Gastrointestinal histopathology in chronic granulomatous disease: a study of 87 patients

A Systematic Review and Metaanalysis to Examine the Utility of Histological Parameters Such as Mucosal Basal Plasmacytosis and Eosinophilia for Distinguishing Inflammatory Bowel Disease and Non-IBD-Type Colitis

Background and aim: Basic differentiation between an inflammatory bowel disease (IBD)-type colitis and a non-IBD type of colitis is the essential histological pre-requisite before further subclassifications are made. The combination of mucosal prominent eosinophilic cell infiltrate along with basal plasmacytosis is supposed to be a useful histological feature that can differentiate between IBD-type and non-IBD-type colitis. Hence, this systematic review and metaanalysis aimed to assess the reliability of mucosal basal plasmacytosis and eosinophilia for histological differentiation of IBD-type versus non-IBD-type colitis. Methods: We searched the PROSPERO, PubMed, Embase, and Scopus from January 1, 2000 to July 30, 2022 for all types of studies (prospective, cross-sectional, or retrospective studies) having histological features (including mucosal basal plasmacytosis, eosinophilia, and neutrophilic infiltration) in IBD and/or non-IBD colitis cases. Two reviewers extracted data, which were aggregated using random-effects models. Results: The 59 selected articles were evaluated for the predecided parameters. Both basal plasmacytosis and lamina propria plasmacytosis did not show any significant correlation between IBD-type and non-IBD-type colitis. The proportions for basal plasmacytosis with 95% CI were 0.50 (0.19-0.82) in IBD-type colitis and 0.46 (0.40-0.52) in non-IBD-type colitis, with a P value of .79. The proportion of lamina propria plasmacytosis with 95% CI was 0.67 (0.42-0.92) in IBD and 0.60 (0.35-0.85) in non-IBD-type colitis, with a P value being .7. Conclusions: This systematic review documented the dearth of published data on key histological features such as basal plasmacytosis and mucosal eosinophilia which are believed to differentiate between IBD-type and non-IBD-type colitis.

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.

Clinical presentation, diagnosis, and treatment of chronic granulomatous disease

Chronic granulomatous disease (CGD) is caused by an impaired respiratory burst reaction in phagocytes. CGD is an X-linked (XL) (caused by pathogenic variants in CYBB) or autosomal recessive inborn error of immunity (caused by pathogenic variants in CYBA, NCF1, NCF2, or CYBC1). Female carriers of XL-CGD and unfavorable lyonization may present with the partial or full picture of CGD. Patients with CGD are at increased risk for invasive bacterial and fungal infections of potentially any organ, but especially the lymph nodes, liver, and lungs. Pathogens most frequently isolated are S. aureus and Aspergillus spp. Autoinflammation is difficult to control with immunosuppression, and patients frequently remain dependent on steroids. To diagnose CGD, reactive oxygen intermediates (O2 - or H2O2) generated by the NADPH oxidase in peripheral blood phagocytes are measured upon in vitro activation with either phorbol-12-myristate-13-acetate (PMA) and/or TLR4 ligands (E. coli or LPS). Conservative treatment requires strict hygienic conduct and adherence to antibiotic prophylaxis against bacteria and fungi, comprising cotrimoxazole and triazoles. The prognosis of patients treated conservatively is impaired: for the majority of patients, recurrent and/or persistent infections, autoinflammation, and failure to thrive remain lifelong challenges. In contrast, cellular therapies (allogeneic stem cell transplantation or gene therapy) can cure CGD. Optimal outcomes in cellular therapies are observed in individuals without ongoing infections or inflammation. Yet cellular therapies are the only curative option for patients with persistent fungal infections or autoinflammation.

Immunohistochemistry and real-time Polymerase Chain Reaction: importance in the diagnosis of intestinal tuberculosis in a Peruvian population

INTRODUCTION

The diagnosis of intestinal tuberculosis is challenging even nowadays. This study aims to report the positivity rates of new diagnostic methods such as immunohistochemistry and Real-Time Polymerase Chain Reaction in patients with intestinal tuberculosis, as well as describe the pathological and endoscopic features of intestinal tuberculosis in our population.

METHODS

This was a retrospective observational study conducted in patients diagnosed with intestinal tuberculosis, between 2010 to 2023 from the Hospital Nacional Daniel Alcides Carrion and a Private Pathology Center, both located in Peru. Clinical data was obtained, histologic features were independently re-evaluated by three pathologists; and immunohistochemistry and real-time Polymerase Chain Reaction evaluation were performed. The 33 patients with intestinal tuberculosis who fulfilled the inclusion criteria were recruited.

RESULTS

Immunohistochemistry was positive in 90.9% of cases, while real-time Polymerase Chain Reaction was positive in 38.7%. The ileocecal region was the most affected area (33.3%), and the most frequent endoscopic appearance was an ulcer (63.6%). Most of the granulomas were composed solely of epithelioid histiocytes (75.8%). Crypt architectural disarray was the second most frequent histologic finding (78.8%) after granulomas, but most of them were mild.

CONCLUSION

Since immunohistochemistry does not require an intact cell wall, it demonstrates higher sensitivity compared to Ziehl-Neelsen staining. Therefore, it could be helpful for the diagnosis of paucibacillary tuberculosis.

Functional neutrophil disorders: Chronic granulomatous disease and beyond

Since their description by Metchnikoff in 1905, phagocytes have been increasingly recognized to be the entities that traffic to sites of infection and inflammation, engulf and kill infecting organisms, and clear out apoptotic debris all the while making antigens available and accessible to the lymphoid organs for future use. Therefore, phagocytes provide the gateway and the first check in host protection and immune response. Disorders in killing and chemotaxis lead not only to infection susceptibility, but also to autoimmunity. We aim to describe chronic granulomatous disease and the leukocyte adhesion deficiencies as well as myeloperoxidase deficiency and G6PD deficiency as paradigms of critical pathways.

Case Report: The leopard sign as a potential characteristic of chronic granulomatous disease-associated colitis, unrelated to colitis severity

Background

Chronic granulomatous disease (CGD) is an inborn immune disorder in which the phagocytic system cannot eradicate pathogens, and autoinflammation occurs. Approximately half of the patients have associated gastrointestinal symptoms. Although most cases with CGD-associated colitis present nonspecific histology, colonoscopy in some cases shows brownish dots over a yellowish oedematous mucosa, which is termed a "leopard sign". However, the significance of these signs remains unclear.

Methods

We collected data from patients with CGD whose colonoscopic findings showed the leopard sign.

