Granulomatous inflammation in inborn errors of immunity

Non-Infectious Complications of Chronic Granulomatous Disease: Knowledge Gaps & Novel Treatment Considerations

Chronic granulomatous disease (CGD) is a rare primary phagocytic immunodeficiency characterized by recurrent infections due to impaired NADPH oxidase activity. Balancing the need for additional immune suppression with the risk of infection in patients with CGD-associated inflammation can be difficult but increased understanding of the underlying pathophysiology may allow for more targeted and rational therapies. Current treatments for inflammatory complications include glucocorticoids, steroid-sparing immunosuppressive agents, antibiotics, and increasingly the use of targeted biologic agents. However, improved curative therapy strategies for patients with suboptimal donor options are needed and autologous gene therapy remains experimental.

The Burden of Non-Infectious Organ-Specific Immunopathology in Pediatric Common Variable Immunodeficiency

The pediatric common variable immunodeficiency (CVID) is the most frequent symptomatic antibody production defect characterized by infectious and non-infectious autoimmune, inflammatory, and lymphoproliferative complications. The background for CVID-related organ-specific immunopathology is associated with immune dysregulation and immunophenotypic biomarkers with expansion of CD21low B cells, and dysfunctional memory B cell, follicular T cell, and regulatory T cell compartments. The ever-increasing progress in immunogenetics shows the heterogeneity of genetic background for CVID related to the complexity of clinical phenotypes. Multiple systemic modulatory pathways are determined by variants in such genes as TACI or TNFRSF13B gene encoding for BAFF-R, CTLA-4, LRBA, NFKB1 and NFKB2, and PIK3CD or PIK3R1. The organ-specific immunopathology encompasses a spectrum of disorders associated with immune dysregulation, such as granulomatous interstitial lung disease, hepatocellular nodular regenerative hyperplasia, enteropathy, neuropathy, endocrinopathies, and dermatoses. This review is aimed to define and delineate the organ-specific immunopathology in pediatric CVID. It is also conducted to gather data facilitating a better understanding of complex and heterogeneous immunophenotypes in the context of immune dysregulation mechanisms and genetic background determining manifestations of the disease and implicating personalized targeted therapies with biological agents.

In-depth immune profiling of a patient with immunodeficiency, centromeric instability, and facial anomalies syndrome type 2 caused by a novel mutation in ZBTB24

Immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome is a rare genetic disorder characterized by recurrent, severe infections. Mutations in DNA methylation genes such as DNMT3B (ICF1), ZBTB24 (ICF2), CDCA7 (ICF3), and HELLS (ICF4) cause ICF. ICF2 syndrome has been previously described, yet the extent of its clinical presentation and immunological consequences needs to be further elucidated. We describe a patient with a novel homozygous mutation in ZBTB24 (Q375Hfs*3). While infections with extracellular pathogens are frequent in other reported ICF2 patients, our patient also displays infections by intracellular pathogens. At the molecular level, we showed that the novel mutation results in a truncated ZBTB24 protein that disrupts its function in DNA methylation. We thoroughly characterized the immunological consequences of ZBTB24 deficiency using mass cytometry coupled with state-of-the-art computational methods. Our analysis revealed reduced frequencies of natural killer cells and class-switched memory B cell populations in our patient, along with low levels of the immunoglobulin isotypes IgG4 and IgM. Despite observing normal cell frequencies within the T and myeloid compartments, the clinical presentation of this patient suggests a functional defect in immune cells known to be critical to combat intracellular pathogens. Overall, this study expands the clinical and immunological features of ZBTB24 deficiency and highlights the importance of ZBTB24 to the human immune response.

Diagnostic and Therapeutic Insights Into Pediatric Neurosarcoidosis: Observations From French Pediatric Rheumatology Centers

BACKGROUND

The diagnosis and management of neurosarcoidosis (NS) in pediatric patients remain challenging, with limited case documentation to guide clinicians. Most existing reports focus on initial presentations. This study aimed to outline the clinical features, management, and medium-term outcomes of pediatric NS METHODS: In this retrospective, multicentric, observational study, we collected data from pediatric patients followed in French pediatric rheumatology centers with a diagnosis of NS between January 2001 and June 2023.

