Search tips
Search criteria

Results 26-50 (103)

Clipboard (0)

Select a Filter Below

Year of Publication
26.  Tailoring of chronic lymphatic leukemia therapy 
Chronic lymphocytic leukemia (CLL) remains an incurable disease, with all patients who require therapy destined to relapse and understanding of the pathophysiology of chronic lymphocytic leukemia has advanced significantly. It is now clear that chronic lymphocytic leukemia is a relatively proliferative disorder that requires the help of its microenvironment to be maintained and to progress. The stimulation of the chronic lymphatic leukemia cell occurs in most, if not all, patients through antigen stimulation via the B cell receptors. In addition, there is now a appreciation of the role of the p53 pathway leading to chemoresistance and the elucidation of the molecular and intracellular signaling mechanisms of disease is just beginning to facilitate the development of several targeted small molecules that promise to revolutionize the treatment of Chronic lymphocytic leukemia.
PMCID: PMC3755525  PMID: 23997983
Chronic lymphocytic leukemia; pathophysiology; target therapy
27.  Romiplostim for delayed platelet recovery and secondary thrombocytopenia following allogeneic stem cell transplantation 
Delayed recovery of platelet count post allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been associated with worse transplant outcomes. Thrombopoietic agents have been successfully used in immune mediated thrombocytopenia or thrombocytopenia from bone marrow failure syndromes; however, the experience regarding their use after allo-HSCT is limited. Here we report on the safety and efficacy of romiplostim used in 3 consecutive patients with thrombocytopenia post allogeneic transplantation. Two patients had prolonged platelet recovery due to poor graft function while one had secondary failure of platelet recovery, likely immune mediated, post transplantation. Successful use of such agents post-transplant may improve platelet recovery, decrease rates of complications and potentially improve outcomes.
PMCID: PMC3755526  PMID: 23997988
Post-transplant thrombocytopenia; romiplostim; allogeneic hematopoietic stem cell transplantation
28.  Aging- and activation-induced platelet microparticles suppress apoptosis in monocytic cells and differentially signal to proinflammatory mediator release 
Background: Platelet microparticles (PM) are the most abundant cell-derived microparticles in the blood, and accumulate in thrombo-inflammatory diseases. Platelets produce PM upon aging via an apoptosis-like process and by activation with strong agonists. We previously showed that long-term treatment of monocytic cells with apoptosis-induced PM (PMap) promotes their differentiation into resident macrophages. Here we investigated shorter term effects of various types of PM on monocyte signalling and function. Methods and results: Flow cytometry and scanning electron microscopy revealed that PM formed upon platelet aging (PMap) or ultra-sonication (PMsonic) expressed activated αIIbβ3 integrins and tended to assemble into aggregates. In contrast, PM formed upon platelet activation with thrombin (PMthr) or Ca2+ ionophore (PMiono) had mostly non-activated αIIbβ3 and little aggregate formation, but had increased CD63 expression. PM from activated and sonicated platelets expressed phosphatidylserine at their surface, while only the latter were enriched in the receptors CD40L and CX3CR1. All PM types expressed P-selectin, interacted with monocytic cells via this receptor, and were internalised into these cells. The various PM types promoted actin cytoskeletal rearrangements and hydrogen peroxide production by monocytic cells. Markedly, both aging- and activation-induced PM types stimulated the phosphoinositide 3-kinase/Akt pathway, suppressing apoptosis induced by several agonists, in a P-selectin-dependent manner. On the other hand, the PM types differentially influenced monocyte signalling in eliciting Ca2+ fluxes (particularly PMap) and in releasing secondary mediators (complement factor C5a with PMap, and pro-inflammatory tumour necrosis factor-α with PMthr). Conclusions: In spite of their common anti-apoptotic potential via Akt activation, aging- and activation-induced PM cause different Ca2+ signalling events and mediator release in monocytic cells. By implication, aging and activated platelets may modulate monocyte function in different way by the shedding of different PM types.