Results

Three patients with CGD and leopard signs were enrolled in this study. One patient underwent colonoscopy for frequent diarrhoea and weight gain failure, and another for anal fistula. The third patient was without gastrointestinal symptoms and underwent colonoscopy as a screening test before allogeneic haematopoietic cell transplantation (HCT). Endoscopic findings showed a mild leopard sign in the first case; however, non-contiguous and diffuse aphthae were observed throughout the colon. The other two cases were unremarkable except for the leopard sign. All the patients achieved remission with oral prednisolone or HCT. One patient underwent colonoscopy after HCT; results revealed improvements in endoscopy (including the leopard sign) and histological findings. However, another patient underwent colonoscopy after prednisolone treatment; this revealed no change in the leopard sign.

Conclusion

The leopard sign in the colon may be a characteristic endoscopic finding of CGD, even in patients who do not develop severe gastrointestinal symptoms; however, it does not reflect the severity of CGD-associated colitis.

Small bowel disease prevalence on video capsule endoscopy in chronic granulomatous disease-associated inflammatory bowel disease

BACKGROUND AND AIM

Patients with chronic granulomatous disease (CGD) may develop inflammatory bowel disease (IBD). Characterization of small bowel disease in this cohort is scarce. Here, we sought to determine the prevalence and characteristics of small bowel disease and evaluate the clinical utility of video capsule endoscopy (VCE) for its diagnosis.

METHODS

A retrospective study was performed on patients with CGD who were evaluated for gastrointestinal disease with VCE as a part of ongoing natural history studies at a single academic center. VCEs were reviewed for inflammatory findings and severity of disease utilizing the Capsule Endoscopy Crohn's Disease Activity Index. Radiographic studies and endoscopies performed within 30 days of VCE were compared with small bowel inflammatory findings.

RESULTS

Twenty-six VCEs corresponding to 25 patients were found. The majority of patients were male and White; mean age was 28 years old. The majority (85%) demonstrated presence of small bowel inflammatory findings on VCE including strictures, ulcers, erosions, and erythema. Duodenal and ileal inflammatory disease on endoscopy did not correlate with disease on VCE. Moderate-severe colonic disease correlated with moderate-severe disease on VCE. Radiography did not correlate with disease on VCE. Prolonged small bowel transit time correlated with moderate-severe small bowel disease.

CONCLUSIONS

Small bowel IBD was highly prevalent in this cohort of patients with CGD. Limitations included small sample size. Given that radiology and duodenal/ileal disease did not correlate with VCE findings, VCE-driven investigation of small bowel disease should be considered in patients with CGD-associated IBD, particularly those with colonic disease.

Intestinal microbiome and metabolome signatures in patients with chronic granulomatous disease

BACKGROUND

Chronic granulomatous disease (CGD) is caused by defects in any 1 of the 6 subunits forming the nicotinamide adenine dinucleotide phosphate oxidase complex 2 (NOX2), leading to severely reduced or absent phagocyte-derived reactive oxygen species production. Almost 50% of patients with CGD have inflammatory bowel disease (CGD-IBD). While conventional IBD therapies can treat CGD-IBD, their benefits must be weighed against the risk of infection. Understanding the impact of NOX2 defects on the intestinal microbiota may lead to the identification of novel CGD-IBD treatments.

OBJECTIVE

We sought to identify microbiome and metabolome signatures that can distinguish individuals with CGD and CGD-IBD.

METHODS

We conducted a cross-sectional observational study of 79 patients with CGD, 8 pathogenic variant carriers, and 19 healthy controls followed at the National Institutes of Health Clinical Center. We profiled the intestinal microbiome (amplicon sequencing) and stool metabolome, and validated our findings in a second cohort of 36 patients with CGD recruited through the Primary Immune Deficiency Treatment Consortium.

RESULTS

We identified distinct intestinal microbiome and metabolome profiles in patients with CGD compared to healthy individuals. We observed enrichment for Erysipelatoclostridium spp, Sellimonas spp, and Lachnoclostridium spp in CGD stool samples. Despite differences in bacterial alpha and beta diversity between the 2 cohorts, several taxa correlated significantly between both cohorts. We further demonstrated that patients with CGD-IBD have a distinct microbiome and metabolome profile compared to patients without CGD-IBD.

CONCLUSION

Intestinal microbiome and metabolome signatures distinguished patients with CGD and CGD-IBD, and identified potential biomarkers and therapeutic targets.

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.

Pharmacologic Management of Monogenic and Very Early Onset Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) is treated with a variety of immunomodulating and immunosuppressive therapies; however, for the majority of cases, these therapies are not targeted for specific disease phenotypes. Monogenic IBD with causative genetic defect is the exception and represents a disease cohort where precision therapeutics can be applied. With the advent of rapid genetic sequencing platforms, these monogenic immunodeficiencies that cause inflammatory bowel disease are increasingly being identified. This subpopulation of IBD called very early onset inflammatory bowel disease (VEO-IBD) is defined by an age of onset of less than six years of age. Twenty percent of VEO-IBDs have an identifiable monogenic defect. The culprit genes are often involved in pro-inflammatory immune pathways, which represent potential avenues for targeted pharmacologic treatments. This review will provide an overview of the current state of disease-specific targeted therapies, as well as empiric treatment for undifferentiated causes of VEO-IBD.

Gastrointestinal and Hepatic Manifestations of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a rare inborn error of immunity, resulting from a defect in nicotinamide adenine dinucleotide phosphate oxidation and decreased production of phagocyte reactive oxygen species. The main clinical manifestations are recurrent infections and chronic inflammatory disorders. Current approaches to management include antimicrobial prophylaxis and control of inflammatory complications. Hematopoietic stem cell transplantation or gene therapy can provide definitive treatment. Gastrointestinal and hepatic manifestations are common in CGD and include structural changes, dysmotility, CGD-associated inflammatory bowel disease, liver abscesses, and noncirrhotic portal hypertension. The findings can be heterogeneous, and the management is complex in light of the underlying immune dysfunction. This review describes the various clinical findings and the latest studies in management of gastrointestinal and hepatic manifestations in CGD, as well as the management experience at the National Institutes of Health.

The first successful bone marrow transplantation in Vietnam for a young Vietnamese boy with chronic granulomatous disease: a case report

Background

Chronic granulomatous disease (CGD) is an inborn error of immunity (IEI) disorder that results from defects in the respiratory burst activity in phagocytes, leading to the inability to kill bacterial and fungal microorganisms. CGD patients usually have a high incidence of morbidity such as infections and autoinflammatory diseases and a high mortality rate. Allogeneic bone marrow transplantation (BMT) is the only definitive cure for patients who suffer from CGD.

