Chronic Granulomatous Disease: a Comprehensive Review

Decoding Immunobiology Through Genetic Errors of Immunity

Throughout biology, the pursuit of genotype-phenotype relationships has provided foundational knowledge upon which new concepts and hypotheses are built. Genetic perturbation, whether occurring naturally or in experimental settings, is the mainstay of mechanistic dissection in biological systems. The unbiased discovery of causal genetic lesions via forward genetics in patients who have a rare disease elucidates a particularly impactful set of genotype-phenotype relationships. Here, we review the field of genetic errors of immunity, often termed inborn errors of immunity (IEIs), in a framework aimed at highlighting the powerful real-world immunology insights provided collectively and individually by these (approximately) 500 disorders. By conceptualizing essential immune functions in a model of the adaptive arsenal of rapid defenses, we organize IEIs based on immune circuits in which sensors, relays, and executioners cooperate to carry out pathogen clearance functions in an effective yet regulated manner. We review and discuss findings from IEIs that not only reinforce known immunology concepts but also offer surprising phenotypes, prompting an opportunity to refine our understanding of immune system function.

Bulk and single-cell RNA sequencing reveal the roles of neutrophils in pediatric Crohn's disease

BACKGROUND

Pediatric Crohn's disease (CD) is a chronic inflammatory bowel disorder that poses significant health risks to children. Although the precise etiology of CD remains elusive, further exploration is needed to identify diagnostic biomarkers and therapeutic targets.

METHODS

This study utilized single-cell and bulk RNA sequencing data derived from ileal and colonic biopsy samples to explore the molecular mechanisms and cell types associated with CD, as well as to pinpoint potential biomarkers and therapeutic targets.

RESULTS

The results revealed a more pronounced alteration in both the quantity and functional state of neutrophils in the CD cohort compared to those with ulcerative colitis and healthy controls. Neutrophils were present in higher proportions in the CD group, primarily in an activated state, potentially correlating with the presence of deep ulcerations and inflammatory histopathological features. Additionally, neutrophil interactions with other cell types were markedly enhanced in the CD group, making neutrophils the dominant participants in cell-to-cell communications. Further analysis indicated a shift in neutrophil phenotype from pro-inflammatory and antimicrobial to tissue-repairing, which may contribute to the progression and exacerbation of CD.

CONCLUSION

IL1B, ICAM1, CXCL1, and CXCL9, primarily expressed in neutrophils, were potential biomarkers for CD. Neutrophils might be considered a potential target for pediatric CD.

IMPACT STATEMENT

This study demonstrated that patients with CD exhibited a greater proportion of activated neutrophils, with enhanced interactions between neutrophils and all other cell types, resulting in neutrophils contributing the most cell-cell interactions within the CD gut. Neutrophils in the CD gut transition from a pro-inflammatory and antibacterial phenotype to one that promotes tissue healing, potentially influencing the progression and exacerbation of CD. Neutrophils represent a promising therapeutic target in pediatric CD. Hub genes associated with CD, including IL1B, ICAM1, CXCL1, and CXCL9, are predominantly expressed in neutrophils, positioning them as promising diagnostic biomarkers for CD.

Viral-based gene therapy clinical trials for immune deficiencies and blood disorders from 2013 until 2023 - an overview

Gene therapy (GT) as a groundbreaking approach holds promise for treating many diseases including immune deficiencies and blood disorders. GT can benefit patients suffering from these diseases, especially those without matched donors or who are at risk after hematopoietic stem cell transplantation (HSCT). Due to all the advances in the field of GT, its main challenge is still gene delivery. Generally, gene delivery systems are categorized into two types depending on utilized vectors: non-viral and viral. Viral vectors are commonly used in GT because of their high efficiency compared to non-viral vectors. In this article, all clinical trials on viral-based GT (with the exclusion of CRISPR and CAR-T cell Therapy) in the last decade for immune deficiencies and blood disorders including Severe combined immune deficiency (SCID), Wiskott-Aldrich syndrome (WAS), Chronic granulomatous disease (CGD), Leukocyte adhesion deficiency (LAD), Fanconi anemia (FA), Hemoglobinopathies, and Hemophilia will thoroughly be discussed. Moreover, viral vectors used in these trials including Retroviruses (RVs), Lentiviruses (LVs), and Adeno-Associated Viruses (AAVs) will be reviewed. This review provides a concise overview of traditional treatments for the mentioned disease and precise details of their viral-based GT clinical trial studies in the last decade, then presents the advantages, disadvantages, and potential adverse events of GT. In conclusion, this review presents GT as a hopeful and growing field in healthcare that could offer cures to diseases that were previously thought to be untreatable.

Decreased T helper 1 cell function underlies recurrent sinopulmonary infections in the 17q12 deletion syndrome

BACKGROUND

The 17q12 deletion syndrome (17q12DS) is a heterozygous deletion of a 1.4 megabase‒spanning DNA sequence on chromosome 17. The clinical characteristics of 17q12DS include neurodevelopmental disorders, kidney and urinary tract abnormalities. In our cohort of 37 subjects with 17q12DS, we observed increased atopic disorders and recurrent sinopulmonary infections, raising the possibility of immune dysregulation in 17q12DS, a feature that has not been previously reported. We tested the hypothesis that individuals with 17q12DS have altered T-cell function, contributing to recurrent infections and atopy.

METHODS

Alteration of CD4+ T-cell functions was assessed on FACS sorted CD4+ T-cells using RNA-seq analysis, and flow cytometry and multiplex assays.

FINDINGS

We found that individuals with 17q12DS had a substantially decreased frequency of CD4+ T-cells producing the T helper (Th) 1 cytokine IFN-γ but not Th2 and Th17 cytokines when compared to age-matched healthy controls (HCs). RNA-seq analysis of CD4+ T-cells from subjects with 17q12DS, when compared to HCs, revealed decreased levels of TBX21 encoding the Th1 transcription factor T-bet, IFNG, and other Th1 chemokine genes. These findings were validated using flow cytometry and multiplex assay.

INTERPRETATION

Our study is the first to demonstrate immune alterations in 17q12DS characterized by decreased T-bet and its downstream effector cytokines such as IFN-γ. These findings warrant further investigation into underlying mechanisms, which would inform precision therapy for individuals with 17q12DS.

FUNDING

National Institutes of HealthKL2 TR001862 to JJS, T35DK104689 to AG, 5T32AR007107 to JPY and LO, 1R01AG056728 to IK, and 1R21AI161838 to IK and JJS.

Tackling Infectious Diseases in the Caribbean and South America: Epidemiological Insights, Antibiotic Resistance, Associated Infectious Diseases in Immunological Disorders, Global Infection Response, and Experimental Anti-Idiotypic Vaccine Candidates Against Microorganisms of Public Health Importance

This paper explores various aspects of microbiology and immunology, with a particular focus on the epidemiology and molecular characterisation of infectious diseases in the Caribbean and South America. Key areas of investigation include tuberculosis (TB), experimental vaccines, and bloodborne pathogens. A retrospective study conducted in Jamaica highlights the significance of early HIV screening, timely diagnosis, and inte-grated care. The paper also examines the challenges posed by nosocomial infections, particularly those caused by antibiotic-resistant Gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA), emphasising the critical importance of infection control measures. Additionally, it explores the regional microbiome, the global response to infectious diseases, and immune responses in patients with immunodeficiency disorders such as severe combined immunodeficiency (SCID) and chronic granulomatous disease (CGD), underscoring their heightened susceptibility to a wide range of infections.