PMCID: PMC3649808  PMID: 23675563
Aging; apoptosis; microparticles; monocytes; platelet activation; tumour necrosis factor
29.  A rare der(Y)t(Y;1)(q12;q12) in a patient with post-polycythemic myelofibrosis: a case report 
We describe a case of post-polycythemic myelofibrosis harboring der(Y)t(Y;1)(q12;q12). The patient was a 69-year-old man and was initially diagnosed with polycythemia vera. During the clinical course of his condition, the polycythemia developed into myelofibrosis. Chromosome analysis detected der(Y)t(Y;1)(q12;q12). We discuss the association between der(Y)t(Y;1)(q11~12;q12~21) and tumorigenesis along with a review of literature.
PMCID: PMC3649809  PMID: 23675569
Post-polycythemic myelofibrosis; der(Y)t(Y;1)(q12;q12); chromosomal abnormality
30.  Guidelines and diagnostic algorithm for patients with suspected systemic mastocytosis: a proposal of the Austrian competence network (AUCNM) 
Systemic mastocytosis (SM) is a hematopoietic neoplasm characterized by pathologic expansion of tissue mast cells in one or more extracutaneous organs. In most children and most adult patients, skin involvement is found. Childhood patients frequently suffer from cutaneous mastocytosis without systemic involvement, whereas most adult patients are diagnosed as suffering from SM. In a smaller subset of patients, SM without skin lesions develops which is a diagnostic challenge. In the current article, a diagnostic algorithm for patients with suspected SM is proposed. In adult patients with skin lesions and histologically confirmed mastocytosis in the skin (MIS), a bone marrow biopsy is recommended regardless of the serum tryptase level. In adult patients without skin lesions who are suffering from typical mediator-related symptoms, the basal serum tryptase level is an important diagnostic parameter. In those with slightly elevated tryptase (15-30 ng/ml), additional non-invasive investigations, including a KIT mutation analysis of peripheral blood cells and sonographic analysis, is performed. In adult patients in whom i) KIT D816V is detected or/and ii) the basal serum tryptase level is clearly elevated (> 30 ng/ml) or/and iii) other clinical or laboratory features are suggesting the presence of occult mastocytosis, a bone marrow biopsy should be performed. In the absence of KIT D816V and other indications of mastocytosis, no bone marrow investigation is required, but the patient’s course and the serum tryptase levels are examined in the follow-up.
PMCID: PMC3649810  PMID: 23675567
Mastocytosis; tryptase; KIT D816V; diagnostic algorithm; staging
31.  Immune surveillance and lymphoid malignancy in immunocompromised host 
Immune surveillance is a dynamic process that involves an intact immune system to identify and protect the host against tumor development. The increased understanding of the genetics, infections and hematological malignancies in congenital immune deficiency states supports the concept that impaired T cells and Natural-killer/T cells leads to B-cell lymphoma. Furthermore, severe combined immunodeficient mice are prone to spontaneous tumor development and therefore serve as experimental models. Here we discuss the acquired conditions and mechanisms involved in dysregulation of the immune system that lead to lymphoma. Preemptive strategies to improve immune regulation and response and restore a competent immune system may lead to a decrease in lymphoid malignancies.
PMCID: PMC3649811  PMID: 23675561
Lymphoma; immune surveillance; immune deficiency
32.  MyD88 is involved in myeloid as well as lymphoid hematopoiesis independent of the presence of a pathogen 
MyD88 was originally described as a primary response gene up-regulated during myeloid differentiation after IL-6 induction. Later, MyD88 was shown to be a key molecule necessary for IL1, IL18 and Toll-like receptor signaling. Since these receptors recognize abundantly produced cytokines during infection or molecular patterns of pathogens, MyD88 itself was suggested to be an important regulator of the first line of defense against invading pathogens, including the differentiation and maturation of myeloid cells. Here we describe that MyD88 is important for early and late hematopoietic events that occur independently of antigen under steady-state conditions. In MyD88-deficient mice the earliest alteration in hematopoiesis was found at the level of long-term hematopoietic stem cells. Moreover, we found that MyD88 influences not only the development of the myeloid lineage but also the differentiation of B cells. The B cell defect observed in Btk-deficient mice is further enhanced when both molecules, Btk and MyD88, are not expressed. Therefore, MyD88 affects myeloid as well as lymphoid hematopoiesis. Since Btk and MyD88 deficiencies influence differentially myeloid and lymphoid development, both molecules seem to act in different signaling pathways important for appropriate developmental events during myelo- and lymphopoiesis.
