Showing papers in "British Journal of Haematology in 2005"

Immunomodulatory effect of human adipose tissue-derived adult stem cells: comparison with bone marrow mesenchymal stem cells.

Abstract: Like mesenchymal stem cells from bone marrow (BM-MSCs), adipose tissue-derived adult stem cells (ADAS cells) can differentiate into several lineages and present therapeutical potential for repairing damaged tissues. The use of allogenic stem cells can enlarge their therapeutical interest, provided that the grafted cells could be tolerated. We investigate here, for the first time, the immunosuppressive properties of ADAS cells compared with the well-characterized immunosuppressive properties of BM-MSCs. ADAS cells did not provoke in vitro alloreactivity of incompatible lymphocytes and, moreover, suppressed mixed lymphocyte reaction (MLR) and lymphocyte proliferative response to mitogens. The impairment of inhibition when ADAS cells and BM-MSCs were separated from lymphocytes by a permeable membrane suggests that cell contact is required for a full inhibitory effect. Hepatocyte growth factor is secreted by both stem cells but, similar to interleukin-10 and transforming growth factor-beta (TGF-beta), the levels of which were undetectable in supernatants of MLR inhibited by ADAS cells or BM-MSCs, it did not seem implicated in the stem cell suppressive effect. These findings support that ADAS cells share immunosuppressive properties with BM-MSCs. Therefore, ADAS cell-based reconstructive therapy could employ allogenic cells and because of their immunosuppressive properties, ADAS cells could be an alternative source to BM-MSCs to treat allogenic conflicts.

The interactions between inflammation and coagulation

Abstract: Inflammation initiates clotting, decreases the activity of natural anticoagulant mechanisms and impairs the fibrinolytic system. Inflammatory cytokines are the major mediators involved in coagulation activation. The natural anticoagulants function to dampen elevation of cytokine levels. Furthermore, components of the natural anticoagulant cascades, like thrombomodulin, minimise endothelial cell dysfunction by rendering the cells less responsive to inflammatory mediators, facilitate the neutralisation of some inflammatory mediators and decrease loss of endothelial barrier function. Hence, downregulation of anticoagulant pathways not only promotes thrombosis but also amplifies the inflammatory process. When the inflammation-coagulation interactions overwhelm the natural defence systems, catastrophic events occur, such as manifested in severe sepsis or inflammatory bowel disease.

Molecular mechanisms of fibrinolysis.

Abstract: The molecular mechanisms that finely co-ordinate fibrin formation and fibrinolysis are now well defined. The structure and function of all major fibrinolytic proteins, which include serine proteases, their inhibitors, activators and receptors, have been characterized. Measurements of real time, dynamic molecular interactions during fibrinolysis of whole blood clots can now be carried out in vitro. The development of gene-targeted mice deficient in one or more fibrinolytic protein(s) has demonstrated expected and unexpected roles for these proteins in both intravascular and extravascular settings. In addition, genetic analysis of human deficiency syndromes has revealed specific mutations that result in human disorders that are reflective of either fibrinolytic deficiency or excess. Elucidation of the fine control of fibrinolysis under different physiological and pathological haemostatic states will undoubtedly lead to novel therapeutic interventions. Here, we review the fundamental features of intravascular plasmin generation, and consider the major clinical syndromes resulting from abnormalities in fibrinolysis.

FRETS-VWF73, a first fluorogenic substrate for ADAMTS13 assay.

Abstract: A plasma metalloprotease, ADAMTS13, cleaves von Willebrand factor (VWF) multimers and downregulates their activity in platelet aggregation. Functional ADAMTS13 deficiency leads to the accumulation of hyperactive large VWF multimers, inducing a life-threatening disease, thrombotic thrombocytopenic purpura (TTP). Although measuring ADAMTS13 activity is important in TTP diagnosis, existing methods require time and skill. Here, we report a fluorescence resonance energy transfer (FRET) assay for ADAMTS13 activity. We developed a synthetic 73-amino-acid peptide, FRETS-VWF73. Cleavage of this substrate between two modified residues relieves the fluorescence quenching in the intact peptide. Incubation of FRETS-VWF73 with normal human plasma quantitatively increased fluorescence over time, while ADAMTS13-deficient plasma had no effect. Quantitative analysis could be achieved within a 1-h period using a 96-well format in commercial plate readers with common filters. The FRETS-VWF73 assay will be useful for the characterization of thrombotic microangiopathies like TTP and may clarify the importance of ADAMTS13 activity as a predictive marker for various thrombotic diseases.