Global Knowledge Map and Emerging Research Trends in Induced Pluripotent Stem Cells and Hereditary Diseases: A CiteSpace-based Visualization and Analysis

The rise of induced pluripotent stem cells (iPSCs) technology has ushered in a landmark shift in the study of hereditary diseases. However, there is a scarcity of reports that offer a comprehensive and objective overview of the current state of research at the intersection of iPSCs and hereditary diseases. Therefore, this study endeavors to categorize and synthesize the publications in this field over the past decade through bibliometric methods and visual knowledge mapping, aiming to visually analyze their research focus and clinical trends. The English language literature on iPSCs and hereditary diseases, published from 2014 to 2023 in the Web of Science Core Collection (WoSCC), was examined. The CiteSpace (version 6.3.R1) software was utilized to visualize and analyze country/region, institution, scholar, co-cited authors, and co-cited journals. Additionally, the co-occurrence, clustering, and bursting of co-cited references were displayed. Analysis of 347 articles that met the inclusion criteria revealed a steady increase in the number of published articles and citation frequency in the field over the past decade. With regard to the countries/regions, institutions, scholars, and journals where the articles were published, the highest numbers were found in the USA, the University of California System, Suren M. Zakian, and Stem Cell Research, respectively. The current research is focused on the construction of disease models, both before and after correction, as well as drug target testing for single-gene hereditary diseases. Chromosome transplantation genomic therapy for hereditary diseases with abnormal chromosome structures may emerge as a future research hotspot in this field.

Standardization of the use of opsonized zymosan as stimulus in the 1,2,3-dihydrorhodamine technique for the assessment of neutrophil respiratory burst

Introduction

Chronic granulomatous disease is a defect in phagocytosis due to deficiency of gp91phox, p22phox, p47phox, p40phox, and p67phox (classic form of the disease). Recently, EROS and p40phox deficiency were described as responsible for the non-classical form of the disease. The 1,2,3-dihydrorhodamine oxidation technique, with phorbol-12-myristate-13-acetate as a stimulus, is performed to diagnose the classic chronic granulomatous disease. However, oxidation mediated by EROS and p40phox requires stimuli such as zymosan, Escherichia coli, or Staphylococcus aureus.

Objective

To optimize the 1,2,3-dihydrorhodamine technique using zymosan to assess neutrophil respiratory burst and detect the non-classical chronic granulomatous disease.

Materials and method

Blood was obtained from five healthy subjects after the signature of the informed consent. The 1,2,3-dihydrorhodamine technique was performed with phorbol-12-myristate-13-acetate as control and different quantities of opsonized zymosan (150, 100, 50, 20, and 10 μg). We obtained through flow cytometry the mean fluorescence intensity of rhodamine 1,2,3 oxidated in the neutrophil population and calculated the oxidation index. The Kolmogorov-Smirnov test, ANOVA, and Tukey’s post-hoc analysis were used. We considered a p value ≤ 0.05 as statistically significant.

Results

The phorbol-12-myristate-13-acetate increased the rhodamine 1,2,3 mean fluorescence intensity in healthy subjects. Among the different zymosan conditions tested, we selected 50 μg as the optimal and reproducible amount in all controls according to the statistical analysis and cytometric findings.

Conclusions

We present the optimization of the 1,2,3-dihydrorhodamine technique using zymosan. We propose its implementation in clinical diagnostic laboratories to expand the diagnosis of chronic granulomatous disease.

Two distinct clinical progressions of P67phox-deficient CGD, both commencing with cervical lymphadenitis

We present two rare cases of p67phox-deficient chronic granulomatous disease (CGD) caused by compound heterozygous mutations in the NCF2 gene. They developed cervical lymphadenitis as the initial manifestation of CGD but had distinct clinical progressions. Patient 1 presented with aspergillous meningitis, an extremely rare manifestation of neurological involvement in CGD, which has not been reported before. Patient 2 presented with non-infectious inflammatory lymphadenitis is also very rare and has not been reported previously. These cases emphasize the importance of considering p67phox-deficient CGD in children with late-onset invasive fungal infections and non-infectious inflammatory lesions. Additionally, we also reviewed previous reports of Chinese patients with P67phox-Deficient CGD. Our objective is to raise awareness about the clinical, diagnostic, and genetic characteristics of P67phox-deficient CGD in China, to reduce misdiagnosis and improve the management and prognosis of the disease.

Scedosporium Brain Abscess: A Rare and Fatal Drawback of Bruton Tyrosine Kinase Inhibitor Therapy

The patient described in this case report was admitted to the San Luigi Hospital in Turin for confusion, drowsiness, and buccal and eye deviation. An acute neurological disease was suspected. He was affected by chronic lymphocytic leukemia (CLL) on active treatment with the novel Bruton tyrosine kinase inhibitor (BTKi) acalabrutinib. Other comorbidities included type II diabetes mellitus, arterial hypertension, and nonalcoholic steatohepatitis. Imaging exams showed multiple brain lesions, which appeared to be of infectious-inflammatory origin. Consequently, therapy with acalabrutinib was withheld. The patient was later transferred to the intensive care unit, because of worsening neurological conditions. The definite diagnosis of fungal abscess was obtained through a stereotactic biopsy of the widest brain lesion. Microbiological tests confirmed Scedosporium spp. as the etiological agent. Once a detailed antibiogram had been obtained, voriconazole therapy was started. However, the patient's clinical conditions decayed rapidly and he later died of neurological complications. BTKis represent a milestone in the treatment of CLL; however, little is known about how these molecules act on the immune system. Fungal brain abscesses are rare conditions more commonly seen in heavily immunocompromised patients, such as those affected by acquired immune deficiency syndrome, after bone marrow transplant or treatment for acute leukemia. Whether or not therapy with BTKis can favor opportunistic fungal infections is still a matter of debate. Various reports of Aspergillosis infections developing after therapy with ibrutinib exist. Evidence does suggest that an iatrogenic impairment in the innate immune system could favor these infections. In addition, the patient's comorbidities, such as diabetes mellitus and advancing hematological disease, might create the ideal breeding ground for these microorganisms.

Not just sugar: metabolic control of neutrophil development and effector functions

The mammalian immune system is constantly surveying our tissues to clear pathogens and maintain tissue homeostasis. In order to fulfill these tasks, immune cells take up nutrients to supply energy for survival and for directly regulating effector functions via their cellular metabolism, a process now known as immunometabolism. Neutrophilic granulocytes, the most abundant leukocytes in the human body, have a short half-life and are permanently needed in the defense against pathogens. According to a long-standing view, neutrophils were thought to primarily fuel their metabolic demands via glycolysis. Yet, this view has been challenged, as other metabolic pathways recently emerged to contribute to neutrophil homeostasis and effector functions. In particular during neutrophilic development, the pentose phosphate pathway, glycogen synthesis, oxidative phosphorylation, and fatty acid oxidation crucially promote neutrophil maturation. At steady state, both glucose and lipid metabolism sustain neutrophil survival and maintain the intracellular redox balance. This review aims to comprehensively discuss how neutrophilic metabolism adapts during development, which metabolic pathways fuel their functionality, and how these processes are reconfigured in case of various diseases. We provide several examples of hereditary diseases, in which mutations in metabolic enzymes validate their critical role for neutrophil function.

