Retrovirus-mediated transfer of the erythropoietin gene in hematopoietic cells improves the erythrocyte phenotype in murine beta- thalassemia

Repeated injections of large doses of erythropoietin (Epo) have been shown to be of benefit in the treatment of murine and human beta- thalassemia. To determine whether Epo gene therapy could replace this treatment for long-term periods, lethally irradiated beta-thalassemic (Hbbd3th haplotype) and normal DBA/2J (Hbbd haplotype) mice were grafted with syngeneic bone marrow cells infected with a retroviral vector carrying the Epo cDNA. In normal mice, dysregulated Epo production induced elevated serum Epo levels (176 +/- 68 mU/mL), high hematocrit levels (73% +/- 8%), and elevated beta-minor globin chain synthesis. In contrast, in thalassemic mice, moderate increases in the hematocrit levels (from 33% +/- 1% to 43% +/- 9%), associated with limited increases in the initially elevated Epo levels (from 83 +/- 22 to 190 +/- 230 mU/mL), were recorded 2 months after transplantation. In mice in which the hematocrit increased most, from 33% +/- 1% before transplantation to 49% +/- 10%, the retroviral Epo gene expression induced a striking improvement of the beta-thalassemic syndrome. These mice exhibited normal or near-normal beta/alpha-globin chain synthesis ratios, induced by the activation of the beta-minor chain. This led to the elimination of the high amounts of unpaired alpha chains in erythrocytes and finally reduced the reticulocyte count despite the permanent Epo stimulation. These results show that efficient Epo gene expression corrects the erythrocyte phenotype of the mouse beta- thalassemic syndrome. However, the incidence of lethal polycythemia or of transient improvements indicates that the present strategy is only the first step toward such indirect gene therapy.     

A platelet abnormality in the Chediak-Higashi syndrome of man

Platelets from two probands homozygous for the Chediak-Higashi syndrome have approximately 10% of the normal number of serotonin-containing dense bodies as visualized electron microscopically in air-dried whole mounts. Since transport of serotonin across the platelet plasma membrane proceeds at a normal rate, and the few dense bodies present appear to store normal amounts of serotonin, the absence of dense bodies may account for the low platelet serotonin values found in these patients.     

Inhibition of granulocyte erythrophagocytosis by HLA antisera

The ability of HLA antisera to inhibit granulocyte erythrophagocytosis (EP) of opsonized red blood cells (RBC) was evaluated. Human granulocytes (PMN) were separated from heparinized whole blood by the Ficoll-Isopaque technique and suspended in McCoy's medium. EP occurred when the PMN were incubated with opsonized RBC. For six HLA antibody specificities evaluated, prior incubation of PMN with HLA antisera resulted in significant inhibition of EP without cytolysis when the PMN donor was positive for the specific HLA antigen, but not when the donor was negative for the antigen. The inhibition was time- and dose- dependent. Prior absorption of HLA antisera with HLA-specific platelets reduced or abolished the inhibition. An example of anti-NB1 also inhibited EP in 4 individuals. These data suggest that HLA antibody may adversely affect granulocyte phagocytic function. Inhibition of EP might be useful in evaluating compatibility prior to granulocyte transfusion.     

Chronic dissection of the anterior tibial artery leading to acute aneurysmal dilatation

We present a clinical case of chronic dissection of the anterior tibial artery leading to acute aneurysmal dilatation. Our patient, a 22-year-old man, had a history of trauma at the middle third of his left leg. Because of impending ischemia, he was diagnosed by emergency arteriography. We ligated the proximal and distal ends of the dissection and used a reversed saphenous vein for a short end-to-end bypass. Although the evolution of this dilatation had been silent, its clinical presentation was spectacular. The case is worthy of attention because of its extreme rarity, both as a dissection of a peripheral artery caused by trauma and as an aneurysmal dilatation at tibial level.     

