HLA and Aplastic Anemia: associations In Large Brazilian Cohorts

Abstract Introduction Aplastic anemia (AA) is perceived as an immune mediated disease where T-lymphocytes recognize and destroy bone marrow elements leading to varying degrees of failure of hematopoiesis. Many autoimmune diseases have been linked to certain HLA alleles and such a relationship has been also been reported in AA. Expansion of CD8+ oligoclones has been reported in AA and likely contributes to pathogenesis. However, the interaction of CD4+ and CD8+ T cells and their targets mediated by human leukocyte antigen (HLA) class I and II peptides remain elusive. Thus, it has been speculated that polymorphic loci of these genes could be implicated in the susceptibility to the disease. Various alleles and haplotypes of HLA molecules have been implicated in the predisposition of AA development. The influence of HLA has been studied in North America, European and Asian countries. Data from Latin America, where there is a large mixture of Hispanic, European, and African descendants, is still lacking. This study focuses on the association between HLA alleles in AA patients in different regions of Brazil with particular ethnic groups. Patients and methods From 2000 to 2013, all patients with a diagnosis of acquired AA in the Brazilian state of Bahia (BA) followed at the Federal University of Bahia Hospital/ Foundation Hemoba who tested the HLA typing were included, totaling 215 patients. In this northeast region there is a predominance of African descendant (25% white, 75% brown/black). The genes in the analysis included HLA A, B, DR and DQ. SPSS was used to statistical calculations. Qui-square test/Fisher test were using the p-value correction of Bonferroni (p significant <0,0016) for comparison of genetic varieties.The HLA of patients with acquired AA Bahia (n = 215) were compared to the control group (3680 healthy non-related bone marrow volunteers donors from Bahia). To address regional differences within the country we also analyzed the HLA of AA patients (n = 344) from the State of Paraná located in the southern portion of the country and is characterized by a diverse ethnic mixture (71.3% white and 27% black/brown). Thus, we compared the findings of HLA associated with acquired AA in the two states, Bahia (northeast region) and Parana( south region). Of those statistically associated with AA (p<0,0016), we considered HLA clinically relevant only those present in at least 10% of cases and/or controls. Results From the 559 AA patients analysed, 45,1% were women, and 54.9% were men.The mean age was 23.4 (± 12.3). Among the HLA antigens with OR of risk or protection only HLA DR15 and B15, were significant, respectively (in both populations: Bahia and Parana). Identified as a risk factor for development of AA, HLA DR15 was found in 41.6% of patients (Bahia) versus 24% in controls (OR: 2.23 - CI: 1.68 to 2.9) (p <0.0001). As protective factor for AA development the HLA B15 was found in only 6% of patients (Bahia) versus 21.3% of controls (OR: 0.213, CI 0.12 to 0.370) (p <0.0001). A stratified analysis was conducted to assess the presence of interaction between the antigens DR15 and B15 in AA patients. When analyzing synergistically, the effects of HLA DR15 and B15, we observed that, in the AA group, the positivity of DR15+ of 41,6% falls significantly to 14,8%, when concurrently with the presence of B15+. The AA risk factor of HLA DR15+ loses its statistical risk power in presence of B15+. The incidence of B15+ patients (6% in AA patients) falls to 4% in the presence of DR15 negativity (p=ns). Conclusion We observed in 2 large AA cohorts (totaling 559 patients) from very distinct ethnic regions of Brazil, that, in both, HLA DR15 positivity was associated with a higher risk of disease, while B15 positivity was associated with a lesser likelihood of developing AA. The synergic combination of these alleles appears to be further associated with AA development. New studies analyzing synergic effect between HLA antigens/alleles should be conducted in immuno-mediated diseases. Disclosures: No relevant conflicts of interest to declare.

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The Interferon Gamma Gene Polymorphism In Acquired Aplastic Anemia and Its Association With HLA

Blood ◽

10.1182/blood.v122.21.1236.1236 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1236-1236

Author(s):

Marco Aurelio Salvino ◽

Marilda Souza Goncalves ◽

Bruno A. V. Cerqueira ◽

Larissa A Medeiros ◽

Flavio Lins ◽

...

