Chronic granulomatous disease

Targeting respiratory virus-induced reactive oxygen species in airways diseases

The immune response to virus infection in the respiratory tract must be carefully balanced to achieve pathogen clearance without excessive immunopathology. For chronic respiratory diseases where there is ongoing inflammation, such as in asthma and COPD, airway immune balance is perturbed, and viral infection frequently worsens (exacerbates) these conditions. Reactive oxygen species (ROS) are critical to the induction and propagation of inflammation, and when appropriately regulated, ROS are vital cell signalling molecules and contribute to innate immunity. However, extended periods of high ROS concentration can cause excessive cellular damage that dysregulates antiviral immunity and promotes inflammation. Traditional antioxidant therapeutics have had limited success treating inflammatory diseases such as viral exacerbations of asthma or COPD, owing to nonspecific pharmacology and poorly understood pharmacokinetic properties. These drawbacks could be addressed with novel drug delivery technologies and pharmacological agents. This review summarises current research on ROS imbalances during virus infection, discusses the commercially available mitochondrial antioxidant drugs that have progressed to clinical trial and assesses novel drug delivery approaches for antioxidant delivery to the airways. Additionally, it provides a perspective on future research into pharmacological targeting of ROS for the treatment of respiratory virus infection and disease.

Psychrobacter Infections in Humans-A Narrative Review of Reported Cases

BACKGROUND

Psychrobacter species are aerobic, Gram-negative, spherical-to-rod-shaped, psychrophilic bacteria that belong to the Moraxellaceae family. In spite of their uncommon manifestation in the general population, infections due to Psychrobacter spp. are increasingly identified especially in immunocompromised individuals or patients with severe comorbidities.

OBJECTIVES

This review aims to analyze all reported instances of Psychrobacter spp. infections in humans, with an emphasis on data pertaining to epidemiology, microbiology, antimicrobial resistance, treatment strategies, and mortality outcomes.

METHODS

A narrative review was performed through a literature search of PubMed/MedLine and Scopus databases.

RESULTS

In total, 12 articles offered data on 12 patients infected with Psychrobacter spp. Their mean age was 33.41 years, while 63.64% of them were male. Immunosuppression was the predominant risk factor (33.3%). Bacteremia was the most commonly observed type of infection (41.6%), followed by meningitis, skin infection, and conjunctivitis. Psychrobacter immobilis was the most usually identified species (33.3%). The pathogen exhibited sensitivity to most antimicrobials. The most widely administered antimicrobials included cephalosporins (70%), followed by aminopenicillins and vancomycin (40%, respectively). The clinical outcome depended primarily on the infection site; mortality rate was high (44.4%), especially in cases of bacteremia (50%).

CONCLUSION

Due to the potential of Psychrobacter spp. to cause serious infection, clinicians and laboratory professionals should consider it in the differential diagnosis in patients with infections by Gram-negative spherical bacteria, particularly in patients with significant comorbidities and immunodeficiency, in order to accurately establish the diagnosis and proceed to the right treatment.

Integrated analysis of proteome and transcriptome revealed changes in multiple signaling pathways involved in immunity in the northern snakehead (Channa argus) during Nocardia seriolae infection

The northern snakehead (Channa argus) is a valuable aquaculture species across certain Asian countries, contributing significantly to economic prosperity and dietary needs. However, its productivity faces significant challenges, particularly from diseases such as nocardiosis, caused by Nocardia seriolae. To date, the majority of research efforts have focused on describing the observed phenomena related to N. seriolae infection. However, there remains a notable gap in knowledge concerning the infectivity of N. seriolae and the immune response it elicits. To better understand the modulation of the immune responses to N. seriolae infection in snakeheads, we investigated the splenic proteome profiles. Specifically, we compared the profiles between uninfected northern snakehead specimens and those infected with N. seriolae at 96 h using the label-free data-independent acquisition methodology. A total of 700 differentially expressed proteins (DEPs) were obtained. Of these, 353 proteins exhibited upregulation, whereas 347 proteins displayed downregulation after the infection. The DEPs were mapped to the reference canonical pathways in Kyoto Encyclopedia of Genes and Genomes database, revealing several crucial pathways that were activated following N. seriolae infection. Noteworthy, among these were pathways such as ferroptosis, complement and coagulation cascades, chemokine signaling, tuberculosis, natural killer cell-mediated cytotoxicity, and Th17 cell differentiation. Furthermore, protein-protein interaction networks were constructed to elucidate the interplay between immune-related DEPs. These results revealed expression changes in multiple signaling pathways during the initial colonization phase of N. seriolae. This discovery offers novel insights into the infection mechanisms and host interaction dynamics associated with N. seriolae.

Spatiotemporal distribution of environmental microbiota around animal farms adjacent to produce fields in central coast California

This study aimed to identify different environmental microbiota in animal farms adjacent to produce fields and to understand their potential flow pattern. Soil and water samples were collected from 16 locations during the winter, spring, summer, and fall seasons. In addition, a high-resolution digital elevation model helped to create a stream network to understand the potential flow of the microbiome. Metagenomic analysis of the 16 S rRNA gene revealed that soil and water samples from the four seasons harbor diverse microbiome profiles. The phylogenetic relationship of operational taxonomic units (OTUs) is separated by a maximum of 0.6 Bray-Curtis distance. Similarly, the Principal Component Analysis (P = 0.001) demonstrated the soil and water microbiome clustering across different locations and seasons. The relative abundance of Proteobacteria, Bacteroidetes, and Firmicutes was higher in the water samples than in the soil samples. In contrast, the relative abundance of Actinobacteria and Chloroflexi was higher in the soil compared to the water samples. Soil samples in summer and water samples in spring had the highest abundance of Bacteroidetes and Firmicutes, respectively. A unique microbial community structure was found in water samples, with an increased abundance of Hydrogenophaga and Solirubrobacter. Genera that were significantly abundant at a 1% false discovery rate (FDR) among seasons and soil or water samples, include Nocardioides, Gemmatimonas, JG30-KF-CM45, Massilia, Gaiellales, Sphingomonas, KD4-96, Bacillus, Streptomyces, Gaiella, and Gemmatimonadaceae. The relative abundance of pathogenic genera, including Mycobacterium, Bacteroides, Nocardia, Clostridium, and Corynebacterium, were significantly (at 1% FDR) affected by seasons and environmental type. The elevation-based stream network model suggests the potential flow of microbiomes from the animal farm to the produce fields.

The pathobiology of human fungal infections

Human fungal infections are a historically neglected area of disease research, yet they cause more than 1.5 million deaths every year. Our understanding of the pathophysiology of these infections has increased considerably over the past decade, through major insights into both the host and pathogen factors that contribute to the phenotype and severity of these diseases. Recent studies are revealing multiple mechanisms by which fungi modify and manipulate the host, escape immune surveillance and generate complex comorbidities. Although the emergence of fungal strains that are less susceptible to antifungal drugs or that rapidly evolve drug resistance is posing new threats, greater understanding of immune mechanisms and host susceptibility factors is beginning to offer novel immunotherapeutic options for the future. In this Review, we provide a broad and comprehensive overview of the pathobiology of human fungal infections, focusing specifically on pathogens that can cause invasive life-threatening infections, highlighting recent discoveries from the pathogen, host and clinical perspectives. We conclude by discussing key future challenges including antifungal drug resistance, the emergence of new pathogens and new developments in modern medicine that are promoting susceptibility to infection.