PMCID: PMC3649812  PMID: 23675564
MyD88; Btk; hematopoiesis; myelopoiesis; lymphopoiesis
33.  Treatment of older patients with acute myeloid leukemia (AML): a Canadian consensus 
Patients over age 60 comprise the majority of those diagnosed with acute myeloid leukemia (AML), but treatment approaches in this population are variable, with many uncertainties and controversies. Our group conducted a literature review to summarize the latest information and to develop a consensus document with practical treatment recommendations. We addressed five key questions: selection criteria for patients to receive intensive induction chemotherapy; optimal induction and post-remission regimens; allogeneic hematopoietic stem cell transplantation (HSCT); treatment of patients not suitable for induction chemotherapy; and treatment of patients with prior hematological disorders or therapy-related AML. Relevant literature was identified through a PubMed search of publications from 1991 to 2012. Key findings included the recognition that cytogenetics and molecular markers are major biologic determinants of treatment outcomes in the older population, both during induction therapy and following HSCT. Although disease-specific and patient-specific risk factors for poor outcomes are more common in the older population, age is not in itself sufficient grounds for withholding established treatments, including induction and consolidation chemotherapy. The role of HSCT and use of hypomethylating agents are discussed. Finally, suggested treatment algorithms are outlined, based on these recommendations.
PMCID: PMC3649813  PMID: 23675565
Acute myeloid leukemia; chemotherapy; cytogenetics; prognosis; hematopoietic stem cell transplantation; hypomethylating agent
34.  Absence of BRAF exon 15 mutations in multiple myeloma and Waldenström’s macroglobulinemia questions its validity as a therapeutic target in plasma cell neoplasias 
Purpose: Recent whole genome and/or exome sequencing in a cohort of 32 Multiple Myeloma (MΜ) patients reported the incidence of BRAF mutations at 4%, while in another exome sequencing study, BRAF mutations were reported in up to 13% of cases tested. We ran a confirmatory study by using High Resolution Melting Analysis (HRMA), which is a low-cost, straightforward and sensitive screening test for detection of BRAF exon 15 mutations in MM and Waldenström’s macroglobulinemia (WM) patients, in order to investigate their incidence in every day clinical practice. We considered this investigation to be of clinical relevance following the recent emergence of potent anti-BRAF compounds. Patients and Methods: We used genomic DNA isolated from 31 bone marrow aspirates obtained from 25 MM patients and 3 patients with WM (14 female; 14 male) who signed an informed consent. Patients’ median age was 69 years (range 43-86) and median follow-up time was 45 months. Myeloma subtypes were as follows: 7 IgGκ, 6 IgGλ, 7 IgAλ, 4 IgAλ and 1 non-secretory. The bone marrow plasma cells ranged from 12 to 100% (mean/median value 45%). By International Staging System (ISS) 9/25 patients were stage Ι, 6/25 stage ΙΙ, 7/25 stage ΙΙΙ, while in 3 cases staging information was missing. In 3 MM cases matched paired samples at diagnosis and at relapse were also available. DNA samples were screened using HRMA. HRMA results were confirmed by subsequent ds-bi-directional sequencing (Sanger method) for somatic mutations in exon 15 of BRAF. Results: At a limit of detection ≥2.5% mutant allelic content by HRMA, we did not detect any BRAF mutations in exon 15 in any of our 31 samples. Conclusions: By using HRMA we do not confirm previously reported results. Lack of detection of BRAF exon 15 mutations in our MM and WM series may be related to different sensitivity of the assays used and/or the relatively small sample size. In any case, we consider that existing data should be taken into account when considering the clinical development of BRAF inhibitors in plasma cell neoplasms.