Keyword(s):

Bone Marrow ◽

Gene Polymorphism ◽

Aplastic Anemia ◽

Interferon Gamma ◽

Gene Polymorphisms ◽

Hla Typing ◽

Control Group ◽

Genotypic Frequency ◽

Ifn Gamma ◽

Ifn Γ

Abstract Introduction Idiopathic acquired aplastic anemia (AAA) is a rare and life-threatening disease, characterized by pancytopenia. Its immune-mediated physiopathology is not yet fully understood. However, important associations have been reported in AAA, which include the association with certain HLAs, the presence of a PNH clone in 40-50% of cases, occurrence of a hepatitis associated variant in about 5-10% of cases, the occurrence of interferon gamma (IFN-g) and tumor necrosis factor alpha (TNF-a) producing T cells in the peripheral blood and bone marrow cells. Not much is known about cytokine gene polymorphisms in AAA and its relationship with HLA alleles. The IFN-γ +874 A/T gene polymorphism, and specially the +874TT genotype, have been associated with elevated levels of IFN-γ production. The individuals can present 3 different phenotype (TT, TA or AA). Some groups have demonstrated that the TT (the IFN-gamma “hyper-producer type”) is possibly overrepresented in AA patients and correlates with susceptibility to the disease. In order to better understand the relationship between these immune parameters, we investigated the associations between IFN-g gene polymorphism in AAA patients and its relationship with the presence of HLADR15 (identified as of greater importance in our local patients). Materials and methods In this study we analyze the variations of the gene polymorphism at position +874 interferon in 30 consecutive patients with confirmed diagnosis of AAA,in 2012 and 2013, at the Federal University of the State of Bahia Hospital/Brazil. Diagnosis of AAA was confirmed by bone marrow biopsy. Patients also had their HLA typing and were tested for the IFN-gamma gene polymorphism at +874 T/A position using the ARMS methodology described by Pravica. As controls, 116 healthy individuals from the same population (Bahia/Brazil) were tested for these polymorphism. The analysis of the association between the gene polymorphism and the chances of developing AAA, and the polymorphism and the HLA-DR15, were performed using qui-square/exact fisher test. The results were expressed as OR. Results We have found genotypic frequency of the A allele in 65%(n=39/60) in the aplastic patients (control 64.2%, n = 232, OR 1.05, p=0.87). The T allele was found in 35%(n =21/60)of the cases (control 34.6%, OR 0.95, p=0.87). Thus, there was no difference between the genotypic frequency of the alleles among patients with aplasia and the control group. In addition, there was NO difference between the frequency of the phenotype (TT, AT or AA) between patients with AAA and control group, respectively 16,5%, 36,5%, 46% (AAA, n =30) versus 18.1% , 35.3%, 46.6% (n = 116 control) (p=n.s.). The association of the polymorphism was tested and compared to the HLA-DR15. There was NO association between the IFN-gamma gene polymorphisms and the presence of HLADR15 (p =,90). Conclusion In our brazilian cohort, the +874 T/A IFN-gamma gene polymorphism was Not associated with the onset of AAA. Also, there was No association between IFN-gamma gene polymorphism and the antigen HLA-DR15. TT phenotype, possibly the predisposing one for disease, was expressed only in 15% of patients with AAA. These findings corroborate the presence of a much more complex pathogenesis in AAA ,and that, regional differences in genetic and immune mechanisms may co-exist. Disclosures: No relevant conflicts of interest to declare.

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Telomerase Enzyme Activity In Egyptian Children With Bone Marrow Failure

Blood ◽

10.1182/blood.v122.21.4662.4662 ◽

2013 ◽

Vol 122 (21) ◽

pp. 4662-4662

Author(s):

Amal M. El-Beshlawy ◽

Mona Mohamed Hamdy ◽

Amina Abd El Salam ◽

Mervet El Ansary ◽

Nelly Abulata ◽

...

Keyword(s):