Polylactic acid-based dressing with oxygen generation and enzyme-like activity for accelerating both light-driven biofilm elimination and wound healing

Background

Photodynamic therapy (PDT) is a widely used therapeutic approach for eradicating bacterial biofilms in infected wound, but its effectiveness is limited by the hypoxic environment within the biofilm. This study aimed to investigate whether the efficiency of photodynamic removing biofilm is improving by providing oxygen (O2), as well as the expression of cytokines involved in infected wound healing.

Methods

Manganese dioxide (MnO2) nanoparticles with catalase-like activity were grown in situ on graphitic phase carbon nitride (g-C3N4, CN) nanosheets to construct an all-in-one CN-MnO2 nanozyme, which was then incorporated into poly-L-lactic acid (PLLA) to prepare CN-MnO2/PLLA wound dressing by electrospinning. Subsequently, the in vitro antibacterial biofilm ratio and antibacterial ratio of CN-MnO2/PLLA wound dressing were examined by spread plate and crystal violet staining under irradiation with 808 nm near-infrared light and 660 nm visible light. Meanwhile, the rat skin injury model was established, and hematoxylin and eosin (H&E), Masson's, tumor necrosis factor-α (TNF-α), Arginase 1 (Arg-1), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (BFGF) were evaluated in vivo to assess the effect of CN-MnO2/PLLA wound dressing on wound healing.

Results

Biofilm density caused by Staphylococcus aureus and Pseudomonas aeruginosa had elimination rates of 83 and 62%, respectively, when treated with CN-MnO2/PLLA dressing. Additionally, the dressing exhibited high antibacterial efficacy against both bacteria, achieving 99 and 98.7% elimination of Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Furthermore, in vivo experiments showed that the CN-MnO2/PLLA wound dressing achieved complete healing of infected wounds on Day 14, with a wound healing rate of >99% by increasing collagen deposition, expression of anti-inflammatory cytokine Arg-1, vascularization cytokine VEGF, and epithelial cell BFGF, and inhibiting the expression of inflammatory cytokine TNF-α.

Conclusions

The CN-MnO2/PLLA wound dressing exhibited excellent antibacterial properties in vitro and in vivo. In addition, CN-MnO2/PLLA wound dressing accelerated rapid wound healing through an anti-inflammatory, pro-vascular regeneration and skin tissue remodeling mechanism.

Phage therapy to treat cystic fibrosis Burkholderia cepacia complex lung infections: perspectives and challenges

Burkholderia cepacia complex is a cause of serious lung infections in people with cystic fibrosis, exhibiting extremely high levels of antimicrobial resistance. These infections are difficult to treat and are associated with high morbidity and mortality. With a notable lack of new antibiotic classes currently in development, exploring alternative antimicrobial strategies for Burkholderia cepacia complex is crucial. One potential alternative seeing renewed interest is the use of bacteriophage (phage) therapy. This review summarises what is currently known about Burkholderia cepacia complex in cystic fibrosis, as well as challenges and insights for using phages to treat Burkholderia cepacia complex lung infections.

Tuberculosis in otherwise healthy adults with inherited TNF deficiency

Severe defects in human IFNγ immunity predispose individuals to both Bacillus Calmette-Guérin disease and tuberculosis, whereas milder defects predispose only to tuberculosis1. Here we report two adults with recurrent pulmonary tuberculosis who are homozygous for a private loss-of-function TNF variant. Neither has any other clinical phenotype and both mount normal clinical and biological inflammatory responses. Their leukocytes, including monocytes and monocyte-derived macrophages (MDMs) do not produce TNF, even after stimulation with IFNγ. Blood leukocyte subset development is normal in these patients. However, an impairment in the respiratory burst was observed in granulocyte-macrophage colony-stimulating factor (GM-CSF)-matured MDMs and alveolar macrophage-like (AML) cells2 from both patients with TNF deficiency, TNF- or TNFR1-deficient induced pluripotent stem (iPS)-cell-derived GM-CSF-matured macrophages, and healthy control MDMs and AML cells differentiated with TNF blockers in vitro, and in lung macrophages treated with TNF blockers ex vivo. The stimulation of TNF-deficient iPS-cell-derived macrophages with TNF rescued the respiratory burst. These findings contrast with those for patients with inherited complete deficiency of the respiratory burst across all phagocytes, who are prone to multiple infections, including both Bacillus Calmette-Guérin disease and tuberculosis3. Human TNF is required for respiratory-burst-dependent immunity to Mycobacterium tuberculosis in macrophages but is surprisingly redundant otherwise, including for inflammation and immunity to weakly virulent mycobacteria and many other infectious agents.

Causes of Oral Granulomatous Disorders: An Update and Narrative Review of the Literature

Granulomatous diseases include a diverse range of chronic inflammatory disorders with a wide variety of pathologies and clinical characteristics. In particular, the orofacial region can be affected by granulomatous conditions-whether as an isolated disease or as part of a systemic disorder. Regardless of the nature of the disease or its mechanism of development, precise diagnosis can be challenging, as etiopathogenesis may be driven by several causes. These include reactions to foreign bodies, infections, immune dysregulation, proliferative disorders,, medications, illicit drugs, and hereditary disorders. Granulomas can be identified using histopathological assessment but are not pathognomonic of a specific disease, and therefore require correlation between clinical, serological, radiographical, and histopathological findings. The purpose of this review is to provide a summary of the etiopathogenesis, clinical and histopathologic characteristics, and treatment of oral granulomatous disorders.

[Pulmonary complications of Chronic Granulomatous Disease]

Chronic Granulomatosis Disease (CGD) is an inherited immune deficiency due to a mutation in the genes coding for the subunits of the NADPH oxidase enzyme that affects the oxidative capacity of phagocytic cells. It is characterized by increased susceptibility to bacterial and fungal infections, particularly Aspergillus, as well as complications associated with hyperinflammation and granulomatous tissue infiltration. There exist two types of frequently encountered pulmonary manifestations: (1) due to their being initially pauci-symptomatic, possibly life-threatening infectious complications are often discovered at a late stage. Though their incidence has decreased through systematic anti-bacterial and anti-fungal prophylaxis, they remain a major cause of morbidity and mortality; (2) inflammatory complications consist in persistent granulomatous mass or interstitial pneumoniae, eventually requiring immunosuppressive treatment. Pulmonary complications recurring since infancy generate parenchymal and bronchial sequelae that impact functional prognosis. Hematopoietic stem cell allograft is a curative treatment; it is arguably life-sustaining and may limit the morbidity of the disease. As a result of improved pediatric management, life expectancy has increased dramatically. That said, new challenges have appeared with regard to adults: difficulties of compliance, increased inflammatory manifestations, acquired resistance to anti-infectious therapies. These different developments underscore the importance of the transition period and the need for multidisciplinary management.