Case presentation

We report the first transplant case of chronic granulomatous disease in Vietnam. A 25-month-old boy with X-linked CGD underwent bone marrow transplantation from his 5-year-old, full-matched human leukocyte antigen (HLA)-carrier sibling after myeloablative conditioning regimen with busulfan 5.1 mg/kg/day for 4 days, fludarabine 30 mg/m²/day for 5 days, and rATG (Grafalon-Fresenius) 10 mg/kg/day for 4 days. Neutrophil was engrafted on day 13 posttransplant, donor chimerism was 100% on day 30 with the dihydrorhodamine-1,2,3 (DHR 123) flow cytometric assay test that reached 38% of the normal 45 days posttransplant. Five months after transplant, the patient was free of infection with stable DHR 123 assay at 37%, and donor chimerism remained 100%. No sign of a graft-versus-host disease had been observed posttransplant.

Conclusion

We suggest that bone marrow transplantation is a safe and effectual cure for CGD patients, especially for patients with HLA-identical siblings.

Understanding inborn errors of immunity: A lens into the pathophysiology of monogenic inflammatory bowel disease

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions of the gastrointestinal tract, including Crohn’s disease, ulcerative colitis and inflammatory bowel disease-undefined (IBD-U). IBD are understood to be multifactorial, involving genetic, immune, microbial and environmental factors. Advances in next generation sequencing facilitated the growing identification of over 80 monogenic causes of IBD, many of which overlap with Inborn errors of immunity (IEI); Approximately a third of currently identified IEI result in gastrointestinal manifestations, many of which are inflammatory in nature, such as IBD. Indeed, the gastrointestinal tract represents an opportune system to study IEI as it consists of the largest mass of lymphoid tissue in the body and employs a thin layer of intestinal epithelial cells as the critical barrier between the intestinal lumen and the host. In this mini-review, a selection of pertinent IEI resulting in monogenic IBD is described involving disorders in the intestinal epithelial barrier, phagocytosis, T and B cell defects, as well as those impairing central and peripheral tolerance. The contribution of disrupted gut-microbiota-host interactions in disturbing intestinal homeostasis among patients with intestinal disease is also discussed. The molecular mechanisms driving pathogenesis are reviewed along with the personalized therapeutic interventions and investigational avenues this growing knowledge has enabled.

Gastrointestinal Computed Tomography Findings in Chronic Granulomatous Disease with Subgroup Clinicopathologic Analysis

BACKGROUND

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency which can lead to gastrointestinal (GI) complications including inflammatory bowel disease. Radiographic findings in this cohort have not been well described.

AIMS

To describe the frequency and spectrum of gastrointestinal abnormalities seen on computed tomography (CT) in patients with CGD and determine whether radiography was predictive of endoscopic or histopathologic inflammatory findings.

METHODS

A retrospective review was conducted on 141 consecutive CGD patients seen at the National Institutes of Health between 1988 and 2011. All corresponding CTs were reviewed for gastrointestinal abnormalities including wall thickening. Endoscopic and histopathologic findings were reviewed in subjects with documented endoscopy within 30 days of an imaging study. Findings were compared between patients with and without wall thickening on CT to determine whether bowel wall thickening was predictive of endoscopic or histologic inflammatory findings.

RESULTS

Two hundred and ninety-two CTs were reviewed. GI wall thickening was present on CT in 61% of patients (n = 86). Among a subgroup of 20 patients who underwent endoscopy at the time of their imaging, there was a statistically significant correlation between radiographic gastrointestinal wall thickening and endoscopic inflammation in the same intestinal segment (p = 0.035). Additionally, there was a significant correlation between radiographic gastrointestinal wall thickening and inflammatory features on histopathology (p = 0.02).

CONCLUSIONS

GI abnormalities are commonly observed on CT in CGD patients. Bowel wall thickening correlates with endoscopic and histopathologic evidence of inflammation. These findings may be used to better facilitate directed endoscopic assessment and histopathologic sampling in patients with CGD.

Chronic Granulomatous Disease With Inflammatory Bowel Disease: Clinical Presentation, Treatment, and Outcomes From the USIDNET Registry

BACKGROUND

Chronic granulomatous disease (CGD) is an inborn error of immunity caused by defects in the phagocytic nicotinamide adenine dinucleotide phosphate oxidase complex, leading to increased susceptibility to infection and inflammatory autoimmune diseases. Up to 50% of patients have gastrointestinal (GI) involvement and meet diagnostic criteria for inflammatory bowel disease (CGD-IBD).

OBJECTIVE

We analyzed patients with CGD from the US Immunodeficiency Network (USIDNET) registry to determine whether IBD changes the presentation, treatment, and outcomes of patients with CGD.

METHODS

A retrospective evaluation of CGD cases from the USIDNET registry was completed. CGD-IBD was defined as the presence of any major physician-reported inflammatory, noninfectious GI disease manifestation. Demographic information, conditions, infections, antimicrobial therapies, immunomodulator use, and hematopoietic stem cell transplantation data were analyzed.

RESULTS

Of 194 patients with a diagnosis of CGD, 96 met criteria for IBD and 98 were categorized in the non-IBD group. Patients with CGD-IBD had an increased rate of infection compared with the non-IBD group (0.66 vs 0.36 infections/patient/year). Enteric organism infections were more common in patients with IBD. Immunomodulators were used at a significantly higher percentage in patients with IBD compared with patients without IBD (80% vs 56%, P < .001). Of the entire CGD cohort, 17 patients died (8.8%), with no significant difference between patients with IBD and patients without IBD (P = 1.00).

CONCLUSION

Infectious events, enteric organism infections, and use of immunomodulatory drugs were higher in patients with IBD than patients without IBD; however, mortality was not increased. Patients with CGD and concurrent IBD are at increased risk for disease complications, supporting the importance of early recognition, diagnosis, and treatment.

Linking Genetic Diagnosis to Therapeutic Approach in Very Early Onset Inflammatory Bowel Disease: Pharmacologic Considerations

Very early onset inflammatory bowel disease (VEO-IBD) is diagnosed in children < 6 years of age, and in rare cases may be due to an identifiable monogenic cause. Recent advances in genetic testing have allowed for more accurate diagnosis, with as many as 100 genes now known to be associated with monogenic inflammatory bowel disease. These genes are involved in many immune pathways and thus may represent potential avenues for targeted precision medicine with pharmacologic treatments aimed at these. This review describes the broad classifications of monogenic disorders known to cause VEO-IBD, as well as empiric and disease-specific medical therapies. These include immune-modulating or immunosuppressant medications, nutritional therapy, surgery, and hematopoietic stem cell transplantation. We aim to provide an overview of the current state of targeted therapy for VEO-IBD.

Germline Variants of CYBA and TRPM4 Predispose to Familial Colorectal Cancer

Simple Summary

Whole-genome sequencing and bioinformatics analysis on unique colorectal cancer families revealed two attractive candidate predisposition genes, CYBA and TRPM4, each with a loss-of-function variant. Supported by our functional studies, we suggest that the two gene defects mechanistically involve intestinal barrier integrity through reactive oxygen species and mucus biology, which converges in chronic bowel inflammation, a known risk factor for colorectal cancer.