Thrombosis and haemorrhage in polycythaemia vera and essential thrombocythaemia

Abstract: Despite decades of clinical and laboratory research, relatively little has been accomplished concerning the pathogenesis as well as the identification of risk factors for thrombosis and bleeding in myeloproliferative disorders. In polycythaemia vera, the pro-thrombotic effect of an elevated haematocrit is well established. In contrast, thrombocytosis per se has not been similarly incriminated in essential thrombocythaemia. In both conditions, advanced age and the presence of a prior event identify thrombosis-prone patients. There is increasing evidence to suggest an additional role by leucocytes that might partly explain the antithrombotic effects of myelosuppressive therapy. A substantial minority of affected patients display reduced levels of high molecular weight von Willebrand protein in the plasma during extreme thrombocytosis and it is believed that this might explain the bleeding diathesis of such patients. Recent controlled studies support the therapeutic value of hydroxyurea and aspirin in essential thrombocythaemia and polycythaemia vera, respectively. The current communication will address the incidence, phenotype, pathogenesis, risk factors, prevention, and treatment of both thrombosis and haemorrhage in these disorders.

Protecting against anthracycline-induced myocardial damage: a review of the most promising strategies.

Abstract: Over the last 40 years, great progress has been made in treating childhood and adult cancers. However, this progress has come at an unforeseen cost, in the form of emerging long-term effects of anthracycline treatment. A major complication of anthracycline therapy is its adverse cardiovascular effects. If these cardiac complications could be reduced or prevented, higher doses of anthracyclines could potentially be used, thereby further increasing cancer cure rates. Moreover, as the incidence of cardiac toxicity resulting in congestive heart failure or even heart transplantation dropped, the quality and extent of life for cancer survivors would improve. We review the proposed mechanisms of action of anthracyclines and the consequences associated with anthracycline treatment in children and adults. We summarise the most promising current strategies to limit or prevent anthracycline-induced cardiotoxicity, as well as possible strategies to prevent existing cardiomyopathy from worsening.

Bortezomib therapy alone and in combination with dexamethasone for previously untreated symptomatic multiple myeloma.

Abstract: Bortezomib, as a single agent and in combination with dexamethasone, was examined as first-line treatment in 32 consecutive patients with untreated symptomatic multiple myeloma. Patients received bortezomib 1.3 mg/m(2) for a maximum of six 3-week cycles; oral dexamethasone 40 mg was added if a less than partial response (PR) was achieved after two cycles or a less than complete response (CR) was achieved after four cycles. The response rate (CR + PR) was 88%, with undetectable paraprotein (CR) in 6%, and detectable by immunofixation only in 19% [near (n)CR]. All 32 patients completed the first two cycles of bortezomib alone, of whom 3% achieved CR, 9% nCR, and 28% PR. Ten patients received single-agent bortezomib on study, and dexamethasone was added in 22, leading to 15 improved responses. The most common adverse events >/=grade 2 included sensory neuropathy (31%), constipation (28%), myalgia (28%) and fatigue (25%). Sensory neuropathy grade 2 or 3 was reversible within a median of 3 months in five of 10 patients. Bortezomib treatment did not affect stem cell mobilization in eight or transplantation in six patients. Bortezomib alone or in combination with dexamethasone is an effective induction therapy with a high CR and nCR rate and manageable toxicities in previously untreated patients with myeloma.

Diagnostic criteria for monoclonal B-cell lymphocytosis.

Abstract: Summary Very low levels of circulating monoclonal B-cell subpopulations can now be detected in apparently healthy individuals using flow cytometry. We propose the term ‘monoclonal B-cell lymphocytosis’ (MBL) to describe this finding. The aim of this document is to provide a working definition of MBL for future clinical, epidemiological and laboratory studies. We propose that the detection of a monoclonal B-cell population by light chain restriction is sufficient to define this condition in individuals not meeting the diagnostic criteria for other B-lymphoproliferative disorders. The majority of individuals with MBL will have cells that are indistinguishable from chronic lymphocytic leukaemia (CLL). However, this blood cell clonal expansion of CD5 + or CD5 ) B-lymphocytes is agedependent and immunophenotypic heterogeneity is common. Longitudinal studies are required to determine whether MBL is a precursor state to CLL or other B-lymphoproliferative disease in a situation analogous to a monoclonal gammopathy of undetermined significance and myeloma. Future studies of MBL should be directed towards determining its relationship to clinical disease, particularly in individuals from families with a genetic predisposition to developing CLL.