Cathepsin C inhibition reduces neutrophil serine protease activity and improves activated neutrophil-mediated disorders

Cathepsin C (CatC) is an enzyme which regulates the maturation of neutrophil serine proteases (NSPs) essential for neutrophil activation. Activated neutrophils are key players in the innate immune system, and are also implicated in the etiology of various inflammatory diseases. This study aims to demonstrate a therapeutic potential for CatC inhibitors against disorders in which activated neutrophil-derived neutrophil extracellular traps (NETs) play a significant role. We demonstrate that a CatC inhibitor, MOD06051, dose-dependently suppresses the cellular activity of NSPs, including neutrophil elastase (NE), in vitro. Neutrophils derived from MOD06051-administered rats exhibit significantly lower NE activity and NET-forming ability than controls. Furthermore, MOD06051 dose-dependently ameliorates vasculitis and significantly decreases NETs when administered to a rat model of myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody-associated vasculitis (AAV). These findings suggest that CatC inhibition is a promising strategy to reduce neutrophil activation and improve activated neutrophil-mediated diseases such as MPO-AAV.

Diagnosis of Chronic Granulomatous Disease: Strengths and Challenges in the Genomic Era

Chronic granulomatous disease (CGD) is a group of rare primary inborn errors of immunity characterised by a defect in the phagocyte respiratory burst, which leads to severe and life-threatening infective and inflammatory complications. Despite recent advances in our understanding of the genetic and molecular pathophysiology of X-linked and autosomal recessive CGD, and growth in the availability of functional and genetic testing, there remain significant barriers to early and accurate diagnosis. In the current review, we provide an up-to-date summary of CGD pathophysiology, underpinning current methods of diagnostic testing for CGD and closely related disorders. We present an overview of the benefits of early diagnosis and when to suspect and test for CGD. We discuss current and historical methods for functional testing of NADPH oxidase activity, as well as assays for measuring protein expression of NADPH oxidase subunits. Lastly, we focus on genetic and genomic methods employed to diagnose CGD, including gene-targeted panels, comprehensive genomic testing and ancillary methods. Throughout, we highlight general limitations of testing, and caveats specific to interpretation of results in the context of CGD and related disorders, and provide an outlook for newborn screening and the future.

An essential role for the Hv1 voltage-gated proton channel in Pseudomonas aeruginosa corneal infection

Assembly of NADPH oxidase 2 (NOX2) proteins in neutrophils plays an essential role in controlling microbial infections by producing high levels of reactive oxygen species (ROS). In contrast, the role of the Hv1 voltage-gated proton channel that is required for sustained NOX2 activity is less well characterized. We examined the role of Hv1 in a murine model of blinding Pseudomonas aeruginosa corneal infection and found that in contrast to C57BL/6 mice, Hvcn1 -/- mice exhibit an impaired ability to kill bacteria and regulate disease severity. In vitro, we used a novel Hv1 Inhibitor Flexible (HIF) to block ROS production by human and murine neutrophils and found that HIF inhibits ROS production in a dose-dependent manner following stimulation with PMA or infection with P. aeruginosa. Collectively, these findings demonstrate an important role for Hv1 on controlling bacterial growth in a clinically relevant bacterial infection model.

A Case of Chronic Granulomatous Disease Masquerading As Tubercular Lymphadenitis in an Infant

Chronic granulomatous disease (CGD) is a rare inborn error of immunity characterized by recurrent fungal and bacterial infections due to defective nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. This case report describes an 11-month-old female who was initially diagnosed with tubercular lymphadenitis and presented with fever and bilateral neck swelling. Despite receiving anti-tubercular treatment (ATT) and intravenous antibiotics, the patient experienced recurrent infections and abscesses, prompting further investigation. Laboratory tests revealed normal immunoglobulin levels but abnormal nitroblue tetrazolium (NBT) and dihydrorhodamine (DHR) tests, indicating CGD. Genetic analysis (clinical exome by next-generation sequencing) confirmed a novel NCF2 gene mutation associated with autosomal recessive CGD. This patient was treated with prophylactic antibiotics and antifungals and subsequently underwent successful hematopoietic stem cell transplantation (HSCT). This highlights the diagnostic challenges associated with CGD, particularly in tuberculosis-endemic regions such as India, emphasizing the importance of considering primary immunodeficiency disorders in patients with recurrent infections. Early diagnosis and appropriate treatment, including HSCT, can significantly improve patient outcomes. The patient remained infection-free on prophylactic antimicrobials for 1.5 years post-discharge, demonstrating the potential for a favorable prognosis with timely intervention and comprehensive management.

Entire expressed peripheral blood transcriptome in pediatric severe malarial anemia

This study on severe malarial anemia (SMA: Hb < 6.0 g/dL), a leading global cause of childhood morbidity and mortality, compares the entire expressed whole blood host transcriptome between Kenyan children (3-48 mos.) with non-SMA (Hb ≥ 6.0 g/dL, n = 39) and SMA (n = 18). Differential expression analyses reveal 1403 up-regulated and 279 down-regulated transcripts in SMA, signifying impairments in host inflammasome activation, cell death, and innate immune and cellular stress responses. Immune cell profiling shows decreased memory responses, antigen presentation, and immediate pathogen clearance, suggesting an immature/improperly regulated immune response in SMA. Module repertoire analysis of blood-specific gene signatures identifies up-regulation of erythroid genes, enhanced neutrophil activation, and impaired inflammatory responses in SMA. Enrichment analyses converge on disruptions in cellular homeostasis and regulatory pathways for the ubiquitin-proteasome system, autophagy, and heme metabolism. Pathway analyses highlight activation in response to hypoxic conditions [Hypoxia Inducible Factor (HIF)-1 target and Reactive Oxygen Species (ROS) signaling] as a central theme in SMA. These signaling pathways are also top-ranking in protein abundance measures and a Ugandan SMA cohort with available transcriptomic data. Targeted RNA-Seq validation shows strong concordance with our entire expressed transcriptome data. These findings identify key molecular themes in SMA pathogenesis, offering potential targets for new malaria therapies.

Other Causes of Chronic Diarrhea in Children

Chronic diarrhea is still an important cause of morbidity and mortality in children. There are several causes of chronic diarrhea which may be due to intestinal, extra-intestinal or underlying systemic diseases. The etiology varies depending on the age of onset and may include both common and uncommon disorders. In this article some of the uncommon disorders such as immune deficiencies, intestinal lymphangiectasias, drug induced diarrhea, eosinophilic gastrointestinal disorders, endocrinopathies, neuroendocrine secretory tumors, malignancy and factitious diarrhea have been included. Though these disorders are uncommon it is essential that they are considered in select situations as detailed below and evaluated so that definitive therapy may be offered.