PMCID: PMC3649814  PMID: 23675568
Multiple myeloma; BRAF; mutation; WaldenstrÖm’s macroglobulinemia; high resolution melting analysis
35.  Understanding basic steps to hematopoietic stem cell transplantation evaluation 
We are celebrating one millionth transplant in year 2013! With continued improvement in hematopoietic cell transplantation (HCT) outcome, the indications for HCT continue to grow. Furthermore the sources of stem cells and the number of suitable matches are expanding. At the same time, modified transplantation regimens have facilitated safer procedures despite increase in patient’s age and comorbidies. In the current era, any patient indicated for HCT has a stem cell source and therefore steps to HCT and coordinated pre-transplant care is an integral part of management to improve transplant outcome. This review discusses our approach to the transplant evaluation process and this article will serve as a valuable tool for primary care physicians and referring hematologists/oncologists.
PMCID: PMC3649815  PMID: 23675562
Transplantation; hematological malignancies; preparation; evaluation
36.  Refinement of IKZF1 recombination hotspots in pediatric BCP-ALL patients 
Chromosomal translocations resulting in chimeric fusion genes are prototypic for pediatric leukemia patients. The most known fusions are ETV6-RUNX1 or BCR-ABL1 in B-cell progenitor (BCP)-ALL, and rearrangements of MLL in pediatric ALL and AML. Genome-wide sequencing projects have revealed additional, recurrent gene mutations in B cell malignancies. One of these mutations comprises the IKZF1 gene, encoding the IKAROS transcription factor which is one of the essential transcription factors driving lymphoid development. IKZF1 deletions were first identified by SNP arrays in ALL patients, and later identified with a high prevalence in BCR-ABL1+ patients. IKZF1 deletions turned out to be an independent prognostic marker associated with a poor outcome. Here, we characterized IKZF1 deletions in pediatric BCP-ALL patients by combining MLPA mapping experiments with long distance inverse PCR. The aim of our study was also to compare existing methods with our approach. Our attempt confirmed many of the existing data but revealed a more complex pattern of recombination sites, including a total of 4 recombination hotspots. This extended knowledge was translated into a novel, multiplex PCR assay that allows to perform IKZF1 deletion analyses by using a 2-tube PCR approach.
PMCID: PMC3649816  PMID: 23675566
Childhood leukemia; cancer genetics; gene deletion; IKAROS; IKZF1; leukemia markers
37.  Regulation of innate immunity by extracellular nucleotides 
Extracellular ATP (eATP) is the most abundant among extracellular nucleotides and is commonly considered as a classical danger signal, which stimulates immune responses in the presence of tissue injury. In fact, increased nucleotide concentration in the extracellular space is generally closely associated with tissue stress or damage. However non-lytic nucleotide release may also occur in many cell types under a variety of conditions. Extracellular nucleotides are sensed by a class of plasma membrane receptors called P2 purinergic receptors (P2Rs). P2 receptors are expressed by all immunological cells and their activation elicits different responses. Extracellular ATP can act as an initiator or terminator of immune responses being able to induce different effects on immune cells depending on the pattern of P2 receptors engaged, the duration of the stimulus and its concentration in the extracellular milieu. Millimolar (high) concentrations of extracellular ATP, induce predominantly proinflammatory effects, while micromolar (low) doses exert mainly tolerogenic/immunosuppressive action. Moreover small, but significant differences in the pattern of P2 receptor expression in mice and humans confer diverse capacities of ATP in regulating the immune response.
PMCID: PMC3555188  PMID: 23358447
Extracellular nucleotides; P2 purinergic receptors; extracellular ATP; innate immunity
38.  Regulatory T-cells in chronic lymphocytic leukemia: actor or innocent bystander? 
Regulatory T (Treg) cells are now under extensive investigation in chronic lymphocytic leukemia (CLL). This small subset of T-cells has been, in fact, considered to be involved in the pathogenesis and progression of CLL. However, whether Treg dysregulation in CLL plays a key role or it rather represents a simple epiphenomenon is still matter of debate. In the former case, Treg cells could be appealing for targeting therapies. Finally, Treg cells have also been proposed as a prognostic indicator of the disease clinical course.
