Molecular mimicry between Helicobacter pylori antigens and H+, K+ --adenosine triphosphatase in human gastric autoimmunity

Update understanding on diagnosis and histopathological examination of atrophic gastritis: A review

Chronic atrophic gastritis (CAG) is a complex syndrome in which long-term chronic inflammatory stimulation causes gland atrophy in the gastric mucosa, reducing the stomach's ability to secrete gastric juice and pepsin, and interfering with its normal physiological function. Multiple pathogenic factors contribute to CAG incidence, the most common being Helicobacter pylori infection and the immune reactions resulting from gastric autoimmunity. Furthermore, CAG has a broad spectrum of clinical manifestations, including gastroenterology and extra-intestinal symptoms and signs, such as hematology, neurology, and oncology. Therefore, the initial CAG evaluation should involve the examination of clinical and serological indicators, as well as diagnosis confirmation via gastroscopy and histopathology if necessary. Depending on the severity and scope of atrophy affecting the gastric mucosa, a histologic staging system (Operative Link for Gastritis Assessment or Operative Link on Gastritis intestinal metaplasia) could also be employed. Moreover, chronic gastritis has a higher risk of progressing to gastric cancer (GC). In this regard, early diagnosis, treatment, and regular testing could reduce the risk of GC in CAG patients. However, the optimal interval for endoscopic monitoring in CAG patients remains uncertain, and it should ideally be tailored based on individual risk evaluations and shared decision-making processes. Although there have been many reports on CAG, the precise etiology and histopathological features of the disease, as well as the diagnosis of CAG patients, are yet to be fully elucidated. Consequently, this review offers a detailed account of CAG, including its key clinical aspects, aiming to enhance the overall understanding of the disease.

Gastric cancer screening in Western countries: A call to action

Gastric cancer is a major cause of cancer-related death worldwide, despite the reduction in its incidence. The disease is still burdened with a poor prognosis, particularly in Western countries. The main risk factor is the infection by Helicobacter pylori, classified as a class I carcinogen by the IARC, and It is well-known that primary prevention of gastric cancer can be achieved with the eradication of the infection. Moreover, non-invasive measurement of pepsinogens (PGI and PGI/PGII ratio) allows the identification of patients that should undergo upper gastrointestinal (GI) endoscopy. Gastric non-cardia adenocarcinoma is indeed preceded by a well-defined precancerous process that involves consecutive stages, described for the first time by Correa et al. more than 40 years ago, and patients with advance stages of gastric atrophy/intestinal metaplasia and with dysplastic changes should be followed-up periodically with upper GI endoscopies. Despite these effective screening and surveillance methods, national-level screening campaigns have been adopted only in few countries in eastern Asia (Japan and South Korea). In this review, we describe primary and secondary preventive measures for gastric cancer, discussing the need to introduce screening also in Western countries. Moreover, we propose a simple algorithm for screening that could be easily applied in clinical practice.

Microbiome modulation of antigen presentation in tolerance and inflammation

The microbiome regulates mammalian immune responses from early life to adulthood. Antigen presentation, orchestrating these responses, integrates commensal and pathogenic signals. However, the temporal and spatial specificity of microbiome impacts on antigen presentation and downstream tolerance versus inflammation remain incompletely understood. Herein, we review the influences of antigen presentation of microbiome-related epitopes on immunity; impacts of microbiome-based modulation of antigen presentation on innate and adaptive immune responses; and their ramifications on homeostasis and immune-related disease, ranging from auto-inflammation to tumorigenesis. We highlight mechanisms driving these influences, such as 'molecular mimicry', in which microbiome auto-antigen presentation aberrantly triggers an immune response driving autoimmunity or influences conferred by microbiome-derived metabolites on antigen-presenting cells in inflammatory bowel disease. We discuss unknowns, controversies, and challenges associated with the study of microbiome regulation of antigen presentation while demonstrating how increasing knowledge may contribute to the development of microbiome-based therapeutics modulating immune responses in a variety of clinical contexts.

Health-promoting worms? Prospects and pitfalls of helminth therapy

In this manuscript, we explore the potential therapeutic use of helminths. After analyzing helminths' role in connection with human health from the perspective of their symbiotic and evolutionary relationship, we critically examine some studies on their therapeutic applications. In doing so, we focus on some prominent mechanisms of action and potential benefits, but also on the exaggerations and theoretical and methodological difficulties of such proposals. We conclude that further studies are needed to fully explore the potential benefits of this perspective, and we encourage the scientific community in doing so.

Clinical characteristics and outcomes of pediatric patients with autoimmune gastritis

OBJECTIVES

Autoimmune gastritis (AIG) is a rare chronic inflammatory disorder with potential long-term sequelae including gastric neoplasia. There is limited data on the natural history of pediatric AIG. We aimed to characterize the clinical course and outcomes of children with AIG.

METHODS

This was a multicenter retrospective study that included pediatric patients diagnosed with AIG between January 1, 2000 and December 31, 2021. Diagnosis of AIG was based on the demonstration of histological corpus-predominant atrophic gastritis, with or without positive antiparietal cell (APCA) or anti-intrinsic factor (IF) antibodies. Demographic, clinical, laboratory, endoscopic, and histologic data were retrieved, along with follow-up data.

