Cryohydrocytosis is an inherited dominant hemolytic anemia characterized by mutations in a transmembrane segment of the anion exchanger (band 3 protein). Transfection experiments performed in Xenopus oocytes suggested that these mutations may convert the anion exchanger into a non-selective cation channel. The present study was performed to characterize so far unexplored ion transport pathways that may render erythrocytes of a single cryohydrocytosis patient cation-leaky.
Cold-induced changes in cell volume were monitored using ektacytometry and density gradient centrifugation. Kinetics, temperature and inhibitor-dependence of the cation and water movements in the cryohydrocytosis patient’s erythrocytes were studied using radioactive tracers and flame photometry. Response of the membrane potential of the patient’s erythrocyte membrane to the presence of ionophores and blockers of anion and cation channels was assessed.
In the cold, the cryohydrocytosis patient’s erythrocytes swelled in KCl-containing, but not in NaCl-containing or KNO3-containing media indicating that volume changes were mediated by an anion-coupled cation transporter. In NaCl-containing medium the net HOE-642-sensitive Na+/K+ exchange prevailed, whereas in KCl-containing medium swelling was mediated by a chloride-dependent K+ uptake. Unidirectional K+ influx measurements showed that the patient’s cells have abnormally high activities of the cation-proton exchanger and the K+,Cl– co-transporter, which can account for the observed net movements of cations. Finally, neither chloride nor cation conductance in the patient’s erythrocytes differed from that of healthy donors.
These results suggest that cross-talk between the mutated band 3 and other transporters might increase the cation permeability in cryohydrocytosis.
Anemia is a common complication of inflammatory bowel disease, but its epidemiology may be changing due to earlier diagnosis and improved treatments. We investigated the prevalence and pathogenesis of anemia in patients with inflammatory bowel disease.
In a cross-sectional study 263 out-patients with inflammatory bowel disease (165 with Crohn’s disease, 98 with ulcerative colitis) were investigated. The influence of time from diagnosis, disease activity, inflammation and the status of iron and hematinic vitamins on the level of hemoglobin and prevalence of anemia were evaluated. In a second group of 27 patients with Crohn’s disease, undergoing anti-tumor necrosis factor- treatment with infliximab because of refractory or fistulizing disease, we determined the effects of infliximab on disease activity, hemoglobin, serum erythropoietin levels, iron status and inflammation.
In all, 104 of the 263 patients with inflammatory bowel disease were anemic. Age, gender and azathioprine treatment had no influence on anemia. The prevalence of anemia was highest at diagnosis (65%), decreased during the first 4 years after disease onset, and was stable thereafter. Active disease was associated with higher rates of anemia. At diagnosis most anemic patients had anemia of chronic disease; during follow-up iron deficiency and multifactorial forms of anemia became more prevalent. Eighteen of 27 patients undergoing treatment with infliximab were anemic; most of them had anemia of chronic disease. Infliximab reduced disease activity and improved anemia in 12 patients. This was mediated by an increased production of erythropoietin for the degree of anemia. In vitro infliximab increased the growth of erythroid progenitors from the peripheral blood of patients with active disease.
Anemia is a common problem in out-patients with inflammatory bowel disease; the prevalence and severity of anemia are related to the activity of the bowel disorder. The pathogenesis of anemia changes during the course of the disease, with anemia of chronic disease having a major role at diagnosis and iron deficiency and multifactorial forms of anemia during follow-up. In patients requiring anti-tumor necrosis factor- treatment, response to therapy improves erythropoiesis.
Diamond-Blackfan anemia is a rare, pure red blood cell aplasia of childhood due to an intrinsic defect in erythropoietic progenitors. About 40% of patients display various malformations. Anemia is corrected by steroid treatment in more than 50% of cases; non-responders need chronic transfusions or stem cell transplantation. Defects in the RPS19 gene, encoding the ribosomal protein S19, are the main known cause of Diamond-Blackfan anemia and account for more than 25% of cases. Mutations in RPS24, RPS17, and RPL35A described in a minority of patients show that Diamond-Blackfan anemia is a disorder of ribosome biogenesis. Two new genes (RPL5, RPL11), encoding for ribosomal proteins of the large subunit, have been reported to be involved in a considerable percentage of patients.