Unilateral cerebellar hypoplasia in a 9-year-old child with chronic granulomatous disease: A case report

Unilateral cerebellar hypoplasia is a rare neurological condition that affects the development of the cerebellum, causing symptoms like poor coordination, balance issues, tremors, and speech problems. Unilateral cerebellar hypoplasia can occur as an isolated finding or as part of a larger neurological disorder or hereditary disease. There have been rare recorded instances where patients with chronic granulomatosis disease have been found to have neurological symptoms, such as brain abscesses or persistent inflammation, even though that CGD primarily affects the immune system and causes recurrent infections. A 9-year-old male with a known diagnosis of CGD presented to our neurology outpatient department with complaints of frequent falls and speech abnormalities. His parents described suspicious seizure-like movements and poor scholarly performance. Neurologic examination showed ataxic gait, slurred speech, and right-sided plantar extensor reflex. Initial laboratory findings were normal. MRI revealed marked reduced volume of the left cerebellar hemisphere with intact vermis and asymmetry of the posterior fossa. The residual left cerebellar hemisphere showed a normal folia and gray-white matter differentiation pattern. CSF filled the space created by the left hypoplastic cerebellum. A diagnosis of unilateral cerebellar hypoplasia was made. There is no known direct association between chronic granulomatous disease and unilateral cerebellar hypoplasia. However, more research is required to discover whether there is any connection between them. Although it is possible for a child to have CGD and UCH, managing such cases requires a multidisciplinary approach involving neurologists, immunologists, and other specialists to provide appropriate care and treatment.

The pentose phosphate pathway in health and disease

The pentose phosphate pathway (PPP) is a glucose-oxidizing pathway that runs in parallel to upper glycolysis to produce ribose 5-phosphate and nicotinamide adenine dinucleotide phosphate (NADPH). Ribose 5-phosphate is used for nucleotide synthesis, while NADPH is involved in redox homoeostasis as well as in promoting biosynthetic processes, such as the synthesis of tetrahydrofolate, deoxyribonucleotides, proline, fatty acids and cholesterol. Through NADPH, the PPP plays a critical role in suppressing oxidative stress, including in certain cancers, in which PPP inhibition may be therapeutically useful. Conversely, PPP-derived NADPH also supports purposeful cellular generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) for signalling and pathogen killing. Genetic deficiencies in the PPP occur relatively commonly in the committed pathway enzyme glucose-6-phosphate dehydrogenase (G6PD). G6PD deficiency typically manifests as haemolytic anaemia due to red cell oxidative damage but, in severe cases, also results in infections due to lack of leucocyte oxidative burst, highlighting the dual redox roles of the pathway in free radical production and detoxification. This Review discusses the PPP in mammals, covering its roles in biochemistry, physiology and disease.

Nontoxic Levels of Se-Containing Compounds Increase Survival by Blocking Oxidative and Inflammatory Stresses via Signal Pathways Whereas High Levels of Se Induce Apoptosis

Selenium is a main group element and an essential trace element in human health. It was discovered in selenocysteine (SeC) by Stadtman in 1974. SeC is an encoded natural amino acid hailed as the 21st naturally occurring amino acid (U) present in several enzymes and which exquisitely participates in redox biology. As it turns out, selenium bears a U-shaped toxicity curve wherein too little of the nutrient present in biology leads to disorders; concentrations that are too great, on the other hand, pose toxicity to biological systems. In light of many excellent previous reviews and the corpus of literature, we wanted to offer this current review, in which we present aspects of the clinical and biological literature and justify why we should further investigate Se-containing species in biological and medicinal contexts, especially small molecule-containing species in biomedical research and clinical medicine. Of central interest is how selenium participates in biological signaling pathways. Several clinical medical cases are recounted; these reports are mainly pertinent to human cancer and changes in pathology and cases in which the patients are often terminal. Selenium was an option chosen in light of earlier chemotherapeutic treatment courses which lost their effectiveness. We describe apoptosis, and also ferroptosis, and senescence clearly in the context of selenium. Other contemporary issues in research also compelled us to form this review: issues with CoV-2 SARS infection which abound in the literature, and we described findings with human patients in this context. Laboratory scientific studies and clinical studies dealing with two main divisions of selenium, organic (e.g., methyl selenol) or inorganic selenium (e.g., sodium selenite), are discussed. The future seems bright with the research and clinical possibilities of selenium as a trace element, whose recent experimental clinical treatments have so far involved dosing simply and inexpensively over a set of days, amounts, and time intervals.

Microbes and the fate of neutrophils

Neutrophils or polymorphonuclear neutrophils (PMNs) are an important component of innate host defense. These phagocytic leukocytes are recruited to infected tissues and kill invading microbes. There are several general characteristics of neutrophils that make them highly effective as antimicrobial cells. First, there is tremendous daily production and turnover of granulocytes in healthy adults-typically 1011 per day. The vast majority (~95%) of these cells are neutrophils. In addition, neutrophils are mobilized rapidly in response to chemotactic factors and are among the first leukocytes recruited to infected tissues. Most notably, neutrophils contain and/or produce an abundance of antimicrobial molecules. Many of these antimicrobial molecules are toxic to host cells and can destroy host tissues. Thus, neutrophil activation and turnover are highly regulated processes. To that end, aged neutrophils undergo apoptosis constitutively, a process that contains antimicrobial function and proinflammatory capacity. Importantly, apoptosis facilitates nonphlogistic turnover of neutrophils and removal by macrophages. This homeostatic process is altered by interaction with microbes and their products, as well as host proinflammatory molecules. Microbial pathogens can delay neutrophil apoptosis, accelerate apoptosis following phagocytosis, or cause neutrophil cytolysis. Here, we review these processes and provide perspective on recent studies that have potential to impact this paradigm.

Gene therapy for inborn error of immunity - current status and future perspectives

PURPOSE OF REVIEW

Development of hematopoietic stem cell (HSC) gene therapy (GT) for inborn errors of immunity (IEIs) continues to progress rapidly. Although more patients are being treated with HSC GT based on viral vector mediated gene addition, gene editing techniques provide a promising new approach, in which transgene expression remains under the control of endogenous regulatory elements.

RECENT FINDINGS

Many gene therapy clinical trials are being conducted and evidence showing that HSC GT through viral vector mediated gene addition is a successful and safe curative treatment option for various IEIs is accumulating. Gene editing techniques for gene correction are, on the other hand, not in clinical use yet, despite rapid developments during the past decade. Current studies are focussing on improving rates of targeted integration, while preserving the primitive HSC population, which is essential for future clinical translation.

SUMMARY

As HSC GT is becoming available for more diseases, novel developments should focus on improving availability while reducing costs of the treatment. Continued follow up of treated patients is essential for providing information about long-term safety and efficacy. Editing techniques have great potential but need to be improved further before the translation to clinical studies can happen.

De Novo Somatic Mosaicism of CYBB Caused by Intronic LINE-1 Element Insertion Resulting in Chronic Granulomatous Disease

Chronic granulomatosis disease (CGD) is a rare inborn error of immunity, characterized by phagocytic respiratory outbreak dysfunction. Mutations causing CGD occur in CYBB on the X chromosome and in the autosomal genes CYBA, NCF1, NCF2, NCF4, RAC2, and CYBC1. Nevertheless, some patients are clinically diagnosed with CGD, due to abnormal respiratory outbursts, while the pathogenic gene mutation is unidentified. Here, we report a patient with CGD who first presented with Bacillus Calmette-Guérin disease and had recurrent pneumonia. He was diagnosed with CGD by nitro blue tetrazolium and respiratory burst tests. Detailed assessment of neutrophil activity revealed that patient neutrophils were almost entirely nonfunctional. Sanger sequencing detected a 6-kb insertion of a LINE-1 transposable element in the third intron of CYBB, leading to abnormal splicing and pseudoexon insertion, as well as introduction of a premature termination codon, resulting in predicted protein truncation. Clonal analysis demonstrated that the patient had somatic mosaicism, and the phagocytes were almost all variant CYBB, while the mosaicism rate of PBMC was about 65%. Finally, deep RNA sequencing and gp91^phox expression analysis confirmed the pathogenicity of the mutation. In conclusion, we demonstrate that insertion of a LINE-1 transposon in a CYBB intron was responsible for CGD in our patient. Intron LINE-1 transposon element insertion should be examined in CGD patients without any known disease-causing gene mutation, in addition to identification of new genes.

