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112 result(s) for "CGD"
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Chronic Granulomatous Disease: a Cohort of 173 Patients—10-Years Single Center Experience from Egypt
Purpose Chronic granulomatous disease (CGD) is an inherited primary immunodeficiency disorder of phagocytes, characterized by recurrent fungal and bacterial infections. Our aim is to describe the different clinical presentations, non-infectious auto-inflammatory features, types and sites of infections, and to estimate the mortality among our large cohort. Methods This is a retrospective study conducted at the Pediatric Department of Cairo University Children’s Hospital in Egypt, including cases with a confirmed CGD diagnosis. Results One hundred seventy-three confirmed CGD patients were included. AR-CGD was diagnosed in 132 patients (76.3%) including 83 patients (48%) with p47 phox defect, 44 patients (25.4%) with p22 phox defect, and 5 patients (2.9%) with p67 phox defect. XL-CGD was diagnosed in 25 patients (14.4%). The most common recorded clinical manifestations were deep-seated abscesses and pneumonia. Gram-negative bacteria and Aspergillus were the most frequently isolated species. Regarding the outcome, 36 patients (20.8%) were lost from follow-up. Among patients with known outcome, 94/137 patients (68.6%) are living, while 43/137 patients (31.4%) died. Conclusion AR-CGD is predominant in Egypt; CGD must always be ruled out in any patient presenting with typical or atypical mycobacterial or BCG-disease.
Common Severe Infections in Chronic Granulomatous Disease
Background. Chronic granulomatous disease (CGD) is due to defective nicotinamide adenine dinucleotide phosphate oxidase activity and characterized by recurrent infections with a limited spectrum of bacteria and fungi as well as inflammatory complications. To understand the impact of common severe infections in CGD, we examined the records of 268 patients followed at a single center over 4 decades. Methods. All patients had confirmed diagnoses of CGD, and genotype was determined where possible. Medical records were excerpted into a standard format. Microbiologic analyses were restricted to Staphylococcus, Burkholderia, Serratia, Nocardia, and Aspergillus. Results. Aspergillus incidence was estimated at 2.6 cases per 100 patient-years; Burkholderia, 1.06 per 100 patient-years; Nocardia, 0.81 per 100 patient-years; Serratia, 0.98 per 100 patient-years, and severe Staphylococcus infection, 1.44 per 100 patient-years. Lung infection occurred in 87% of patients, whereas liver abscess occurred in 32%. Aspergillus incidence was 55% in the lower superoxide-producing quartiles (quartiles 1 and 2) but only 41% in the higher quartiles (rate ratio, <0.0001). Aspergillus and Serratia were somewhat more common in lower superoxide producing gp91phox deficiency. The median age at death has increased from 15.53 years before 1990 to 28.12 years in the last decade. Fungal infection carried a higher risk of mortality than bacterial infection and was the most common cause of death (55%).Gastrointestinal complications were not associated with either infection or mortality. Conclusions. Fungal infections remain a major determinant of survival in CGD. X-linked patients generally had more severe disease, and this was generally in those with lower residual superoxide production. Survival in CGD has increased over the years, but infections are still major causes of morbidity and mortality.
Reliable genetic diagnosis of NCF1 (p47phox)-deficient chronic granulomatous disease using high-throughput sequencing
Chronic granulomatous disease is caused by mutations in any of the 6 components of the phagocytic NADPH oxidase complex including gp91 , p47 , p22 , p40 , p67 , or EROS. Functional assays include reactive oxygen species (ROS) production, flow cytometry, and immunoblotting for NADPH proteins. The advent of high-throughput sequencing allows genetic diagnosis for all components except (p47 ) due to two, nearly identical, pseudogenes ( , ). The majority of NCF1-CGD patients carry a 2-base deletion caused by crossover between and or . Currently, NCF1 deficiency is diagnosed functionally: a characteristic DHR with low levels of residual ROS, loss of p47 on immunoblot, or digital droplet PCR or Gene-scan to enumerate intact (GTGT) or deleted (ΔGT). While this provides patients a clinical CGD diagnosis, for the 20% of NCF1-CGD patients with a non-ΔGT mutation a definitive genetic diagnosis is still lacking. We developed a bioinformatic method using existing short or long-read sequencing data from 48 NCF1-CGD patients or carriers. We identified both ΔGT and non-ΔGT gene mutations. Additionally, we confirm that the presence of ΔGT in is due to pseudogene copy into the locus. We compare sequence from NCF1-CGD patients to cohorts of non-NCF1-CGD and healthy controls (1000Genomes), demonstrating pseudogene replacement of in NCF1-CGD as well as the reciprocal replacement of or by in some healthy controls. With this method, reanalysis of existing sequence data may provide genetic diagnosis to NCF1-CGD patients. This technique may be modified for other diagnostically relevant pseudogenes.
