donors (45 ± 2% (5:1); 25 ± 5% (1:1); 11 ± 5% (0.5:1) in lyl-1−/− FL cells versus 83 ± 1% (5:1); 70 ± 3% (1:1); 53 ± 6% (0.5:1) in lyl-1+/+ FL cells). This altered defect in HSC was also confirmed using LTC-IC in vitro experiments. Altogether, our results demonstrate an important role of the transcription factor LYL-1 on the maintenance of HSC properties.

A Complex Karyotype but Not Monosomy 7 Is an Independent Prognostic Factor in Advanced Childhood MDS.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2452-2452
Author(s):  
Gudrun Gohring ◽  
Kyra Michalova ◽  
Berna Beverloo ◽  
David Betts ◽  
Jochen Harbott ◽  
...  
Keyword(s):  
Chromosome Aberrations ◽  
Conflicts Of Interest ◽  
Bone Marrow Failure ◽  
Prognostic Significance ◽  
Complex Karyotype ◽  
Similar Frequency ◽  
Hematopoietic Stem ◽  
Monosomy 7 ◽  
Significant Difference ◽  
Secondary Mds

Abstract Disclosure: No relevant conflicts of interest to declare. To study the clinical significance of recurrent chromosome aberrations in childhood MDS, cytogenetic data of 394 consecutive children with refractory cytopenia (RC) (N=215), RAEB (N=141) and RAEB-T (N=38) analyzed in the regional cytogenetic reference centers and registered in the prospective study EWOG-MDS 98 between 1998 and 2005 were evaluated. At diagnosis, a karyotype could be defined in 279/394 patients (pts) (71%). No karyotype was obtained in 16% of pts with RC compared to 8% pts with RAEB and RAEB-t (p&lt;0.001). Clonal chromosome aberrations were more common in pts with advanced MDS (RAEB and RAEB-T, 61%) compared to RC (29%), and in pts with secondary (69%) compared to primary MDS (36%) (p&lt;0.001). Monosomy 7 was the most frequent aberration occurring with similar frequency in RC (47% of abnormal karyotypes) compared to advanced MDS (49%) and in primary (53%) compared to secondary (41%) MDS. In addition, aberrations typical for de novo AML such as aberrations involving 11q23 or 3q, t(6;9) and del(9q) were noted in morphologically and clinically unequivocal MDS cases. Recurrent aberrations of adult MDS like isolated del(5q), del(20q) and -Y were very uncommon indicating a different pathogenesis of these cases. In pts with advanced MDS, there was no significant difference in overall survival (OS) of pts with normal karyotype (44% ± 18) compared to pts with monosomy 7 (58% ± 19) and patients with other karyotypes (61% ± 22). However, pts with advanced MDS and a complex karyotype (defined by ≥ 3 chromosome aberrations, presence of structural aberrations and excluding clonal evolution of monosomy 7) had a shorter OS (16% ±15, p&lt;0.01). OS and event-free survival after hematopoietic stem cell transplantation (HSCT) in pts with complex karyotypes was inferior compared to that of pts with other cytogenetic aberrations (p=0.012 and 0.039, respectively). Within the group of pts with secondary MDS, complex karyotypes were found in MDS evolving from inherited bone marrow failure disorders or after radio-/ chemotherapy, but absent in familial MDS and cases evolving from acquired aplastic anemia. As shown in a multivariate Cox analysis, advanced MDS, secondary MDS, the presence of a complex karyotype and HSCT were identified as independent prognostic factors for OS. Thus, this study demonstrates the prognostic significance of cytogenetic findings in advanced childhood MDS independent of HSCT.