Bone involvement in sickle cell disease.

Abstract: Summary Bone involvement is the commonest clinical manifestation of sickle cell disease both in the acute setting such as painful vaso-occlusive crises, and as a source of chronic, progressive disability such as avascular necrosis. Management of these problems is often difficult because of the diagnostic imprecision of most laboratory and imaging investigations and because of the lack of evidence for most surgical procedures in sickle cell disease. This review first discusses the acute problems related to bone involvement in sickle cell disease, with particular reference to differentiating infection from infarction, and then describes the long-term effects of sickle cell disease on bone mineral density, growth, and chronic bone and joint damage.

The immune response to fungal infections

Abstract: During the past two decades, invasive fungal infections have emerged as a major threat to immunocompromised hosts. Patients with neoplastic diseases are at significant risk for such infections as a result of their underlying illness and its therapy. Aspergillus, Candida, Cryptococcus and emerging pathogens, such as the zygomycetes, dark walled fungi, Trichosporon and Fusarium, are largely opportunists, causing infection when host defences are breached. The immune response varies with respect to the fungal species and morphotype encountered. The risk for particular infections differs, depending upon which aspect of immunity is impaired. This article reviews the current understanding of the role and relative importance of innate and adaptive immunity to common and emerging fungal pathogens. An understanding of the host response to these organisms is important in decisions regarding use of currently available antifungal therapies and in the design of new therapeutic modalities.

The aetiology and management of Castleman disease at 50 years: translating pathophysiology to patient care.

Abstract: Summary Fifty years ago, Dr Benjamin Castleman first described the unusual lymphoproliferative disorder that now bears his name. Over the subsequent decades, astute clinical and pathologic observations coupled with clever molecular biologic research have increased our understanding of the aetiology of Castleman disease (CD). This article proposes three broad CD variants based on both distinctive histopathology and clinical behaviour. The pivotal roles of infection with human herpesvirus 8 and interleukin-6 production in the development of CD are emphasized. Finally, the natural history of CD and the myriad of therapeutic options are reviewed in the context of a unified model of CD pathophysiology, and continued areas of uncertainty are discussed.

PAD combination therapy (PS-341/bortezomib, doxorubicin and dexamethasone) for previously untreated patients with multiple myeloma

Abstract: Bortezomib (formerly PS-341) has significant activity in patients with relapsed multiple myeloma (MM), its efficacy is increased with the addition of dexamethasone and it demonstrates synergy with doxorubicin, thus providing the rationale for combination therapy with bortezomib, doxorubicin and dexamethasone (PAD). Patients with untreated MM received four 21-d cycles of PAD, comprising bortezomib 1.3 mg/m(2) on days 1, 4, 8 and 11, along with dexamethasone 40 mg on days 1-4, 8-11 and 15-18 during cycle 1 and days 1-4 during cycles 2-4. During days 1-4, patients also received 0, 4.5 or 9 mg/m(2) of doxorubicin at dose levels 1, 2, and 3 respectively. Following peripheral blood stem cell (PBSC) collection, patients received high-dose melphalan (MEL200) with PBSC transplantation (PBSCT). After PAD induction alone, 20 of 21 patients (95%) achieved at least a partial response (PR), including complete response (CR) in five patients (24%). Twenty of 21 had PBSC mobilized, and 18 of 20 received MEL200/PBSCT. In an intention-to-treat analysis, response rates were: CR 43%, near CR 14%, very good PR 24%, PR 14% and stable disease 5%. PAD was effective, did not prejudice subsequent PBSC collection, and should be further evaluated in prospective randomized trials.

Predicting clinical severity in sickle cell anaemia.

Abstract: The ability to predict the phenotype of an individual with sickle cell anaemia would allow a reliable prognosis and could guide therapeutic decision making. Some risk factors for individual disease complications are known but are insufficiently precise to use for prognostic purposes; predicting the global disease severity is not yet possible. Genetic association studies, which attempt to link gene polymorphisms with selected disease subphenotypes, may eventually provide useful methods of foretelling the likelihood of certain complications and allow better individualized treatment.

