Real-life management of primary immune thrombocytopenia (ITP) in adult patients and adherence to practice guidelines.

Very few data exist on the management of adult patients diagnosed with primary immune thrombocytopenia (ITP). The objectives of this study were to describe the diagnostic and treatment patterns for ITP and to compare the findings to recent ITP guidelines. We retrospectively analyzed the medical records of adult ITP patients diagnosed with primary ITP between January 2011 and June 2012 and examined whether management strategies were consistent or not with eight recent guideline-recommended practices. Overall, median age at the diagnosis of the disease (n = 101) was 58 years and median platelet count 12 × 10(9)/L with 75.2 % of patients having symptoms of ITP. The study perceived two major shortcomings in the diagnostic approach: (1) failure to perform peripheral blood film examination in 22.8 % of patients, a test that is mandatory by all guidelines, and (2) ordinary bone marrow assessment in more than half of the patients at diagnosis (50.5 %), a test not routinely recommended by guidelines. Low appropriateness in therapeutic management of patients included (1) unjustified use of intravenous immunoglobulin in the absence of bleeding in 54.8 % of patients and (2) splenectomy not being deferred until 6-12 months from diagnosis (median 161 days). Data also reflect a trend towards the early use of thrombopoietin receptor agonists in the treatment of patients who are refractory to any first-line therapy. We have recognized important areas of inapropriateness in the diagnostic and therapeutic management of adult ITP patients. Compliance with established guidelines should be encouraged in order to improve patient outcomes.

Design and application of a 23-gene panel by next-generation sequencing for inherited coagulation bleeding disorders.

INTRODUCTION: Molecular testing of Inherited bleeding coagulation disorders (IBCDs) not only offers confirmation of diagnosis but also aids in genetic counselling, prenatal diagnosis and in certain cases genotype-phenotype correlations are important for predicting the clinical course of the disease and to allow tailor-made follow-up of individuals. Until recently, genotyping has been mainly performed by Sanger sequencing, a technique known to be time consuming and expensive. Currently, next-generation sequencing (NGS) offers a new potential approach that enables the simultaneous investigation of multiple genes at manageable cost. AIM: The aim of this study was to design and to analyse the applicability of a 23-gene NGS panel in the molecular diagnosis of patients with IBCDs. METHODS: A custom target enrichment library was designed to capture 31 genes known to be associated with IBCDs. Probes were generated for 296 targets to cover 86.3 kb regions (all exons and flanking regions) of these genes. Twenty patients with an IBCDs phenotype were studied using NGS technology. RESULTS: In all patients, our NGS approach detected causative mutations. Twenty-one pathogenic variants were found; while most of them were missense (18), three deletions were also identified. Six novel mutations affecting F8, FGA, F11, F10 and VWF genes, and 15 previously reported variants were detected. NGS and Sanger sequencing were 100% concordant. CONCLUSION: Our results demonstrate that this approach could be an accurate, reproducible and reliable tool in the rapid genetic diagnosis of IBCDs.

Relationship between calcium mobilization and platelet α- and δ-granule secretion. A role for TRPC6 in thrombin-evoked δ-granule exocytosis.

Changes in cytosolic Ca(2+) concentration ([Ca(2+)]c) regulate granule secretion in different cell types. Thrombin activates PAR1 and PAR4 receptors and promotes release of Ca(2+) from distinct intracellular stores, which, in turn, activates store-operated Ca(2+) entry (SOCE). A crucial step during platelet function is the release of physiological agonists stored in secretory granules to the extracellular compartment during activation. We aim to study the role of Ca(2+) mobilization from the extracellular compartment or from different intracellular stores in platelet granule secretion. By using flow cytometry, we have found that α- and δ-granules are secreted in thrombin-stimulated platelets in the absence of extracellular Ca(2+), and in a concentration-dependent manner. Our findings show that thrombin-stimulated granule secretion depends on Ca(2+) mobilization from intracellular stores. Analysis of the kinetics of granule secretion reveals that platelet stimulation with thrombin results in rapid release of α-granules which precedes the secretion of δ-granules. Incubation of platelets with a specific antibody, which recognizes the extracellular amino acid sequence 573-586 of TRPC6, inhibited thrombin-evoked δ-granule exocytosis. Our results indicate that the mechanisms underlying thrombin-induced α- and δ-granule secretion show differences in dependency on Ca(2+) mobilization.

Identification of seven novel SMPD1 mutations causing Niemann-Pick disease types A and B.

