55 research outputs found
Factor eight inhibitor bypass activity (FEIBA) in the management of bleeds in hemophilia patients with high-titer inhibitors
The development of high-titer inhibitors to FVIII and less often to other coagulation factors are the most serious complication of hemophilia therapy and makes treatment of bleeds very challenging. At present, bypassing agents, such as factor eight inhibitor bypass activity (FEIBA) and activated recombinant factor VII (rFVIIa) are the only coagulation factor concentrates available for the treatment of bleeds in inhibitor patients. Both products are effective and safe, and their efficacy has been found to be comparable (approximately 80%) in a recent prospective study. A significant number of patients report a better effect of one or the other of the products, and in a minority of the patients none of the products are particularly effective. The hemostatic efficacy of bypassing agents is not considered equal to that of coagulation factor replacement in patients without inhibitors by most physicians. An improvement in hemostatic efficacy may be achieved by optimizing the dosing of by passing agents. However, the lack of standardized and validated laboratory assays reflecting the hemostatic efficacy of the bypassing agents is an obstacle to this achievement
Identification of copy number variants from exome sequence data
Background
With advances in next generation sequencing technologies and genomic capture techniques, exome sequencing has become a cost-effective approach for mutation detection in genetic diseases. However, computational prediction of copy number variants (CNVs) from exome sequence data is a challenging task. Whilst numerous programs are available, they have different sensitivities, and have low sensitivity to detect smaller CNVs (1–4 exons). Additionally, exonic CNV discovery using standard aCGH has limitations due to the low probe density over exonic regions. The goal of our study was to develop a protocol to detect exonic CNVs (including shorter CNVs that cover 1–4 exons), combining computational prediction algorithms and a high-resolution custom CGH array.
Results
We used six published CNV prediction programs (ExomeCNV, CONTRA, ExomeCopy, ExomeDepth, CoNIFER, XHMM) and an in-house modification to ExomeCopy and ExomeDepth (ExCopyDepth) for computational CNV prediction on 30 exomes from the 1000 genomes project and 9 exomes from primary immunodeficiency patients. CNV predictions were tested using a custom CGH array designed to capture all exons (exaCGH). After this validation, we next evaluated the computational prediction of shorter CNVs. ExomeCopy and the in-house modified algorithm, ExCopyDepth, showed the highest capability in detecting shorter CNVs. Finally, the performance of each computational program was assessed by calculating the sensitivity and false positive rate.
Conclusions
In this paper, we assessed the ability of 6 computational programs to predict CNVs, focussing on short (1–4 exon) CNVs. We also tested these predictions using a custom array targeting exons. Based on these results, we propose a protocol to identify and confirm shorter exonic CNVs combining computational prediction algorithms and custom aCGH experiments
Targeted DNA vaccines eliciting crossreactive anti-idiotypic antibody responses against human B cell malignancies in mice
Background
Therapeutic idiotypic (Id) vaccination is an experimental treatment for selected B cell malignancies. A broader use of Id-based vaccination, however, is hampered by the complexity and costs due to the individualized production of protein vaccines. These limitations may be overcome by targeted DNA vaccines encoding stereotyped immunoglobulin V regions of B cell malignancies. We have here investigated whether such vaccines might elicit cross-reactive immune responses thus offering the possibility to immunize subsets of patients with the same vaccine.
Methods
Fusion vaccines targeting patient Id to mouse Major Histocompatibility Complex (MHC) class II molecules (chimeric mouse/human) or chemokine receptors (fully human) on antigen-presenting cells (APC) were genetically constructed for two Chronic Lymphocytic Leukemia (CLL) patients and one prototypic stereotyped B-cell receptor (BCR) commonly expressed by Hepatitis C Virus (HCV)-associated Non Hodgkin Lymphoma (NHL). The A20 murine B lymphoma cells were engineered to express prototypic HCV-associated B cell lymphoma BCR. Anti-Id antibody responses were studied against stereotyped and non-stereotyped BCRs on CLL patients’ cells as well as transfected A20 cells.
Results
DNA vaccination of mice with Id vaccines that target APC elicited increased amounts of antibodies specific for the patient’s Id as compared with non targeted control vaccines. Anti–Id antibodies cross-reacted between CLL cells with closely related BCR. A20 cells engineered to express patients’ V regions were not tumorigenic in mice, preventing tumor challenge experiments.
Conclusions
These findings provide experimental support for use of APC-targeted fusion Id DNA vaccines for the treatment of B cell lymphoma and CLL that express stereotyped BCRs
Paroxysmal nocturnal haemoglobinuria at Oslo University Hospital 2000-2010.