Population Pharmacokinetics of Cyclophosphamide in Patients with Thalassaemia Major Undergoing HSCT Shows Body Weight, CYP450, GST and ALDH Polymorphisms as Covariates Explaining Inter-Individual Variation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1182-1182 ◽  
Author(s):  
Poonkuzhali Balasubramanian ◽  
John Carl Panetta ◽  
Salamun Desire ◽  
Shaji R Velayudhan ◽  
Vikram Mathews ◽  
...  
Keyword(s):  
Body Weight ◽  
Individual Variation ◽  
Conflicts Of Interest ◽  
Conditioning Regimen ◽  
Elimination Rate ◽  
Pharmacokinetic Parameters ◽  
Thalassaemia Major ◽  
Hematopoietic Stem ◽  
Beta Thalassaemia ◽  
Population Pk

Abstract Abstract 1182 Poster Board I-204 Cyclophosphamide (Cy) in combination with busulfan is an important component of myeloablative conditioning regimen used prior to hematopoietic stem cell transplantation (HSCT) for both malignant and non-malignant conditions. We have previously reported up to 20 fold inter-individual variation in the pharmacokinetics (PK) of Cy in patients with beta thalassaemia undergoing HSCT [Blood (ASH Annual Meeting Abstracts), Nov 2004; 104: 99]. PK parameters of Cy have been shown to be associated with regimen related toxicity and outcome of transplant. To explain the basis of the inter-individual variation in Cy PK, we have developed a population PK model. We analyzed the PK of Cy in consecutive children with beta thalassaemia major who received HSCT from HLA identical matched sibling donor at the Christian Medical College, Vellore from 2001 till 2004. A total of 900 cyclophosphamide concentration measurements from 55 patients were included and correlated with age, sex, body weight and 10 polymorphisms in enzymes involved in the metabolism or biotransformation of Cy namely GST A1, M1, T1, P1, CYP2B6, CYP2C9, CYP2C19 and ALDH genes. Non-linear mixed effects modeling analysis was performed with Monolix (version 2.4, www.monolix.org) to investigate the effect of patient covariates on PK, and to estimate the relative magnitude of inter-individual and inter-occasion variability. A two-compartment pharmacokinetic model was used to describe the data. The pharmacokinetic parameters estimated included elimination rate constant and volume (ke (1/hr), V (L or L/kg)), and the inter-compartmental parameters (k12 and k21 (1/hr)). The distribution of the parameters was assumed log-normal. Body weight was the main covariate which explained the largest portion of the IIV (28% and 20% of V and ke IIV, respectively). In addition, the following genotypes showed differences in the pharmacokinetics: GSTP1*B (1.7X higher ke in MUT versus WT or HET; p<0.05), CYP3A4*1B (2X higher ke in HET versus WT; p<0.05), and ALDH1A1*2 (2X higher ke in HET versus WT; p<0.05). We have developed a population PK model for Cy in thalassaemic children by considering morphological and biological covariates, which explains more than 45% and 22% (V and ke IIV, respectively) of the variation in Cy PK in these patients. This model-based algorithm may be used to design and plan targeted dose therapy in this group of pediatric patients and to predict the risk of toxicity and outcome of HSCT. Disclosures: No relevant conflicts of interest to declare.

Long-Term Clinical Outcome of Children with Acquired Aplastic Anemia in Brazil.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4216-4216
Author(s):  
Marlene Pereira Garanito ◽  
Vicente Odone Filho ◽  
Marcela Vieira dos Santos ◽  
Elvira Velloso ◽  
Frederico L. Dulley ◽  
...  
Keyword(s):  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Aplastic Anemia ◽  
Immunosuppressive Therapy ◽  
Cell Transplantation ◽  
Survival Probability ◽  
Conflicts Of Interest ◽  
Time History ◽  
Hematopoietic Stem ◽  
Significant Difference