Abstract

Familial colorectal cancer (CRC) is only partially explained by known germline predisposing genes. We performed whole-genome sequencing in 15 Polish families of many affected individuals, without mutations in known CRC predisposing genes. We focused on loss-of-function variants and functionally characterized them. We identified a frameshift variant in the CYBA gene (c.246delC) in one family and a splice site variant in the TRPM4 gene (c.25–1 G > T) in another family. While both variants were absent or extremely rare in gene variant databases, we identified four additional Polish familial CRC cases and two healthy elderly individuals with the CYBA variant (odds ratio 2.46, 95% confidence interval 0.48–12.69). Both variants led to a premature stop codon and to a truncated protein. Functional characterization of the variants showed that knockdown of CYBA or TRPM4 depressed generation of reactive oxygen species (ROS) in LS174T and HT-29 cell lines. Knockdown of TRPM4 resulted in decreased MUC2 protein production. CYBA encodes a component in the NADPH oxidase system which generates ROS and controls, e.g., bacterial colonization in the gut. Germline CYBA variants are associated with early onset inflammatory bowel disease, supported with experimental evidence on loss of intestinal mucus barrier function due to ROS deficiency. TRPM4 encodes a calcium-activated ion channel, which, in a human colonic cancer cell line, controls calcium-mediated secretion of MUC2, a major component of intestinal mucus barrier. We suggest that the gene defects in CYBA and TRPM4 mechanistically involve intestinal barrier integrity through ROS and mucus biology, which converges in chronic bowel inflammation.

EROS is a selective chaperone regulating the phagocyte NADPH oxidase and purinergic signalling

EROS (essential for reactive oxygen species) protein is indispensable for expression of gp91phox, the catalytic core of the phagocyte NADPH oxidase. EROS deficiency in humans is a novel cause of the severe immunodeficiency, chronic granulomatous disease, but its mechanism of action was unknown until now. We elucidate the role of EROS, showing it acts at the earliest stages of gp91phox maturation. It binds the immature 58 kDa gp91phox directly, preventing gp91phox degradation and allowing glycosylation via the oligosaccharyltransferase machinery and the incorporation of the heme prosthetic groups essential for catalysis. EROS also regulates the purine receptors P2X7 and P2X1 through direct interactions, and P2X7 is almost absent in EROS-deficient mouse and human primary cells. Accordingly, lack of murine EROS results in markedly abnormal P2X7 signalling, inflammasome activation, and T cell responses. The loss of both ROS and P2X7 signalling leads to resistance to influenza infection in mice. Our work identifies EROS as a highly selective chaperone for key proteins in innate and adaptive immunity and a rheostat for immunity to infection. It has profound implications for our understanding of immune physiology, ROS dysregulation, and possibly gene therapy.

Upper Gastrointestinal Tract Involvement in Inflammatory Bowel Diseases: Histologic Clues and Pitfalls

The upper gastrointestinal (UGI) manifestations of inflammatory bowel diseases (IBDs) are frequently obscured by classic ileal and colonic symptoms and are reported to involve only 0.5% to 4% of adult patients. However, because of the improvement of endoscopic techniques and the growing use of esophagogastroduodenososcopy with biopsy, both asymptomatic and clinically significant esophageal, gastric, and duodenal manifestations are increasingly recognized. The UGI involvement in IBD was historically synonymous with Crohn's disease (CD), but the doctrine of ulcerative colitis (UC) being limited to the colon has been challenged, and UC-related gastroduodenal lesions have been reported. The diagnosis of UGI IBD should ideally rely on a combination of the clinical history, endoscopic picture, and histologic features. Although endoscopic changes such as aphthoid or longitudinal ulcers and bamboo-joint-like pattern are suggestive of CD, histologic evaluation increases the sensitivity of the IBD diagnosis since histologic alterations may be present in endoscopically unremarkable mucosa. Conversely, in many cases, the histologic findings are nonspecific, and the knowledge of clinical history is vital for reaching an accurate diagnosis. The presence of epithelioid granuloma is highly suggestive of CD but is present in a minority of CD cases; thus, pathologists should be aware of how to diagnose UGI IBD in the absence of granulomata. This article reviews the most important clinical, endoscopic, and histologic features of IBD-associated esophagitis, gastritis, and duodenitis, as well as the IBD-related manifestations in the biliary tract and the postcolectomy setting.

Needs for Increased Awareness of Gastrointestinal Manifestations in Patients With Human Inborn Errors of Immunity

The gastrointestinal (GI) tract is frequently affected by inborn errors of immunity (IEI), and GI manifestations can be present in IEI patients before a diagnosis is confirmed. We aimed to investigate clinical features, endoscopic and histopathologic findings in IEI patients. This was a retrospective cohort study conducted from 1995 to 2020. Eligible patients were diagnosed with IEI and had GI manifestations that were enough to require endoscopies. IEI was classified according to the International Union of Immunological Societies classification. Of 165 patients with IEI, 55 (33.3%) had GI manifestations, and 19 (11.5%) underwent endoscopy. Among those 19 patients, nine (47.4%) initially presented with GI manifestations. Thirteen patients (68.4%) were male, and the mean age of patients 11.5 ± 7.9 years (range, 0.6 – 26.6) when they were consulted and evaluated with endoscopy. The most common type of IEI with severe GI symptoms was “Disease of immune dysregulation” (31.6%) followed by “Phagocyte defects” (26.3%), according to the International Union of Immunological Societies classification criteria. Patients had variable GI symptoms such as chronic diarrhea (68.4%), hematochezia (36.8%), abdominal pain (31.6%), perianal disease (10.5%), and recurrent oral ulcers (10.5%). During the follow-up period, three patients developed GI tract neoplasms (early gastric carcinoma, mucosa associated lymphoid tissue lymphoma of colon, and colonic tubular adenoma, 15.8%), and 12 patients (63.2%) were diagnosed with inflammatory bowel disease (IBD)-like colitis. Investigating immunodeficiency in patients with atypical GI symptoms can provide an opportunity for correct diagnosis and appropriate disease-specific therapy. Gastroenterologists and immunologists should consider endoscopy when atypical GI manifestations appear in IEI patients to determine if IBD-like colitis or neoplasms including premalignant and malignant lesions have developed. Also, if physicians in various fields are better educated about IEI-specific complications, early diagnosis and disease-specific treatment for IEI will be made possible.