Bone Marrow ◽

Aplastic Anemia ◽

Immunosuppressive Therapy ◽

Mononuclear Cells ◽

Conflicts Of Interest ◽

Bone Marrow Failure ◽

Telomerase Activity ◽

Telomere Maintenance ◽

Control Group ◽

Egyptian Children

Background Telomeres are structural elements that seal the ends of chromosomes protecting them from recombination and end to end fusion. Maintenance of the integrity of telomeres requires the telomerase ribonucleoprotein complex. Abnormal telomere maintenance is a feature of a variety of human diseases including constitutional aplastic anemia. Predisposition to the development of marrow failure has been conferred by genetic alternations results in low telomerase activity. Short telomeres in leukocytes and reduced hematopoietic function. Aim To evaluate the telomerase functional activity in Egyptian children with inherited and acquired bone marrow failure and its relation to the phenotypic features of the acquired disease and its response to immunosuppressive therapy. Patients and Methods This was a case-control study conducted on unrelated children (n=40) with bone marrow failure syndromes and forty healthy subjects age and sex-matched as controls. The diagnosis of bone marrow failure was based on the bone marrow biopsy and blood-count results. Patients with acquired aplastic anemia (AAA) were considered severe if at least 2 of the following were noted: neutrophil count < 0.5×109/L; platelet count < 20×109/L with hypocellular marrow. Response to immunosuppressive therapy (IST) was evaluated after 6 months of initiation of therapy. Assessment of Telomerase Activity Telomerase activity was measured in mononuclear cells utilizing the Telomeric Repeat Amplification Protocol (TRAP )using the TeloTAGGG Telomerase PCR ELISA. Results Forty patients were included in the study (30 AAA , 6 Fanconi Anemia (FA), 2 Pure Red Cell Aplasia (PRCA), one case with Dyskeratosis Congenita (DCK) and one case with constitutional aplastic anemia. The Mean age was 11.1±4.9 years (range 3.5 to 18 years, median 11 years ) and the duration of follow-up mean; 5.14 (±3.84) years (range 1-13 years). Patients with AAA (n=30) received treatment with cyclosporine A( n =27) and ATG( n=3). Telomerase level The median telomerase level was significantly lower in inherited BMF syndromes when compared to controls [5.05 (4.60 – 8.70 IQR) Vs 11.15 (5.90-16.60 IQR), p=0.04]. In AAA the median telomerase level was insignificantly lower than controls [5.4 (2.3 – 21.0 IQR) Vs 11.15 (5.90-16.60 IQR), p=0.228]. A good inverse correlation was detected between the telomerase level and age of the patients (r=-0.39, p=0.026). No correlation was found between the telomerase level and disease duration in hereditary or AAA (r= -0.303, p=0.111 and r=0.305, p=0.156 respectively). Telomerase activity and clinical variables We classified our cases into two groups according to the median value of the control group (11.5): Low telomerase level group: (n=27): included 18 AAA (66.7%) and 9 hereditary aplastic Anemia (33.3%). Cases with AAA 14/18 (77.8%) with low telomerase activity were severe cases with bone marrow cellularity less than 10 % Vs 6/12 (50%) with normal telomerase. Fifty per cent of cases (9/18) with low telomerase responded partially or completely to IST Vs. 83.4% of the normal telomerase (10/12) group. Patients of AAA who received cyclosporine therapy (n=27), 19 cases (70.4%) were responders versus zero % of patients who received ATG (n=3). The median telomerase of responders was 16.5 + 4.7 Vs 11.6 + 3.8 of none responders. Conclusion • Telomerase activity was affected in hereditary and acquired bone marrow failure. • Evaluation of telomerase activity is essential for therapeutic and prognostic aspects of these diseases. Cyclosporin A can be used as a monotherapy in the treatment of acquired aplastic anemia even in the presence of decreased telomerase activity Disclosures: No relevant conflicts of interest to declare.

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Epimedium Polysaccharide Ameliorates Benzene-Induced Aplastic Anemia in Mice

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2020/5637507 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Jin He ◽

Ru Han ◽

Gongchang Yu ◽

Martin F. Lavin ◽

Qiang Jia ◽

...

Keyword(s):

Bone Marrow ◽

Aplastic Anemia ◽

Immune Modulation ◽

Mononuclear Cells ◽

Peripheral Blood Cell ◽

Environmental Pollutant ◽

Control Group ◽

High Dose ◽

Dependent Manner ◽

Protective Effects

Benzene (BZ) is an important occupational and environmental pollutant. Exposure to BZ may cause aplastic anemia which is characterized as bone marrow hematopoietic failure. In order to reduce the harmful effects of this pollutant, it is necessary to identify additional preventative measures. In this study, we investigated the protective effects of epimedium polysaccharide (EPS), a natural compound with antioxidant and immune-enhancing potency, on aplastic anemia induced by benzene exposure in mice. Male CD-1 mice were randomly divided into five groups including control, BZ (880 mg/kg), LE (EPS low-dose, 20 mg/kg + BZ), ME (EPS middle-dose, 100 mg/kg + BZ), and HE (EPS high-dose, 200 mg/kg + BZ) groups. Animals were exposed to BZ by subcutaneous injection in the presence or absence of EPS via oral administration. All mice were treated 3 times a week for 8 consecutive weeks to develop a mouse model of benzene-induced aplastic anemia (BIAA). Results showed that BZ induced a significant decrease in both white and red blood cells, platelet counts, and hemoglobin level compared with that in the control group (p<0.01). Treatment of EPS led to a protective effect against these changes particularly in the highest-dose group (HE, p<0.01). EPS also recovered the decreased number of nucleated cells in peripheral blood cell smears and femur biopsies by BZ exposure. The increased level of reactive oxygen species (ROS) in bone marrow mononuclear cells (BMMNCs) in mice from the BZ group was significantly lower (p<0.01) in the mice from the highest concentration of EPS (HE) group when compared with that from the control group. In addition, BZ exposure led to a significant increase in the apoptosis rate in BMMNCs which was prevented by EPS in a dose-dependent manner (p<0.01). The antiapoptosis effect of EPS was through reversing apoptotic proteins such as BAX, Caspase-9 and Caspase-3, and Bcl-2. Finally, EPS treatment partially restored the levels of T cells and the different subtypes except CD80+ and CD86+ compared with the BZ group (HE, p<0.05). These results suggest that EPS has protective effects against BIAA via antioxidative stress, immune modulation, and antiapoptosis mechanisms.