Immune chromatin reader SP140 regulates microbiota and risk for inflammatory bowel disease

Inflammatory bowel disease (IBD) is driven by host genetics and environmental factors, including commensal microorganisms. Speckled Protein 140 (SP140) is an immune-restricted chromatin "reader" that is associated with Crohn's disease (CD), multiple sclerosis (MS), and chronic lymphocytic leukemia (CLL). However, the disease-causing mechanisms of SP140 remain undefined. Here, we identify an immune-intrinsic role for SP140 in regulating phagocytic defense responses to prevent the expansion of inflammatory bacteria. Mice harboring altered microbiota due to hematopoietic Sp140 deficiency exhibited severe colitis that was transmissible upon cohousing and ameliorated with antibiotics. Loss of SP140 results in blooms of Proteobacteria, including Helicobacter in Sp140-/- mice and Enterobacteriaceae in humans bearing the CD-associated SP140 loss-of-function variant. Phagocytes from patients with the SP140 loss-of-function variant and Sp140-/- mice exhibited altered antimicrobial defense programs required for control of pathobionts. Thus, mutations within this epigenetic reader may constitute a predisposing event in human diseases provoked by microbiota.

Discovery of Homogentisic Acid as a Precursor in Trimethoprim Metabolism and Natural Product Biosynthesis

Opportunistic infections by Burkholderia cenocepacia are life threatening for patients suffering from cystic fibrosis and chronic granulomatous disease. These infections are often associated with variable clinical outcomes, prompting an interest in molecular investigations of phenotypes associated with disease severity. The production of the pyomelanin pigment is one such phenotype, which was recently linked to the ability of clinical strains to carry out biotransformation of the antibiotic trimethoprim. However, this biotransformation product was not identified, and differences in metabolite production associated with pyomelanin pigmentation are poorly understood. Here, we identify several key metabolites produced exclusively by the pyomelanin-producing strains. To provide insight into the structures and biosynthetic origin of these metabolites, we developed a mass spectrometry-based strategy coupling unsupervised in silico substructure prediction with stable isotope labeling referred to as MAS-SILAC (Metabolite Annotation assisted by Substructure discovery and Stable Isotope Labeling by Amino acids in Cell culture). This approach led to discovery of homogentisic acid as a precursor for biosynthesis of several natural products and for biotransformation of trimethoprim, representing a previously unknown mechanism of antibiotic tolerance. This work presents application of computational methods for analysis of untargeted metabolomic data to link the chemotype of pathogenic microorganisms with a specific phenotype. The observations made in this study provide insights into the clinical significance of the melanated phenotype.

Paediatric Behçet's Disease: A Comprehensive Review with an Emphasis on Monogenic Mimics

Behçet's disease (BD) is a polygenic condition with a complex immunopathogenetic background and challenging diagnostic and therapeutic concepts. Advances in genomic medicine have provided intriguing insights into disease pathogenesis over the last decade, especially into monogenic mimics of BD. Although a rare condition, paediatric BD should be considered an important differential diagnosis, especially in cases with similar phenotypes. Emerging reports of monogenic mimics have indicated the importance of genetic testing, particularly for those with early-onset, atypical features and familial aggregation. Treatment options ought to be evaluated in a multidisciplinary setting, given the complexity and diverse organ involvement. Owing to the rarity of the condition, there is a paucity of paediatric trials; thus, international collaboration is warranted to provide consensus recommendations for the management of children and young people. Herein, we summarise the current knowledge of the clinical presentation, immunopathogenetic associations and disease mechanisms in patients with paediatric BD and BD-related phenotypes, with particular emphasis on recently identified monogenic mimics.

Effects of voriconazole on population pharmacokinetics and optimization of the initial dose of tacrolimus in children with chronic granulomatous disease undergoing hematopoietic stem cell transplantation

Background

This study aimed to explore the effects of voriconazole on population pharmacokinetics and optimization of the initial dose of tacrolimus in children with chronic granulomatous disease (CGD) undergoing hematopoietic stem cell transplantation (HSCT).

Methods

Thirty-four children with CGD undergoing HSCT were assessed to establish a population pharmacokinetic model (PPM) using the non-linear mixed effect. Tacrolimus concentrations were simulated by the Monte Carlo method in children weighing <25 kg at different doses.

Results

In the final model, weight and concomitant use of voriconazole were included as covariates. With the same weight, the relative value of tacrolimus clearance was 1:0.388 in children not taking voriconazole: children taking voriconazole. Compared with children not taking voriconazole, the measured tacrolimus concentrations were all higher in children taking voriconazole (P<0.01); however, these were not corrected by dose or body weight for concentration differences. Thus, we simulated the tacrolimus concentrations using different body weights (5–25 kg) and different dose regimens (0.1–0.8 mg/kg/day) for the same body weight and dose. Tacrolimus concentrations in children taking voriconazole were higher than those in children not taking voriconazole (P<0.01). Also, in children with CGD undergoing HSCT who were not taking voriconazole, the initial dose regimen of 0.5 mg/kg/day was recommended for body weights of 5–10 kg, and 0.4 mg/kg/day was recommended for body weights of 10–25 kg. In children with CGD undergoing HSCT who were taking voriconazole, an initial dose regimen of 0.3 mg/kg/day was recommended for body weights of 5–25 kg.

Conclusions

We established, for the first time, a PPM of tacrolimus in children with CGD undergoing HSCT in which voriconazole significantly increased tacrolimus concentrations. In addition, the initial dose of tacrolimus in children with CGD undergoing HSCT was recommended.

Neonatal Manifestations of Chronic Granulomatous Disease: MAS/HLH and Necrotizing Pneumonia as Unusual Phenotypes and Review of the Literature

Chronic granulomatous disease (CGD) is a rare inborn error of immunity (IEI), characterized by a deficient phagocyte killing due to the inability of NADPH oxidase to produce reactive oxygen species in the phagosome. Patients with CGD suffer from severe and recurrent infections and chronic inflammatory disorders. Onset of CGD has been rarely reported in neonates and only as single case reports or small case series. We report here the cases of three newborns from two different kindreds, presenting with novel infectious and inflammatory phenotypes associated with CGD. A girl with CYBA deficiency presented with necrotizing pneumonia, requiring a prolonged antibiotic treatment and resulting in fibrotic pulmonary changes. From the second kindred, the first of two brothers developed a fatal Burkholderia multivorans sepsis and died at 24 days of life. His younger brother had a diagnosis of CYBB deficiency and presented with Macrophage Activation Syndrome/Hemophagocytic Lympho-Histiocytosis (MAS/HLH) without any infection, that could be controlled with steroids. We further report the findings of a review of the literature and show that the spectrum of microorganisms causing infections in neonates with CGD is similar to that of older patients, but the clinical manifestations are more diverse, especially those related to the inflammatory syndromes. Our findings extend the spectrum of the clinical presentation of CGD to include unusual neonatal phenotypes. The recognition of the very early, potentially life-threatening manifestations of CGD is crucial for a prompt diagnosis, improvement of survival and reduction of the risk of long-term sequelae.