PMCID: PMC3555189  PMID: 23358515
Tregs; chronic lymphocytic leukemia; prognosis
39.  Gene mutations and molecularly targeted therapies in acute myeloid leukemia 
Acute myelogenous leukemia (AML) can progress quickly and without treatment can become fatal in a short period of time. However, over the last 30 years fine-tuning of therapeutics have increased the rates of remission and cure. Cytogenetics and mutational gene profiling, combined with the option of allogeneic hematopoietic stem cell transplantation offered in selected patients have further optimized AML treatment on a risk stratification basis in younger adults. However there is still an unmet medical need for effective therapies in AML since disease relapses in almost half of adult patients becoming refractory to salvage therapy. Improvements in the understanding of molecular biology of cancer and identification of recurrent mutations in AML provide opportunities to develop targeted therapies and improve the clinical outcome. In the spectrum of identified gene mutations, primarily targetable lesions are gain of function mutations of tyrosine kinases FLT3, JAK2 and cKIT for which specific, dual and multi-targeted small molecule inhibitors have been developed. A number of targeted compounds such as sorafenib, quizartinib, lestaurtinib, midostaurin, pacritinib, PLX3397 and CCT137690 are in clinical development. For loss-of-function gene mutations, which are mostly biomarkers of favorable prognosis, combined therapeutic approaches can maximize the therapeutic efficacy of conventional therapy. Apart from mutated gene products, proteins aberrantly overexpressed in AML appear to be clinically significant therapeutic targets. Such a molecule for which targeted inhibitors are currently in clinical development is PLK1. We review characteristic gene mutations, discuss their biological functions and clinical significance and present small molecule compounds in clinical development, which are expected to have a role in treating AML subtypes with characteristic molecular alterations.
PMCID: PMC3555190  PMID: 23358589
Acute myeloid leukemia; targeted therapy; mutation; FLT3; NPM1; CEBPA; JAK2
40.  Repeated treatment with high dose cyclophosphamide for severe autoimmune diseases 
High dose cyclophosphamide (HiCY) without stem cell rescue has been shown to induce remissions in patients with severe autoimmune disorders (SADS). However, up to 80% of these patients ultimately relapse. Here we review the outcomes of seven patients treated with two cycles and one patient treated with three cycles of HiCY. The diseases re-treated were scleroderma, multiple sclerosis, three patients with severe aplastic anemia (SAA), and three patients with myasthenia gravis (MG). All but two patients with SAA had received standard immunomodulatory therapy for their disease up front and had been refractory. All patients had complete hematologic recovery. Overall survival in this cohort was 100%. All patients relapsed after the initial cycle but event free survival thereafter was 93.3%. All are still in remission except two MG patients, one of whom relapsed after a severe GI infection requiring hospitalization, and the other relapsed 3 years after the second treatment and she did not respond to the third treatment. This shows that HiCY can be safely re-administered in patients with SAA and refractory SADS. The quality and duration of second remissions appears to be equal or superior to the first remission.
PMCID: PMC3555191  PMID: 23358715
Autoimmunity; cyclophosphamide; severe autoimmune diseases
41.  Suppression of STAT5A and STAT5B chronic myeloid leukemia cells via siRNA and antisense-oligonucleotide applications with the induction of apoptosis 
Signal transducers and activators of transcription (STAT) proteins function in the JAK/STAT signaling pathway and are activated by phosphorylation. As a result of this signaling event, they affect many cellular processes including cell growth, proliferation, differentiation, and survival. Increases in the expressions of STAT5A and STAT5B play a remarkable role in the development of leukemia in which leukemic cells gain uncontrolled proliferation and angiogenesis ability. At the same time, these cells acquire ability to escape from apoptosis and host immune system. In this study, we aimed to suppress STAT-5A and -5B genes in K562 CML cells by siRNA transfection and antisense oligonucleotides (ODN) targeting and then to evaluate apoptosis rate. Finally, we compared the transfection efficiencies of these approaches. Quantitative RT-PCR and Western blot results indicated that STAT expressions were downregulated at both mRNA and protein levels following siRNA transfection. However, electroporation mediated ODN transfection could only provide limited suppression rates at mRNA and protein levels. Moreover, it was displayed that apoptosis were significantly induced in siRNA treated leukemic cells as compared to ODN treated cells. As a conclusion, siRNA applications were found to be more effective in terms of gene silencing when compared to ODN treatment based on the higher apoptosis and mRNA suppression rates. siRNA application could be a new and alternative curative method as a supporting therapy in CML patients.