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Parvovirus B19 and Aplastic Anemia: Case Control Study: Preliminary Report from the ITESM Hematology Study Group.

Blood ◽

10.1182/blood.v106.11.3765.3765 ◽

2005 ◽

Vol 106 (11) ◽

pp. 3765-3765

Author(s):

Jose R. Borbolla Escoboza ◽

Marcos E. Garza-Madrid ◽

Luis Villela ◽

Manuel A. Lopez-Hernandez ◽

Jorge Vela-Ojeda

Keyword(s):

Bone Marrow ◽

Aplastic Anemia ◽

Peripheral Blood ◽

Blood Cells ◽

Parvovirus B19 ◽

Bone Marrow Failure ◽

Control Group ◽

Number Of Patients ◽

Two Samples ◽

Sense Primer

Abstract Aplastic anemia (AA) is a classic bone marrow failure syndrome simply defined as peripheral blood pancytopenia and a hypocelular bone marrow, yet the diagnosis must be made by excluding other causes of bone marrow failure. The incidence rate of AA reported by the International Aplastic Anemia and Agranulocytosis Study (IAAAS) in the 1980s was 2 cases per 1 million people. This disease is known to be caused by exposure to radiation, chemotherapy and some viral agents, yet most of the cases are idiopathic. Epstein Barr virus and non-A, non-B or non-C Hepatitis virus have classically been related to the development of some AA cases. Recently there have been some reports of AA following Parvovirus B19 (PvB19) infection. This virus, the only parvoviridae virus capable of infecting humans, attacks erythrocyte precursors attaching to the P antigen in their surface and requiring Beta1 integrin for viral entry. Although PvB19 seems to infect only erytroid precursors, it is widely recognized that the infection with this virus can cause not only anemia, but neutropenia and thrombocytopenia as well, producing aplastic crisis of varying intensity. A correlation has recently been found between PvB19 DNA in peripheral blood and AA in children. We pretend to corroborate this observation and include adult patients in order to improve our understanding of the relationship between PvB19 and AA. So far we have taken peripheral blood samples from 9 AA patients and 9 controls paired by age, sex and community; we plan to include 100 AA patients and their controls from several hospitals around Mexico. DNA was extracted using the PUREGENE DNA extraction kit (Gentra, Minneapolis MN). Nested PCR was performed using the sense primer (P1) 5-AATACACTGTGGTTTTATGGGCCG-3, antisense (P2) 5-CCATTGCTGGTTATAACCACAGGT-3 for the first round and the sense primer (P3) 5-AATGAAAACTTTCCATTTAATGATGTAG-3 and antisense primer (P4) 5-CTAAAATGGCTTTTGCAGCTTCTAC-3for the second round. A DNA sample from a patient with active infectious mononucleosis with positive IgG and IgM against PvB19 in serum was used as positive control. Two samples from the AA group (22%) and 1 from the control group (11%) have turned positive for PvB19 DNA. The reported incidence for the presence of this virusDNA in the peripheral blood of the population is 3%. We expect that, as the number of patients grows, the percentage of positive samples in the control group will decrease, while the percentage of positive samples in the AA group will rise or be sustained. Our partial results point towards a possible relationship between AA and the presence of PvB19 DNA in the peripheral blood cells. It is possible that this virus is one of many factors capable of precipitating the development of AA by limiting the bone marrows capacity to produce blood cells. We are in the process of gathering more samples to prove if a relationship really exists and, if so, future studies will likely shed light upon the mechanism by which PvB19 contributes to the development of AA and other marrow failure syndromes.

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Study on Mechanism of Human Marrow Mesenchymal Stem Cell in Treating Patients with Aplastic Anemia.

Blood ◽

10.1182/blood.v110.11.4099.4099 ◽

2007 ◽

Vol 110 (11) ◽

pp. 4099-4099

Author(s):