Reactive Oxygen Species in Macrophages: Sources and Targets

Reactive oxygen species (ROS) are fundamental for macrophages to eliminate invasive microorganisms. However, as observed in nonphagocytic cells, ROS play essential roles in processes that are different from pathogen killing, as signal transduction, differentiation, and gene expression. The different outcomes of these events are likely to depend on the specific subcellular site of ROS formation, as well as the duration and extent of ROS production. While excessive accumulation of ROS has long been appreciated for its detrimental effects, there is now a deeper understanding of their roles as signaling molecules. This could explain the failure of the “all or none” pharmacologic approach with global antioxidants to treat several diseases. NADPH oxidase is the first source of ROS that has been identified in macrophages. However, growing evidence highlights mitochondria as a crucial site of ROS formation in these cells, mainly due to electron leakage of the respiratory chain or to enzymes, such as monoamine oxidases. Their role in redox signaling, together with their exact site of formation is only partially elucidated. Hence, it is essential to identify the specific intracellular sources of ROS and how they influence cellular processes in both physiological and pathological conditions to develop therapies targeting oxidative signaling networks. In this review, we will focus on the different sites of ROS formation in macrophages and how they impact on metabolic processes and inflammatory signaling, highlighting the role of mitochondrial as compared to non-mitochondrial ROS sources.

Liver Abscesses as a Sign of Chronic Granulomatous Disease in Adolescent

Chronic granulomatous disease (CGD) is an inherited primary immunodeficiency disease caused by a genetic defect in the nicotinamide adenine dinucleotide phosphate oxidase (NADPH) complex that affects phagocytes. This leads to recurrent severe bacterial and fungal infections manifested by recurrent pneumonia, also involving soft tissue, bones, and liver. Usually, CGD is presented and diagnosed in the first five years of life. In this case report, we describe a late presentation in an adolescent with multiple liver abscesses, the approach of diagnosis, and management.

Ubiquitination of ATF6 by disease-associated RNF186 promotes the innate receptor-induced unfolded protein response

Properly balancing microbial responses by the innate immune system through pattern recognition receptors (PRRs) is critical for intestinal immune homeostasis. Ring finger protein 186 (RNF186) genetic variants are associated with inflammatory bowel disease (IBD). However, functions for the E3 ubiquitin ligase RNF186 are incompletely defined. We found that upon stimulation of the PRR nucleotide-binding oligomerization domain containing 2 (NOD2) in human macrophages, RNF186 localized to the ER, formed a complex with ER stress sensors, ubiquitinated the ER stress sensor activating transcription factor 6 (ATF6), and promoted the unfolded protein response (UPR). These events, in turn, led to downstream signaling, cytokine secretion, and antimicrobial pathway induction. Importantly, RNF186-mediated ubiquitination of K152 on ATF6 was required for these outcomes, highlighting a key role for ATF6 ubiquitination in PRR-initiated functions. Human macrophages transfected with the rare RNF186-A64T IBD risk variant and macrophages from common rs6426833 RNF186 IBD risk carriers demonstrated reduced NOD2-induced outcomes, which were restored by rescuing UPR signaling. Mice deficient in RNF186 or ATF6 demonstrated a reduced UPR in colonic tissues, increased weight loss, and less effective clearance of bacteria with dextran sodium sulfate-induced injury and upon oral challenge with Salmonella Typhimurium. Therefore, we identified that RNF186 was required for PRR-induced, UPR-associated signaling leading to key macrophage functions; defined that RNF186-mediated ubiquitination of ATF6 was essential for these functions; and elucidated how RNF186 IBD risk variants modulated these outcomes.

The E3 ubiquitin ligase RNF186 and RNF186 risk variants regulate innate receptor-induced outcomes

Balancing microbial-induced cytokines and microbial clearance is critical at mucosal sites such as the intestine. How the inflammatory bowel disease (IBD)-associated gene RNF186 regulates this balance is unclear. We found that macrophages from IBD-risk rs6426833 carriers in the RNF186 region showed reduced cytokines to stimulation through multiple pattern recognition receptors (PRRs). Upon stimulation of PRRs, the E3-ubiquitin ligase RNF186 promoted ubiquitination of signaling complex molecules shared across PRRs and those unique to select PRRs. Furthermore, RNF186 was required for PRR-initiated signaling complex assembly and downstream signaling. RNF186, along with its intact E3-ubiquitin ligase activity, was required for optimal PRR-induced antimicrobial reactive oxygen species, reactive nitrogen species, and autophagy pathways and intracellular bacterial clearance in human macrophages and for bacterial clearance in intestinal myeloid cells. Cells transfected with the rare RNF186-A64T IBD-risk variant and macrophages from common rs6426833 RNF186 IBD-risk carriers demonstrated a reduction in these RNF186-dependent outcomes. These studies identify mechanisms through which RNF186 regulates innate immunity and show that RNF186 IBD-risk variants demonstrate a loss of function in PRR-initiated outcomes.

Non-Coding RNAs and Reactive Oxygen Species–Symmetric Players of the Pathogenesis Associated with Bacterial and Viral Infections

Infections can be triggered by a wide range of pathogens. However, there are few strains of bacteria that cause illness, but some are quite life-threatening. Likewise, viral infections are responsible for many human diseases, usually characterized by high contagiousness. Hence, as bacterial and viral infections can both cause similar symptoms, it can be difficult to determine the exact cause of a specific infection, and this limitation is critical. However, recent scientific advances have geared us up with the proper tools required for better diagnoses. Recent discoveries have confirmed the involvement of non-coding RNAs (ncRNAs) in regulating the pathogenesis of certain bacterial or viral infections. Moreover, the presence of reactive oxygen species (ROS) is also known as a common infection trait that can be used to achieve a more complete description of such pathogen-driven conditions. Thus, this opens further research opportunities, allowing scientists to explore infection-associated genetic patterns and develop better diagnosis and treatment methods. Therefore, the aim of this review is to summarize the current knowledge of the implication of ncRNAs and ROS in bacterial and viral infections, with great emphasis on their symmetry but, also, on their main differences.

