[Primary immunodeficiencies and Bruton's disease genetic analysis: which prospects offers this genetic diagnosis?]. / Déficits immunitaires primitifs et analyse génétique de la maladie de Bruton: quelles perspectives offre ce diagnostic génétique?

Bruton's disease is the most frequently primary X-linked immunodeficiency. Bruton's tyrosine kinase (Btk) is encoded by the XLA gene that when mutated causes bruton's disease. This protein acts in multiple intracellular signaling pathways where the BCR (B-cell receptor) pathway is the most elucidated. Moreover 400 mutations were found and identified as responsible for B-cells differentiation block; consequences are a lack of B-cells in peripheral blood and hypo/agammaglobulinemia. Thus, patients are more susceptible to early and recurring infections occurring before the age of one year. Laboratory testing allow differential diagnosis among primary immunodeficiencies in which others hypogammaglobulinemia. Genetic analyses help physicians for clinical and biological diagnosis, and allow prenatal diagnosis for patient's family. Patient's management is based upon polyclonal immunoglobulin supplementation, infectious diseases prevention and genetic advice.

[Validation of a Bruton's disease genetic analysis method]. / Validation d'une méthode d'analyse génétique de la maladie de Bruton.

Bruton's disease is the most frequently primary X-linked immunodeficiency. Patients are more susceptible to early and recurring infections associated with hypo/agammaglobulinemia and a severe B-cell deficiency. Moreover, 400 mutations were found in the XLA gene which codes the Btk tyrosine kinase and were identified as responsible for Bruton's disease. Genetic study was carried out with one group of patients named NECKER, composed by five XLA patients and two parents whose XLA gene was sequenced by an Italian crew. Results were obtained by PCR of 19 exons and initial/terminal intron's parts, followed by PCR-sequencing with universal primers and sequencing. The results from this study allowed the validation of the sequencing technique by comparing NECKER group data (equivalent results with Italian data). In addition, the mutation multiplicity (described or not, coding/non coding) need an exact analysis that should be given to clinicians through clear and trustful results. In this way, a strategy to analyse untreated results was created based on the mutation type. The genetic analysis could help physicians for uncertain diagnosis in immune defficiencies, allows proposing a genetic advice to the patient's family and the construction of a data base permits a best understanding of this disease.

Underestimation of plasma level of factor V coagulant activity and fibrinogen concentration together with prolonged prothrombin time, activated partial thromboplastin time and thrombin time can result from pre-analytical very low calcium level in citrated sample tube.

INTRODUCTION: Pre-analytical phase is a critical step in the haemostasis laboratory cycle. Numerous variations affect tests results, and it is crucial to detect them in order to reject improper specimens before reporting test results. Comparing to prior results or requesting, a repeat sample can help in pre-analytical irregularity assessment. METHODS: Each time a sample addressed to our laboratory displayed aberrant results or discordant with a prior report, another specimen was asked and both were analysed through calcium (Ca) level, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen concentration, factor II, factor VII+X and factor V coagulant activity measurements. Among these, all the primary citrated samples from inpatients without anticoagulant treatment, displaying very low calcium level ('Ca 0' samples), were selected for this 2 years study. RESULTS: A total of 17 samples could be identified. Ca level in their paired repeat samples was always >1.00 mmol/L. Coagulation testing for 'Ca 0' samples showed a significant prolongation of PT, APTT, TT and a significant decrease for fibrinogen concentration and factor V coagulant activity. CONCLUSION: We identified factor V coagulant activity, as the parameter with the most important variation in case of very low calcium level in presumed citrated sample tubes probably contaminated with EDTA.

The profibrotic cytokine transforming growth factor-ß1 increases endothelial progenitor cell angiogenic properties.

BACKGROUND: Transforming growth factor-ß1 (TGF-ß1) is a profibrotic cytokine that plays a major role in vascular biology, and is known to regulate the phenotype and activity of various vascular cell populations. Because most fibrotic diseases, such as idiopathic pulmonary fibrosis (IPF), are associated with vascular remodeling, and as endothelial progenitor cells (EPCs) may be involved in this process, we investigated the impact of TGF-ß1 modulation of EPC angiogenic properties. METHODS: TGF-ß1 plasma levels were determined in 64 patients with IPF and compared with those in controls. The effect of TGF-ß1 on angiogenesis was studied in vivo in a Matrigel plug model and in vitro on endothelial colony-forming cells (ECFCs). We studied the effects of inhibiting the expression of the three main receptors of TGF-ß1 in ECFCs by using short interfering RNA. RESULTS: Total TGF-ß1 plasma levels were significantly increased in patients with IPF as compared with controls (P < 0.0001). TGF-ß1 had proangiogenic effects in vivo by increasing hemoglobin content and blood vessel formation in Matrigel plugs implanted in C57/Bl6 mice, and in vitro by enhancing ECFC viability and migration. The effects were abolished by silencing the three main TGF-ß1 receptors. CONCLUSIONS: TGF-ß1 is proangiogenic in vivo and induces ECFC angiogenic properties in vitro, suggesting that TGF-ß1 may play a role during vascular remodeling in fibrotic disease states via EPCs.