Zhenhua Qiao ◽

Xiujuan Zhao

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

T Cells ◽

Aplastic Anemia ◽

Hematopoietic Cell ◽

Control Group ◽

Rt Pcr ◽

Tnf Α ◽

Ifn Γ ◽

Tgf Β1

Abstract Objective: To explore mechanism of human marrow mesenchymal stem cells (MSCs) in treating patients with aplastic anemia(AA). Methods: MSCs in patients with aplastic anemia(AA) and the control group were separated with Percoll(1.073g/m L) and cultured in low glucose DMEM. Then, observed their morphologies,checked their molecule surface antigen by flow cytometry and examined the process of adipogenic differention. The mononuclear cells (MNC)of marrow in patients with AA were enriched based 1.077g/L density centrifuge and cultured in the 1640 medium. (1)MSC in control group and MNC in AA group were co-cultured with or without cytokines. The function of supporting hematopoiesis for MSC was to be observed in single confluence layer after plating by counting the total cells and the clones in every well every week. Then analyzed the dynamics of proliferation. T cells were harvested by using nylon column. MSC in control group and T cells in AA group were co-cultured. The proliferation of T cell was measured by MTT method. The CD25,CD69,CD4,CD8,Annexin-V expression rates of CD3+T cells were analyzed by flow cytometry .The gene and protein of IL-2, IL-4,IL-10,TNF-α,IFN-γ,TGF-β1 were examined by RT-PCR and ELISA respectively. MSC treated to the model of AA, by the examination of peripheral hemogram, bone marrow biopsy, pathological section of spleen. Results: There was no significant difference between control group MSC and AA-MSC in morphologies but adipogenic differentiation in AA patients is earlier than controls. The clones of CFU-GM in group(MSC)(78.46±3.58)/2×105 cells, after 14 days cultured was significantly higher than(9.21±4.32)/2×105 cells in group(CK + DMEM medium), while lower than (99.32±4.34)/2×105 cells in group(MSC+CK). (1)the Treg cells (TCD4+CD25+) in AA group (2.01±1.21)/ 2×105 was significantly lower than (4.43±1.67)/2×105 cells in control group, while(5.43±2.31) / 2×105 in group (MSC+AAT) was no more than (4.43±1.67)/2×105 cells in control group. (2) MSCs significantly inhibited T cell proliferation (P< 0. O5)by MTT. (3) RT-PCR and ELISA analysis showed that MSCs induced the expression of IL-4, IL-10, TGF-β1 and decreased significantly the expression of IL-2, TNF-α, IFN -γ in T cells of AA. the model of AA treated by MSCs showed improvements in 3 blood components greatly(p<0.05), Bone marrow proliferated and restored to the normal level, hematopoietic cell increased obviously (hematopoietic cell capacity was more than 40%), and atrophied spleen restore to normality. Conclusions: morphologies of AA’MSC had no evident different with the control but was more easy adipogenic differention. aplastic anemia belongs to autoimmune diseases in which T cells effect organ-specific destruction. The fundamental mechanism of MSC in treating AA should be potential to promote hematopoietic cell proliferation by adjusting immunity.

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23 Years of Management: A Retrospective Review of Treatment for Aplastic Anemia.

Blood ◽

10.1182/blood.v114.22.1091.1091 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1091-1091

Author(s):

Connie M Piccone ◽

Marie Boorman Martin ◽

Zung Vu Tran ◽

Kim Smith-Whitley

Keyword(s):

Bone Marrow ◽

Aplastic Anemia ◽

Retrospective Review ◽

Pediatric Patients ◽

Conflicts Of Interest ◽

Bone Marrow Failure ◽

Complete Response ◽

Primary Objective ◽

Hematopoietic Stem ◽

Transfusion Independence

Abstract Abstract 1091 Poster Board I-113 Introduction Aplastic anemia (AA) is a syndrome of bone marrow failure characterized by peripheral pancytopenia and marrow hypoplasia. In the past, AA was considered to be a fatal disease; however, current therapies, including bone marrow transplantation or immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and cyclosporine (CSA), are curative in the majority of patients. IST is effective at restoring hematopoietic stem cell production, but relapse and evolution to myelodysplastic syndromes remain clinical challenges. Additionally, there is no real consensus regarding optimal CSA levels, duration of CSA treatment, or the optimal use of growth factors and their relationship to the development of clonal disease. Objectives The primary objective was to review treatment management for severe AA in pediatric patients in order to elucidate treatment differences and review morbidity and mortality as they relate to treatment variation. Study Design/Methods A retrospective review of pediatric patients treated at the Children's Hospital of Philadelphia for AA (both severe and moderate) over a 23 year period was performed. Results A total of 70 patients with AA were treated at our institution from 1985 to July 2008. Exclusions included: 6 patients who received some type of initial treatment at outside institutions, 4 patients who had missing records, and 2 patients who had a diagnosis of moderate AA. Thus, a total of 58 patient records were included in the analysis. Of the total patients reviewed, 60% were male and 40% were female. 34.5% of patients were African-American, and 57% were diagnosed in 2000 or later. The mean age at diagnosis was 9.5±5.8 years. 52% fell into the category of very severe AA based on published diagnostic criteria, 45% had severe AA, and 2 patients (3%) had moderate AA. 15.5% of patients developed AA in the setting of acute hepatitis. More than half of the patients treated with IST had a complete response (CR). The average time to CR was 15±15 months. Average duration of CSA treatment was 15±13 months and 8.6±10.7 months for growth factor. Two patients (3.5%) died, one from complications unrelated to AA and one from infectious complications post-BMT after initial IST failure. Average time to transfusion independence for all patients was 8±11 months (with a range of 0-54 months). Not surprisingly, the time to transfusion independence was significantly associated with IST failure (p=0.010). Patients who failed treatment had an average time to transfusion independence of 17±16 months as compared to those who were complete responders who had an average time to transfusion independence of 3±3 months. Additionally, there was a significant association between IST failure and CSA levels (p=0.014). Patients who had nontherapeutic CSA levels overall had an increased rate of treatment failure. Of those patients who were nontherapeutic, 56% were noncompliant with CSA administration. There was no significant association between IST failure and bone marrow cellularity (p=0.251). PNH was diagnosed in 5% of patients; there were no patients with evidence of myelodysplastic syndrome (MDS). Two of the 3 patients with PNH failed initial IST. Another 2 patients had evidence of a cytogenetic abnormality (16q deletion), but never progressed to MDS. (Note: averages presented as mean±SD) Conclusions/Methods With current IST regimens, AA is curative in the majority of pediatric patients. IST failure was associated with nonadherence to CSA treatment. For patients with confirmed clonal disease, it is possible that IST failure and the ultimate development of clonal disease are related. Disclosures No relevant conflicts of interest to declare.