Benefit of dexamethasone compared with prednisolone for childhood acute lymphoblastic leukaemia: results of the UK Medical Research Council ALL97 randomized trial.

Abstract: Summary Corticosteroids are an essential component of treatment for acute lymphoblastic leukaemia (ALL). Prednisolone is the most commonly used steroid, particularly in the maintenance phase of therapy. There is increasing evidence that, even in equipotent dosage for glucocorticoid effect, dexamethasone has enhanced lymphoblast cytotoxicity and penetration of the central nervous system (CNS) compared with prednisolone. Substitution of dexamethasone for prednisolone in the treatment of ALL might, therefore, result in improved event-free and overall survival. Children with newly diagnosed ALL were randomly assigned to receive either dexamethasone or prednisolone in the induction, consolidation (all received dexamethasone in intensification) and continuation phases of treatment. Among 1603 eligible randomized patients, those receiving dexamethasone had half the risk of isolated CNS relapse (P = 0·0007). Event-free survival was significantly improved with dexamethasone (84·2% vs. 75·6% at 5 years; P = 0·01), with no evidence of differing effects in any subgroup of patients. The use of 6·5 mg/m2 dexamethasone throughout treatment for ALL led to a significant decrease in the risk of relapse for all risk-groups of patients and, despite the increased toxicity, should now be regarded as part of standard therapy for childhood ALL.

Molecular mechanisms whereby immunomodulatory drugs activate natural killer cells: clinical application.

Abstract: Thalidomide and immunomodulatory drugs (IMiDs), which target multiple myeloma (MM) cells and the bone marrow microenvironment, can overcome drug resistance. These agents also have immunomodulatory effects. Specifically, we have reported that thalidomide increased serum interleukin-2 (IL-2) levels and natural killer (NK) cell numbers in the peripheral blood of responding MM patients. In this study, we investigated the mechanisms whereby IMiDs augment NK cell cytotoxicity. NK cytotoxicity and antibody-dependent cell-mediated cytotoxicity (ADCC) of peripheral blood mononuclear cells cultured with IMiDs were examined in the presence or absence of anti-IL-2 antibody, ciclosporin A or depletion of CD56-positive cells. IMiDs-induced signalling pathways, triggering IL-2 transcription in T cells, were also delineated. IMiDs facilitated the nuclear translocation of nuclear factor of activated T cells-2 and activator protein-1 via activation of phosphoinositide-3 kinase signalling, with resultant IL-2 secretion. IMiDs enhanced both NK cell cytotoxicity and ADCC induced by triggering IL-2 production from T cells. These studies defined the mechanisms whereby IMiDs trigger NK cell-mediated tumour-cell lysis, further supporting their therapeutic use in MM.

Guidelines for the diagnosis, investigation and management of polycythaemia/erythrocytosis

Abstract: Traditionally, polycythaemia has been used to identify a group of varied disorders with an increase in circulating red cells that are typified by a persistently raised haematocrit (Hct). Since only the red cell lineage is involved, the term erythrocytosis has more validity and will be used throughout this article. Polycythaemia will be retained in relation to the clonal disorder, polycythaemia vera (PV), in which three cell lineages are involved.

Histopathology, cell proliferation indices and clinical outcome in 304 patients with mantle cell lymphoma (MCL): a clinicopathological study from the European MCL Network.

Abstract: Mantle cell lymphoma (MCL) is a distinct lymphoma subtype with a particularly poor clinical outcome. The clinical relevance of the morphological characteristics of these tumours remains uncertain. The European MCL Network reviewed 304 cases of MCL to determine the prognostic significance of histopathological characteristics. Cytomorphological subtypes, growth pattern and markers of proliferation (mitotic and Ki-67 indices) were analysed. In addition to the known cytological subtypes, classical (87.5%), small cell (3.6%), pleomorphic (5.9%) and blastic (2.6%), we identified new pleomorphic subgroups with mixtures of cells (classical + pleomorphic type; 1.6%) or transitions (classical/pleomorphic type; 1.6%), which, however, did not differ significantly in overall survival time. Exactly 80.5% of cases displayed a diffuse growth pattern, whereas 19.5% of cases had a nodular growth pattern, which was associated with a slightly more favourable prognosis. A high proliferation rate (mitotic or Ki-67 indices) was associated with shorter overall survival. Cut-off levels were defined that allowed three subgroups with different proliferation rates to be discriminated, which showed significantly different clinical outcomes (P < 0.0001). Based on this large clinicopathological study of prospective clinical trials, multivariate analysis confirmed the central prognostic role of cell proliferation and its superiority to all other histomorphological and clinical criteria.