PMCID: PMC3555192  PMID: 23358828
Chronic myeloid leukemia; K562; STAT5; siRNA knockdown; antisense oligonucleotides; apoptosis
42.  Function of Ikaros as a tumor suppressor in B cell acute lymphoblastic leukemia 
The Ikaros transcription factor is crucial for many aspects of hematopoiesis. Loss of function mutations in IKZF1, the gene encoding Ikaros, have been implicated in adult and pediatric B cell acute lymphoblastic leukemia (B-ALL). These mutations result in haploinsufficiency of the Ikaros gene in approximately half of the cases. The remaining cases contain more severe or compound mutations that lead to the generation of dominant-negative proteins or complete loss of function. All IKZF1 mutations are associated with a poor prognosis. Here we review the current genetic, clinical and mechanistic evidence for the role of Ikaros as a tumor suppressor in B-ALL.
PMCID: PMC3555193  PMID: 23358883
B cell leukemia; Ikaros; tumor suppressor
43.  Bruton’s tyrosine kinase mediated signaling enhances leukemogenesis in a mouse model for chronic lymphocytic leukemia 
In chronic lymphocytic leukemia (CLL) signals from the B cell receptor (BCR) play a major role in disease development and progression. In this light, new therapies that specifically target signaling molecules downstream of the BCR continue to be developed. While first studies on the selective small molecule inhibitor of Bruton’s tyrosine kinase (Btk), Ibrutinib (PCI-32765), demonstrated that Btk inhibition sensitizes CLL cells to apoptosis and alters their migratory behavior, these studies however did not address whether Btk-mediated signaling is involved in the process of CLL leukemogenesis. To investigate the requirement of Btk signaling for CLL development, we modulated Btk expression in the IgH.ETμ CLL mouse model, which is based on sporadic expression of the simian oncovirus SV40 T-antigen in mature B cells. To this end, we crossed IgH.ETμ mice on a Btk-deficient background or introduced a human Btk transgene (CD19-hBtk). Here we show that Btk deficiency fully abrogates CLL formation in IgH.ETμ mice, and that leukemias formed in Btk haplo-insufficient mice selectively expressed the wild-type Btk allele on their active X chromosome. Conversely, Btk overexpression accelerated CLL onset, increased mortality, and was associated with selection of non-stereotypical BCRs into CLL clones. Taken together, these data show that Btk expression represents an absolute prerequisite for CLL development and that Btk mediated signaling enhances leukemogenesis in mice. We therefore conclude that in CLL Btk expression levels set the threshold for malignant transformation.
PMCID: PMC3555194  PMID: 23359016
Chronic lymphocytic leukemia (CLL); bruton’s tyrosine kinase (Btk); B cell receptor signaling
44.  Kinetics of iron removal by phlebotomy in patients with iron overload after allogeneic hematopoietic cell transplantation 
Excess body iron could persist for years after allogeneic hematopoietic cell transplantation (HCT) with possible deleterious sequels. An iron depletive therapy with phlebotomy seems rational. Kinetics of iron removal by phlebotomy without erythropoietin support in non-thalassemic adult patients with iron overload after HCT and the impact of pre- and post-HCT hemochromatosis (HFE) genotype on iron mobilization were investigated. Patients and methods: Phlebotomy was initiated in 61 recipients of allografts due to hematologic malignancies (median age 48 years) after a median of 18 months. The prephlebotomy median serum ferritin (SF) was 1697ng/ml and the median number of blood transfusions 28 units. Alanine aminotransferase (ALT)/aspartate aminotransferase (AST), alkaline phosphates (AP), and bilirubin were elevated in 55.7%, 64% and 11.5% patients respectively. HFE-genotype was elucidated by polymerase chain reaction using hybridization probes and melting curve analysis. Results: Phlebotomy was well-tolerated irrespective of age or conditioning. A negative iron balance in 80% of patients (median SF 1086 ng/ml) and a rise in hemoglobin were observed (p<0.0001). Higher transfusional burden and SF were associated with a greater iron mobilization per session (p=0.02). In 58% of patients, a plateau after an initial steady decline in SF was followed by a second decline under further phlebotomy. The improvement in ALT (p=0.002), AST (p=0.03), AP (p=0.01), and bilirubin (p<0.0001) did not correlate with the decline in SF. Mutant HFE-gene variants were detected in 14/55 (25%) pre-HCT and 22/55 (40%) patients post-HCT. Overall, dissimilar pre- and posttransplantational HFE-genotypes were detected in 20/55 (40%) patients. Posttransplantational mutant HFE variants correlated with a slower decline in SF (p=0.007). Conclusions: Phlebotomy is a convenient therapy of iron overload in survivors of HCT. A negative iron balance and a rise in hemoglobin were observed in the majority of patients. Liver dysfunction improved irrespective of SF reduction suggesting a probable rapid decline of the deleterious labile plasma iron. In recipients of grafts with mutant HFE variants a “mixed chimerism” of HFE in body tissues might be created with a change in the set point for iron regulation. The transient plateau in SF after an initial decline might reflect iron mobilization from various tissues.