Abstract Abstract 4216 Introdution/ Backgound Acquired Aplastic Anemia (AAA) is a rare hematologic disorder characterized by pancytopenia and hypocelular bone marrow. The pathophysiology is immune mediated in most cases. Environmental exposures to drugs, viruses and toxins, are thought to trigger the aberrant immune response in some patients. However, 50 to 74 percent of cases are classified as idiopathic. The highest frequency occurs in young population (15 to 25 years) with a second peak at age of 65 to 69 years. Immunosuppressive therapy is the best treatment in children with AAA who do not have a suitable donor for allogeneic stem cell transplantation. Materials and methods We reviewed the medical records of patients diagnosed with severe (SAA) and very severe acquired aplastic anemia (vSAA) at the Department of Pediatrics, Instituto da Criança – Hospital das Clínicas, University of Sào Paulo, Brazil from December, 1992 to December, 2007. We analyzed the clinical characteristics of the patients at diagnosis and the response to immunosuppressive therapy (IST) and hematopoietic stem cell transplantation (HSCT). Results In this study, 47 patients (27 boys and 20 girls), younger than 16 years, were diagnosed with vSAA (n= 21) or SAA (n=26). The median age was 7,71 years, ranging from 0.5 to 16 years and the average time history (beginning of signs and symptoms related to the disease and diagnosis) of the disease was 4,82 months, ranging from 0,25 to 48 months. Of the 47 patients, 45 had idiopathic AAA and 2 had hepatitis-associated. The median follow-up was 6,91 years for the patients treated with IST and 3,10 years for the patients who underwent to HSCT. One patient died before any treatment. For the eight patients who underwent to allogenic HLA-matched HSCT the 5-years-survival probability was 50%. For the 38 patients treated with IST, ten of them received cyclosporine and a short course of corticosteroids (CsA/CE) and 28 received antithymocyte globulin plus cyclosporine (ATG/CSA). The 5 years survival probability was 40% and 55%, respectively (p:0,0054). According to the severity of AAA, we did not show a significant difference in survival (p:0,32). Eight patients received second treatment after 1 year and 6 months (6 ATG from different species and CsA, 1 CsA and 1 thalidomide) and the probably of survival at 5 years was 60%. Among the 18 patients who responded to IST, four relapsed (22%). Two patients developed acute myeloid leukemia at 5 and 12 years after diagnosis. Conclusion Our results both for patients undergoing HSCT, as well as patients undergoing IST are lower in comparison to other hematological centers. Probably, this discrepancy is related to the prolonged time of disease when patients are admitted to our service. Unfortunately, the difficulty of access to specialized centers for diagnosis and early treatment in our country is a reality and this fact contributes to the delay to the beginning of treatment. Disclosures: No relevant conflicts of interest to declare.

Cytogenetic Evolution (CE) In Patients (pts) with Low and Intermediate Risk Myelodysplastic Syndromes (MDS) Is Associated with Poor Prognosis

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2941-2941
Author(s):  
Liunan Li ◽  
Elias Jabbour ◽  
Gautam Borthakur ◽  
Stefan Faderl ◽  
Tapan Kadia ◽  
...  
Keyword(s):  
Disease Progression ◽  
Cytogenetic Analysis ◽  
Conflicts Of Interest ◽  
Myelogenous Leukemia ◽  
Intermediate Risk ◽  
Hematopoietic Stem ◽  
Increased Risk ◽  
Significant Difference ◽  
The Impact ◽  
Cytogenetic Evolution

