Modes d’invasion et d’expression de Botrytis cinerea, champignon pathogène de la Vigne

Introduction : Le champignon phytopathogène Botrytis cinerea est un polyphage qui cause d’énormes dégâts en agriculture. La culture de la vigne représente en France des enjeux économiques importants. La vigne est touchée par la maladie de la pourriture grise due à B. cinerea, conduisant à des pertes de rendement importantes. L’objectif de cette étude est, compte tenu des effets sur le développement fongique de facteurs environnementaux (Sautour et al., 2001a, b), la caractérisation du caractère pathogène et la comparaison des structures de populations de B. cinerea isolées de différentes régions de France : Bourgogne, Languedoc et Champagne.Matériel et méthodes : Les suspensions de conidies à une concentration de 105-106 spores/ml sont déposées sur la surface extérieure de feuilles de vigne. Les étapes d’expansion de la nécrose sont suivies toutes les 24 h ; au bout de 10 jours, les symptômes sont classés selon leurs niveaux d’expression et leur mode de colonisation de la feuille. La liaison entre les caractères suivants : le début de l’infection, les symptômes, l’infection primaire, l’apparence du mycélium, la production des spores, a été testée sous l’hypothèse nulle d’une association aléatoire.Résultats : Observation et classification de types des symptômes, selon le début de l’infection et les niveaux d’infection primaire :Trois types de symptômes ont été identifiés : l’infection humide radiale (WN), l’infection ponctuelle (SN), et l’infection par les nervures (VN).Les effets de l’infection primaire se manifestent au sixième jour suivant l’inoculation, comme une tache (is) ou comme une diffusion de lésion moyenne (mi 40 mm).Les tests statistiques de l’hypothèse nulle d’homogénéité (χ2 d’homogénéité) montrent que certains couples de caractères ont une tendance à la corrélation : l’initiation de l’infection à 24 heures avec li (χ2= 31,98), une forte association entre WN et li et mi, d’une part, avec SN et is d’autre part (χ2= 76,7). On note une tendance à l’association entre WN et SN avec 10 jours (χ2 = 14,9) de l’apparition de mycéliums; entre WN et SN, et 10 jours (χ2 = 12,9) de la production de spores. Ainsi, la vitesse d’apparition du mycélium et la formation des spores sont corrélés (χ2 = 16,6).Perspectives ; La variation de l’expression de la virulence pourrait être liée à la capacité d’infection du champignon pathogène, incluant la germination des spores, la pénétration dans les cellules hôtes vivantes et l’invasion tissulaire.En combinaison avec des études de génétique moléculaire, le mécanisme de l’infection pourrait être expliqué. Ces recherches devraient conduire au contrôle efficace du développement de B. cinerea

Protective effect of IgM against colonization of the respiratory tract by nontypeable Haemophilus influenzae in patients with hypogammaglobulinemia.

International audienceBACKGROUND: Primary immunoglobulin deficiencies lead to recurrent bacterial infections of the respiratory tract and bronchiectasis, even with adequate immunoglobulin replacement therapy. It is not known whether patients able to secrete IgM (eg, those with hyper-IgM [HIgM] syndrome) are as susceptible to these infections as patients who lack IgM production (eg, those with panhypogammaglobulinemia [PHG]). OBJECTIVE: This study is aimed at identifying specific microbiological and clinical (infections) characteristics that distinguish immunoglobulin-substituted patients with PHG from patients with HIgM syndrome. METHODS: A cohort of patients with HIgM syndrome (n = 25) and a cohort of patients with PHG (n = 86) were monitored prospectively for 2 years while receiving similar polyvalent immunoglobulin replacement therapies. Regular bacterial analyses of nasal swabs and sputum were performed, and clinical events were recorded. In parallel, serum and saliva IgM antibody concentrations were measured. RESULTS: When compared with patients with PHG, patients with HIgM syndrome were found to have a significantly lower risk of nontypeable Haemophilus influenzae carriage in particular (relative risk, 0.39; 95% CI, 0.21-0.63). Moreover, patients with HIgM syndrome (including those unable to generate somatic hypermutations of immunoglobulin genes) displayed anti-nontypeable H influenzae IgM antibodies in their serum and saliva. Also, patients with HIgM syndrome had a lower incidence of acute respiratory tract infections. CONCLUSIONS: IgM antibodies appear to be microbiologically and clinically protective and might thus attenuate the infectious consequences of a lack of production of other immunoglobulin isotypes in patients with HIgM syndrome. Polyvalent IgG replacement therapy might not fully compensate for IgM deficiency. It might thus be worth adapting long-term antimicrobial prophylactic regimens according to the underlying B-cell immunodeficiency phenotype