A comparative investigation on the role and interaction of EsxA and EsxB in host immune response

Staphylococcus aureus (S. aureus) is a frequent and major cause of bovine mastitis; it poses a tremendous economic burden to dairy industries of numerous countries. Early-secretion antigen-6 secretion system (ESS) has been viewed as an essential virulence and pathogenic factor of S. aureus. EsxA and EsxB are small acidic proteins secreted by ESS and identified as potential T-cell antigens of S. aureus. Unlike those of Mycobacterium tuberculosis (M. tuberculosis), the EsxA and EsxB of S. aureus do not form a dimer. Instead, EsxA dimerizes with itself or EsaC. Therefore, the interaction of EsxA and EsxB remains incompletely understood. In this study, to explore their interactions, EsxA and EsxB were expressed and used for immunization, alone or in combination, of murine infection models. Both components can interact with each other. Through the analysis of the immune response by immunological method, EsxB could significantly enhance the EsxA-specific IgG2a antibody level and increase the proliferation proportion of CD8⁺ T cells. These results indicate that when vaccinated with EsxA, EsxB can play a critical role in stimulating T helper 1 immunity by activating IgG2a and CD8⁺ T cells. We further show that vaccination with the combination of EsxA and EsxB resulted in enhanced stimulation of TLR-4 and improved protection against S. aureus. The findings may help us better understand the role of EsxB in the virulence and pathogenesis of S. aureus.

The Emergence of Co-Infection of Visceral Leishmaniasis in an Iranian Child with Chronic Granulomatous Disease: A Case Report

Chronic granulomatous disease (CGD) described as an essential immunodeficiency problem of phagocytic cells resulting in a phagocyte dysfunction and inability to kill a spectrum of bacteria and fungi. Despite the fact that CGD patients are more susceptible to intracellular infections, visceral leishmaniasis has been reported rarely in these cases. Here, we report an uncommon case of visceral leishmaniasis in a child with CGD. An 8-yr old boy with CGD presented to the infectious disease ward, Children’s Medical Center, Tehran University of Medical Sciences, Iran after the onset of 20 days fever with chronic crusted ulcer approximately 3 cm × 3cm on the left upper limb and a small ulcer measuring 0.5 cm × 0.5 cm on the right knee with moderate secretion. Bone Marrow Aspiration (BMA) and Bone Marrow Biopsies (BMB) of fragmented samples were performed and polymorphic population of hematopoietic cells, Megakaryocytes and Leishman bodies were seen. The patient was treated with meglumine antimoniate (Glucantime^®) 20 mg/kg for 28 days and after partial improvement patient discharged and continue the treatment at home. Amphotericin B lipid complex (Ambisome^®) (3–5 mg/kg per dose once) was administered every 3–4 weeks for 18 months as secondary prophylaxis that was well tolerated and effective.

Evasion of Immunological Memory by S. aureus Infection: Implications for Vaccine Design

Recurrent S. aureus infections are common, suggesting that natural immune responses are not protective. All candidate vaccines tested thus far have failed to protect against S. aureus infections, highlighting an urgent need to better understand the mechanisms by which the bacterium interacts with the host immune system to evade or prevent protective immunity. Although there is evidence in murine models that both cellular and humoral immune responses are important for protection against S. aureus, human studies suggest that T cells are critical in determining susceptibility to infection. This review will use an “anatomic” approach to systematically outline the steps necessary in generating a T cell-mediated immune response against S. aureus. Through the processes of bacterial uptake by antigen presenting cells, processing and presentation of antigens to T cells, and differentiation and proliferation of memory and effector T cell subsets, the ability of S. aureus to evade or inhibit each step of the T-cell mediated response will be reviewed. We hypothesize that these interactions result in the redirection of immune responses away from protective antigens, thereby precluding the establishment of “natural” memory and potentially inhibiting the efficacy of vaccination. It is anticipated that this approach will reveal important implications for future design of vaccines to prevent these infections.

Immune-Based Anti-Staphylococcal Therapeutic Approaches

Widespread methicillin-resistant Staphylococcus aureus (S. aureus) infections within community and healthcare settings are responsible for accelerated development of antibiotic resistance. As the antibiotic pipeline began drying up, alternative strategies were sought for future treatment of S. aureus infections. Here, we review immune-based anti-staphylococcal strategies that, unlike conventional antibiotics, target non-essential gene products elaborated by the pathogen. These strategies stimulate narrow or broad host immune mechanisms that are critical for anti-staphylococcal defenses. Alternative approaches aim to disrupt bacterial virulence mechanisms that enhance pathogen survival or induce immunopathology. Although immune-based therapeutics are unlikely to replace antibiotics in patient treatment in the near term, they have the potential to significantly improve upon the performance of antibiotics for treatment of invasive staphylococcal diseases.

Neutrophil-derived granule cargoes: paving the way for tumor growth and progression

Neutrophils are the key cells of our innate immune system mediating host defense via a range of effector functions including phagocytosis, degranulation, and NETosis. For this, they employ an arsenal of anti-microbial cargoes packed in their readily mobilizable granule subsets. Notably, the release of granule content is tightly regulated; however, under certain circumstances, their unregulated release can aggravate tissue damage and could be detrimental to the host. Several constituents of neutrophil granules have also been associated with various inflammatory diseases including cancer. In cancer setting, their excessive release may modulate tissue microenvironment which ultimately leads the way for tumor initiation, growth and metastasis. Neutrophils actively infiltrate within tumor tissues, wherein they show diverse phenotypic and functional heterogeneity. While most studies are focused at understanding the phenotypic heterogeneity of neutrophils, their functional heterogeneity, much of which is likely orchestrated by their granule cargoes, is beginning to emerge. Therefore, a better understanding of neutrophil granules and their cargoes will not only shed light on their diverse role in cancer but will also reveal them as novel therapeutic targets. This review provides an overview on existing knowledge of neutrophil granules and detailed insight into the pathological relevance of their cargoes in cancer. In addition, we also discuss the therapeutic approach for targeting neutrophils or their microenvironment in disease setting that will pave the way forward for future research.

Gene Therapy for Primary Immunodeficiency

Over the past 3 decades, there has been significant progress in refining gene therapy technologies and procedures. Transduction of hematopoietic stem cells ex vivo using lentiviral vectors can now create a highly effective therapeutic product, capable of reconstituting many different immune system dysfunctions when reinfused into patients. Here, we review the key developments in the gene therapy landscape for primary immune deficiency, from an experimental therapy where clinical efficacy was marred by adverse events, to a commercialized product with enhanced safety and efficacy. We also discuss progress being made in preclinical studies for challenging disease targets and emerging gene editing technologies that are showing promising results, particularly for conditions where gene regulation is important for efficacy.

Gene therapy for primary immunodeficiencies

Primary immunodeficiencies (PIDs) are a group of rare inherited disorders of the immune system. Many PIDs are devastating and require a definitive therapy to prevent progressive morbidity and premature mortality. Allogeneic haematopoietic stem cell transplantation (alloHSCT) is curative for many PIDs, and while advances have resulted in improved outcomes, the procedure still carries a risk of mortality and morbidity from graft failure or graft-versus-host disease (GvHD). Autologous haematopoietic stem cell gene therapy (HSC GT) has the potential to correct genetic defects across haematopoietic lineages without the complications of an allogeneic approach. HSC GT for PID has been in development for the last two decades and the first licensed HSC-GT product for adenosine deaminase-deficient severe combined immunodeficiency (ADA-SCID) is now available. New gene editing technologies have the potential to circumvent some of the problems associated with viral gene-addition. HSC GT for PID shows great promise, but requires a unique approach for each disease and carries risks, notably insertional mutagenesis from gamma-retroviral gene addition approaches and possible off-target toxicities from gene-editing techniques. In this review, we discuss the development of HSC GT for PID and outline the current state of clinical development before discussing future developments in the field.