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SRC Is a Critical Signaling Mediator in FLT3-ITD Positive AML.

Blood ◽

10.1182/blood.v114.22.477.477 ◽

2009 ◽

Vol 114 (22) ◽

pp. 477-477

Author(s):

Hannes Leischner ◽

Rebekka Grundler ◽

Corinna Albers ◽

Anna Lena Illert ◽

Karsten Spiekermann ◽

...

Keyword(s):

Bone Marrow ◽

Conflicts Of Interest ◽

Point Mutations ◽

Kinase Domain ◽

Sh2 Domain ◽

Control Group ◽

Tyrosine Kinase Domain ◽

Myeloproliferative Disease ◽

Activating Mutations ◽

Tandem Duplications

Abstract Abstract 477 Activating mutations of FLT3 are frequent in patients with AML. Two types of mutations are most common: Internal tandem duplications (ITD) of the juxtamembrane domain in approximately 30% of patients and point mutations within the second tyrosine kinase domain (TKD) in about 7% of AML patients. Patients carrying the FLT3-ITD mutation have a significantly worse prognosis whereas FLT3-TKD mutations do not appear to influence the clinical outcome. Studies have shown that mice receiving a transplant of bone marrow expressing FLT3 ITD develop a myeloproliferative disease. In contrast, mice which were transplanted with FLT3 TKD infected bone marrow, suffer from a lymphoid disease. Thus, both FLT3 mutations seem to exert different biological functions. Interestingly, FLT3-ITD but not FLT3-TKD or FLT3-WT leads to a strong activation of the STAT5 signaling pathway. Therefore, STAT5 activation may be responsible for the observed differences in biology. Here we investigated the signalling pathways leading to STAT5 activation downstream of FLT3-ITD. FLT3-ITD does not bind STAT5 directly nor does it activate the classical JAK2 pathway. Instead FLT3-ITD utilizes c-Src to activate STAT5. Co-immunoprecipitations and GST pull downs revealed a strong and exclusive interaction between Src and FLT3 ITD, which is mediated by the Src-SH2 domain. This interaction is absent in FLT3-TKD or FLT3-WT after ligand stimulation. The sequence duplication in FLT3-ITD leads to additional potential Src-SH2 binding sites. We identified tyrosines 589 and 591 of FLT3-ITD to be essential for Src binding and subsequent STAT5 activation. Specific Src inhibitors or Src-siRNA blocked STAT5 activation and growth induced by FLT3-ITD but not FLT3-TKD. FLT3-ITD positive cells with a stable Src knockdown injected into syngenic mice led to a leukemic disease with a significant delayed onset and prolonged survival in comparison to the control group. Finally, a combination of FLT3 and Src inhibitors was tested. This combination was highly efficient in FLT3-ITD positive cells but not in FLT-TKD positive cells. Together these findings show that Src plays an important role in the signalling of FLT3-ITD but not FLT3-TKD. Thus, Src might be an interesting therapeutic target for FLT3-ITD positive AML. Disclosures: No relevant conflicts of interest to declare.

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Antithymocyte Rabbit Globulin Is Safe and Effective in Children with Severe Aplastic Anemia Report Polish Pediatric Hematology Group (Warszawa, Krakow, Wroclaw, Bydgoszcz, Poznan, Lodz, Bialystok, Szczecin, Gdansk).