The Growing Need to Understand Very Early Onset Inflammatory Bowel Disease

Very Early Onset Inflammatory Bowel Disease (VEO-IBD) represents a cohort of inflammatory bowel disease (IBD) patients diagnosed before 6 years of age. Unlike IBD diagnosed at older ages, VEO-IBD can be associated with underlying primary immunodeficiencies. VEO-IBD has been linked to monogenic variations in over 70 genes involved in multiple pathways of immunity. As sequencing technologies and platforms evolve and become readily available, an increasing number of genes linked to VEO-IBD have emerged. Although monogenic defects are rare in VEO-IBD, diagnosis of these variants can often dictate specific treatment. In this mini-review, we set out to describe monogenic variants previously characterized in multiple patients in the literature that contribute to VEO-IBD, diagnostic tools, unique treatment modalities for specific genetic diagnoses, and future directions in the field of VEO-IBD. Although this mini-review is by no means comprehensive of all the novel monogenic variants linked to VEO-IBD, we hope to provide relevant information that is readily accessible to clinicians and educators.

From Flies to Men: ROS and the NADPH Oxidase in Phagocytes

The cellular formation of reactive oxygen species (ROS) represents an evolutionary ancient antimicrobial defense system against microorganisms. The NADPH oxidases (NOX), which are predominantly localized to endosomes, and the electron transport chain in mitochondria are the major sources of ROS. Like any powerful immunological process, ROS formation has costs, in particular collateral tissue damage of the host. Moreover, microorganisms have developed defense mechanisms against ROS, an example for an arms race between species. Thus, although NOX orthologs have been identified in organisms as diverse as plants, fruit flies, rodents, and humans, ROS functions have developed and diversified to affect a multitude of cellular properties, i.e., far beyond direct antimicrobial activity. Here, we focus on the development of NOX in phagocytic cells, where the so-called respiratory burst in phagolysosomes contributes to the elimination of ingested microorganisms. Yet, NOX participates in cellular signaling in a cell-intrinsic and -extrinsic manner, e.g., via the release of ROS into the extracellular space. Accordingly, in humans, the inherited deficiency of NOX components is characterized by infections with bacteria and fungi and a seemingly independently dysregulated inflammatory response. Since ROS have both antimicrobial and immunomodulatory properties, their tight regulation in space and time is required for an efficient and well-balanced immune response, which allows for the reestablishment of tissue homeostasis. In addition, distinct NOX homologs expressed by non-phagocytic cells and mitochondrial ROS are interlinked with phagocytic NOX functions and thus affect the overall redox state of the tissue and the cellular activity in a complex fashion. Overall, the systematic and comparative analysis of cellular ROS functions in organisms of lower complexity provides clues for understanding the contribution of ROS and ROS deficiency to human health and disease.

Gut Microbiota-Host Interactions in Inborn Errors of Immunity

Inborn errors of immunity (IEI) are a group of disorders that are mostly caused by genetic mutations affecting immune host defense and immune regulation. Although IEI present with a wide spectrum of clinical features, in about one third of them various degrees of gastrointestinal (GI) involvement have been described and for some IEI the GI manifestations represent the main and peculiar clinical feature. The microbiome plays critical roles in the education and function of the host's innate and adaptive immune system, and imbalances in microbiota-immunity interactions can contribute to intestinal pathogenesis. Microbial dysbiosis combined to the impairment of immunosurveillance and immune dysfunction in IEI, may favor mucosal permeability and lead to inflammation. Here we review how immune homeostasis between commensals and the host is established in the gut, and how these mechanisms can be disrupted in the context of primary immunodeficiencies. Additionally, we highlight key aspects of the first studies on gut microbiome in patients affected by IEI and discuss how gut microbiome could be harnessed as a therapeutic approach in these diseases.

Candida Glabrata Lymphadenitis Following Infliximab Therapy for Inflammatory Bowel Disease in a Patient With Chronic Granulomatous Disease: Case Report and Literature Review

Chronic granulomatous disease (CGD) is an inborn error of immunity caused by inactivating genetic mutations in any one of the components of the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. Phagocytic cell reactive oxygen species generation is impaired in the absence of a functional NADPH oxidase complex. As a result, patients with CGD are at high risk of developing deep-seated infections with certain bacteria and fungi. Additionally, aberrant inflammation and granuloma formation may occur in multiple organs including the bowels, with inflammatory bowel disease seen as a common inflammatory complication of CGD. Traditionally, TNF-α inhibitors are considered effective biological therapies for moderate-to-severe inflammatory bowel disease. While limited case series and reports of patients with CGD have shown improvement in fistula healing with use of TNF-α inhibitors, several patients have developed severe, even fatal, infections with CGD-related pathogens while on TNF-inhibitor therapy. In this case report, we describe an adolescent male with X-linked CGD and steroid-refractory colitis with perirectal fistula and abscesses, who was initiated on treatment with infliximab, a TNF-α inhibitor. Following his first two infliximab doses, the patient developed a Candida glabrata lymphadenitis and associated ulcerating oropharyngeal lesions, requiring hospitalization and therapy with amphotericin B for resolution. We compare our patient's case to prior reports of infliximab use in CGD-related inflammatory bowel disease.

[The gut: center of immunity : Rare inflammatory bowel diseases caused by immunodeficiencies]

The gut is the largest immune organ of the human body with an enormous mucosal interface. By acting as a physical barrier and by hosting many of the body's immune cells and tissues, the gut is the first line of defense against potentially harmful substances. Therefore, diseases leading to impaired immune response or disruption of the epithelial barrier result in autoimmune, infectious, or inflammatory bowel disease, frequently associated with diarrhea, malabsorption, melena, and growth failure. The differential diagnosis represents an interdisciplinary challenge in this group of rare diseases. The diseases are characterized by clinical, immunological, and histopathological features caused by mutations in single genes. In the following, we will focus on histological findings within the various entities of immunodeficiencies.

Molecular and Phenotypic Characterization of Escherichia coli Associated with Granulomatous Colitis of Boxer Dogs

Invasive Escherichia coli is causally associated with granulomatous colitis (GC) of Boxer dogs and French Bulldogs. The virulence determinants of GC E. coli are unclear. E. coli isolated from 16 GC (36 strains) and 17 healthy control (HC: 33 strains) dogs were diverse in phylogeny, genotype, and serotype and lacked diarrheagenic genes. Genes encoding type II (gsp), IV (traC), and VI (hcp) secretion systems, long polar fimbriae (lpfA154/141), and iron acquisition (fyuA, chuA) were frequent in GC and HC. E. coli from 14/15 GC and 10/11 HC invaded Caco-2 better than non-pathogenic E. coli strain DH5α, with invasion correlated with motility and presence of chuA and colV. E. coli from all GC and 10/11 HC survived better than DH5α in J774 macrophages, with adherent-invasive E. coli (AIEC) in 60% GC and 73% HC. AIEC replicated in monocyte derived macrophages from a GC Boxer with CD48/SLAM risk haplotype but not the HC. Fluroquinolone resistant E. coli were less motile and invasive than fluoroquinolone sensitive (p < 0.05), and only 1/8 resistant strains met criteria for AIEC. In conclusion GC E. coli are diverse, resemble extraintestinal pathogenic E. coli (ExPEC), including AIEC, and can replicate in GC-susceptible macrophages. They are likely resident pathosymbionts that can opportunistically persist within macrophages of a GC-susceptible dog.