Protein kinase C activates NAD kinase in human neutrophils

NAD kinase (NADK) is required for the de novo synthesis of NADP⁺ from NAD⁺. In neutrophils, NADK plays an essential role by providing sufficient levels of NADPH to support a robust oxidative burst. Activation of NADPH oxidase-2 (NOX-2) in neutrophils by stimulators of protein kinase C (PKC), such as phorbol myristate acetate (PMA), results in the rapid generation of superoxide at the expense of oxidation of NADPH to NADP⁺. In this study, we measured the levels of pyridine nucleotides following the addition of PMA to neutrophils. PMA elicited a rapid increase in NADP⁺ in neutrophils, which was not due to oxidation of NADPH, the levels of which also rose. This was mirrored by a rapid reduction in NAD⁺ levels, suggesting that NADK had been activated. PMA-induced depletion of NAD⁺ in neutrophils was blocked by PKC inhibitors, but was not dependent on NOX-2, as it was not blocked by the NOX inhibitor, diphenyleneiodonium. PMA also increased NADK activity in neutrophil lysates as well as NADK phosphorylation, as revealed by a monoclonal antibody selective for phospho-NADK. Human recombinant NADK was phosphorylated by PKCδ, resulting in increased immunoreactivity, but unchanged enzyme activity, suggesting that PKC-induced phosphorylation alone is insufficient to increase NADK activity in neutrophils. This leads us to speculate that phosphorylation of NADK promotes the dissociation of an inhibitory molecule from a complex, thereby increasing enzyme activity. Activation of NADK by PKC in phagocytic cells could be critical for the rapid provision of sufficient levels of superoxide for host defence against invading microorganisms.

The Neutrophil: Constant Defender and First Responder

The role of polymorphonuclear neutrophils (PMNs) in biology is often recognized during pathogenesis associated with PMN hyper- or hypo-functionality in various disease states. However, in the vast majority of cases, PMNs contribute to resilience and tissue homeostasis, with continuous PMN-mediated actions required for the maintenance of health, particularly in mucosal tissues. PMNs are extraordinarily well-adapted to respond to and diminish the damaging effects of a vast repertoire of infectious agents and injurious processes that are encountered throughout life. The commensal biofilm, a symbiotic polymicrobial ecosystem that lines the mucosal surfaces, is the first line of defense against pathogenic strains that might otherwise dominate, and is therefore of critical importance for health. PMNs regularly interact with the commensal flora at the mucosal tissues in health and limit their growth without developing an overt inflammatory reaction to them. These PMNs exhibit what is called a para-inflammatory phenotype, and have reduced inflammatory output. When biofilm growth and makeup are disrupted (i.e., dysbiosis), clinical symptoms associated with acute and chronic inflammatory responses to these changes may include pain, erythema and swelling. However, in most cases, these responses indicate that the immune system is functioning properly to re-establish homeostasis and protect the status quo. Defects in this healthy everyday function occur as a result of PMN subversion by pathological microbial strains, genetic defects or crosstalk with other chronic inflammatory conditions, including cancer and rheumatic disease, and this can provide some avenues for therapeutic targeting of PMN function. In other cases, targeting PMN functions could worsen the disease state. Certain PMN-mediated responses to pathogens, for example Neutrophil Extracellular Traps (NETs), might lead to undesirable symptoms such as pain or swelling and tissue damage/fibrosis. Despite collateral damage, these PMN responses limit pathogen dissemination and more severe damage that would otherwise occur. New data suggests the existence of unique PMN subsets, commonly associated with functional diversification in response to particular inflammatory challenges. PMN-directed therapeutic approaches depend on a greater understanding of this diversity. Here we outline the current understanding of PMNs in health and disease, with an emphasis on the positive manifestations of tissue and organ-protective PMN-mediated inflammation.

LACC1 Required for NOD2-Induced, ER Stress-Mediated Innate Immune Outcomes in Human Macrophages and LACC1 Risk Variants Modulate These Outcomes

LACC1 genetic variants are associated with multiple immune-mediated diseases. However, laccase domain containing-1 (LACC1) functions are incompletely defined. We find that upon stimulation of the pattern-recognition receptor (PRR) NOD2, LACC1 localizes to the endoplasmic reticulum (ER) and forms a complex with ER-stress sensors. All three ER-stress branches, PERK, IRE1α, and ATF6, are required for NOD2-induced signaling, cytokines, and antimicrobial pathways in human macrophages. LACC1, and its localization to the ER, is required for these outcomes. Relative to wild-type (WT) LACC1, transfection of the common Val254 and rare Arg284 immune-mediated disease-risk LACC1 variants into HeLa cells and macrophages, as well as macrophages from LACC1 Val254 carriers, shows reduced NOD2-induced ER stress-associated outcomes; these downstream outcomes are restored by rescuing ER stress. Therefore, we identify ER stress to be essential in PRR-induced outcomes in macrophages, define a critical role for LACC1 in these ER stress-dependent events, and elucidate how LACC1 disease-risk variants mediate these outcomes.

Complement Receptor 3 Contributes to the Sexual Dimorphism in Neutrophil Killing of Staphylococcus aureus

We previously reported sex differences in innate susceptibility to Staphylococcus aureus skin infection and that bone marrow neutrophils (BMN) from female mice have an enhanced ability to kill S. aureus ex vivo compared with those of male mice. However, the mechanism(s) driving this sex bias in neutrophil killing have not been reported. Given the role of opsonins such as complement, as well as their receptors, in S. aureus recognition and clearance, we investigated their contribution to the enhanced bactericidal capacity of female BMN. We found that levels of C3 in the serum and CR3 (CD11b/CD18) on the surface of BMN were higher in female compared with male mice. Consistent with increased CR3 expression following TNF-α priming, production of reactive oxygen species (ROS), an important bactericidal effector, was also increased in female versus male BMN in response to serum-opsonized S. aureus Furthermore, blocking CD11b reduced both ROS levels and S. aureus killing by murine BMN from both sexes. However, at the same concentration of CD11b blocking Ab, S. aureus killing by female BMN was greatly reduced compared with those from male mice, suggesting CR3-dependent differences in bacterial killing between sexes. Overall, this work highlights the contributions of CR3, C3, and ROS to innate sex bias in the neutrophil response to S. aureus Given that neutrophils are crucial for S. aureus clearance, understanding the mechanism(s) driving the innate sex bias in neutrophil bactericidal capacity could identify novel host factors important for host defense against S. aureus.

Harnessing antifungal immunity in pursuit of a Staphylococcus aureus vaccine strategy

Staphylococcus aureus (S. aureus) is one of the most common bacterial infections worldwide, and antibiotic resistant strains such as Methicillin-Resistant S. aureus (MRSA) are a major threat and burden to public health. MRSA not only infects immunocompromised patients but also healthy individuals and has rapidly spread from the healthcare setting to the outside community. However, all vaccines tested in clinical trials to date have failed. Immunocompromised individuals such as patients with HIV or decreased levels of CD4+ T cells are highly susceptible to S. aureus infections, and they are also at increased risk of developing fungal infections. We therefore wondered whether stimulation of antifungal immunity might promote the type of immune responses needed for effective host defense against S. aureus. Here we show that vaccination of mice with a fungal β-glucan particle (GP) loaded with S. aureus antigens provides protective immunity to S. aureus. We generated glucan particles loaded with the four S. aureus proteins ClfA, IsdA, MntC, and SdrE, creating the 4X-SA-GP vaccine. Vaccination of mice with three doses of 4X-SA-GP promoted protection in a systemic model of S. aureus infection with a significant reduction in the bacterial burden in the spleen and kidneys. 4X-SA-GP vaccination induced antigen-specific Th1 and Th17 CD4+ T cell and antibody responses and provided long-term protection. This work suggests that the GP vaccine system has potential as a novel approach to developing vaccines for S. aureus.