Altered X-chromosome inactivation predisposes to autoimmunity

In mammals, males and females show marked differences in immune responses. Males are globally more sensitive to infectious diseases, while females are more susceptible to systemic autoimmunity. X-chromosome inactivation (XCI), the epigenetic mechanism ensuring the silencing of one X in females, may participate in these sex biases. We perturbed the expression of the trigger of XCI, the noncoding RNA Xist, in female mice. This resulted in reactivation of genes on the inactive X, including members of the Toll-like receptor 7 (TLR7) signaling pathway, in monocyte/macrophages and dendritic and B cells. Consequently, female mice spontaneously developed inflammatory signs typical of lupus, including anti-nucleic acid autoantibodies, increased frequencies of age-associated and germinal center B cells, and expansion of monocyte/macrophages and dendritic cells. Mechanistically, TLR7 signaling is dysregulated in macrophages, leading to sustained expression of target genes upon stimulation. These findings provide a direct link between maintenance of XCI and female-biased autoimmune manifestations and highlight altered XCI as a cause of autoimmunity.

Function and regulation of GPR84 in human neutrophils

Human neutrophils are components of the innate immune system and are the most abundant white blood cells in the circulation. They are professional phagocytes and express several G protein-coupled receptors (GPCRs), which are essential for proper neutrophil functions. So far, the two formyl peptide receptors, FPR1 and FPR2, have been the most extensively studied group of neutrophil GPCRs, but recently, a new group, the free fatty acid (FFA) receptors, has attracted growing attention. Neutrophils express two FFA receptors, GPR84 and FFA2, which sense medium- and short-chain fatty acids respectively, and display similar activation profiles. The exact pathophysiological role of GPR84 is not yet fully understood, but it is generally regarded as a pro-inflammatory receptor that mediates neutrophil activation. In this review, we summarize current knowledge of how GPR84 affects human neutrophil functions and discuss the regulatory mechanisms that control these responses, focusing on the similarities and differences in comparison to the two FPRs and FFA2. LINKED ARTICLES: This article is part of a themed issue GPR84 Pharmacology. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.10/issuetoc.

Integrative analysis and validation of necroptosis-related molecular signature for evaluating diagnosis and immune features in Rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease that is characterized by persistent morning stiffness, joint pain, and swelling. However, there is a lack of reliable diagnostic markers and therapeutic targets that are both effective and trustworthy.

METHODS

In this study, gene expression profiles (GSE89408, GSE55235, GSE55457, and GSE77298) were obtained from the Gene Expression Omnibus database. Differentially expressed necroptosis-related genes were attained from intersection of necroptosis-related gene set, differentially expressed genes, and weighted gene co-expression network analysis. The LASSO, random forest, and SVM-RFE machine learning algorithms were utilized to further screen potential diagnostic genes for RA. Immune cell infiltration was analyzed using the CIBERSORT method. The expressions of diagnostic genes were validated through quantitative real-time PCR, western blotting, immunohistochemistry, and immunofluorescence staining in synovial tissues collected from three trauma controls and three RA patients.

RESULTS

Five core necroptosis-related genes (FAS, CYBB, TNFSF10, EIF2AK2, and BIRC2) were identified as potential biomarkers for RA. Two different necroptosis patterns based on these five genes were confirmed to significantly correlated with immune cells (especially macrophages). In vitro experiments showed significantly higher mRNA and protein expression levels of CYBB and EIF2AK2 in RA patients compared to normal controls, consistent with the bioinformatics analysis results.

CONCLUSION

Our study identified a novel necroptosis-related subtype and five diagnostic biomarkers of RA, revealed vital roles in the development and occurrence of RA, and offered potential targets for clinical diagnosis and immunotherapy.

The New Frontiers of Gene Therapy and Gene Editing in Inflammatory Diseases

Inflammatory diseases are conditions characterized by abnormal and often excessive immune responses, leading to tissue and organ inflammation. The complexity of these disorders arises from the intricate interplay of genetic factors and immune responses, which challenges conventional therapeutic approaches. However, the field of genetic manipulation has sparked unprecedented optimism in addressing these complex disorders. This review aims to comprehensively explore the application of gene therapy and gene editing in the context of inflammatory diseases, offering solutions that range from correcting genetic defects to precise immune modulation. These therapies have exhibited remarkable potential in ameliorating symptoms, improving quality of life, and even achieving disease remission. As we delve into recent breakthroughs and therapeutic applications, we illustrate how these advancements offer novel and transformative solutions for conditions that have traditionally eluded conventional treatments. By examining successful case studies and preclinical research, we emphasize the favorable results and substantial transformative impacts that gene-based interventions have demonstrated in patients and animal models of inflammatory diseases such as chronic granulomatous disease, cryopyrin-associated syndromes, and adenosine deaminase 2 deficiency, as well as those of multifactorial origins such as arthropathies (osteoarthritis, rheumatoid arthritis) and inflammatory bowel disease. In conclusion, gene therapy and gene editing offer transformative opportunities to address the underlying causes of inflammatory diseases, ushering in a new era of precision medicine and providing hope for personalized, targeted treatments.

Neutrophils: from IBD to the gut microbiota

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract that results from dysfunction in innate and/or adaptive immune responses. Impaired innate immunity, which leads to lack of control of an altered intestinal microbiota and to activation of the adaptive immune system, promotes a secondary inflammatory response that is responsible for tissue damage. Neutrophils are key players in innate immunity in IBD, but their roles have been neglected compared with those of other immune cells. The latest studies on neutrophils in IBD have revealed unexpected complexities, with heterogeneous populations and dual functions, both deleterious and protective, for the host. In parallel, interconnections between disease development, intestinal microbiota and neutrophils have been highlighted. Numerous IBD susceptibility genes (such as NOD2, NCF4, LRRK2, CARD9) are involved in neutrophil functions related to defence against microorganisms. Moreover, severe monogenic diseases involving dysfunctional neutrophils, including chronic granulomatous disease, are characterized by intestinal inflammation that mimics IBD and by alterations in the intestinal microbiota. This observation demonstrates the dialogue between neutrophils, gut inflammation and the microbiota. Neutrophils affect microbiota composition and function in several ways. In return, microbial factors, including metabolites, regulate neutrophil production and function directly and indirectly. It is crucial to further investigate the diverse roles played by neutrophils in host-microbiota interactions, both at steady state and in inflammatory conditions, to develop new IBD therapies. In this Review, we discuss the roles of neutrophils in IBD, in light of emerging evidence proving strong interconnections between neutrophils and the gut microbiota, especially in an inflammatory context.

X-linked chronic granulomatous disease secondary to skewed X-chromosome inactivation in female patients

BACKGROUND

Chronic granulomatous disease (CGD) is a heterogeneous primary immunodeficiency. X-linked (XL) CGD caused by gene defects of CYBB is the most prevalent type of CGD.

OBJECTIVE

We aim to understand the clinical and molecule features of XL-CGD secondary to skewed X-chromosome inactivation (XCI) in female.

METHODS

We retrospectively reviewed the medical records of a female patient diagnosed with XL-CGD. Flow cytometry was used to detect the respiratory burst function. After restriction enzyme digestion of DNA, XCI was calculated by detecting fluorescent PCR products with capillary electrophoresis. The previously published female XL-CGD cases secondary to skewed XCI was summarized.

RESULTS

Clinical data were available for 15 female subjects. The median age of diagnosis was 16 years. Consistent with XL-CGD in males, infection was the most frequent manifestation in the female patients. Catalase-positive pathogens including Serratia marcescens and Staphylococcus aureus infections were the most common pathogens. Autoimmune/autoinflammation manifestations were observed in five patients. Dihydrorhodamine (DHR) assay showed that median %DHR+ values were 6.5% and the values varying with age were observed in 2 patients. All patients had a skewing XCI and there was no consistency between the daughter and carrier mother. Anti-infective treatment was effective in majority and there was no mortality reported in XL-CGD female patients to date.