Differential expression of interferon alpha protein provides clues to tissue specificity across type I interferonopathies

International audienceWhilst upregulation of type I interferon (IFN) signaling is common across the type I interferonopathies (T1Is), central nervous system (CNS) involvement varies between these disorders, the basis of which remains unclear. We collected cerebrospinal fluid (CSF) and serum from patients with Aicardi-Goutières syndrome (AGS), STING-associated vasculopathy with onset in infancy (SAVI), presumed monogenic T1Is (pT1I), childhood systemic lupus erythematosus with neuropsychiatric features (nSLE), non-IFN-related autoinflammation (AI) and non-inflammatory hydrocephalus (as controls). We measured IFN-alpha protein using digital ELISA. Eighty-two and 63 measurements were recorded respectively in CSF and serum of 42 patients and 6 controls. In an intergroup comparison (taking one sample per individual), median CSF IFN-alpha levels were elevated in AGS, SAVI, pT1I, and nSLE compared to AI and controls, with levels highest in AGS compared to all other groups. In AGS, CSF IFN-alpha concentrations were higher than in paired serum samples. In contrast, serum IFN was consistently higher compared to CSF levels in SAVI, pT1I, and nSLE. Whilst IFN-alpha is present in the CSF and serum of all IFN-related diseases studied here, our data suggest the primary sites of IFN production in the monogenic T1I AGS and SAVI are, respectively, the CNS and the periphery. These results inform the diagnosis of, and future therapeutic approaches to, monogenic and multifactorial T1Is

A 1-Year Prospective French Nationwide Study of Emergency Hospital Admissions in Children and Adults with Primary Immunodeficiency

International audiencePURPOSE: Patients with primary immunodeficiency (PID) are at risk of serious complications. However, data on the incidence and causes of emergency hospital admissions are scarce. The primary objective of the present study was to describe emergency hospital admissions among patients with PID, with a view to identifying "at-risk" patient profiles.METHODS: We performed a prospective observational 12-month multicenter study in France via the CEREDIH network of regional PID reference centers from November 2010 to October 2011. All patients with PIDs requiring emergency hospital admission were included.RESULTS: A total of 200 admissions concerned 137 patients (73 adults and 64 children, 53% of whom had antibody deficiencies). Thirty admissions were reported for 16 hematopoietic stem cell transplantation recipients. When considering the 170 admissions of non-transplant patients, 149 (85%) were related to acute infections (respiratory tract infections and gastrointestinal tract infections in 72 (36%) and 34 (17%) of cases, respectively). Seventy-seven percent of the admissions occurred during winter or spring (December to May). The in-hospital mortality rate was 8.8% (12 patients); death was related to a severe infection in 11 cases (8%) and Epstein-Barr virus-induced lymphoma in 1 case. Patients with a central venous catheter (n = 19, 13.9%) were significantly more hospitalized for an infection (94.7%) than for a non-infectious reason (5.3%) (p = 0.04).CONCLUSION: Our data showed that the annual incidence of emergency hospital admission among patients with PID is 3.4%. The leading cause of emergency hospital admission was an acute infection, and having a central venous catheter was associated with a significantly greater risk of admission for an infectious episode

Genetic diagnosis of primary immunodeficiencies: A survey of the French national registry

International audienceTo the Editor:Since the mid-1980s, continuous progress in genetics and genomics has accelerated the rapid identification of causative genetic variants leading to primary immunodeficiencies (PIDs; >300 genes),1 with the noticeable exception of B-cell disorders, such as common variable immunodeficiency (CVID). The identification of these mutations not only validates a clinical diagnosis but also is useful in several other respects (more accurate prognosis on phenotype/genotype correlation, targeted therapy, and genetic counseling). [...

Outcome after failure of allogeneic hematopoietic stem cell transplantation in children with acute leukemia: a study by the société Francophone de greffe de moelle et de thérapie cellulaire (SFGM-TC)

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