JAK2V617F mutation in essential thrombocythaemia: clinical associations and long‐term prognostic relevance

Abstract: Clinical correlates and long-term prognostic relevance of the JAK2(V617F) mutation was studied in 150 patients with essential thrombocythaemia (ET) from a single institution and followed for a median of 11.4 years. During this period, thrombotic complications were documented in 62 patients (41.3%) and transformation into acute myeloid leukaemia (AML), polycythaemia vera (PV), or myelofibrosis with myeloid metaplasia (MMM) occurred in 4 (2.7%), 8 (5.3%), and 15 (10%) patients, respectively. JAK2(V617F) was detected in either archived bone marrow or blood cells from 73 patients (48.7%) but none were homozygous for the mutant allele. Parameters at diagnosis that were significantly associated with the presence of JAK2(V617F) included advanced age and higher counts of both haemoglobin and leucocytes. During follow-up, patients with the mutation were more likely to transform into PV but the incidences of AML, MMM, or thrombotic events were similar between patients with and without the mutation. Multivariate analysis identified advanced age, higher haemoglobin level, and thrombosis history but not the presence of JAK2(V617F) as independent predictors of inferior survival. Therefore, although the presence of JAK2(V617F) in ET appears to promote a PV phenotype, it might not carry treatment-relevant information.

Lysosomal storage disorders.

Abstract: Although the first description of a lysosomal storage disorder was that of Tay-Sachs disease in 1881, the lysosome was not discovered until 1955, by Christian De Duve. The first demonstration by Hers in 1963 of a link between an enzyme deficiency and a storage disorder (Pompe's disease) paved the way for a series of seminal discoveries about the intracellular biology of these enzymes and their substrates, culminating in the successful treatment of Gaucher's disease with beta-glucosidase in the early 1990s. It is now recognized that these disorders are not simply a consequence of pure storage, but result from perturbation of complex cell signalling mechanisms. These in turn give rise to secondary structural and biochemical changes, which have important implications for therapy. Significant challenges remain, particularly the treatment of central nervous system disease. It is hoped that recent advances in our understanding of lysosomal biology will enable successful therapies to be developed.

Gaucher disease: pathological mechanisms and modern management.

Abstract: Gaucher disease, the most common lysosomal storage disorder, is caused by the defective activity of the lysosomal enzyme, acid-beta-glucosidase (GlcCerase), leading to accumulation of glucosylceramide (GlcCer), particularly in cells of the macrophage lineage. Nearly 200 mutations in GlcCerase have been described, but for the most part, genotype-phenotype correlations are weak, and little is known about the down-stream biochemical changes that occur upon GlcCer accumulation that result in cell and tissue dysfunction. In contrast, the clinical course of Gaucher disease has been well described, and at least one treatment is available, namely enzyme replacement therapy. One other treatment, substrate reduction therapy, has recently been marketed, and others are in early stages of development. This review, after discussing pathological mechanisms, evaluates the advantages and disadvantages of existing therapies.

The impact of age and gender on biology, clinical features and treatment outcome of non-Hodgkin lymphoma in childhood and adolescence.

Abstract: We analysed the impact of age and gender on biology and outcome of 2084 patients diagnosed with non-Hodgkin lymphoma (NHL) between October 1986 and December 2002 and treated according to the Berlin-Frankfurt-Munster (BFM) multicentre protocols NHL-BFM-86, -90 and -95. Median age at diagnosis was 8.0 years for 97 precursor B-lymphoblastic lymphoma (pB-LBL) patients, 8.8 years for 335 T-lymphoblastic lymphoma (T-LBL) patients, 8.4 years for 1004 Burkitt's lymphoma/leukaemia (BL/B-AL) patients, 11.4 years for 173 diffuse large B-cell lymphoma (centroblastic subtype) (DLBCL-CB) patients, 13.2 years for 40 primary mediastinal large B-cell lymphoma (PMLBL) patients and 10.8 years for 215 anaplastic large-cell lymphoma (ALCL) patients (P < 0.00001). The male:female ratio was 0.9:1 for pB-LBL and PMLBL, 1.7:1 for DLBCL-CB, 1.8:1 for ALCL, 2.5:1 for T-LBL and 4.5:1 for BL/B-AL (P < 0.00001). The probability of event-free survival at 5 years (5-year pEFS) was 85 +/- 1% for all 2084 patients [median follow-up 5.7 (0.1-15.9) years], and was significantly superior for male T-LBL and DLBCL-CB patients. Comparing age-groups 0-4, 5-9, 10-14 and 15-18 years, pEFS was inferior for the youngest patients only in the pB-LBL- and ALCL-groups. T-LBL and DLBCL-CB adolescent females had worse outcome than younger girls while age had no impact on pEFS for boys. We conclude that the distribution of age and gender differed between NHL-subtypes. The impact of gender on outcome differed between NHL subgroups. The prognostic impact of age differed not only by NHL-subtype but also according to gender in some subtypes.