RESULTS

We identified 11 patients diagnosed with NS, comprising eight girls and three boys. The mean age at diagnosis of sarcoidosis was 10 (5 to 15) years, and the mean age of diagnosis of NS was 11.5 (5 to 17) years. Predominant neurological symptoms included headache (nine of 11 patients), papilledema (6 of 11 patients), facial palsy (two patients), seizures (one patient), and motor deficit (two patients). Nine of 11 patients had eye involvement, which consisted of granulomatous and bilateral uveitis. All patients exhibited meningitis, with cerebrospinal fluid white blood cell counts ranging from 6 to 70 cells/mm3. Six individuals presented neurological abnormalities on imaging, detailed in this study. Treatment primarily involved corticosteroids, methotrexate, and tumor necrosis factor alpha (TNF-alpha) inhibitors. Biologics targeting TNF-alpha were necessary to achieve remission in eight of 11 patients. In two patients who did not receive this treatment initially, it was required later in the course of evolution.

CONCLUSIONS

This study enhances understanding of the clinical course of pediatric NS and supports the early use of TNF-alpha biologics for improved management in affected children.

Unmasking inborn errors of immunity: identifying the red flags of immune dysregulation

Inborn errors of immunity (IEI) are rare diseases that affect the immune system. According to the latest International Union of Immunological Societies (IUIS) classification, 485 different IEI have been identified. Even if increased susceptibility to infections is the best-known symptom, IEI are no longer defined by the higher likelihood of infections alone. Immune dysregulation with autoimmune disease and hyperinflammation, lymphoproliferation, and malignancy are common manifestations and could be the only symptoms of IEI that must be recognized. An exclusive focus on infection-centered warning signs would miss around 25% of patients with IEI who initially present with other manifestations. Timely and appropriate diagnosis and treatment are essential to enhance the quality of life (QoL) and, in some cases, survival, as patients are susceptible to life-threatening infections or autoimmunity. In addition, the advantage of early diagnosis in IEI with immune dysregulation (i.e. CTLA4 deficiency, LRBA deficiency, NF-kB1/NF-kB2 deficiency, activated phosphoinositide 3-kinase delta syndrome -APDS-) is the initiation of targeted therapies with precise re-balancing of the dysregulated immune pathways (i.e., biologicals, selective inhibitors) or definitive therapy (i.e., HSCT).

The multidisciplinary approach to diagnosing inborn errors of immunity: a comprehensive review of discipline-based manifestations

INTRODUCTION

Congenital immunodeficiency is named primary immunodeficiency (PID), and more recently inborn errors of immunity (IEI). There are more than 485 conditions classified as IEI, with a wide spectrum of clinical and laboratory manifestations.

AREAS COVERED

Regardless of the developing knowledge of IEI, many physicians do not think of IEI when approaching the patient's complaint, which leads to delayed diagnosis, misdiagnosis, serious infectious and noninfectious complications, permanent end-organ damage, and even death. Due to the various manifestations of IEI and the wide spectrum of associated conditions, patients refer to specialists in different disciplines of medicine and undergo - mainly symptomatic - treatments, and because IEI are not included in physicians' differential diagnosis, the main disease remains undiagnosed.

EXPERT OPINION

A multidisciplinary approach may be a proper solution. Manifestations and the importance of a multidisciplinary approach in the diagnosis of main groups of IEI are discussed in this article.

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.