High-fat diet selectively decreases bone marrow lin- /CD117+ cell population in aging mice through increased ROS production

Bone marrow (BM) stem cells (BMSCs) are an important source for cell therapy. The outcome of cell therapy could be ultimately associated with the number and function of donor BMSCs. The present study was to evaluate the effect of long-term high-fat diet (HFD) on the population of BMSCs and the role of reactive oxygen species (ROS) in aging mice. Forty-week-old male C57BL/6 mice were fed with HFD for 3 months with regular diet as control. Experiments were repeated when ROS production was reduced in mice treated with N-acetylcysteine (NAC) or using mice overexpressing antioxidant enzyme network (AON) of superoxide dismutase (SOD)1, SOD3, and glutathione peroxidase. BM and blood cells were analyzed with flowcytometry for lineage negative (lin^- ) and Sca-1⁺ , or lin^- /CD117⁺ , or lin^- /CD133⁺ cells. Lin^- /CD117⁺ cell population was significantly decreased with increased intracellular ROS and apoptosis and decreased proliferation in BM, not in blood, in HFD-treated mice without change for Sca-1⁺ or CD133⁺ cell populations in BM or blood. NAC treatment or AON overexpression effectively prevented HFD-induced intracellular ROS production and reduction of BM lin^- /CD117⁺ population. These data suggested that long-term HFD selectively decreased BM lin^- /CD117⁺ cell population in aging mice through increased ROS production.

North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Position Paper on the Evaluation and Management for Patients With Very Early-onset Inflammatory Bowel Disease

The rate of pediatric inflammatory bowel disease (IBD) has been increasing over the last decade and this increase has occurred most rapidly in the youngest children diagnosed <6 years, known as very early-onset inflammatory bowel disease (VEO-IBD). These children can present with more extensive and severe disease than older children and adults. The contribution of host genetics in this population is underscored by the young age of onset and the distinct, aggressive phenotype. In fact, monogenic defects, often involving primary immunodeficiency genes, have been identified in children with VEO-IBD and have led to targeted and life-saving therapy. This position paper will discuss the phenotype of VEO-IBD and outline the approach and evaluation for these children and what factors should trigger concern for an underlying immunodeficiency. We will then review the immunological assays and genetic studies that can facilitate the identification of the underlying diagnosis in patients with VEO-IBD and how this evaluation may lead to directed therapies. The position paper will also aid the pediatric gastroenterologist in recognizing when a patient should be referred to a center specializing in the care of these patients. These guidelines are intended for pediatricians, allied health professionals caring for children, pediatric gastroenterologists, pediatric pathologists, and immunologists.

Gastrointestinal Disorders Associated with Primary Immunodeficiency Diseases

There are now 354 inborn errors of immunity (primary immunodeficiency diseases (PIDDs)) with 344 distinct molecular etiologies reported according to the International Union of Immunological Sciences (IUIS) (Clin Gastroenterol Hepatol 11: p. 1050-63, 2013, Semin Gastrointest Dis 8: p. 22-32, 1997, J Clin Immunol 38: p. 96-128, 2018). Using the IUIS document as a reference and cross-checking PubMed ( www.ncbi.nlm.nih.pubmed.gov ), we found that approximately one third of the 354 diseases of impaired immunity have a gastrointestinal component [J Clin Immunol 38: p. 96-128, 2018]. Often, the gastrointestinal symptomatology and pathology is the heralding sign of a PIDD; therefore, it is important to recognize patterns of disease which may manifest along the gastrointestinal tract as a more global derangement of immune function. As such, holistic consideration of immunity is warranted in patients with clinically significant gastrointestinal disease. Here, we discuss the manifold presentations and GI-specific complications of PIDDs which could lead patients to seek advice from a variety of clinician specialists. Often, patients with these medical problems will engage general pediatricians, surgeons, gastroenterologists, rheumatologists, and clinical immunologists among others. Following delineation of the presenting concern, accurate and often molecular diagnosis is imperative and a multi-disciplinary approach warranted for optimal management. In this review, we will summarize the current state of understanding of PIDD gastrointestinal disease involvement. We will do so by focusing upon gastrointestinal disease categories (i.e., inflammatory, diarrhea, nodular lymphoid hyperplasia, liver/biliary tract, structural disease, and oncologic disease) with an intent to aid the healthcare provider who may encounter a patient with an as-yet undiagnosed PIDD who presents initially with a gastrointestinal symptom, sign, or problem.

Cellular Therapies in Chronic Granulomatous Disease

Allogeneic hematopoietic stem cell transplantation (HSCT) has become the main curative treatment in patients with chronic granulomatous disease (CGD). CGD is caused by inherited defects of the phagolysomal NADPH-oxidase, leading to a lifelong propensity for invasive infections and granulomatous inflammation. After successful allogeneic HSCT, chronic infections and inflammation resolve and quality-of-life improves. Favorable long-term outcome after HSCT is dependent on the prevention of primary and secondary graft failure (GF), including falling myeloid donor chimerism (DC) below 10 %, and chronic graft-vs.-host-disease (cGVHD). The risk of GF and GvHD increases with the use of HLA-incompatible donors and this may outweigh the benefits of HSCT, mainly in patients with severe co-morbidities and in asymptomatic patients with residual NADPH-oxidase function. Seventeen scientific papers have reported on a total of 386 CGD-patients treated by HSCT with HLA-matched family/sibling (MFD/MSD), 9/10-/10/10-matched-unrelated volunteer (MUD) and cord blood donors. The median OS/EFS-rate of these 17 studies was 91 and 82%, respectively. The median rates of GF, cGVHD and de-novo autoimmune diseases were 14, 10, and 12%, respectively. Results after MFD/MSD and 10/10-MUD-transplants were rather similar, but outcome in adults with significant co-morbidities and after transplants with 9/10 HLA-MUD were less successful, mainly due to increased GF and chronic GVHD. Transplantation protocols using T-cell depleted haploidentical donors with post-transplant cyclophosphamide or TCR-alpha/beta depletion have recently reported promising results. Autologous gene-therapy after lentiviral transduction of HSC achieved OS/EFS-rates of 78/67%, respectively. Careful retrospective and prospective studies are mandatory to ascertain the most effective cellular therapies in patients with CGD.