Epidemiology and outcome of infections due to Aspergillus terreus: 10-year single centre experience

Abstract: Aspergillus terreus, a less common pathogen, appears to be an emerging cause of infection at our institution, the Medical University Hospital of Innsbruck. Thus the epidemiology and outcome of A. terreus infections over the past 10 years was assessed. We analysed 67 cases of proven invasive aspergillosis (IA) according to the European Organisation for Research and Treatment of Cancer/Mycoses Study Group criteria, investigated antifungal susceptibility of amphotericin B (AMB), voriconazole and caspofungin and performed molecular typing of A. terreus. Patients with proven IA caused by A. terreus (n = 32) and non-A. terreus (n = 35) were evaluated. The two groups were comparable in terms of age, gender, underlying disease, antifungal prophylaxis and duration of neutropenia (P > 0.05). Leukaemia was the most common underlying malignancy. Fungal dissemination occurred in 63% of the patients. Aspergillus terreus infections were associated with a lower response rate to AMB therapy (20%), compared with 47% for patients with non-A. terreus infections (P < 0.05). In vitro, A. terreus was found to be resistant to AMB and molecular typing discriminated between patients isolates, showing a high strain diversity with 26 distinct types (I-XXVI) identified by combination of three primers. Aspergillus terreus infections displayed evidence of AMB resistance in vitro and in vivo and were associated with a high rate of dissemination and poor outcome; A. terreus causes systemic infections of endemic character in Tyrol, Austria. The onset of A. terreus infection depends not on the degree of immunosuppression but on environmental Aspergillus spp. exposure.

Platelet size deviation width, platelet large cell ratio, and mean platelet volume have sufficient sensitivity and specificity in the diagnosis of immune thrombocytopenia

Abstract: We investigated the significance of the platelet indices, mean platelet volume (MPV), platelet size deviation width (PDW), and platelet-large cell ratio (P-LCR), in the diagnosis of thrombocytopenia by comparing these levels in 40 patients with hypo-productive thrombocytopenia (aplastic anaemia; AA) and 39 patients with hyper-destructive thrombocytopenia (immune thrombo-cytopenia; ITP). The sensitivity and specificity of platelet indices to make a diagnosis of ITP were also compared. All platelet indices were significantly higher in ITP than in AA, and platelet indices showed sufficient sensitivity and specificity. The area under the curve (AUC) of the receiver operating characteristics curve of platelet indices was large enough to enable the diagnosis of ITP. P-LCR and PDW had the largest AUCs, which indicated that these values were very reliable for immune thrombocytopenia. Our results suggest that these indices provide clinical information about the underlying conditions of thrombocytopenia. More attention should be paid to these indices in the diagnosis of thrombocytopenia.

AIDS-related lymphomas: from pathogenesis to pathology.

Abstract: Human immunodeficiency virus (HIV)-associated lymphomas include: (1) lymphomas also occurring, although sporadically, in the absence of HIV infection. The vast majority of these lymphomas are high-grade B-cell lymphomas: Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL) with centroblastic (CB) features and DLBCL with immunoblastic (IBL) features; (2) unusual lymphomas occurring more specifically in HIV-positive patients and include two rare entities, namely 'primary effusion lymphoma' (PEL) and 'plasmablastic lymphoma' of the oral cavity. The pathological heterogeneity of acquired immunodeficiency syndrome-associated non-Hodgkin's lymphomas (AIDS-NHL) reflects the heterogeneity of their associated molecular lesions. In AIDS-BL, the molecular lesions involve activation of cMYC, inactivation of P53, and infection with Epstein-Barr virus (EBV). AIDS-IBL infected with EBV are characterised by frequent expression of latent membrane protein 1--an EBV oncoprotein. The biological heterogeneity of AIDS-NHL is highlighted by their histogenetic differences. Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV8)-associated lymphomas, which often develop in persons with advanced AIDS, present predominantly as PEL. KSHV/HHV8 has also been recently detected in solid extracavitary-based lymphomas. The KSHV/HHV8-associated solid lymphomas are (1) unusual lymphomas that occur more specifically in HIV-positive patients; (2) extracavitary and arise in nodal and/or extranodal sites; and (3) histologically, they usually display a PEL-like morphology and plasma cell-related phenotype.