Wegener's granulomatosis autoantigen is a novel neutrophil serine proteinase [see comments]

Circulating IgG autoantibodies that produce cytoplasmic immunofluorescence staining of ethanol-fixed normal neutrophils have recently been found in a large percentage of patients with active Wegener's granulomatosis. Such autoantibodies are rarely found in other diseases and are therefore virtually diagnostic of Wegener's granulomatosis. The nature of the neutrophil antigen defined by these autoantibodies is controversial and the roles of the antigen and/or autoantibodies in the pathogenesis of Wegener's granulomatosis are unknown. We studied serum samples that produce the cytoplasmic pattern of staining from 10 patients with a diagnosis of Wegener's granulomatosis. By Western blot analysis, all 10 sera reacted with a 29- Kd neutrophil protein (p29). We generated a mouse monoclonal antibody directed against this antigen. The monoclonal antibody produced the same immunofluorescence staining pattern as the serum autoantibodies and was used to affinity-purify p29. The purified antigen had a novel N- terminal sequence homologous to members of the serine proteinase family and bound to radiolabeled diisopropyl fluorophosphate (DFP). We conclude that the neutrophil antigen responsible for the cytoplasmic staining pattern produced by autoantibodies in patients with active Wegener's granulomatosis is a distinctive serine proteinase.     

A composite metric for assessing data on mortality and causes of death: the vital statistics performance index

Background

Timely and reliable data on causes of death are fundamental for informed decision-making in the health sector as well as public health research. An in-depth understanding of the quality of data from vital statistics (VS) is therefore indispensable for health policymakers and researchers. We propose a summary index to objectively measure the performance of VS systems in generating reliable mortality data and apply it to the comprehensive cause of death database assembled for the Global Burden of Disease (GBD) 2013 Study.

Methods

We created a Vital Statistics Performance Index, a composite of six dimensions of VS strength, each assessed by a separate empirical indicator. The six dimensions include: quality of cause of death reporting, quality of age and sex reporting, internal consistency, completeness of death reporting, level of cause-specific detail, and data availability/timeliness. A simulation procedure was developed to combine indicators into a single index. This index was computed for all country-years of VS in the GBD 2013 cause of death database, yielding annual estimates of overall VS system performance for 148 countries or territories.

Results

The six dimensions impacted the accuracy of data to varying extents. VS performance declines more steeply with declining simulated completeness than for any other indicator. The amount of detail in the cause list reported has a concave relationship with overall data accuracy, but is an important driver of observed VS performance. Indicators of cause of death data quality and age/sex reporting have more linear relationships with simulated VS performance, but poor cause of death reporting influences observed VS performance more strongly. VS performance is steadily improving at an average rate of 2.10% per year among the 148 countries that have available data, but only 19.0% of global deaths post-2000 occurred in countries with well-performing VS systems.

Conclusions

Objective and comparable information about the performance of VS systems and the utility of the data that they report will help to focus efforts to strengthen VS systems. Countries and the global health community alike need better intelligence about the accuracy of VS that are widely and often uncritically used in population health research and monitoring.

     

Alpha-1 antitrypsin deficiency targeted testing and augmentation therapy: A Canadian Thoracic Society clinical practice guideline

Alpha-1 antitrypsin (A1AT) functions primarily to inhibit neutrophil elastase, and deficiency predisposes individuals to the development of chronic obstructive pulmonary disease (COPD). Severe A1AT deficiency occurs in one in 5000 to one in 5500 of the North American population. While the exact prevalence of A1AT deficiency in patients with diagnosed COPD is not known, results from small studies provide estimates of 1% to 5%. The present document updates a previous Canadian Thoracic Society position statement from 2001, and was initiated because of lack of consensus and understanding of appropriate patients suitable for targeted testing for A1AT deficiency, and for the use of A1AT augmentation therapy. Using revised guideline development methodology, the present clinical practice guideline document systematically reviews the published literature and provides an evidence-based update. The evidence supports the practice that targeted testing for A1AT deficiency be considered in individuals with COPD diagnosed before 65 years of age or with a smoking history of <20 pack years. The evidence also supports consideration of A1AT augmentation therapy in nonsmoking or exsmoking patients with COPD (forced expiratory volume in 1 s of 25% to 80% predicted) attributable to emphysema and documented A1AT deficiency (level ≤11 μmol/L) who are receiving optimal pharmacological and nonpharmacological therapies (including comprehensive case management and pulmonary rehabilitation) because of benefits in computed tomography scan lung density and mortality.