Gastrointestinal Manifestations and Complications of Primary Immunodeficiency Disorders

Gastrointestinal (GI) involvement can be the presenting disease manifestation in patients with primary immunodeficiency disorders (PIDs). Infections and noninfectious diarrhea are frequent manifestations; however, malignancy and inflammatory and autoimmune-related GI diseases are also described. GI symptoms and disease seen in association with PIDs can mimic other diseases but are often resistant to conventional treatments owing to alternate disease mechanisms. Despite the advances in treatments for these conditions, therapy for immunodeficiency-related GI disease is often empiric.

Colitis susceptibility in mice with reactive oxygen species deficiency is mediated by mucus barrier and immune defense defects

Reactive oxygen species (ROS) generated by NADPH oxidases (NOX/DUOX) provide antimicrobial defense, redox signaling, and gut barrier maintenance. Inactivating NOX variants are associated with comorbid intestinal inflammation in chronic granulomatous disease (CGD; NOX2) and pediatric inflammatory bowel disease (IBD; NOX1); however Nox-deficient mice do not reflect human disease susceptibility. Here we assessed if a hypomorphic patient-relevant CGD mutation will increase the risk for intestinal inflammation in mice. Cyba (p22^phox) mutant mice generated low intestinal ROS, while maintaining Nox4 function. The Cyba variant caused profound mucus layer disruption with bacterial penetration into crypts, dysbiosis, and a compromised innate immune response to invading microbes, leading to mortality. Approaches used in treatment-resistant CGD or pediatric IBD such as bone marrow transplantation or oral antibiotic treatment ameliorated or prevented disease in mice. The Cyba mutant mouse phenotype implicates loss of both mucus barrier and efficient innate immune defense in the pathogenesis of intestinal inflammation due to ROS deficiency, supporting a combined-hit model where a single disease variant compromises different cellular functions in interdependent compartments.

WHIM Syndrome: from Pathogenesis Towards Personalized Medicine and Cure

WHIM syndrome is a rare combined primary immunodeficiency disease named by acronym for the diagnostic tetrad of warts, hypogammaglobulinemia, infections, and myelokathexis. Myelokathexis is a unique form of non-cyclic severe congenital neutropenia caused by accumulation of mature and degenerating neutrophils in the bone marrow; monocytopenia and lymphopenia, especially B lymphopenia, also commonly occur. WHIM syndrome is usually caused by autosomal dominant mutations in the G protein-coupled chemokine receptor CXCR4 that impair desensitization, resulting in enhanced and prolonged G protein- and β-arrestin-dependent responses. Accordingly, CXCR4 antagonists have shown promise as mechanism-based treatments in phase 1 clinical trials. This review is based on analysis of all 105 published cases of WHIM syndrome and covers current concepts, recent advances, unresolved enigmas and controversies, and promising future research directions.

Primary Immunodeficiency and the Gut

This article presents the most common gastrointestinal, hepatic, and pancreatic manifestations of the primary immunodeficiency diseases, including the appropriate laboratory testing, endoscopic evaluation, and recommendations for further management.

Inflammatory consequences of inherited disorders affecting neutrophil function

Primary immunodeficiencies affecting the function of neutrophils and other phagocytic leukocytes are notable for an increased susceptibility to bacterial and fungal infections as a result of impaired leukocyte recruitment, ingestion, and/or killing of microbes. The underlying molecular defects can also impact other innate immune responses to infectious and inflammatory stimuli, leading to inflammatory and autoimmune complications that are not always directly related to infection. This review will provide an update on congenital disorders affecting neutrophil function in which a combination of host defense and inflammatory complications are prominent, including nicotinamide dinucleotide phosphate oxidase defects in chronic granulomatous disease and β2 integrin defects in leukocyte adhesion deficiency.

The microbiome and immunodeficiencies: Lessons from rare diseases

Primary immunodeficiencies (PIDs) are inherited disorders of the immune system, associated with a considerable increase in susceptibility to infections. PIDs can also predispose to malignancy, inflammation and autoimmunity. There is increasing awareness that some aspects of the immune dysregulation in PIDs may be linked to intestinal microbiota. Indeed, the gut microbiota and its metabolites have been shown to influence immune functions and immune homeostasis both locally and systemically. Recent studies have indicated that genetic defects causing PIDs lead to perturbations in the conventional mechanisms underlying homeostasis in the gut, resulting in poor immune surveillance at the intestinal barrier, which associates with altered intestinal permeability and bacterial translocation. Consistently, a substantial proportion of PID patients presents with clinically challenging IBD-like pathology. Here, we describe the current body of literature reporting on dysbiosis of the gut microbiota in different PIDs and how this can be either the result or cause of immune dysregulation. Further, we report how infections in PIDs enhance pathobionts colonization and speculate how, in turn, pathobionts may be responsible for increased disease susceptibility and secondary infections in these patients. The potential relationship between the microbial composition in the intestine and other sites, such as the oral cavity and skin, is also highlighted. Finally, we provide evidence, in preclinical models of PIDs, for the efficacy of microbiota manipulation to ameliorate disease complications, and suggest that the potential use of dietary intervention to correct dysbiotic flora in PID patients may hold promise.

Gastrointestinal Complications in Chronic Granulomatous Disease

Almost half of patients with chronic granulomatous disease (CGD) suffer from gastrointestinal (GI) inflammation, the pathogenesis of which is complex and multifactorial. As a result, the management of CGD-associated GI inflammation remains challenging due to its chronicity and difficulty in managing the simultaneous need for immunomodulation with increased susceptibility to infection. In order to contextualize prospective treatment interventions for CGD-associated GI inflammation, we have reviewed the clinical presentation, pathogenesis and current management of this disease. Increased understanding of the role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex 2 (NOX2)-derived reactive oxygen species (ROS) in inflammatory bowel disease (IBD) will likely reveal novel targets for therapeutic intervention.

Chronic regional intestinal inflammatory disease: A trans-species slow infection?

Crohn's disease and ulcerative colitis in humans and paratuberculosis in domestic and wild ruminants can be defined as chronic regional intestinal inflammatory diseases (CRIID). This review is a literature overview on these diseases in humans, non-human primates, dogs, cats, rabbits, equids and ruminants with a focus on pathological and microbiological features aimed identifying common characteristics that could lead to a unified pathological classification for a better understanding of their mechanisms and causes. The result is a framework of inflammatory forms throughout the different species indicative of common mechanisms of the slow infection type characterized by a time course varying from weeks to months or even years, and where the inflammatory component would be more prominent in the intestinal interphase between host and environment and be morphologically characterized by an infiltrate ranging from lymphoplasmacytic to histiocytic. This should provide new insights for causation demonstration and therapeutic approaches in human IBD.

Very early onset IBD: novel genetic aetiologies

PURPOSE OF REVIEW

To summarize the current understanding and recent advances on the genetic aetiology in the pathogenesis of very early onset inflammatory bowel disease (VEO-IBD).