Late diagnosis of chronic granulomatous disease

Modern era advancements in medical care, with improved treatment of infections, can result in delayed diagnosis of congenital immunodeficiencies. In this study we present a retrospective cohort of 16 patients diagnosed with Chronic Granulomatous Disease (CGD) at adulthood. Some of the patients had a milder clinical phenotype, but others had a classic phenotype with severe infectious and inflammatory complications reflecting a profoundly impaired neutrophil function. It is therefore of great importance to investigate the individual journey of each patient through different misdiagnoses and the threads which led to the correct diagnosis. Currently the recommended definitive treatment for CGD is hematopoietic stem cell transplantation (HSCT). Although survival of our patients to adulthood might argue against the need for early HSCT during infancy, we claim that the opposite is correct, as most of them grew to be severely ill and diagnosed at a stage when HSCT is debatable with potentially an unfavorable outcome. This cohort stresses the need to increase awareness of this severe congenital immunodeficiency among clinicians of different specialties who might be treating undiagnosed adult patients with CGD.

Granulomatous diseases: Oral manifestations and recommendations

Granulomatous diseases may present with oral manifestations that are detectable by dental care providers. In certain cases, oral manifestations may precede systemic signs and symptoms. Dentists managing patients with these conditions may modify the dental treatment plan and possibly retain the support of other health professionals. This review gives an update on granulomatous diseases that can be faced by the dental practitioner.

NOX2 Is Critical to Endocardial to Mesenchymal Transition and Heart Development

NADPH oxidases (NOX) are a major source of reactive oxygen species (ROS) production in the heart. ROS signaling regulates gene expression, cell proliferation, apoptosis, and migration. However, the role of NOX2 in embryonic heart development remains elusive. We hypothesized that deficiency of Nox2 disrupts endocardial to mesenchymal transition (EndMT) and results in congenital septal and valvular defects. Our data show that 34% of Nox2^−/− neonatal mice had various congenital heart defects (CHDs) including atrial septal defects (ASD), ventricular septal defects (VSD), atrioventricular canal defects (AVCD), and malformation of atrioventricular and aortic valves. Notably, Nox2^−/− embryonic hearts show abnormal development of the endocardial cushion as evidenced by decreased cell proliferation and an increased rate of apoptosis. Additionally, Nox2 deficiency disrupted EndMT of atrioventricular cushion explants ex vivo. Furthermore, treatment with N-acetylcysteine (NAC) to reduce ROS levels in the wild-type endocardial cushion explants decreased the number of cells undergoing EndMT. Importantly, deficiency of Nox2 was associated with reduced expression of Gata4, Tgfβ2, Bmp2, Bmp4, and Snail1, which are critical to endocardial cushion and valvoseptal development. We conclude that NOX2 is critical to EndMT, endocardial cushion cell proliferation, and normal embryonic heart development.

Susceptibility to infection in early life: a growing role for human genetics

The unique vulnerability to infection of newborns and young infants is generally explained by a constellation of differences between early-life immune responses and immune responses at later ages, often referred to as neonatal immune immaturity. This developmental view, corroborated by robust evidence, offers a plausible, population-level description of the pathogenesis of life-threatening infectious diseases during the early-life period, but provides little explanation on the wide inter-individual differences in susceptibility and resistance to specific infections during the first months of life. In this context, the role of individual human genetic variation is increasingly recognized. A life-threatening infection caused by an opportunistic pathogen in an otherwise healthy infant likely represents the first manifestation of an inborn error of immunity. Single-gene disorders may also underlie common infections in full-term infants with no comorbidities or in preterm infants. In addition, there is increasing evidence of a possible role for common genetic variation in the pathogenesis of infection in preterm infants. Over the past years, a unified theory of infectious diseases emerged, supporting a hypothetical, age-dependent general model of genetic architecture of human infectious diseases. We discuss here how the proposed genetic model can be reconciled with the widely accepted developmental view of early-life infections in humans.

Neutrophil swarming delays the growth of clusters of pathogenic fungi

Neutrophils employ several mechanisms to restrict fungi, including the action of enzymes such as myeloperoxidase (MPO) or NADPH oxidase, and the release of neutrophil extracellular traps (NETs). Moreover, they cooperate, forming “swarms” to attack fungi that are larger than individual neutrophils. Here, we designed an assay for studying how these mechanisms work together and contribute to neutrophil's ability to contain clusters of live Candida. We find that neutrophil swarming over Candida clusters delays germination through the action of MPO and NADPH oxidase, and restricts fungal growth through NET release within the swarm. In comparison with neutrophils from healthy subjects, those from patients with chronic granulomatous disease produce larger swarms against Candida, but their release of NETs is delayed, resulting in impaired control of fungal growth. We also show that granulocyte colony-stimulating factors (GCSF and GM-CSF) enhance swarming and neutrophil ability to restrict fungal growth, even during treatment with chemical inhibitors that disrupt neutrophil function.

Neutrophils employ several mechanisms to control the growth of fungi, including enzymes, reactive oxygen species, extracellular traps, and formation of “swarms”. Here, Hopke et al. study how the different mechanisms work together, using an in vitro assay with human neutrophils and clusters of live Candida cells.

Primary Immunodeficiency in the NICU

Primary immunodeficiency disorders (PIDs) are genetic diseases that lead to increased susceptibility to infection. Hundreds of PIDs have now been described, but a select subset commonly presents in the neonatal period. Neonates, especially premature newborns, have relative immune immaturity that makes it challenging to differentiate PIDs from intrinsic immaturity. Nonetheless, early identification and appropriate management of PIDs are critical, and the neonatal clinician should be familiar with a range of PIDs and their presentations. The neonatal clinician should also be aware of the importance of consulting with an immunologist when a PID is suspected. The role of newborn screening for severe combined immunodeficiency, as well as the initial steps of laboratory evaluation for a PID should be familiar to those caring for neonates. Finally, it is important for providers to be familiar with the initial management steps that can be taken to reduce the risk of infection in affected patients.

Juvenile-onset Behçet's syndrome and mimics

Behçet's syndrome (BS) presents in childhood in up to 20% of reported cases. Diagnosis is clinical and multiple classification criteria have been developed. Presentation is heterogenous with recurrent oral ulceration often being the presenting feature. Mucocutaneous disease including genital ulceration and skin involvement is a common phenotype. Vascular and neurological manifestations are rarer, particularly in childhood. Musculoskeletal and gastro-intestinal involvement which do not form part of commonly used classification criteria, appear more frequent in children. Treatment approaches are extrapolated from studies of adult onset disease. The pathogenesis of BS is not well defined although dysregulation in both innate and adaptive immune systems, together with abnormal antigen presentation have been described. The recent discovery of monogenic mimics of BS requires further genetic studies to understand the burden of monogenic autoinflammatory conditions affecting those with a BS phenotype.