CONCLUSION

XL-CGD should not be neglected in female patients manifested as CGD phenotype and it is necessary to make periodic clinical evaluation of CGD female carriers as the neutrophil oxidative function may decline with aging and increase the risk for infection.

Preimplantation genetic testing for X-linked chronic granulomatous disease induced by a CYBB gene variant: A case report

INTRODUCTION

X-linked recessive chronic granulomatous disease (XR-CGD) is a severe primary immunodeficiency principally caused by a CYBB (OMIM: 300481) gene variant. Recurrent fatal bacterial or fungal infections are the main clinical manifestations of XR-CGD.

PATIENT CONCERNS

In the current case, in vitro fertilization (IVF) associated with preimplantation genetic testing for monogenic disorder (PGT-M) was applied for a Chinese couple who had given birth to a boy with XR-CGD.

DIAGNOSIS

Next-generation sequencing-based SNP haplotyping and Sanger-sequencing were used to detect the CYBB gene variant (c.804 + 2T>C, splicing) in this family.

INTERVENTIONS

The patient was treated with IVF and PGT-M successively.

OUTCOMES

In this IVF cycle, 7 embryos were obtained, and 2 of them were euploid and lacked the CYBB gene variant (c.804 + 2T>C). The PGT results were verified by prenatal diagnosis after successful pregnancy, and a healthy girl was eventually born.

CONCLUSION

PGT-M is an effective method for helping families with these fatal and rare inherited diseases to have healthy offspring. It can availably block the transmission of disease-causing loci to descendant.

Hematopoietic stem cell transplantation in children with chronic granulomatous disease: the Spanish experience

Introduction

Hematopoietic stem cell transplantation (HCT) can cure chronic granulomatous disease (CGD). However, transplant-associated morbidity or mortality may occur, and it is still controversial which patients benefit from this procedure. The aim of this retrospective study was to evaluate the outcome of pediatric patients who received HCT in one of the Spanish pediatric transplant units.

Results

Thirty children with a median age of 6.9 years (range 0.6-12.7) were evaluated: 8 patients received a transplant from a sibling donor (MSD), 21 received a transplant from an unrelated donor (UD), and 1 received a haploidentical transplant. The majority of the patients received reduced-intensity conditioning regimens based on either busulfan plus fludarabine or treosulfan. Relevant post-HCT complications were as follows: i) graft failure (GF), with a global incidence of 28.26% (CI: 15.15-48.88), 11.1% in patients with MSD (1.64-56.70) and 37.08% in unrelated donors (19.33-63.17); and ii) chronic graft-versus-host disease (GVHD), with an incidence of 20.5% (8.9-43.2), 11.1% in patients with MSD (1.64-56.70) and 26.7% in unrelated donors (10.42-58.44). Post-HCT infections were usually manageable, but two episodes of pulmonary aspergillosis were diagnosed in the context of graft rejection. The 2-year OS was 77.3% (55.92-89.23). There were no statistically significant differences among donor types.

Discussion

HCT in patients with CGD is a complex procedure with significant morbidity and mortality, especially in patients who receive grafts from unrelated donors. These factors need to be considered in the decision-making process and when discussing conditioning and GVHD prophylaxis.

Viperin mutation is linked to immunity, immune cell dynamics, and metabolic alteration during VHSV infection in zebrafish

Viperin is a prominent antiviral protein found in animals. The primary function of Viperin is the production of 3'-deoxy-3',4'-didehydro-cytidine triphosphate (ddhCTP), an inhibitory nucleotide involved in viral RNA synthesis. Studies in mammalian models have suggested that ddhCTP interferes with metabolic proteins. However, this hypothesis has yet to be tested in teleost. In this study, the role of Viperin in regulating metabolic alterations during viral hemorrhagic septicemia virus (VHSV) infection was tested. When infected with VHSV, viperin -/- fish showed considerably higher mortality rates. VHSV copy number and the expression of the NP gene were significantly increased in viperin -/- fish. Metabolic gene analysis revealed significant differences in soda, hif1a, fasn, and acc expression, indicating their impact on metabolism. Cholesterol analysis in zebrafish larvae during VHSV infection showed significant upregulation of cholesterol production without Viperin. In vitro analysis of ZF4 cells suggested a considerable reduction in lipid production and a significant upregulation of reactive oxygen species (ROS) generation with the overexpression of viperin. Neutrophil and macrophage recruitment were significantly modulated in viperin -/- fish compared to the wild-type (WT) fish. Thus, we have demonstrated that Viperin plays a role in interfering with metabolic alterations during VHSV infection.

Donor Cell Acute Myeloid Leukemia after Hematopoietic Stem Cell Transplantation for Chronic Granulomatous Disease: A Case Report and Literature Review

The patient reported here underwent hematopoietic stem cell transplantation (HSCT) due to chronic granulomatous disease (CGD) caused by biallelic mutations of the NCF1 gene. Two years later, he developed AML, which was unexpected and was recognized via sex-mismatched chromosomes as deriving from the donor cells; the patient was male, and the donor was his sister. Donor cell leukemia (DCL) is very rare, and it had never been reported in patients with CGD after HSCT. In the subsequent ten years, the AML relapsed three times and the patient underwent chemotherapy and three further HSCTs; donors were the same sister from the first HSCT, an unrelated donor, and his mother. The patient died during the third relapse. The DCL was characterized since onset by an acquired translocation between chromosomes 9 and 11, with a molecular rearrangement between the MLL and MLLT3 genes-a quite frequent cause of AML. In all of the relapses, the malignant clone had XX sex chromosomes and this rearrangement, thus indicating that it was always the original clone derived from the transplanted sister's cells. It exhibited the ability to remain quiescent in the BM during repeated chemotherapy courses, remission periods and HSCT. The leukemic clone then acquired different additional anomalies during the ten years of follow-up, with cytogenetic results characterized both by anomalies frequent in AML and by different, non-recurrent changes. This type of cytogenetic course is uncommon in AML.

Molecular Challenges in the Diagnosis of X-Linked Chronic Granulomatous Disease: CNVs, Intronic Variants, Skewed X-Chromosome Inactivation, and Gonosomal Mosaicism

Chronic granulomatous disease (CGD) is a prototypical inborn error of immunity affecting phagocytes, in which these cells are unable to produce reactive oxygen species. CGD is caused by defects in genes encoding subunits of the NADPH oxidase enzyme complex (CYBA, CYBB, CYBC1, NCF1, NCF2, NCF4); inflammatory responses are dysregulated, and patients are highly susceptible to recurrent severe bacterial and fungal infections. X-linked CGD (XL-CGD), caused by mutations in the CYBB gene, is the most common and severe form of CGD. In this study, we describe the analytical processes undertaken in 3 families affected with XL-CGD to illustrate several molecular challenges in the genetic diagnosis of this condition: in family 1, a girl with a heterozygous deletion of CYBB exon 13 and skewed X-chromosome inactivation (XCI); in family 2, a boy with a hemizygous deletion of CYBB exon 7, defining its consequences at the mRNA level; and in family 3, 2 boys with the same novel intronic variant in CYBB (c.1151 + 6 T > A). The variant affected the splicing process, although a small fraction of wild-type mRNA was produced. Their mother was a heterozygous carrier, while their maternal grandmother was a carrier in form of gonosomal mosaicism. In summary, using a variety of techniques, including an NGS-based targeted gene panel and deep amplicon sequencing, copy number variation calling strategies, microarray-based comparative genomic hybridization, and cDNA analysis to define splicing defects and skewed XCI, we show how to face and solve some uncommon genetic mechanisms in the diagnosis of XL-CGD.