In this genotype-phenotype analysis we screened the coding sequence and intron-exon boundaries of RPS14, RPS16, RPS24, RPL5, RPL11, and RPL35A in 92 Italian patients with Diamond-Blackfan anemia who were negative for RPS19 mutations.
About 20% of the patients screened had mutations in RPL5 or RPL11, and only 1.6% in RPS24. All but three mutations that we report here are new mutations. No mutations were found in RPS14, RPS16, or RPL35A. Remarkably, we observed a higher percentage of somatic malformations in patients with RPL5 and RPL11 mutations. A close association was evident between RPL5 mutations and craniofacial malformations, and between hand malformations and RPL11 mutations.
Mutations in four ribosomal proteins account for around 50% of all cases of Diamond-Blackfan anemia in Italian patients. Genotype-phenotype data suggest that mutation screening should begin with RPL5 and RPL11 in patients with Diamond-Blackfan anemia with malformations.
Somatic mutation in the X-linked phosphatidylinositol glycan class A gene (PIG-A) causes glycosyl phosphatidylinositol anchor deficiency in human patients with paroxysmal nocturnal hemoglobinuria.
We produced an animal model of paroxysmal nocturnal hemoglobinuria by conditional Pig-a gene inactivation (Pig-a–/–) in hematopoietic cells; mice carrying two lox sites flanking exon 6 of the Pig-a gene were bred with mice carrying the transgene Cre-recombinase under the human c-fes promoter. We characterized the phenotypic and functional properties of glycosyl phosphatidylinositol-deficient and glycosyl phosphatidylinositol-normal hematopoietic cells from these Pig-a–/– mice using gene expression microarray, flow cytometry, bone marrow transplantation, spectratyping, and immunoblotting.
In comparison to glycosyl phosphatidylinositol-normal bone marrow cells, glycosyl phosphatidylinositol-deficient bone marrow cells from the same Pig-a–/– animals showed up-regulation of the expression of immune function genes and contained a significantly higher proportion of CD8 T cells. Both characteristics were maintained when glycosyl phosphatidylinositol-deficient cells were transplanted into lethally-irradiated recipients. Glycosyl phosphatidylinositol-deficient T cells were inactive, showed pronounced Vβ5.1/5.2 skewing, had fewer -interferon-producing cells after lectin stimulation, and contained fewer CD4+CD25+FoxP3+ regulatory T cells. However, the levels of T-cell receptor signaling proteins from glycosyl phosphatidylinositol-deficient cells were normal relative to glycosyl phosphatidylinositol-normal cells from wild type animals, and cells were capable of inducing target cell apoptosis in vitro.
Deletion of the Pig-a gene in hematopoietic cells does not cause frank marrow failure but leads to the appearance of clonally-restricted, inactive yet functionally competent CD8 T cells.
Second-generation tyrosine kinase inhibitors induce cytogenetic responses in approximately 50% of patients with chronic myeloid leukemia in chronic phase in whom imatinib treatment has failed. However, it has not yet been established which of the patients in whom imatinib treatment fails are likely to benefit from therapy with second-generation tyrosine kinase inhibitors.
We analyzed a cohort of 80 patients with chronic myeloid leukemia who were resistant to imatinib and who were treated with dasatinib or nilotinib while still in first chronic phase. We devised a scoring system to predict the probability of these patients achieving complete cytogenetic response when treated with second-generation tyrosine kinase inhibitors.
The system was based on three factors: cytogenetic response to imatinib, Sokal score and recurrent neutropenia during imatinib treatment. We validated the score in an independent group of 28 Scottish patients. We also studied the relationship between cytogenetic responses at 3, 6 and 12 months and subsequent outcome. We classified the 80 patients into three categories, those with good risk (n=24), intermediate risk (n=27) and poor risk (n=29) with 2.5-year cumulative incidences of complete cytogenetic response of 100%, 52.2% and 13.8%, respectively (P<0.0001). Moreover, patients who had less than 95% Philadelphia chromosome-positive metaphases at 3 months, those with 35% or less Philadelphia chromosome-positive metaphases at 6 months and patients in complete cytogenetic response at 12 months all had significantly better outcomes than patients with lesser degrees of cytogenetic response.
Factors measurable before starting treatment can accurately predict response to second-generation tyrosine kinase inhibitors. Cytogenetic responses at 3, 6 and 12 months may influence the decision to continue treatment with second-generation tyrosine kinase inhibitors.