BACKGROUND Paroxysmal nocturnal haemoglobinuria (PNH) is a rare haematological disease characterised by chronic haemolysis, pancytopenia and venous thrombosis. The condition is attributable to a lack of control of complement attack on erythrocytes, thrombocytes and leukocytes, and can be diagnosed by means of flow cytometry. In this quality assurance study, we have reviewed information from the medical records of all patients tested for PNH using flow cytometry at our laboratory over a ten-year period.MATERIAL AND METHOD In the period 2000-2010 a total of 28 patients were tested for PNH using flow cytometry at the Department of Immunology and Transfusion Medicine, Oslo University Hospital. We have reviewed the results of these examinations retrospectively together with information from medical records and transfusion data for the patients concerned.RESULTS Flow cytometry identified 22 patients with PNH: four with classic disease and 18 with PNH secondary to another bone marrow disease. Five patients had atypical thrombosis. Seventeen patients received antithymocyte globulin or drug treatment; of these, six recovered from their bone marrow disease, while six died and five had a need for long-term transfusion. Five patients with life-threatening bone marrow disease underwent allogeneic stem cell transplantation, three of whom died. Six of 22 patients received eculizumab; the need for transfusion has been reduced or eliminated in three patients treated with eculizumab over a longer period.INTERPRETATION Flow cytometry identified PNH in a majority of patients from whom we obtained samples. Most patients had a PNH clone secondary to bone marrow failure. Atypical thrombosis should be borne in mind as an indication for the test. Treatment with eculizumab is relevant for selected patients with PNH
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The PI3K p110δ Isoform Inhibitor Idelalisib Preferentially Inhibits Human Regulatory T Cell Function.
In chronic lymphocytic leukemia (CLL), signaling through several prosurvival B cell surface receptors activates the PI3K signaling pathway. Idelalisib is a highly selective PI3K (PI3Kδ) isoform-specific inhibitor effective in relapsed/refractory CLL and follicular lymphoma. However, severe autoimmune adverse effects in association with the use of idelalisib in the treatment of CLL, particularly as a first-line therapy, gave indications that idelalisib may preferentially target the suppressive function of regulatory T cells (Tregs). On this background, we examined the effect of idelalisib on the function of human Tregs ex vivo with respect to proliferation, TCR signaling, phenotype, and suppressive function. Our results show that human Tregs are highly susceptible to PI3Kδ inactivation using idelalisib compared with CD4+ and CD8+ effector T cells (Teffs) as evident from effects on anti-CD3/CD28/CD2-induced proliferation (order of susceptibility [IC50]: Treg [.5 μM] > CD4+ Teff [2.0 μM] > CD8+ Teff [6.5 μM]) and acting at the level of AKT and NF-κB phosphorylation. Moreover, idelalisib treatment of Tregs altered their phenotype and reduced their suppressive function against CD4+ and CD8+ Teffs. Phenotyping Tregs from CLL patients treated with idelalisib supported our in vitro findings. Collectively, our data show that human Tregs are more dependent on PI3Kδ-mediated signaling compared with CD4+ and CD8+ Teffs. This Treg-preferential effect could explain why idelalisib produces adverse autoimmune effects by breaking Treg-mediated tolerance. However, balancing effects on Treg sensitivity versus CD8+ Teff insensitivity to idelalisib could still potentially be exploited to enhance inherent antitumor immune responses in patients
Superior Graft-versus-Host Disease-Free Relapse-Free Survival in Matched Unrelated Donor Hematopoietic Stem Cell Transplantation with Anti-Thymocyte Globulin (ATG) Compared to Matched Related Donor without ATG
The use of anti-T cell globulin (ATG) in allogeneic stem cell transplantation with matched unrelated donors (MUDs) is considered standard of care in many transplant centers, as these patients are at higher risk of developing acute and chronic graft-versus-host disease (GVHD). Several publications have reported reduced incidence of chronic GVHD compared to matched related donors (MRDs). This may support the idea of introducing ATG in prospective clinical trials, also in MRDs, in an effort to reduce the long-term complications with moderate and severe GVHD. We retrospectively analyzed 169 patients, in whom ATG was given to patients who underwent transplantation with MUDs (n = 124) and not MRDs (n = 45). The incidence acute GVHD II to IV and III to IV was significantly lower in the MUD group compared to the MRD group (28.2% versus 51.3% and 8.1% versus 24.7%). Extensive chronic GVHD incidence was 5% versus 40%. Our results further support the rationale for examining the efficacy of ATG in MRDs in prospective randomized trials
Open Access
Targeted DNA vaccines eliciting crossreactive anti-idiotypic antibody responses against human B cell malignancies in mic
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