Niemann-Pick disease (NPD) types A and B are autosomal, recessively inherited, lysosomal storage disorders caused by deficient activity of acid sphingomyelinase (E.C. 3.1.4.12) because of mutations in the sphingomyelin phosphodiesterase-1 (SMPD1) gene. Here, we present the molecular analysis and clinical characteristics of 15 NPD type A and B patients. Sequencing the SMDP1 gene revealed eight previously described mutations and seven novel mutations including four missense [c.682T>C (p.Cys228Arg), c.1159T>C (p.Cys387Arg), c.1474G>A (p.Gly492Ser), and c.1795C>T (p.Leu599Phe)], one frameshift [c.169delG (p.Ala57Leufs*20)] and two splicing (c.316+1G>T and c.1341delG). The most frequent mutations were p.Arg610del (21%) and p.Gly247Ser (12%). Two patients homozygous for p.Arg610del and initially classified as phenotype B showed different clinical manifestations. Patients homozygous for p.Leu599Phe had phenotype B, and those homozygous for c.1341delG or c.316+1G>T presented phenotype A. The present results provide new insight into genotype/phenotype correlations in NPD and emphasize the difficulty of classifying patients into types A and B, supporting the idea of a continuum between these two classic phenotypes.

Diagnosis of secondary myelodysplastic syndromes (MDS) following autologous transplantation should not be based only on morphological criteria used for diagnosis of de novo MDS.

Secondary myelodysplastic syndromes (MDS) are increasingly being reported after autologous transplantation. Transient dysplastic changes have also been observed after this type of treatment. However, to the best of our knowledge no systematic morphological analysis has been performed to determine the influence of stem cell transplantation on bone marrow morphology. In 53 patients undergoing autologous transplantation, we evaluated the bone marrow, before and 6 and 12 months after the transplant, in order to analyze the appearance of dyshemopoietic changes, assessed according to a pre-established score. We also studied 25 bone marrow samples obtained at the time of diagnosis, prior to treatment, but we did not find morphological atypia. Six months after transplant, cellularity and thrombopoiesis had decreased in 38% and 49% of patients respectively, although 1 year after the process they were normal in most cases. Myelodysplasia was already present in bone marrow before transplantation and continued to be in evidence for a long time afterwards. This suggests that chemotherapy and radiotherapy used prior to transplantation are responsible for dysplastic changes. The myeloid line was the most affected with 100% of patients showing dysgranulopoiesis 1 year after autografting. Cytopenias were observed in 51% and 44% of patients 6 and 12 months after transplantation. Moreover, concomitant presence of cytopenia and myelodysplasia was observed in 37.7% of patients at 6 months after transplantation and 25% at 12 months, and therefore they could be diagnosed with MDS. These data contrast with the incidence of secondary MDS reported in earlier publications. According to these findings, the value of the French-American-British Co-operative Group criteria for the diagnosis of MDS following autologous transplantation is questionable. Moreover, since dyshemopoietic features are almost always present after autologous transplant, morphological criteria are not useful for early recognition of patients with secondary MDS after transplantation.

Platelet serotonin is a mediator potentially involved in anaphylactic reaction to neuromuscular blocking drugs.

A platelet serotonin release test was performed on blood from 10 patients who had suffered from an IgE-dependent allergic reaction to a neuromuscular blocking drug. The results were compared with those of a leukocyte histamine release test. The upper limit of serotonin release induced by neuromuscular blockers was estimated to be 2.3% in non-allergic patients. The test was positive in six patients and was consistent with histamine release in five. Serotonin release induced by neuromuscular blockers comprised 2.9-25% of total platelet serotonin content. We conclude that serotonin is one of the mediators associated with histamine release during anaphylaxis to neuromuscular blockers. Platelet serotonin release tests may be useful for the investigation of anaphylactic responses to neuromuscular blocking drugs.

Clinical evaluation of in vitro leukocyte histamine release in allergy to muscle relaxant drugs.

We have evaluated the in vitro leukocyte histamine release tests for the diagnosis of allergy to muscle relaxant drugs in 40 patients (Group A) and a control group of 44 subjects with negative leukocyte histamine release (Group B). Non-IgE dependent histamine release, expressed as a percentage of the total blood histamine, was 3.94% +/- 0.49 in Group B. The upper limit of positivity was estimated to be 5% (mean + 2 SD). Leukocyte histamine release tests were positive in 65% of the patients from Group A. The concordance between LHR and QAS-RIA was 64%. The maximal histamine release was observed at dilutions of 10(-2)-10(-4) in 20 of the 26 positive cases. The maximal histamine release was 43.8% +/- 23.3. The spontaneous histamine release was as low as 1.7% +/- 1.1. Cross-reactivity among the 5 different muscle relaxant drugs has been investigated and compared by intradermal testing. The muscle relaxant drugs which gave the lower skin reaction (M2) and the drug responsible for shock (M1) were selected for the study of in vitro leukocyte histamine release. Of 20 M2. All of the 10 cases had negative ID tests with M2. Three of these patients subsequently underwent general anesthesia with the muscle relaxant chosen as harmless (M2) without any clinical reaction.