5-hydroxymethyl-2-furfural modifies intracellular sickle haemoglobin and inhibits sickling of red blood cells.

Abstract: In an attempt to find new types of anti-sickling agents that specifically bind to intracellular sickle haemoglobin (HbS) without inhibition by plasma and tissue proteins or other undesirable consequences, we identified 5-hydroxymethyl-2-furfural (5HMF), a naturally occurring aromatic aldehyde, as an agent that fulfils this criterion. Preliminary studies in vitro showed that 5HMF forms a high-affinity Schiff-base adduct with HbS and inhibits red cell sickling by allosterically shifting oxygen equilibrium curves towards the left. Further studies with transgenic (Tg) sickle mice showed that orally administered 5HMF was rapidly absorbed into the bloodstream from the gastrointestinal tract without being destroyed, traversed the red blood cell membrane and specifically bound with, and modified, HbS molecules at levels as high as 90%. Pretreatment of Tg sickle mice with 5HMF inhibited the formation of sickle cells and significantly prolonged survival time under severe hypoxia, compared with untreated mice, which died within 15 min because of sickling-dependent pulmonary sequestration. These results indicate the feasibility of 5HMF as an attractive potential candidate for therapy of sickle cell disease.

The JAK2V617F tyrosine kinase mutation in myelofibrosis with myeloid metaplasia: lineage specificity and clinical correlates

Abstract: An association between an activating JAK2 mutation (JAK2(V617F)) and BCR/ABL-negative myeloproliferative disorders was recently reported in multiple simultaneous publications. In the current study, mutation analysis for JAK2(V617F) was performed in peripheral blood mononuclear cells (PBMC) from 157 patients with myelofibrosis with myeloid metaplasia (MMM) including 117 with agnogenic (AMM), 22 with postpolycythaemic (PPMM), and 18 with post-thrombocythaemic (PTMM) myeloid metaplasia. The detection rate for JAK2(V617F) was significantly higher in PPMM (91%; homozygous in 18%) compared with either AMM (45.3%; homozygous in 2.6%) or PTMM (38.9%; homozygous in 11.1%). Concomitant analysis in granulocytes (n=57) and CD34(+) cells (n=25) disclosed a higher incidence of homozygous JAK2(V617F) mutation but the overall mutation rate was similar to that obtained from PBMC. JAK2(V617F) was not detected in DNA derived from T cells (n=19). In AMM, the presence of JAK2(V617F) was associated with an older age at diagnosis and a history of thrombosis or pruritus. Multivariate analysis identified only age and the Dupriez prognostic score as independent prognostic factors; JAK2(V617F) had no prognostic significance. In conclusion, JAK2(V617F) is a myeloid lineage-specific event, its incidence in MMM is significantly higher with an antecedent history of polycythaemia vera (PV), and its presence in AMM does not affect prognosis but is associated with PV-characteristic clinical features.

Childhood acute lymphoblastic leukaemia and relapse

Abstract: Acute lymphoblastic leukaemia (ALL) is the most common childhood cancer. Treatment has improved but relapsed ALL remains more common than new cases of many 'common' paediatric malignancies. We have salvage regimens with substantial complete remission (CR) rates and increasing access to haematopoietic stem cell transplantation, but most patients who relapse die. We need better therapies. Insights into pharmacology may guide more effective use of existing agents. Novel agents with activity against resistant lymphoblasts offer an appealing strategy. However, most candidate agents fail, despite enthusiastic investigators, intriguing mechanisms of action and 'compelling' preclinical data. A number of existing combinations provide a 40% complete response rate in second or third relapse. Yet survival in third remission is <10%. Novel agents must, most likely, be integrated into multiagent combinations that provide a higher CR rate or better quality CR's than our conventional combinations in order to contribute substantially to cure. The march from bench to bedside requires careful consideration of the intermediate steps.