Abstract Abstract 2941 Introduction: MDS is a spectrum of abnormalities in the proliferation and differentiation of hematopoietic stem cells that result in peripheral cytopenias, bone marrow dysplasia and increased risk of transformation to acute myelogenous leukemia (AML). Cytogenetic abnormalities occur in more than 50% of patients (pts) and have an impact on survival and risk of transformation to AML. CE, or acquisition of additional clonal chromosomal abnormalities, has been reported to occur in 30 to 50% of primary MDS pts. Their impact on prognosis and transformation into AML among pts with low and intermediate risk MDS is not known. In this study, we analyzed the impact of CE on prognosis in lower risk MDS. Methods: we reviewed 722 pts clinic records of low and intermediate risk MDS pts at MD Anderson Cancer Center (MDACC) from 2000–2010 and conducted a retrospective analysis of all MDS pts with at least two consecutive cytogenetic analysis (365 patients, 50.6%) and compared the cytogenetic evolution group (CE group) with the group without cytogenetic changes (no CE group). Cytogenetic analysis was performed in the Cytogenetics Laboratory at MDACC. Results: CE was detected in 200 pts (55%). Characteristics of patients with CE are: median age 65 years (23-91), IPSS int-1 79%, diploid CG 42%, excess blasts 25%. Pts with CE were more frequently female (p=0.005), and had more frequently abnormalities of chromosome 5 and 7 (p<0.001) at baseline. There were no statistically significant difference between these two groups (p>0.05) regarding age, WBC, platelet, hgb, ANC, BM blasts percent, diagnosis (RA or RAEB), and IPSS score. There were more chr.-5/-7, insufficient metaphases, and other abnormalities, but less diploid cases in CE group compared with no CE group (p<0.001). History of malignancy (p=0.001) and prior chemotherapy exposure were also associated with CE (p=0.001), but this was not as strong for radiation exposure (p=0.066). Also, more CE patients required therapy for MDS compared to no CE patients (p=0.039). Progression free survival was significantly extended in no CE patients (p=0.02). Overall survival was a longer in no CE (34.1months), compared with CE group (26.2 months), although this was not statistically significant. Conclusion: CE is more commonly observed among pts with high-risk features, and is usually associated with disease progression and resistance. Also, prior malignancy and chemotherapy exposure were associated with CE in this study. This data indicates that genomic instability has a role in disease progression in MDS. Further analysis of CE in MDS is needed. Disclosures: No relevant conflicts of interest to declare.

Innate Lymphoid Cell-Derived IL-22 Mediates Endogenous Thymic Repair Under the Control of IL-23

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 143-143
Author(s):  
Jarrod A Dudakov ◽  
Alan M Hanash ◽  
Lauren F. Young ◽  
Natalie V Singer ◽  
Mallory L West ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Critical Role ◽  
Lymphoid Cells ◽  
Thymic Epithelial Cells ◽  
Immune Competence ◽  
Strong Negative Correlation ◽  
Hematopoietic Stem ◽  
Stimulation Of