Dasatinib 100 mg once daily achieves intermittent BCR-ABL kinase inhibition and is approved for chronic-phase chronic myeloid leukemia patients resistant or intolerant to imatinib. To better assess durability of response to and tolerability of dasatinib, data from a 2-year minimum follow-up for a dose-optimization study in chronic-phase chronic myeloid leukemia are reported here.
In a phase 3 study, 670 chronic-phase chronic myeloid leukemia patients with resistance, intolerance, or suboptimal response to imatinib were randomized to dasatinib 100 mg once-daily, 50 mg twice-daily, 140 mg once-daily, or 70 mg twice-daily.
Data from a 2-year minimum follow-up demonstrate that dasatinib 100 mg once daily achieves major cytogenetic response and complete cytogenetic response rates comparable to those in the other treatment arms, and reduces the frequency of key side effects. Comparable 2-year progression-free survival and overall survival rates were observed (80% and 91%, respectively, for 100 mg once daily, and 75%–76% and 88%–94%, respectively, in other arms). Complete cytogenetic responses were achieved rapidly, typically by 6 months. In patients treated with dasatinib 100 mg once daily for 6 months without complete cytogenetic response, the likelihood of achieving such a response by 2 years was 50% for patients who had achieved a partial cytogenetic response, and only 8% or less for patients with minor, minimal, or no cytogenetic response. Less than 3% of patients suffered disease transformation to accelerated or blast phase.
Intermittent kinase inhibition can achieve rapid and durable responses, indistinguishable from those achieved with more continuous inhibition.
The t(9;22) and t(4;11) chromosomal translocations, which generate the BCR-ABL and MLL-AF4 fusion genes, define high-risk subtypes of acute lymphoblastic leukemia in adults. However, the prognostic impact of other rarer fusion genes is less well established in adult acute lymphoblastic leukemia than in the childhood form.
In the context of the German Multicenter Therapy Study Group for Adult Acute Lymphoblastic Leukemia (GMALL) we used reverse transcriptase polymerase chain reaction to investigate 441 cases of BCR-ABL- and MLL-AF4-negative B-precursor acute lymphoblastic leukemia for the TCF3-PBX1 (E2A-PBX1) and ETV6-RUNX1 (TEL-AML1) fusion transcripts generated by the t(1;19)(q23;p13.3) and t(12;21)(p13;q22) translocations. Both are well-known molecular alterations in pediatric acute lymphoblastic leukemia in which they have favorable prognostic implications.
We identified 23 adult patients with TCF3-PBX1 and ten with ETV6-RUNX1. In contrast to previous reports we found no significant difference in overall survival between TCF3-PBX1-positive and -negative patients. At 2 years after diagnosis all the ETV6-RUNX1-positive patients were alive and in continuous complete remission, but their long-term outcome was negatively affected by late relapses. TCF3-PBX1-positive patients exhibited a characteristic CD34–/CD33– and mostly cyIg+ immunophenotype. ETV6-RUNX1 only occurred in patients under 35 years old and was associated with a significantly lower white blood count.
In contrast to previous suggestions, adult patients with TCF3-PBX1-positive acute lymphoblastic leukemia do not appear to have a worse outcome than their negative counterparts. ETV6-RUNX1-positive patients had a very favorable performance status during the first few years but their long-term survival was negatively affected by late relapses. Both groups of patients are characterized by distinct clinicobiological features which facilitate their diagnostic identification.
Malignant lymphomas are classified based on morphology, immunophenotype, genetics and clinical features. The pathological diagnosis is generally considered difficult and prone to mistakes. Since non-random chromosomal translocations are specifically involved in specific entities, their detection is an important adjunct for increasing the reliability of the diagnosis. Recently, split-signal fluorescence in situ hybridization has become available as a robust method to detect chromosomal breaks in paraffin-embedded formalin-fixed tissues. A bright field approach would bring this technology within the reach of every pathology laboratory.
Our study was initiated to determine the consistency between chromogenic in situ hybridization and fluorescence in situ hybridization, both using split-signal probes developed for the detection of chromosomal breaks. Five hundred and forty cases of 11 lymphoma entities and reactive, benign lymphoid tissues, collected from eight different pathology laboratories, placed on 15 fluorescence in situ hybridization pre-stained tissue microarray slides, were double stained for the chromogenic hybridization. For each core morphology and actual signal were compared to the original fluorescence hybridization results. In addition, hematoxylin background staining intensity and signal intensity of the double-staining chromogenic in situ hybridization procedure were analyzed.