Allogeneic HSCT for Symptomatic Female X-linked Chronic Granulomatous Disease Carriers

X-linked chronic granulomatous disease (XL-CGD) is an inherited disorder of superoxide production, causing failure to generate the oxidative burst in phagocytes. It is characterized by invasive bacterial and fungal infections, inflammation, and chronic autoimmune disease. While XL-CGD carriers were previously assumed to be healthy, a range of clinical manifestations with significant morbidity have recently been described in a subgroup of carriers with impaired neutrophil oxidative burst due to skewed lyonization. Allogeneic hematopoietic stem cell transplantation (HSCT) is the standard curative treatment for CGD but has rarely been reported in individual symptomatic carriers to date. We undertook a retrospective international survey of outcome of HSCT for symptomatic XL-CGD carriers. Seven symptomatic female XL-CGD carriers aged 1-56 years underwent HSCT in four centers, indicated for severe and recurrent infection, colitis, and autoimmunity. Two patients died from transplant-related complications, following donor engraftment and restoration of oxidative burst. All surviving patients demonstrated resolution of their neutrophil oxidative burst defect with concordant reduction in infection and inflammatory symptoms and freedom from further immunosuppressive therapy. In conclusion, allogeneic HSCT may cure the phagocyte defect in symptomatic XL-CGD carriers and improve their recurrent and disabling infective and inflammatory symptoms but risks transplant-related complications.

Improved Outcome Following Busulfan-Based Conditioning in Children with Functional Neutrophil Disorders Undergoing Hematopoietic Stem Cell Transplant from HLA-Matched Donors

Hematopoietic stem-cell transplantation (HSCT) is the only curative treatment for chronic granulomatous disease (CGD) and leukocyte-adhesion deficiency (LAD), but both diseases have high rates of graft failure in transplant and patients with these diseases are often referred to HSCT with significant comorbidity. The intensity of the conditioning regimen should be balanced between the need to ensure durable engraftment and to minimize toxicity when transplanting young children with infections and organ damage. We report on 26 children transplanted at our institution with CGD and LAD over 24 years. We found a higher incidence of graft failure in patients receiving treosulfan based conditioning for their first transplant. There was no effect of conditioning regimen on overall survival, as all 8 patients that proceeded to a second busulfan-based HSCT were salvaged. We recommend giving patients with CGD and LAD fully myeloablative conditioning with either a busulfan-based regimen or the combination of treosulfan, fludarabine, and thiotepa.

Non-infectious Pulmonary Complications in Children with Primary Immunodeficiency

Primary immune deficiency (PID) is a large group of diseases characterized by defective immune function, leading to recurrent infections, and immune dysregulation. Clinical presentations, severity, and complications differ for each disease, based on the components of the immune system that are impacted. When patients with PID present with respiratory symptoms, infections should be initially suspected, investigated, and promptly managed. However, non-infectious complications of PID also frequently occur and can lead to significant morbidity and mortality. They can involve both the upper and lower respiratory systems, resulting in various presentations that mimic infectious diseases. Thus, clinicians should be able to detect these conditions and make an appropriate referral to an immunologist and a pulmonologist for further management. In this article, we use case-based scenarios to review the differential diagnosis, investigation, and multidisciplinary treatment of non-infectious pulmonary complications in patients with primary immune deficiencies.

Chronic Granulomatous Disease (CGD): Commonly Associated Pathogens, Diagnosis and Treatment

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by a defect in the phagocytic function of the innate immune system owing to mutations in genes encoding the five subunits of the nicotinamide adenine dinucleotide phosphatase (NADPH) oxidase enzyme complex. This review aimed to provide a comprehensive approach to the pathogens associated with chronic granulomatous disease (CGD) and its management. Patients with CGD, often children, have recurrent life-threatening infections and may develop infectious or inflammatory complications. The most common microorganisms observed in the patients with CGD are Staphylococcus aureus, Aspergillus spp., Candida spp., Nocardia spp., Burkholderia spp., Serratia spp., and Salmonella spp. Antibacterial prophylaxis with trimethoprim-sulfamethoxazole, antifungal prophylaxis usually with itraconazole, and interferon gamma immunotherapy have been successfully used in reducing infection in CGD. Haematopoietic stem cell transplantation (HCT) have been successfully proven to be the treatment of choice in patients with CGD.

Nontypeable Haemophilus influenzae released from biofilm residence by monoclonal antibody directed against a biofilm matrix component display a vulnerable phenotype

Bacterial biofilms contribute significantly to pathogenesis, recurrence and/or chronicity of the majority of bacterial diseases due to their notable recalcitrance to clearance. Herein, we examined kinetics of the enhanced sensitivity of nontypeable Haemophilus influenzae (NTHI) newly released (NRel) from biofilm residence by a monoclonal antibody against a bacterial DNABII protein (α-DNABII) to preferential killing by a β-lactam antibiotic. This phenotype was detected within 5 min and lasted for ~ 6 h. Relative expression of genes selected due to their known involvement in sensitivity to a β-lactam showed transient up-regulated expression of penicillin binding proteins by α-DNABII NTHI NRel, whereas there was limited expression of the β-lactamase precursor. Transient down-regulated expression of mediators of oxidative stress supported similarly timed vulnerability to NADPH-oxidase sensitive intracellular killing by activated human PMNs. Further, transient up-regulated expression of the major NTHI porin aligned well with observed increased membrane permeability of α-DNABII NTHI NRel, a characteristic also shown by NRel of three additional pathogens. These data provide mechanistic insights as to the transient, yet highly vulnerable, α-DNABII NRel phenotype. This heightened understanding supports continued validation of this novel therapeutic approach designed to leverage knowledge of the α-DNABII NRel phenotype for more effective eradication of recalcitrant biofilm-related diseases.

Cytomegalovirus and Epstein-Barr Virus Co-infection in a Patient With Chronic Granulomatous Disease Co-existing With Familial Mediterranean Fever and Early-Onset Inflammatory Bowel Disease: A Case Report

The association between primary immunodeficiencies and autoinflammatory disorders has been popularized over the past decade. In this report, we illustrated the co-infection of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in a three-year-old Jordanian male patient with an extremely rare variant of the CYBB gene (c.125C>G, p.Thr42Arg) associated with chronic granulomatous disease (CGD) coexisting with familial Mediterranean fever (FMF). CGD and FMF co-existence induced early-onset inflammatory bowel disease mainly resembling Crohn's disease.