Blood ◽

10.1182/blood.v114.22.4220.4220 ◽

2009 ◽

Vol 114 (22) ◽

pp. 4220-4220

Author(s):

Katarzyna Pawelec ◽

Michal Matysiak ◽

Malgorzata Salamonowicz ◽

Walentyna Balwierz ◽

Ewa Zaleska-Czepko ◽

...

Keyword(s):

Bone Marrow ◽

Aplastic Anemia ◽

Conflicts Of Interest ◽

Working Party ◽

Bone Marrow Examination ◽

Observation Time ◽

Response To Treatment ◽

Severe Aplastic Anemia ◽

Pediatric Hematology

Abstract Abstract 4220 Bone marrow transplantation (BMT) is a therapy of choice in children with severe aplastic anemia (SAA), but it is possible only in about 15-20% patients who have family donors, so the majority of them received the immunosuppressive therapy (IST). We want to present the results of IST obtained in 116 children treated between 1993-2008 years at 11 pediatric hematology centers of the Polish Pediatric Hematology Group (PPHG),, 55 patients (22 girls and 33 boys aged 0,6-17,5 years) received antithymocyte rabbit globulin (ATG) as a first course of therapy. ATG was administered according to PPHG and Working Party SAA Group of EBMT protocol: ATG 3.75mg/kg iv for 5 days, cyclosporin A (CSA) 5mg/kg orally from day 1 to day 180 and granulocyte-stimulating factor during deep neutropenia. Remission of the disease was assessed on days 112, 180 and 360 from start of therapy on the basis of blood and bone marrow examination. The results on 112 and 180 were similar. The remission was achieved in 28 of 55 children (51%), complete remission (CR) in 5 children (9%), and partial remission (PR) in 23 children (42%). On day 360 remission was obtained in 30 of 55 patients (42 %), CR in 10 children (18%) and PR in 20 children (36%) There was no response to treatment (NR) in 25 patients (45%). In the group of 55 patients, 15 died (27%). 5 of them died early (day 52 and day 72 of therapy) due to septicemia and central nervous system (CNS) hemorrhage. The other 10 died late (day 99 and day 360 of therapy) due to CNS hemorrhage. Observation time of patients ranged from 1 to 14 years. During this time we noted four relapse. PNH was observed in one patient. The probability of 14 year survival in our group of patients treated initially with rabbit ATG is 72,7%. The results in the last follow up (Jun 2009) are better then earlier. We observed CR in 23/55 children (42%), PR in 10/55 (18%), NR 18/55 (33%). o information about 4 patients. We conclude that initial treatment with rabbit ATG is safe and effective in children. Further studies are needed, to assess long-term effectiveness of rabbit ATG in IST. Disclosures: No relevant conflicts of interest to declare.

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Impact of Cytokine Gene Polymorphisms on Risk and Treatment Outcomes of Aplastic Anemia In Korea

Blood ◽

10.1182/blood.v116.21.4432.4432 ◽

2010 ◽

Vol 116 (21) ◽

pp. 4432-4432

Author(s):

Yun-Gyoo Lee ◽

Ji-Hyun Kwon ◽

Dong-Yeop Shin ◽

Eun-Young Song ◽

Hyun Kyung Kim ◽

...

Keyword(s):

Aplastic Anemia ◽

Conflicts Of Interest ◽

Recessive Model ◽

Multivariate Logistic Regression Model ◽

Control Group ◽

Dominant Model ◽

Cytokine Genes ◽

Hematologic Response ◽

Tnf Α ◽

Ifn Γ

Abstract Abstract 4432 Introduction The clinical evidence of responsiveness to immunosuppressive therapy (IST) supports immune pathophysiology for acquired aplastic anemia (AA). Recent studies suggested that auto-reactive cytotoxic T-cells against hematopoietic cells play a key role in the pathogenesis of AA with various cytokines. The purpose of this study is to investigate whether single nucleotide polymorphisms (SNP) of cytokine genes are related to the risk of AA and, furthermore, the response to IST. Methods We analyzed 80 adult patients diagnosed as acquired AA. The 84 unrelated, age and sex matched healthy subjects served as a control group. In 3 cytokine genes (IFN-γ, TNF-α, TGF-β) and one FAS gene, we selected 10 polymorphisms on the basis of allelic frequency and the assumption of clinical relevance from previously reported associations. To assess the association between polymorphisms and risk of AA, we calculated statistical differences in allele, genotype, and haplotype distributions between patients and controls using chi-square test in 3 genetic models (dominant, recessive, and additive). For the association between polymorphisms and response to initial course of IST, we analyzed 44 patients who were treated with IST using a multivariate logistic regression model. Results Among 10 SNPs in 4 genes, one SNP and one haplotype in IFN-γ gene were significantly associated with the development of AA: IFN-γ -2353A/T; the presence of the T allele in dominant model was protective and was related to a 2.3-fold reduction in the risk for AA (P =.012); the presence of the IFN-γ TCA haplotype was related to a two-fold reduced risk for AA (P =.038). The IFN-γ -2353 T allele was shown to be resistant to IST; the presence of T allele and TCA haplotype in IFN-γ gene (dominant model) was related to a 13.2-fold reduced hematologic response at 6 months following initial IST (P =.034). However, 4 SNPs and 2 haplotypes in TNF-α gene did not show any significant associations with the response at 3 and 6 months. In terms of 2 SNPs in TGF-β gene, TGF-β P10L T/C was independently related; the T allele (recessive model) was related to a 4.3-fold reduced response to IST at 3 months (P =.038). Accordingly, the response was related to the TGF-β haplotype; the TC haplotype homozygote (recessive model) was related to a 4.6-fold reduced response to IST at 6 months (P =.036); the presence of CT haplotype (dominant model) was favorable to IST and was related to a 5.7-fold higher response at 3 months than the absence of the CT haplotype (P =.038). Conclusion This exploratory study found that the genetic polymorphism of IFN-γ was susceptible to the development of AA and was related to the hematologic response following initial IST. In case of TGF-β, the polymorphisms were related to the response to IST, though they were not be related to the disease susceptibility. Large studies with a prospective design are needed to better understand the determinants of risk of AA and responsiveness to IST. Disclosures: No relevant conflicts of interest to declare.