Abstract Abstract 143 Despite being exquisitely sensitive to insult, the thymus is remarkably resilient in young healthy animals. Endogenous regeneration of the thymus is a crucial function that allows for renewal of immune competence following infection or immunodepletion caused by cytoreductive chemotherapy or radiation. However, the mechanisms governing this regeneration remain poorly understood. Thymopoiesis is a highly complex process involving cross-talk between developing thymocytes and their supporting non-hematopoietic stromal microenvironment, which includes highly specialized thymic epithelial cells (TECs) that are crucial for T cell development. IL-22 is a recently identified cytokine predominantly associated with maintenance of barrier function at mucosal surfaces. Here we demonstrate for the first time a critical role for IL-22 in endogenous thymic repair. Comparing IL-22 KO and WT mice we observed that while IL-22 deficiency was redundant for steady-state thymopoiesis, it led to a pronounced and prolonged loss of thymus cellularity following sublethal total body irradiation (SL-TBI), which included depletion of both thymocytes (p=0.0001) and TECs (p=0.003). Strikingly, absolute levels of IL-22 were markedly increased following thymic insult (p<0.0001) despite the significant depletion of thymus cellularity. This resulted in a profound increase in the production of IL-22 on a per cell basis (p<0.0001). These enhanced levels of IL-22 peaked at days 5 to 7 after SL-TBI, immediately following the nadir of thymic cellularity. This was demonstrated by a strong negative correlation between thymic cellularity and absolute levels of IL-22 (Fig 1a). In mucosal tissues the regulation of IL-22 production has been closely associated with IL-23 produced by dendritic cells (DCs) and ex vivo incubation of cells with IL-23 stimulates the production of IL-22. Following thymic insult there was a significant increase in the amount of IL-23 produced by DCs (Fig 1b) resulting in similar kinetics of intrathymic levels of IL-22 and IL-23. We identified a population of radio-resistant CD3−CD4+IL7Ra+RORg(t)+ thymic innate lymphoid cells (tILCs) that upregulate both their production of IL-22 (Fig 1c) and expression of the IL-23R (p=0.0006) upon exposure to TBI. This suggests that they are responsive to IL-23 produced by DCs in vivo following TBI and, in fact, in vitro stimulation of tILCs by IL-23 led to upregulation of Il-22 production by these cells (Fig 1d). We found expression of the IL-22Ra on cortical and medullary TECs (cTECs and mTECs, respectively), and uniform expression across both mature MHCIIhi mTEC (mTEChi) and immature MHCIIlo mTECs (mTEClo). However, in vitro stimulation of TECs with recombinant IL-22 led to enhanced TEC proliferation primarily in cTEC and mTEClo subsets (p=0.002 and 0.004 respectively). It is currently unclear if IL-22 acts as a maturation signal for mTECs, however, the uniform expression of IL-22Ra between immature mTEClo and mature Aire-expressing mTEChi, together with the preferential promotion of proliferation amongst mTEClo and cTEC seem to argue against IL-22 as a maturational signal but rather as promoter of proliferation, which ultimately leads to terminal differentiation of TECs. Of major clinical importance, administration of exogenous IL-22 led to enhanced thymic recovery (Fig. 1e) following TBI, primarily by promoting the proliferation of TECs. Consistent with this, the administration of IL-22 also led to significantly enhanced thymopoiesis following syngeneic BMT. Taken together these findings suggest that following thymic insult, and specifically the depletion of developing thymocytes, upregulation of IL-23 by DCs induces the production of IL-22 by tILCs and regeneration of the supporting microenvironment. This cascade of events ultimately leads to rejuvenation of the thymocyte pool (Fig. 1f). These studies not only reveal a novel pathway underlying endogenous thymic regeneration, but also identify a novel regenerative strategy for improving immune competence in patients whose thymus has been damaged from infection, age or cytoreductive conditioning required for successful hematopoietic stem cell transplantation. Finally, these findings may also provide an avenue of study to further understand the repair and regeneration of other epithelial tissues such as skin, lung and breast. Disclosures: No relevant conflicts of interest to declare.

Evaluation of Enteral Versus Parenteral Feeding As Nutritional Support In Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4576-4576
Author(s):  
Richard Lemal ◽  
Romain Guièze ◽  
Cécile Moluçon-Chabrot ◽  
Eric Hermet ◽  
Aurélie Ravinet ◽  
...  
Keyword(s):  
Stem Cell ◽  
Median Duration ◽  
Nutritional Support ◽  
Conflicts Of Interest ◽  
Conditioning Regimen ◽  
Hematopoietic Stem ◽  
Early Outcome ◽  
Transfusion Requirements ◽  
Significant Difference ◽  
The Impact