Neutrophils to the ROScue: Mechanisms of NADPH Oxidase Activation and Bacterial Resistance
Reactive oxygen species (ROS) generated by NADPH oxidase play an important role in antimicrobial host defense and inflammation. Their deficiency in humans results in recurrent and severe bacterial infections, while their unregulated release leads to pathology from excessive inflammation. The release of high concentrations of ROS aids in clearance of invading bacteria. Localization of ROS release to phagosomes containing pathogens limits tissue damage. Host immune cells, like neutrophils, also known as PMNs, will release large amounts of ROS at the site of infection following the activation of surface receptors. The binding of ligands to G-protein-coupled receptors (GPCRs), toll-like receptors, and cytokine receptors can prime PMNs for a more robust response if additional signals are encountered. Meanwhile, activation of Fc and integrin directly induces high levels of ROS production. Additionally, GPCRs that bind to the bacterial-peptide analog fMLP, a neutrophil chemoattractant, can both prime cells and trigger low levels of ROS production. Engagement of these receptors initiates intracellular signaling pathways, resulting in activation of downstream effector proteins, assembly of the NADPH oxidase complex, and ultimately, the production of ROS by this complex. Within PMNs, ROS released by the NADPH oxidase complex can activate granular proteases and induce the formation of neutrophil extracellular traps (NETs). Additionally, ROS can cross the membranes of bacterial pathogens and damage their nucleic acids, proteins, and cell membranes. Consequently, in order to establish infections, bacterial pathogens employ various strategies to prevent restriction by PMN-derived ROS or downstream consequences of ROS production. Some pathogens are able to directly prevent the oxidative burst of phagocytes using secreted effector proteins or toxins that interfere with translocation of the NADPH oxidase complex or signaling pathways needed for its activation. Nonetheless, these pathogens often rely on repair and detoxifying proteins in addition to these secreted effectors and toxins in order to resist mammalian sources of ROS. This suggests that pathogens have both intrinsic and extrinsic mechanisms to avoid restriction by PMN-derived ROS. Here, we review mechanisms of oxidative burst in PMNs in response to bacterial infections, as well as the mechanisms by which bacterial pathogens thwart restriction by ROS to survive under conditions of oxidative stress.
Cancers Related to Immunodeficiencies: Update and Perspectives
The life span of patients with primary and secondary immunodeficiency is increasing due to recent improvements in therapeutic strategies. While the incidence of primary immunodeficiencies (PIDs) is 1:10,000 births, that of secondary immunodeficiencies are more common and are associated with posttransplantation immune dysfunction, with immunosuppressive medication for human immunodeficiency virus or with human T-cell lymphotropic virus infection. After infection, malignancy is the most prevalent cause of death in both children and adults with (PIDs). PIDs more often associated with cancer include common variable immunodeficiency (CVID), Wiskott-Aldrich syndrome, ataxia-telangiectasia, and severe combined immunodeficiency. This suggests that a protective immune response against both infectious non-self-(pathogens) and malignant self-challenges (cancer) exists. The increased incidence of cancer has been attributed to defective elimination of altered or \"transformed\" cells and/or defective immunity towards cancer cells. The concept of aberrant immune surveillance occurring in PIDs is supported by evidence in mice and from patients undergoing immunosuppression after transplantation. Here, we discuss the importance of PID defects in the development of malignancies and the current limitations associated with molecular pathogenesis of these diseases and emphasize the need for further knowledge of how specific mutations can modulate the immune system to alter immunosurveillance and thereby play a key role in the etiology of malignancies in PID patients.
Structure of human phagocyte NADPH oxidase in the resting state
Phagocyte oxidase plays an essential role in the first line of host defense against pathogens. It oxidizes intracellular NADPH to reduce extracellular oxygen to produce superoxide anions that participate in pathogen killing. The resting phagocyte oxidase is a heterodimeric complex formed by two transmembrane proteins NOX2 and p22. Despite the physiological importance of this complex, its structure remains elusive. Here, we reported the cryo-EM structure of the functional human NOX2-p22 complex in nanodisc in the resting state. NOX2 shows a canonical 6-TM architecture of NOX and p22 has four transmembrane helices. M3, M4, and M5 of NOX2, and M1 and M4 helices of p22 are involved in the heterodimer formation. Dehydrogenase (DH) domain of NOX2 in the resting state is not optimally docked onto the transmembrane domain, leading to inefficient electron transfer and NADPH binding. Structural analysis suggests that the cytosolic factors might activate the NOX2-p22 complex by stabilizing the DH in a productive docked conformation.