Hematopoietic stem cell transplantation for CYBB heterozygous mutation resulting in very early onset inflammatory bowel disease in children: a case report

BACKGROUND

Inflammatory bowel disease (IBD) is a heterogeneous group of disorders associated with environmental triggers and dysregulated immune responses resulting in chronic, recurrent intestinal inflammation. Very early-onset IBD (VEO-IBD) refers to patients with symptoms or diagnosis before the age of 6 years and is widely thought to be associated with monogenic mutations. Traditional drug therapy is often ineffective in this patient population, while hematopoietic stem cell transplantation (HSCT) represents the definitive cure for patients with gene mutations.

CASE PRESENTATION

We report a case of VEO-IBD associated with a monogenic mutation in a 2-year-old girl presenting mainly with gastrointestinal symptoms, including recurrent hematochezia and abdominal pain for more than 3 months. A gastroscopy revealed erosive gastritis and bulbar duodenitis, while a colonoscopy indicated erosive colitis. Abnormal results were obtained from the dihydrohodamine (DHR) assay and immunoglobulin testing. Whole-exome sequencing identified a heterozygous and de novo nonsense mutation (c.388 C > T; p.R130X) in the CYBB gene leading to deficiency of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) (encoded by CYBB), a critical component of phagocytes. HSCT was performed successfully, and the DHR assay showed that normal neutrophil function was restored. Six months after HSCT, clinical remission was observed, and a repeat colonoscopy revealed intestinal mucosal healing was attained.

CONCLUSIONS

Patients with CYBB mutations often develop recurrent or severe bacterial or fungal infections, mostly in the lungs, skin, lymph nodes, and liver. Here, we report on a young female child with CYBB mutations presenting predominantly with gastrointestinal symptoms. This study explores the mechanisms of inflammatory bowel disease caused by a monogenic mutation in CYBB to improve early diagnosis and effective treatment rates of this patient population.

Characterization and CRISPR/Cas9-mediated genetic manipulation of neutrophils derived from Hoxb8-ER-immortalized myeloid progenitors

Neutrophils represent a first line of defense against a wide variety of microbial pathogens. Transduction with an estrogen receptor-Hoxb8 transcription factor fusion construct conditionally immortalizes myeloid progenitor cells (NeutPro) capable of differentiation into neutrophils. This system has been very useful for generating large numbers of murine neutrophils for in vitro and in vivo studies. However, some questions remain as to how closely neutrophils derived from these immortalized progenitors reflect primary neutrophils. Here we describe our experience with NeutPro-derived neutrophils as it relates to our studies of Yersinia pestis pathogenesis. NeutPro neutrophils have circular or multilobed nuclei, similar to primary bone marrow neutrophils. Differentiation of neutrophils from NeutPro cells leads to increased expression of CD11b, GR1, CD62L, and Ly6G. However, the NeutPro neutrophils expressed lower levels of Ly6G than bone marrow neutrophils. NeutPro neutrophils produced reactive oxygen species at slightly lower levels than bone marrow neutrophils, and the 2 cell types phagocytosed and killed Y. pestis in vitro to a similar degree. To further demonstrate their utility, we used a nonviral method for nuclear delivery of CRISPR/Cas9 guide RNA complexes to delete genes of interest in NeutPro cells. In summary, we have found these cells to be morphologically and functionally equivalent to primary neutrophils and useful for in vitro assays related to studies of bacterial pathogenesis.

Inflammation and Neutrophil Oxidative Burst in a Family with NFKB1 p.R157X LOF and Sterile Necrotizing Fasciitis

Loss-of-function (LOF) mutations in NFKB1, coding for p105, may cause common variable immunodeficiency due to dysregulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κΒ) pathway. Monoallelic LOF variants of NFKB1 can predispose to uncontrolled inflammation including sterile necrotizing fasciitis or pyoderma gangrenosum. In this study, we explored the impact of a heterozygous NFKB1 c.C936T/p.R157X LOF variant on immunity in sterile fasciitis patients and their family members. The p50 or p105 protein levels were reduced in all variant carriers. Interleukin-1β (IL-1β) and interleukin-8 (IL-8) levels were elevated in vitro, potentially contributing to the very high neutrophil counts observed during fasciitis episodes. Phosphorylation of p65/RelA was reduced in p.R157X neutrophils suggesting defective activation of canonical NF-κB. Oxidative burst after NF-κB-independent phorbol 12-myristate 13-acetate (PMA) stimulation was similar in both p.R157X and control neutrophils. Comparable amounts of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex subunits were found in p.R157X and control neutrophils. However, a compromised oxidative burst was observed in p.R157X neutrophils following activation of NF-κB-dependent mechanisms following stimulation of toll-like receptor 2 (TLR2) and Dectin-1. Neutrophil extracellular trap formation was not affected by p.R157X. In summary, the NFKB1 c.C936T/p.R157X LOF variant has an impact on inflammation and neutrophil function and may play a role in the pathogenesis of sterile necrotizing fasciitis.

R, Eley B, Bhattad S. Genetically confirmed chronic granulomatous disease in a Kenyan child: case report

Introduction

We report the first case of genetically confirmed chronic granulomatous disease (CGD) in a Kenyan child.

Clinical findings

A 7-month-old male infant, the only child of non-consanguineous parents, presented with cough, fever, fast breathing, oral thrush, and axillary lymphadenopathy ipsilateral to the Calmette-Guérin bacillus scar. He had been hospitalized 5 weeks prior for severe pneumonia. Plain chest radiography showed bilateral patchy airspace opacification; chest computed tomography revealed multiple large lung nodules and left axillary lymphadenopathy. HIV ELISA was negative; tuberculin skin test was positive; lymph node biopsy macroscopically revealed caseous granulomas seen on histology; isoniazid- and rifampicin-susceptible Mycobacterium tuberculosis complex isolate was detected on the Hain test. First-line anti-tuberculous drugs were added to his empiric treatment comprising piperacillin-tazobactam, amikacin, cotrimoxazole, and fluconazole. He was discharged after 10 days based on clinical resolution.

Diagnoses interventions and outcome

An inborn error of immunity (IEI) was considered given the recurrent fevers and atypical lung nodules. Genetic analysis revealed a hemizygous pathogenic variant on CYBB in keeping with X-linked CGD. The child's fevers recurred 2 weeks post-discharge but completely resolved on prophylactic itraconazole and cotrimoxazole. He underwent a successful haplo-identical hematopoietic stem cell transplantation at an experienced center in India with his father as the donor and is currently doing well on post-transplant follow-up.

Conclusion

Genetic testing is relatively accessible and cost-effective for the diagnosis of IEI in low-and-middle-income countries. Expert multi-disciplinary collaboration is key for successful outcomes.

A rare case of concurrent pneumonia, rib osteomyelitis, spondylodiscitis, paravertebral and epidural abscesses in a patient with chronic granulomatous disease

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disorder that is characterized by deficiencies in the phagocytes capacity to eliminate ingested microorganisms, which frequently causes bacterial and fungal infections. The extensive involvement of the lungs, ribs, and vertebrae that is complicated by multiple abscesses from aspergillosis is rare. in this study, we report a 13-year-old boy with CGD who experienced concurrent pneumonia, rib osteomyelitis, spondylodiscitis, paravertebral, and epidural abscesses as a result of Aspergillus flavus infection with associated computed tomography scan and magnetic resonance imaging findings. Patients with CGD are susceptible to Aspergillus infection. Correct diagnosis based on clinical and paraclinical findings as well as choosing the best treatment regimen is essential for achieving a favorable outcome.