Abstract Abstract 4576 Introduction Allo-HSCT procedure is associated with a frequent and potentially severe malnutrition which could highly participate to the transplant-related morbidity (TRM). Optimal nutritional management is still poorly known while both enteral nutrition (EN) and parenteral nutrition (PN) are effective. We proposed to retrospectively evaluate the impact of EN versus PN as nutritional support on early outcome of allo-HSCT. Patients and methods We retrospectively analyzed all the successive patients who needed a nutritional support during their first allo-HSCT in our center from January 2009 to October 2010, excepting whose who had a progressive disease at time of transplant. Datas were compared in an intent to treat analysis according the EN or PN initial nutritional support strategy. Results We analysed early outcome of 56 successive patients. Twenty of them received a myeloablative conditioning regimen and 36 a reduced intensity one. A total of 28 agreed to receive EN via a nasogastric feeding tube and the remaining 28 received PN. No significant difference in terms of age, diagnosis, disease status at transplant, conditioning regimens, stem cell source, GVHD nor antifungal secondary prophylaxis could be observed between the EN and PN groups. We found a lower median duration of fever in EN (2[0–8] vs. 5[0–17] (days); p=0.0026) and a lower need for antifungal therapy in EN group (7/28 vs. 17/28; p=0.0069), with a lower median duration of intravenous antifungal use (0 day [0–99] in EN vs. 7 days [0–93] in PN; p=0.00034) while incidence of bacteriemiae was not different. We observed a lower rate of replacement of central veinous catheter in EN group (3/28 in EN vs. 9/28 in PN; p=0.05) and a lower rate of transfer to ICU in the EN group (2/28 in EN vs. 8/28 in PN, p=0.036) but early death rate (<100 days) was the same in each group (4/28 vs. 4/28, p=NS). Median neutropenia and thrombopenia duration and median transfusion requirements were not significantly different. Fourteen patients in EN group and 18 in PN group presented a grade 3–4 oral mucositis (p=NS). Grade III-IV GVHD incidence was comparable in both groups (4/28 vs. 8/28; p=0.19). Conclusion Compared with PN, EN directly decreases the infectious risk, particularly the fungal risk, and its complications in allo-HSCT, without influencing hematopoietic toxicity nor GVHD incidence. Based on these encouraging results, we are now conducting a prospective, multicentric and randomized trial to confirm EN benefice in allo-HSCT. Disclosures: No relevant conflicts of interest to declare.

Comparative Analysis on Cellular Components of Bone Marrow Microenvironment in Normal and Aberrant Hematopoiesis

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4808-4808
Author(s):  
Young-Ho Lee ◽  
Young-hee Kwon ◽  
Kyoujung Hwang ◽  
Hyunju Jun ◽  
Byungbae Park ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cell ◽  
Conflicts Of Interest ◽  
T Cell Subsets ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Significant Difference ◽  
Stromal Cell Derived Factor ◽  
And Control ◽  
Cellular Components

Abstract Abstract 4808 Background: It is now evident that hematopoietic stem cells (HSCs) reside preferentially at the endosteal region within the bone marrow (BM) where bone-lining osteoblasts are a key cellular component of the HSC niche that directly regulates HSC fate. We investigated the microenvironmental differences including osteoblastic activities and HSC components in myeloproliferative (chronic myeloid leukemia, CML) and hypogenerative disease (aplastic anemia, AA) as well as normal control (NC). Methods: The immunohistochemistry for osteonectin, osteocalcin, stromal cell derived factor (SDF, CXCL12), T cell, T helper/inducer cell, T suppressor/cytotoxic cell, hematopoietic stem/progenitor (CD34, CD117) and megakaryocytes was performed on BM biopsy specimens from 10 AA patients, 10 CML patients and 10 NC (lymphoma without BM involvement). The positive cells for immunohistochemical stainings except osteocalcin on each slide were calculated on 10 high power fields (HPF, ×400), and then corrected by the cellularity. The positive cells for osteocalcin were counted on the peritrabecular line on each slide, and then corrected by the mean length measured. Results: The CD34+ cells (p=0.012) and megakaryocytes (p<0.0001) were significantly lower in AA than in NC, but CD117+ cells was comparable in AA, CML, and control samples. The osteonectin+ cells (p=0.0003) were lower in CML than in AA and NC, however the osteocalcin+ cells showed wide variation (0-903/2035um) and no significant difference. The SDF+ cells (p<0.0001) was significantly higher in AA and very lower in CML, compared with NC. The counts for T cell and T cell subsets were significantly lower in CML than in NC, and higher in AA than in NC (p<0.0001). Conclusions: Cellular components of BM microenvironment in 2 hematologic diseases representative of myeloproliferation (CML) and hyporegeneration (AA) respectively are quite different. Further studies would be required to explore the role of these components for hematopoiesis and the rationale for therapeutic application. Disclosures: No relevant conflicts of interest to declare.

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