From Flies to Men: ROS and the NADPH Oxidase in Phagocytes
The cellular formation of reactive oxygen species (ROS) represents an evolutionary ancient antimicrobial defense system against microorganisms. The NADPH oxidases (NOX), which are predominantly localized to endosomes, and the electron transport chain in mitochondria are the major sources of ROS. Like any powerful immunological process, ROS formation has costs, in particular collateral tissue damage of the host. Moreover, microorganisms have developed defense mechanisms against ROS, an example for an arms race between species. Thus, although NOX orthologs have been identified in organisms as diverse as plants, fruit flies, rodents, and humans, ROS functions have developed and diversified to affect a multitude of cellular properties, i.e., far beyond direct antimicrobial activity. Here, we focus on the development of NOX in phagocytic cells, where the so-called respiratory burst in phagolysosomes contributes to the elimination of ingested microorganisms. Yet, NOX participates in cellular signaling in a cell-intrinsic and -extrinsic manner, e.g., via the release of ROS into the extracellular space. Accordingly, in humans, the inherited deficiency of NOX components is characterized by infections with bacteria and fungi and a seemingly independently dysregulated inflammatory response. Since ROS have both antimicrobial and immunomodulatory properties, their tight regulation in space and time is required for an efficient and well-balanced immune response, which allows for the reestablishment of tissue homeostasis. In addition, distinct NOX homologs expressed by non-phagocytic cells and mitochondrial ROS are interlinked with phagocytic NOX functions and thus affect the overall redox state of the tissue and the cellular activity in a complex fashion. Overall, the systematic and comparative analysis of cellular ROS functions in organisms of lower complexity provides clues for understanding the contribution of ROS and ROS deficiency to human health and disease.
Simulation on the Solid Flow in COREX Shaft Furnace with CGD Using DEM
In order to obtain the resonable gas distribution, a Center Gas Distribution (CGD) technology was introduced into a new set of COREX-3000 in Baosteel. However, CGD can affect the solid flow in the shaft furnace. In this paper, DEM was used to investigate the basic solid flow pattern, the influence of discharging rates and non-uniform discharging rates on the burden movement and the influence of CGD on the solid flow pattern. The influence of CGD on the velocity and distribution of solid flow was also studied. The results confirm that there are three types of flow zones in furnace. The discharging rate has almost no effect on the overall burdern movement. The non-uniform discharging rate leads to a large stagnant zone on one side of the shaft furnace. CGD has a great influence on the solid flow pattern of furnace, and there may be two stagnant zones where the small particles tend to segregate. The distribution of particles velocity along the radial is different with the distance from the bottom.
Beyond the Extra Respiration of Phagocytosis: NADPH Oxidase 2 in Adaptive Immunity and Inflammation
Reactive oxygen species (ROS) derived from the phagocyte NADPH oxidase (NOX2) are essential for host defence and immunoregulation. Their levels must be tightly controlled. ROS are required to prevent infection and are used in signalling to regulate several processes that are essential for normal immunity. A lack of ROS then leads to immunodeficiency and autoinflammation. However, excess ROS are also deleterious, damaging tissues by causing oxidative stress. In this review, we focus on two particular aspects of ROS biology: (i) the emerging understanding that NOX2-derived ROS play a pivotal role in the development and maintenance of adaptive immunity and (ii) the effects of excess ROS in systemic disease and how limiting ROS might represent a therapeutic avenue in limiting excess inflammation.
A low switching loss GaN trench MOSFET design utilizing a triple-shield structure
An innovative GaN trench MOSFET featuring an ultra-low gate-drain charge ( Q gd ) is proposed, with its operational mechanisms thoroughly investigated using TCAD simulations. This novel MOSFET design introduces a triple-shield structure (BPSG-MOS) comprising three critical components: (1) a grounded split gate (SG), (2) a P+ shield region (PSR), and (3) a semi-wrapped BP layer that extends the P-shield beneath the gate and along the sidewalls of the trench gate. Both the SG and PSR effectively reduce gate-drain coupling, transforming most of the gate-drain capacitance ( C gd ) into a series combination of gate-source capacitance ( C gs ) and drain-source capacitance ( C ds ). Furthermore, the BP layer refines the gate-drain capacitance by converting the C gd at the trench gate sidewalls into C gs . This configuration significantly lowers C gd , resulting in an ultra-low Q gd . Compared to the dual-shield MOSFET (PSGT-MOS) and the conventional trench MOSFET (TG-MOS), the BPSG-MOS achieves reductions in C gd by 81% and 98%, respectively.