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Prospective Evaluation of plasma Levels of FVIII in Patients with venous Thromboembolism,

Blood ◽

10.1182/blood.v118.21.3348.3348 ◽

2011 ◽

Vol 118 (21) ◽

pp. 3348-3348

Author(s):

Luis Fernando Bittar ◽

Bruna Mazetto Fonseca ◽

Silmara Lima Montalvão ◽

Fernanda Loureiro de Andrade Orsi ◽

Erich V de Paula ◽

...

Keyword(s):

Risk Factor ◽

Venous Thromboembolism ◽

Plasma Levels ◽

Conflicts Of Interest ◽

Coagulation Factor ◽

Geographic Area ◽

First Episode ◽

Control Group ◽

Post Thrombotic Syndrome

Abstract Abstract 3348 Introduction: Venous thromboembolism (VTE) is a multifactorial disease, and increased levels of coagulation factor VIII (FVIII) has been demonstrated as risk factor for first and recurrent episodes of VTE. Some authors reported that these high levels of FVIII were still persistent after 4 years of the episode, but median follow-up in these studies are relatively short. The aim of the study was investigate if after a long-term follow-up of 4–15 years (median of 10 years), patients with high levels of FVIII after anticoagulant treatment still showed this alteration. Design and Methods: Previously, we selected 174 adult patients with a first episode of acute VTE between January 1990 and September 2004. One hundred seventy four healthy adult individuals selected from blood donors were chosen as controls, from the same geographic area of origin. Of this group of VTE patients, 68 patients with plasma FVIII: C levels above the 90th percentile were selected. FVIII levels (FVIII:C) were measured by a one-stage clotting assay with FVIII-deficient plasma in duplicate in an automated coagulometer. Levels were measured twice, in 2004 and then in 2011. C-reactive protein (CRP) levels were determined in the same samples by a nephelometric method to evaluate the influence of inflammation on FVIII levels. For individuals with CRP values higher than 1mg/dL, an additional blood sample was analyzed. High FVIII levels were only considered for further analysis when in the presence of normal CRP levels. The presence of post-thrombotic syndrome (PTS) was evaluated and classified clinically by the Clinical-Etiologic-Anatomic-Pathophysiologic (CEAP) classification System. Results: 68 patients with VTE and high levels of FVIII (19M:49F) with a median age of 47 years (range 20–70) were included in the study. The control group consisted of 59 subjects (42M:17F) with a median age of 35 years (range 21–56 years). VTE was spontaneous in 26 (38.2%) patients and secondary to an acquired risk factor in 61.8%. In the 1st evaluation, in 2004, patients with VTE had higher plasma levels of FVIII:C (median 235.8 IU/dL vs. 127.0 IU/dL; p<0.001) compared to controls. In 2011, seven years after the first evaluation and after a median follow-up of 10 years after the first VTE episode, this difference was still present (median 144.6 IU/dL vs. 96.4 IU/dL; p<0.001). Patients with severe PTS (167 IU/dL) showed higher plasma levels of FVIII when compared with patients without PTS (median 141.4 IU/dL), mild PTS patients (median 142.8 IU/dL), and moderate PTS patients (median 143.2); p=0.04. Conclusions: Our results show that even after a median of 10 years of VTE, patients still have increased levels of FVIII. Moreover, there seems to be a relationship between severe post-thrombotic syndrome and increased plasma levels of FVIII. Disclosures: No relevant conflicts of interest to declare.

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