PMCID: PMC3512175  PMID: 23226624
Iron overload; ferritin; phlebotomy; allogeneic HCT
45.  Management of respiratory viral infections in hematopoietic cell transplant recipients 
Advances in stem cell transplantation procedures and the overall improvement in the clinical management of hematopoietic cell transplant (HCT) recipients over the past 2 decades have led to an increase in survival duration, in part owing to better strategies for prevention and treatment of post-transplant complications, including opportunistic infections. However, post-HCT infections remain a concern for HCT recipients, particularly infections caused by community respiratory viruses (CRVs), which can lead to significant morbidity and mortality. These viruses can potentially cause lower respiratory tract illness, which is associated with a higher mortality rate among HCT recipients. Clinical management of CRV infections in HCT recipients includes supportive care and antiviral therapy, especially in high-risk individuals, when available. Directed antiviral therapy is only available for influenza infections, where successful use of neuraminidase inhibitors (oseltamivir or zanamivir) and/or M2 inhibitors (amantadine or rimantadine) has been reported. Data on the successful use of ribavirin, with or without immunomodulators, for respiratory syncytial virus infections in HCT recipients has emerged over the past 2 decades but is still controversial at best because of a lack of randomized controlled trials. Because of the lack of directed antiviral therapy for most of these viruses, prevention should be emphasized for healthcare workers, patients, family, and friends and should include the promotion of the licensed inactivated influenza vaccine for HCT recipients, when indicated. In this review, we discuss the clinical management of respiratory viruses in this special patient population, focusing on commercially available antivirals, adjuvant therapy, and novel drugs under investigation, as well as on available means for prevention.
PMCID: PMC3512176  PMID: 23226621
RSV; influenza; parainfluenza; adenovirus; rhinovirus; metapneumovirus; HCT; transplant; cancer; immunocompromised host; antiviral therapy; infection prevention
46.  Growth factor independence 1 (Gfi1) regulates cell-fate decision of a bipotential granulocytic-monocytic precursor defined by expression of Gfi1 and CD48 
The transcriptional repressor Gfi1 regulates the expression of genes important for survival, proliferation and differentiation of hematopoietic cells. Gfi1 deficient mice are severely neutropenic and accumulate ill-defined CD11b+GR1int myeloid cells. Here we show that Gfi1 expression levels determine mono- or granulocytic lineage choice in precursor cells. In addition, we identify CD48 as a cell surface marker which enables a better definition of monocytes and granulocytes in mouse bone marrow. Using the CD48/Gr1/Gfi1 marker combination we can show that the CD11b+GR1int cells accumulating in Gfi1 deficient mice are monocytes and not granulocyte precursors. Expression of CD48, Gr1 and Gfi1 define different bone marrow subpopulations that are either committed to the granulocytic lineage, or bipotential precursors of granulocytes or monocytes. Finally, a comparison of genes differentially expressed between murine Gfi1 high granulocytic precursors and mature granulocytes with gene expression changes from human myeloblasts versus neutrophils show a strong resemblance of human and mouse differentiation pathways. This underlines the value of the markers CD48 and Gfi1 identified here to study human and murine granulo-monocytic differentiation.