Red cell pyruvate kinase deficiency: molecular and clinical aspects

Abstract: Red cell pyruvate kinase (PK) deficiency is the most frequent enzyme abnormality of the glycolytic pathway causing hereditary non-spherocytic haemolytic anaemia. The degree of haemolysis varies widely, ranging from very mild or fully compensated forms, to life-threatening neonatal anaemia and jaundice necessitating exchange transfusions. Erythrocyte PK is synthesized under the control of the PK-LR gene located on chromosome 1. To date, more than 150 different mutations in the PK-LR gene have been associated with PK deficiency. First attempts to delineate the biochemical and clinical consequences of the molecular defect were mainly based on the observation of the few homozygous patients and on the analysis of the three-dimensional structure of the enzyme. More recently, the comparison of the recombinant mutants of human red cell PK with the wild-type enzyme has enabled the effects of amino acid replacements on the enzyme molecular properties to be determined and help to correlate genotype to clinical phenotype.

Individual time within target range in patients treated with vitamin K antagonists: main determinant of quality of anticoagulation and predictor of clinical outcome. A retrospective study of 2300 consecutive patients with venous thromboembolism

Abstract: The efficacy and safety of vitamin K antagonists (VKA) are related to the actual level of anticoagulation (given as the international normalized ratio, INR). It is often difficult to maintain an optimal INR over time. We assessed the clinical impact of the individual time spent within INR target range (ITTR) in 2304 consecutive patients with venous thromboembolism. Annual incidences of recurrent thromboembolism and major bleeding were 6.2% and 2.8% respectively. The relative risk (RR) of thromboembolism was 4.5 [95% confidence interval (CI) 3.1-6.6, P 5.0, compared with INR 2.0-3.0. Patients with ITTR 65% (RR 2.8, 1.9-4.3, P 65% (RR 1.2, 0.7-1.8, P = 0.54). Annual incidences of recurrent thromboembolism were 16.0%, 4.9% and 4.6% at ITTR 65% respectively. For major bleeding these were 8.7%, 2.1% and 1.9% respectively. ITTR < 37% during the first 30 treatment days was highly predictive for the total treatment time ITTR < 45% (RR 24.2, 13.5-43.1, P < 0.001). In conclusion, ITTR can be used to identify patients on VKA at risk of recurrent thromboembolism or major bleeding. Since the 30-d ITTR is highly predictive for total treatment ITTR, these patients can be identified soon after start of treatment.

Haematopoietic stem cell transplantation in haemophagocytic lymphohistiocytosis.

Abstract: Summary Haemophagocytic lymphohistiocytosis (HLH) poses major therapeutic challenges, and the primary inherited form, familial haemophagocytic lymphohistiocytosis (FHL), is usually fatal. We evaluated, including Cox regression analysis, survival in 86 children (29 familial) that received HLH-94-therapy (etoposide, dexamethasone, ciclosporin) followed by allogeneic stem cell transplantation (SCT) between 1995 and 2000. The overall estimated 3-year-survival post-SCT was 64% [confidence interval (CI) ¼ ±10%] (n ¼ 86); 71 ± 18% in those patients with a matched related donor (MRD, n ¼ 24), 70 ± 16% with a matched unrelated donor (MUD, n ¼ 33), 50 ± 24% with a family haploidentical donor (haploidentical, n ¼ 16), and 54 ± 27% with a mismatched unrelated donor (MMUD, n ¼ 13). After adjustment for potential confounding factors, estimated odds ratios (OR) for mortality were 1AE93 (CI ¼ 0AE61‐6AE19) for MUD, 3AE31 (1AE02‐10AE76) for haploidentical, and 3AE01 (0AE91‐9AE97) for MMUD, compared with MRD. In children with active disease after 2-months of therapy (n ¼ 43) the OR was 2AE75 (1AE26‐5AE99), compared with inactive disease (n ¼ 43). In children with active disease at SCT (n ¼ 37), the OR was 1AE80 (0AE80‐4AE06) compared with inactive disease (n ¼ 49), after adjustment for disease activity at 2-months. Mortality was predominantly transplant-related. Most HLH patients survived SCT using MRD or MUD, and survival with partially mismatched donors was also acceptable. Patients that responded well to initial pretransplant-induction therapy fared best, but some persisting HLH activity should not automatically preclude performing SCT.