A LTB4/CD11b self-amplifying loop drives pyogranuloma formation in chronic granulomatous disease

Sterile pyogranulomas and heightened cytokine production are hyperinflammatory hallmarks of Chronic Granulomatous Disease (CGD). Using peritoneal cells of zymosan-treated CGD (gp91phox-/-) versus wild-type (WT) mice, an ex vivo system of pyogranuloma formation was developed to determine factors involved in and consequences of recruitment of neutrophils and monocyte-derived macrophages (MoMacs). Whereas WT cells failed to aggregate, CGD cells formed aggregates containing neutrophils initially, and MoMacs recruited secondarily. LTB4 was key, as antagonizing BLT1 blocked neutrophil aggregation, but acted only indirectly on MoMac recruitment. LTB4 upregulated CD11b expression on CGD neutrophils, and the absence/blockade of CD11b inhibited LTB4 production and cell aggregation. Neutrophil-dependent MoMac recruitment was independent of MoMac Nox2 status, BLT1, CCR1, CCR2, CCR5, CXCR2, and CXCR6. As proof of concept, CD11b-deficient CGD mice developed disrupted pyogranulomas with poorly organized neutrophils and diminished recruitment of MoMacs. Importantly, the disruption of cell aggregation and pyogranuloma formation markedly reduced proinflammatory cytokine production.

Case report: Rubella virus-associated cutaneous granuloma in an adult with TAP1 deficiency

Rubella virus-associated granulomas commonly occur in immunocompromised individuals, exhibiting a diverse range of clinical presentations. These manifestations can vary from predominantly superficial cutaneous plaques or nonulcerative nodules to more severe deep ulcerative lesions, often accompanied by extensive necrosis and significant tissue destruction. TAP1 deficiency, an exceedingly rare primary immune-deficiency disorder, presents with severe chronic sino-pulmonary infection and cutaneous granulomas. This report highlights the occurrence of rubella virus-associated cutaneous granulomas in patients with TAP1 deficiency. Notably, the pathogenic mutation responsible for TAP1 deficiency stems from a novel genetic alteration that has not been previously reported. This novel observation holds potential significance for the field of diagnosis and investigative efforts in the context of immunodeficiency disorders.

Inflammatory Complications in Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a rare inborn error of immunity that typically manifests with infectious complications. As the name suggest though, inflammatory complications are also common, often affecting the gastrointestinal, respiratory, urinary tracts and other tissues. These can be seen in all various types of CGD, from X-linked and autosomal recessive to X-linked carriers. The pathogenetic mechanisms underlying these complications are not well understood, but are likely multi-factorial and reflect the body's attempt to control infections. The different levels of neutrophil residual oxidase activity are thought to contribute to the large phenotypic variations. Immunosuppressive agents have traditionally been used to treat these complications, but their use is hindered by the fact that CGD patients are predisposed to infection. Novel therapeutic agents, like anti-TNFa monoclonal antibodies, anakinra, ustekinumab, and vedolizumab offer promise for the future, while hematopoietic stem cell transplantation should also be considered in these patients.

Decline of gastric cancer mortality in common variable immunodeficiency in the years 2018-2022

Introduction

In patients with Common Variable Immunodeficiency, malignancy has been reported as the leading cause of death in adults, with a high risk of B-cell lymphomas and gastric cancer.

Methods

We conducted a five-year prospective study aiming to update the incidence and mortality of gastric cancer and the incidence of gastric precancerous lesions in 512 CVID patients who underwent a total of 400 upper gastrointestinal endoscopies.

Results

In the pre-pandemic period, 0.58 endoscopies were performed per patient/year and in the COVID-19 period, 0.39 endoscopies were performed per patient/year. Histology revealed areas with precancerous lesions in about a third of patients. Patients who had more than one gastroscopy during the study period were more likely to have precancerous lesions. Two patients received a diagnosis of gastric cancer in the absence of Helicobacter pylori infection. The overall prevalence of Helicobacter pylori infection in biopsy specimens was 19.8% and related only to active gastritis. Among patients who had repeated gastroscopies, about 20% progressed to precancerous lesions, mostly independent of Helicobacter pylori.

Discussion

While gastric cancer accounted for one in five deaths from CVID in our previous survey, no gastric cancer deaths were recorded in the past five years, likely consistent with the decline in stomach cancer mortality observed in the general population. However, during the COVID-19 pandemic, cancer screening has been delayed. Whether such a delay or true decline could be the reason for the lack of gastric cancer detection seen in CVID may become clear in the coming years. Due to the high incidence of precancerous lesions, we cannot rely on observed and predicted trends in gastric cancer mortality and strongly recommend tailored surveillance programs.