RECENT FINDINGS

IBD is a chronic disorder of the gastrointestinal tract whose manifestation is a result of complex interactions between genetics, environment, immune system and microbial flora. Over 230 IBD risk loci have been reported in genome wide association studies but the genetic contribution of the majority of these loci in the manifestation of IBD is very low. Patients with VEO-IBD present with a more severe disease than older patients, characterized by poor prognosis and failure of conventional therapy. Recent studies have reported several monogenic diseases with high penetrance that present with IBD and IBD-like intestinal manifestations and overlap with primary immunodeficiencies. Increasing body of evidence supports a prominent role of genetics in the onset of VEO-IBD. New genetic variants and diagnoses in VEO-IBD are reviewed and current challenges in therapy with potential strategy to manage the disease are discussed.

SUMMARY

Functional analysis of the genes implicated in monogenic IBD has increased the understanding of the underlying pathobiological mechanism of the disease. This knowledge can be used to personalize medicine for specific patients, improving the standard of care and quality of life.

Cytologic and Ultrastructural Findings of Bronchoalveolar Lavage in Patients With Chronic Granulomatous Disease

Background Chronic granulomatous disease (CGD) is a hereditary immunodeficiency caused by mutations in genes encoding nicotinamide adenine dinucleotide phosphate oxidase enzyme complex, which lead to the inability to kill intracellular pathogens. Patients with CGD are susceptible to recurrent bacterial and fungal infections in their early lives. Although the recent survival rate has been significantly improved, early diagnosis is critical to prevent multiple organ impairment. In 1950s, CGD was first described as a disease with recurrent infections and visceral infiltration of granulomas and pigmented histiocytes. Bronchoalveolar lavage (BAL) is commonly performed for patients with CGD; however, no study has described the cytologic features of alveolar macrophages. Methods Cytology of 20 BALs from 11 CGD patients was examined. The greatest diameters of randomly selected 100 alveolar macrophages in each BAL were measured using image analysis and compared with 20 disease control BALs from non-CGD patients. Macrophages from 2 groups were compared with repeated measures mixed-model analysis. Ultrastructural analysis was performed on a representative CGD BAL. Results BALs from CGD patients showed variable numbers of neutrophils and lipid-laden macrophages. Macrophages in CGD BALs were significantly larger than disease control BALs ( P < .0001) and showed "foamy" vacuolated cytoplasm. Ultrastructural analysis revealed the macrophages filled with enlarged lysosomes containing lipofuscin-like materials, which made their appearance "foamy." Conclusion In this study, we demonstrate novel BAL findings in CGD patients. The presence of enlarged "foamy" alveolar macrophages is not specific for CGD, but CGD should be considered as a differential diagnosis when foamy macrophages are present.

Inflammatory and infectious manifestations of immunodeficiency in the gastrointestinal tract

Immune compromise may result from genetic abnormalities, HIV/AIDS, or consequences of therapy for neoplastic and autoimmune diseases. Many immunocompromised patients develop severe gastrointestinal symptoms, particularly diarrhea, accompanied by non-specific or mild endoscopic abnormalities; mucosal biopsy with pathologic interpretation has a major role in the diagnosis and management of these patients. Immunocompromised individuals are at risk for all the diseases that affect those with a healthy immune system, but they are also prone to other illnesses that rarely affect immunocompetent patients. This review discusses the gastrointestinal manifestations of primary and acquired immunodeficiency, chemotherapy-related injury, and infections that show a predilection for immunocompromised patients. Key histologic features and relevant differential diagnoses are emphasized.

Noninfectious Manifestations and Complications of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD), a primary immunodeficiency characterized by a deficient neutrophil oxidative burst and the inadequate killing of microbes, is well known to cause a significantly increased risk of invasive infection. However, infectious complications are not the sole manifestations of CGD; substantial additional morbidity is driven by noninfectious complications also. These complications can include, for example, a wide range of inflammatory diseases that affect the gastrointestinal tract, lung, skin, and genitourinary tract and overt autoimmune disease. These diseases can occur at any age and are especially problematic in adolescents and adults with CGD. Many of these noninfectious complications present a highly challenging therapeutic conundrum, wherein immunosuppression must be balanced against an already markedly increased risk of invasive fungal and bacterial infections. In this review, the myriad noninfectious complications of CGD are discussed, as are important gaps in our understanding of these processes, which warrant further investigation.

Inflammatory Bowel Disease in Primary Immunodeficiencies

PURPOSE OF REVIEW

Inflammatory bowel disease is most often a polygenic disorder with contributions from the intestinal microbiome, defects in barrier function, and dysregulated host responses to microbial stimulation. There is, however, increasing recognition of single gene defects that underlie a subset of patients with inflammatory bowel disease, particularly those with early-onset disease, and this review focuses on the primary immunodeficiencies associated with early-onset inflammatory bowel disease.

RECENT FINDINGS

The advent of next-generation sequencing has led to an improved recognition of single gene defects underlying some cases of inflammatory bowel disease. Among single gene defects, immune response genes are the most frequent category identified. This is also true of common genetic variants associated with inflammatory bowel disease, supporting a pivotal role for host responses in the pathogenesis. This review focuses on practical aspects related to diagnosis and management of children with inflammatory bowel disease who have underlying primary immunodeficiencies.

A Review of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by defects in any of the five subunits of the NADPH oxidase complex responsible for the respiratory burst in phagocytic leukocytes. Patients with CGD are at increased risk of life-threatening infections with catalase-positive bacteria and fungi and inflammatory complications such as CGD colitis. The implementation of routine antimicrobial prophylaxis and the advent of azole antifungals has considerably improved overall survival. Nevertheless, life expectancy remains decreased compared to the general population. Inflammatory complications are a significant contributor to morbidity in CGD, and they are often refractory to standard therapies. At present, hematopoietic stem cell transplantation (HCT) is the only curative treatment, and transplantation outcomes have improved over the last few decades with overall survival rates now > 90% in children less than 14 years of age. However, there remains debate as to the optimal conditioning regimen, and there is question as to how to manage adolescent and adult patients. The current evidence suggests that myeloablative conditioning results is more durable myeloid engraftment but with increased toxicity and high rates of graft-versus-host disease. In recent years, gene therapy has been proposed as an alternative to HCT for patients without an HLA-matched donor. However, results to date have not been encouraging. with negligible long-term engraftment of gene-corrected hematopoietic stem cells and reports of myelodysplastic syndrome due to insertional mutagenesis. Multicenter trials are currently underway in the United States and Europe using a SIN-lentiviral vector under the control of a myeloid-specific promoter, and, should the trials be successful, gene therapy may be a viable option for patients with CGD in the future.