Le botulisme infantile (à propos d'un cas)

Un cas suspecté de botulisme infantile chez une fillette de 11 mois est ici rapporté. Le botulisme infantile, est dû à la production in vivo de la toxine botulique chez l'enfant de moins de 1 an, le plus souvent par Clostridum botulinum, bactérie anaérobie dont le réservoir est tellurique et animal. Cette toxine bloque la transmission cholinergique au niveau de la jonction neuromusculaire des systèmes nerveux périphériques et autonome. Il en découle une paralysie des paires crâniennes, des membres ainsi qu'une atteinte des fonctions de la musculature lisse dont l'intensité est extrêmement variable. Le diagnostic est réalisé par la mise en évidence de la toxine ou de la bactérie dans différents prélèvements (sérum, selles, aliments consommés) grâce au test de létalité sur souris. L'EMG est le seul autre examen informatif en révélant la présence d'un bloc pré-synaptique. L'évolution est capricieuse, et la prise en charge, symptomatique, doit se faire à proximité d'une unité de réanimation.A suspected case of infantile botulism in a 11 month old young girl is reported here. Infant botulism, results of the in vivo production of botulinal toxin (BoTox) from the child of less than 1 year, generally by Clostridium botulinum, anaerobic bacteria whose tank is telluric and animal. This toxin blocks the cholinergic transmission at the neuromuscular junction of the autonomic and peripheral nervous systems. It results from this a paralysis of the cranial and members nerves and a dysfunction of the smoothe musculature whose intensity is extremely variable. Infant botulism is confirmed by isolation of Clostridium botulinum from stool or identification of botulinal toxin by the mouse bioassay . Electromyography is the only other informative investigation by revealing the presence of a presynaptic block. It evolution is capricious, and the management, symptomatic, must be done near an intensive care unit.GRENOBLE1-BU Médecine pharm. (385162101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Hyper-IgM syndrome type 4 with a B lymphocyte–intrinsic selective deficiency in Ig class-switch recombination

Hyper-IgM syndrome (HIGM) is a heterogeneous condition characterized by impaired Ig class-switch recombination (CSR). The molecular defects that have so far been associated with this syndrome — which affect the CD40 ligand in HIGM type 1 (HIGM1), CD40 in HIGM3, and activation-induced cytidine deaminase (AID) in HIGM2 — do not account for all cases. We investigated the clinical and immunological characteristics of 15 patients with an unidentified form of HIGM. Although the clinical manifestations were similar to those observed in HIGM2, these patients exhibited a slightly milder HIGM syndrome with residual IgG production. We found that B cell CSR was intrinsically impaired. However, the generation of somatic hypermutations was observed in the variable region of the Ig heavy chain gene, as in control B lymphocytes. In vitro studies showed that the molecular defect responsible for this new HIGM entity (HIGM4) occurs downstream of the AID activity, as the AID gene was induced normally and AID-induced DNA double-strand breaks in the switch μ region of the Ig heavy chain locus were detected during CSR as normal. Thus, HIGM4 is probably the consequence of a selective defect either in a CSR-specific factor of the DNA repair machinery or in survival signals delivered to switched B cells

Clinical and immunologic phenotype associated with activated phosphoinositide 3-kinase δ syndrome 2: A cohort study

BACKGROUND: Activated phosphoinositide 3-kinase δ syndrome (APDS) 2 (p110δ-activating mutations causing senescent T cells, lymphadenopathy, and immunodeficiency [PASLI]-R1), a recently described primary immunodeficiency, results from autosomal dominant mutations in PIK3R1, the gene encoding the regulatory subunit (p85α, p55α, and p50α) of class IA phosphoinositide 3-kinases. OBJECTIVES: We sought to review the clinical, immunologic, and histopathologic phenotypes of APDS2 in a genetically defined international patient cohort. METHODS: The medical and biological records of 36 patients with genetically diagnosed APDS2 were collected and reviewed. RESULTS: Mutations within splice acceptor and donor sites of exon 11 of the PIK3R1 gene lead to APDS2. Recurrent upper respiratory tract infections (100%), pneumonitis (71%), and chronic lymphoproliferation (89%, including adenopathy [75%], splenomegaly [43%], and upper respiratory tract lymphoid hyperplasia [48%]) were the most common features. Growth retardation was frequently noticed (45%). Other complications were mild neurodevelopmental delay (31%); malignant diseases (28%), most of them being B-cell lymphomas; autoimmunity (17%); bronchiectasis (18%); and chronic diarrhea (24%). Decreased serum IgA and IgG levels (87%), increased IgM levels (58%), B-cell lymphopenia (88%) associated with an increased frequency of transitional B cells (93%), and decreased numbers of naive CD4 and naive CD8 cells but increased numbers of CD8 effector/memory T cells were predominant immunologic features. The majority of patients (89%) received immunoglobulin replacement; 3 patients were treated with rituximab, and 6 were treated with rapamycin initiated after diagnosis of APDS2. Five patients died from APDS2-related complications. CONCLUSION: APDS2 is a combined immunodeficiency with a variable clinical phenotype. Complications are frequent, such as severe bacterial and viral infections, lymphoproliferation, and lymphoma similar to APDS1/PASLI-CD. Immunoglobulin replacement therapy, rapamycin, and, likely in the near future, selective phosphoinositide 3-kinase δ inhibitors are possible treatment options

Dual Energy X-ray Absorptiometry Interpretation and Reporting in Children and Adolescents: The 2007 ISCD Pediatric Official Positions

The International Society for Clinical Densitometry Official Positions on reporting of densitometry results in children represent an effort to consolidate opinions to assist healthcare providers determine which skeletal sites should be assessed, which adjustments should be made in these assessments, appropriate pediatric reference databases, and elements to include in a dual energy X-ray absorptiometry (DXA) report. Skeletal sites recommended for assessment are the lumbar spine and total body less head, the latter being valuable as it provides information on soft tissue, as well as bone. Interpretation of DXA findings in children with growth or maturational delay requires special consideration; adjustments are required to prevent erroneous interpretation. Normative databases used as a reference should be based on a large sample of healthy children that characterizes the variability in bone measures relative to gender, age, and race/ethnicity, and should be specific for each manufacturer and model of densitometer and software. Pediatric DXA reports should provide relevant demographic and health information, technical details of the scan, Z-scores, and should not include T-scores. The rationale and evidence for development of the Official Positions are provided. Given the sparse data currently available in many of these areas, it is likely that these positions will change over time as new data become available. © 2008 The International Society for Clinical Densitometry