Zebrafish: A Relevant Genetic Model for Human Primary Immunodeficiency (PID) Disorders?

Primary immunodeficiency (PID) disorders, also commonly referred to as inborn errors of immunity, are a heterogenous group of human genetic diseases characterized by defects in immune cell development and/or function. Since these disorders are generally uncommon and occur on a variable background profile of potential genetic and environmental modifiers, animal models are critical to provide mechanistic insights as well as to create platforms to underpin therapeutic development. This review aims to review the relevance of zebrafish as an alternative genetic model for PIDs. It provides an overview of the conservation of the zebrafish immune system and details specific examples of zebrafish models for a multitude of specific human PIDs across a range of distinct categories, including severe combined immunodeficiency (SCID), combined immunodeficiency (CID), multi-system immunodeficiency, autoinflammatory disorders, neutropenia and defects in leucocyte mobility and respiratory burst. It also describes some of the diverse applications of these models, particularly in the fields of microbiology, immunology, regenerative biology and oncology.

Co-Occurring X-Linked Agammaglobulinemia and X-Linked Chronic Granulomatous Disease: Two Isolated Pathogenic Variants in One Patient

We present a unique and unusual case of a male patient diagnosed with two coexisting and typically unassociated X-linked conditions: he was initially diagnosed with X-linked agammaglobulinemia (XLA) followed by a diagnosis of X-linked chronic granulomatous disease (XCGD) and an as of yet unpublished hypomorphic gp91phox variant in the CYBB gene. The latter was tested after the finding of granulomatous gingivitis. Hematopoietic stem cell transplant (HSCT) was performed due to severe colitis and nodular regenerative hyperplasia (NRH) of the liver. Following transplant, complete donor engraftment was observed with the restoration of a normal oxidative burst and full restoration of normal levels of circulating, mature CD19+ B cells. This case is singular in that it does not involve a contiguous gene syndrome in which deleted genes are in close proximity to either BTK and CYBB, which has been previously reported. To our knowledge, this is the first reported case of XLA and XCGD co-existing in a single patient and of having both inborn errors of immunity successfully treated by HSCT.

Staphylococcus aureus stimulates neutrophil itaconate production that suppresses the oxidative burst

Neutrophils are critical in the host defense against Staphylococcus aureus, a major human pathogen. However, even in the setting of a robust neutrophil response, S. aureus can evade immune clearance. Here, we demonstrate that S. aureus impairs neutrophil function by triggering the production of the anti-inflammatory metabolite itaconate. The enzyme that synthesizes itaconate, Irg1, is selectively expressed in neutrophils during S. aureus pneumonia. Itaconate inhibits neutrophil glycolysis and oxidative burst, which impairs survival and bacterial killing. In a murine pneumonia model, neutrophil Irg1 expression protects the lung from excessive inflammation but compromises bacterial clearance. S. aureus is thus able to evade the innate immune response by targeting neutrophil metabolism and inducing the production of the anti-inflammatory metabolite itaconate.

Multiparametric Profiling of Neutrophil Function via a High-Throughput Flow Cytometry-Based Assay

Neutrophils are a vital component of the innate immune system and play an essential function in the recognition and clearance of bacterial and fungal pathogens. There is great interest in understanding mechanisms of neutrophil dysfunction in the setting of disease and deciphering potential side effects of immunomodulatory drugs on neutrophil function. We developed a high throughput flow cytometry-based assay for detecting changes to four canonical neutrophil functions following biological or chemical triggers. Our assay detects neutrophil phagocytosis, reactive oxygen species (ROS) generation, ectodomain shedding, and secondary granule release in a single reaction mixture. By selecting fluorescent markers with minimal spectral overlap, we merge four detection assays into one microtiter plate-based assay. We demonstrate the response to the fungal pathogen, Candida albicans and validate the assay's dynamic range using the inflammatory cytokines G-CSF, GM-CSF, TNFα, and IFNγ. All four cytokines increased ectodomain shedding and phagocytosis to a similar degree while GM-CSF and TNFα were more active in degranulation when compared to IFNγ and G-CSF. We further demonstrated the impact of small molecule inhibitors such as kinase inhibition downstream of Dectin-1, a critical lectin receptor responsible for fungal cell wall recognition. Bruton's tyrosine kinase (Btk), Spleen tyrosine kinase (Syk), and Src kinase inhibition suppressed all four measured neutrophil functions but all functions were restored with lipopolysaccharide co-stimulation. This new assay allows for multiple comparisons of effector functions and permits identification of distinct subpopulations of neutrophils with a spectrum of activity. Our assay also offers the potential for studying the intended and off-target effects of immunomodulatory drugs on neutrophil responses.

Clinical features and outcomes of patients with chronic granulomatous disease in Taiwan

BACKGROUND

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disease characterized by defective neutrophil killing of microbial pathogens and recurrent infections. We aimed to investigate the clinical, genetic features, treatment, and outcomes in patients with CGD.

METHODS

Pediatric patients diagnosed with CGD from a medical center in Taiwan were enrolled from January 1999 to Oct 2021.

RESULTS

Nine pediatric patients with CGD were enrolled: six X-linked (XL) CGD with CYBB gene mutations, three autosomal recessive (AR) CGD with two NCF1 and one CYBA gene mutations. The median age of onset and age of diagnosis was 0.92 and 2.64 years, respectively. Patients with XL-CGD had a younger age of onset (4.6 months vs. 1.83 years, P = 0.06) and age of diagnosis (1.71 vs. 8.86 years, P = 0.024) than AR-CGD patients. The most common sites of infections were skin and soft tissue abscesses. The most common pathogens were Staphylococcus, Serratia, and Salmonella spp. Prophylactic antibiotics, anti-fungal agents, and interferon-gamma (IFN-γ) were given in 9 (100%), 7 (77.8%), and 8 (88.9%) patients, respectively. The mean duration of IFN-γ usage was 5.15 years. One male patient with XL-CGD was successfully treated with hematopoietic stem cell transplantation at 2.2 years. The mortality rate was 11.1%, and the estimated overall survival at 20 years was 66.7%.

CONCLUSION

Staphylococcus aureus, Serratia marcescens, and Salmonella infections are important in Taiwanese CGD patients. Patients with XL-CGD have early disease onset. IFN-γ prophylaxis and prophylactic anti-microbial agents might have an effect on alleviating the infection episodes in CGD patients.

Dendritic cells in inborn errors of immunity

Dendritic cells (DCs) are crucial cells for initiating and maintaining immune response. They play critical role in homeostasis, inflammation, and autoimmunity. A number of molecules regulate their functions including synapse formation, migration, immunity, and induction of tolerance. A number of IEI are characterized by mutations in genes encoding several of these molecules resulting in immunodeficiency, inflammation, and autoimmunity in IEI. Currently, there are 465 Inborn errors of immunity (IEI) that have been grouped in 10 different categories. However, comprehensive studies of DCs have been reported in only few IEI. Here we have reviewed biology of DCs in IEI classified according to recently published IUIS classification. We have reviewed DCs in selected IEI in each group category and discussed in depth changes in DCs where significant data are available regarding role of DCs in clinical and immunological manifestations. These include severe immunodeficiency diseases, antibody deficiencies, combined immunodeficiency with associated and syndromic features, especially disorders of synapse formation, and disorders of immune regulation.