With respect to the presence or absence of chromosomal breaks, 97% concordance was found between the results of the two techniques. Hematoxylin background staining intensity and signal intensity were found to correspond. The overall morphology after double-staining chromogenic in situ hybridization had decreased compared to the initial morphology scored after split-signal fluorescence in situ hybridization staining.
We conclude that double-staining chromogenic in situ hybridization is equally reliable as fluorescence in situ hybridization in detecting chromosomal breaks in lymphoid tissue. Although differences in morphology, hematoxylin staining and chromogenic signal intensity vary between the tumor entities none of the entities appeared more easy or difficult to score.
Pediatric follicular lymphoma has recently been recognized as a novel variant of follicular lymphoma in the World Health Organization classification of lymphomas. Given the rarity of the disease, histopathological and genetic data on this type of lymphoma are still scarce.
We analyzed 25 cases of pediatric follicular lymphoma (patients aged ≤18 years) by morphology, immunohistochemistry and interphase fluorescence in situ hybridization. All patients analyzed were treated within Non-Hodgkin’s Lymphoma - Berlin-Frankfurt-Münster (NHL-BFM) multicenter trials, and the cohort was representative of the German population.
The genetic hallmark of adult follicular lymphoma, t(14;18)(q32;q21), was not detectable in any of the pediatric cases, although BCL2 protein was expressed in 55% of the latter cases. No correlation was found between BCL2 protein expression and outcome. Chromosomal breaks in the immunoglobulin heavy chain gene (IGH) and the BCL6 locus were detected in 5 of 17 and 1 of 18 cases, respectively. Patients with pediatric follicular lymphoma had long event-free survival and, in contrast to adult follicular lymphoma, the clinical course was not dominated by relapses. A simultaneous diffuse large B-cell lymphoma was frequently detected at initial diagnosis in children but did not indicate an aggressive clinical course.
Our data suggest that pediatric follicular lymphoma is a disease that differs from its adult counterpart both genetically and clinically.
The histone deacetylase inhibitor ITF2357 has potent cytotoxic activity in multiple myeloma in vitro and has entered clinical trials for this disease.
In order to gain an overall view of the activity of ITF2357 and identify specific pathways that may be modulated by the drug, we performed gene expression profiling of the KMS18 multiple myeloma cell line treated with the drug. The modulation of several genes and their biological consequence were verified in a panel of multiple myeloma cell lines and cells freshly isolated from patients by using polymerase chain reaction analysis and western blotting.
Out of 38,500 human genes, we identified 140 and 574 up-regulated genes and 102 and 556 down-modulated genes at 2 and 6 h, respectively, with a significant presence of genes related to transcription regulation at 2 h and to cell cycling and apoptosis at 6 h. Several of the identified genes are particularly relevant to the biology of multiple myeloma and it was confirmed that ITF2357 also modulated their encoded proteins in different multiple myeloma cell lines. In particular, ITF2357 down-modulated the interleukin-6 receptor (CD126) transcript and protein in both cell lines and freshly isolated patients’ cells, whereas it did not significantly modify interleukin-6 receptor β (CD130) expression. The decrease in CD126 expression was accompanied by decreased signaling by interleukin-6 receptor, as measured by STAT3 phosphorylation in the presence and absence of inter-leukin-6. Finally, the drug significantly down-modulated the MIRHG1 transcript and its associated microRNA, miR-19a and miR-19b, known to have oncogenic activity in multiple myeloma.
ITF2357 inhibits several signaling pathways involved in myeloma cell growth and survival.
Hematocrit above the normal range for the population, such as in primary or secondary erythrocytosis, predisposes to both arterial and venous thrombosis. However, little is known about the association between hematocrit and risk of venous thromboembolism in a general population.
Hematocrit and related hematologic variables such as hemoglobin, red blood cell count, mean corpuscular volume, and baseline characteristics were measured in 26,108 subjects, who participated in the Tromsø Study in 1994–1995. Incident venous thromboembolic events during follow-up were registered up to September 1st, 2007.