PMCID: PMC3512177  PMID: 23226623
Gfi1; CD48; CD106; granulocyte; monocyte; myelopoiesis; neutropenia
47.  Acute myeloid leukemia with t(10;17)(p13;q12) chromosome translocation: a case report and literature review 
More than 50% of adult patients with acute myeloid leukemia (AML) carry chromosome abnormalities, like t(8;21)(q22;q22), t(15;17), t(8;21)inv(16) or t(16;16). t(10;17) translocation was very rare in AML. There are only 10 such cases reported in the literature. Here, we describe a case of acute myeloid leukemia with t(10;17)(p13;q12) chromosome translocation, who had complete remission after one course of chemotherapy.
PMCID: PMC3512178  PMID: 23226626
Acute myeloid leukemia; t(10;17)(p13;q12); chromosome translocation
48.  Prognostic significance of IDH1 mutations in acute myeloid leukemia: a meta-analysis 
Isocitrate dehydrogenase 1 (IDH1) gene aberrations have recently been reported in acute myeloid leukemia (AML). To evaluate the prognostic significance of IDH1 mutations in AML, we performed a meta-analysis. Fifteen studies covering a total of 8121 subjects were included in this analysis. The frequency of IDH1 R132 mutations were 4.4–9.3% for AML patients and 10.9–16.0% for cytogenetically normal (CN)-AML patients. The IDH1 mutations were associated with NPM1 mutations in 6 studies and normal cytogenetics in 5 studies. AML patients with IDH1 mutations had inferior overall survival compared to patients without the mutations (hazard ratio 1.17, 95% CI: 1.02–1.36). Additionally, in CN-AML patients, IDH1 mutations were associated with a lower complete remission rate (risk ratio 1.30, 95% CI: 1.04–1.63). Although the available literature is limited to observational studies, these results may justify the risk-adapted therapeutic strategies for AML according to the IDH1 status.
PMCID: PMC3512179  PMID: 23226625
Acute myeloid leukemia; IDH1; mutation; prognosis; meta-analysis
49.  Hematopoietic stem cells: interplay with immunity 
Ample evidence indicated that hematopoietic stem cells (HSCs) receive signaling from infection or other immune responses to adjust their differentiation and self-renewal. More recent reports also suggested that, while the bone marrow microenvironment or niche may provide the immune privilege for HSCs, HSCs can present surface immune inhibitors per se to suppress innate immunity and adaptive immunity to evade potential immune surveillance and attack. These findings support the hypothesis that HSCs are capable of interacting with the immune system as signal “receivers” and signal “providers”. On the one hand, HSCs are capable of directly sensing the signals from the immune system through their surface receptors to modulate their self-renewal and differentiation (“in” signaling); on the other hand, HSCs display surface immune inhibitory molecules to evade the attack from the innate and adaptive immune systems (“out” signaling). The continuing investigation of the interplay between HSCs and immunity may lead to the open-up of a new research filed – the immunology of stem cells.
PMCID: PMC3512180  PMID: 23226622
Hematopoietic stem cells; immunity; immune privilege; CD47; CD274; LILRB2; PIR-B; immune inhibitory receptors; infection; inflammation
50.  Unbalanced replication as a major source of genetic instability in cancer cells 
The origin of genetic instability in tumors is a matter of debate: while the prevailing model postulates a mutator phenotype resulting from an alteration in a caretaker gene as a prerequisite for genetic alterations leading to tumor formation, there is evidence against this model in the majority of cancers. A model for chromosomal instability should take into account the role of oncogenes in directly stimulating DNA and cellular component replication, creating aberrant structures when overexpressed. I will distinguish here two distinct mechanisms for the genetic instability of tumors: primary and secondary. Primary genetic instability is dependent on the inactivation of genes involved in maintaining genetic stability (caretaker genes), whereas secondary genetic instability is dependent on genes involved in tumor progression, i.e. oncogenes and tumor suppressor genes of the gatekeeper type. Secondary genetic instability, the most frequent condition, can be explained by the fact that some of the genes involved in tumor progression control replication of cell structures from within, leading to replication unbalance.
PMCID: PMC3484411  PMID: 23119227
Genetic instability; tumorigenesis; oncogenes; tumor suppressor genes; DNA replication; cell replication; replication unbalance; chromosomal instability

Results 26-50 (103)