There were 447 venous thromboembolic events during a median of 12.5 years of follow-up. Multivariable hazard ratios per 5% increment of hematocrit for the total population, adjusted for age, body mass index and smoking, were 1.25 (95% CI: 1.08–1.44) for total venous thromboembolism and 1.37 (95% CI: 1.10–1.71) for unprovoked venous thromboembolism. In category-based analyses, men with a hematocrit in the upper 20th percentile (≥46% in men) had a 1.5-fold increased risk of total venous thromboembolism (95% CI: 1.08–2.21) and a 2.4-fold increased risk of unprovoked venous thromboembolism (95% CI: 1.36–4.15) compared to men whose hematocrit was in the lower 40th percentile. The risk estimates were higher for men than for women both in continuous and category-based analyses. The findings for hemoglobin and red blood cell count were similar to those for hematocrit, whereas mean corpuscular volume was not associated with venous thromboembolism.
Our findings suggest that hematocrit and related hematologic variables such as hemoglobin and red blood cell count are risk factors for venous thromboembolism in a general population.
Many genetic factors play major roles in the outcome of hematopoietic stem cell transplants from unrelated donors. Transforming growth factor β1 is a member of a highly pleiotrophic family of growth factors involved in the regulation of numerous immunomodulatory processes.
We investigated the impact of single nucleotide polymorphisms at codons 10 and 25 of TGFB1, the gene encoding for transforming growth factor β1, on outcomes in 427 mye-loablative-conditioned transplanted patients. In addition, transforming growth factor β1 plasma levels were measured in 263 patients and 327 donors.
Patients homozygous for the single nucleotide polymorphism at codon 10 had increased non-relapse mortality (at 3 years: 46.8% versus 29.4%, P=0.014) and reduced overall survival (at 5 years 29.3% versus 42.2%, P=0.013); the differences remained statistically significant in multivariate analysis. Donor genotype alone had no impact, although multiple single nucleotide polymorphisms within the pair were significantly associated with higher non-relapse mortality (at 3 years: 44% versus 29%, P=0.021) and decreased overall survival (at 5 years: 33.8% versus 41.9%, P=0.033). In the 10/10 HLA matched transplants (n=280), recipients of non-wild type grafts tended to have a higher incidence of acute graft-versus-host disease grades II-IV (P=0.052). In multivariate analysis, when analyzed with patients’ genotype, the incidences of both overall and grades II-IV acute graft-versus-host disease were increased (P=0.025 and P=0.009, respectively) in non-wild-type pairs.
We conclude that increasing numbers of single nucleotide polymorphisms in codon 10 of TGFB1 in patients and donors are associated with a worse outcome following hematopoietic stem cell transplantation from unrelated donors.
Autologous hematopoietic stem cell transplantation has been used since 1996 for the treatment of severe autoimmune diseases refractory to approved therapies. We evaluated the long-term outcomes of these transplants and aimed to identify potential prognostic factors.
In this observational study we analyzed all first autologous hematopoietic stem cell transplants for autoimmune diseases reported to the European Group for Blood and Marrow Transplantation (EBMT) registry between 1996–2007. The primary end-points for analysis were overall survival, progression-free survival and transplant-related mortality at 100 days.
Nine hundred patients with autoimmune diseases (64% female; median age, 35 years) who underwent a first autologous hematopoietic stem cell transplant were included. The main diseases were multiple sclerosis (n=345), systemic sclerosis (n=175), systemic lupus erythematosus (n=85), rheumatoid arthritis (n=89), juvenile arthritis (n=65), and hematologic immune cytopenia (n=37). Among all patients, the 5-year survival was 85% and the progression-free survival 43%, although the rates varied widely according to the type of autoimmune disease. By multivariate analysis, the 100-day transplant-related mortality was associated with the transplant centers’ experience (P=0.003) and type of autoimmune disease (P=0.03). No significant influence of transplant technique was identified. Age less than 35 years (P=0.004), transplantation after 2000 (P=0.0015) and diagnosis (P=0.0007) were associated with progression-free survival.
This largest cohort studied worldwide shows that autologous hematopoietic stem cell transplantation can induce sustained remissions for more than 5 years in patients with severe autoimmune diseases refractory to conventional therapy. The type of autoimmune disease, rather than transplant technique, was the most relevant determinant of outcome. Results improved with time and were associated with the transplant centers’ experience. These data support ongoing and planned phase III trials to evaluate the place of autologous hematopoietic stem cell transplantation in the treatment strategy for severe autoimmune diseases.