RESULTS

Thirty-three patients, (23 females [69.7%], median age 12.0 [interquartile range 7.0-15.0] years at diagnosis) were identified. Twenty-two patients (66.7%) had positive APCA and/or anti-IF serology. The most common presenting manifestation was iron deficiency anemia (75%), and accompanying autoimmune disorders were significantly more common in patients with positive serology (62% vs. 18%, p < 0.05). Pseudo-pyloric or intestinal-type metaplasia was present at diagnosis in eight patients (24%), and 11 additional patients (33%) developed metaplasia during a median follow-up time of 27 (17.5-48.3) months. One patient developed a type 1 gastric neuroendocrine tumor. Helicobacter pylori was identified in only one patient, while two patients had prior eradication. Endoscopic and histologic improvements weren't identified in any patients.

CONCLUSIONS

AIG should be considered in patients with autoimmunity and resistant iron-deficiency anemia. H. pylori infection may not be associated with pediatric AIG. The development of neuroendocrine tumor in one patient, and the high rates of metaplasia, highlight the importance of surveillance.

Protein Biomarkers of Gastric Preneoplasia and Cancer Lesions in Blood: A Comprehensive Review

Gastric cancer (GC) is a major cause of cancer-related mortality worldwide. It is often associated with a bad prognosis because of its asymptomatic phenotype until advanced stages, highlighting the need for its prevention and early detection. GC development is preceded by the emergence of gastric preneoplasia lesions (GPNLs), namely atrophic gastritis (AG), intestinal metaplasia (IM), and dysplasia (DYS). GC is currently diagnosed by endoscopy, which is invasive and costly and has limited effectiveness for the detection of GPNLs. Therefore, the discovery of non-invasive biomarkers in liquid biopsies, such as blood samples, in order to identify the presence of gastric preneoplasia and/or cancer lesions at asymptomatic stages is of paramount interest. This comprehensive review provides an overview of recently identified plasma/serum proteins and their diagnostic performance for the prediction of GPNLs and early cancer lesions. Autoantibodies appear to be promising biomarkers for AG, IM and early gastric cancer detection, along with inflammation and immunity-related proteins and antibodies against H. pylori virulence factors. There is a lack of specific protein biomarkers with which to detect DYS. Despite the need for further investigation and validation, some emerging candidates could pave the way for the development of reliable, non-invasive diagnostic tests for the detection and prevention of GC.

Autoimmune Gastritis and Hypochlorhydria: Known Concepts from a New Perspective

Autoimmune atrophic gastritis is an immune-mediated disease resulting in autoimmune destruction of the specialized acid-producing gastric parietal cells. As a consequence, in autoimmune atrophic gastritis, gastric acid secretion is irreversibly impaired, and the resulting hypochlorhydria leads to the main clinical manifestations and is linked, directly or indirectly, to the long-term neoplastic complications of this disease. In the last few years, autoimmune atrophic gastritis has gained growing interest leading to the acquisition of new knowledge on different aspects of this disorder. Although reliable serological biomarkers are available and gastrointestinal endoscopy techniques have substantially evolved, the diagnosis of autoimmune atrophic gastritis is still affected by a considerable delay and relies on histopathological assessment of gastric biopsies. One of the reasons for the diagnostic delay is that the clinical presentations of autoimmune atrophic gastritis giving rise to clinical suspicion are very different, ranging from hematological to neurological-psychiatric up to gastrointestinal and less commonly to gynecological-obstetric symptoms or signs. Therefore, patients with autoimmune atrophic gastritis often seek advice from physicians of other medical specialties than gastroenterologists, thus underlining the need for increased awareness of this disease in a broad medical and scientific community.

Gastric Carcinoma in Autoimmune Gastritis: A Histopathologic and Molecular Study

Patients with autoimmune gastritis (AIG) have a 13-fold risk of developing type-1 neuroendocrine tumors, whereas the risk for gastric adenocarcinoma is still uncertain. Here we describe the clinicopathologic and molecular features of a series of gastric carcinomas (GC) arising in the context of AIG. A total of 26 AIG-associated GC specimens were collected from 4 Italian Institutions. Immunohistochemistry for MUC1, MUC2, MUC5AC, MUC6, CDX2, HER2, PD-L1, CLDN18, mismatch repair (MMR) proteins, and p53 and EBV-encoded RNA (EBER) in situ hybridization were performed. Histologic and immunohistochemical features were jointly reviewed by 5 expert gastrointestinal pathologists. Next-generation sequencing analysis (TrueSight Oncology 500, Illumina) of 523 cancer-related genes was performed on 19 cases. Most tumors were diagnosed as pT1 (52%) and they were located in the corpus/fundus (58%) and associated with operative link for gastritis assessment stage II gastritis (80.8%), absence of parietal cells, complete intestinal metaplasia, and enterochromaffin-like-cell micronodular hyperplasia. Only 4 (15.4%) GCs were diagnosed during follow-up for AIG. The following histotypes were identified: 20 (77%) adenocarcinomas; 3 (11%) mixed neuroendocrine-non-neuroendocrine neoplasms, and 2 (8%) high-grade solid adenocarcinomas with focal neuroendocrine component, 1 (4%) adenocarcinoma with an amphicrine component. Overall, 7 cases (27%) showed MMR deficiency, 3 (12%) were positive (score 3+) for HER2, 6 (23%) were CLDN18 positive, and 11 (42%) had PD-L1 combined positive score ≥ 10. EBER was negative in all cases. Molecular analysis revealed 5/19 (26%) microsatellite instability (MSI) cases and 7 (37%) tumor mutational burden (TMB) high. The most frequently altered genes were TP53 (8/19, 42%), RNF43 (7/19, 37%), ERBB2 (7/19, 37% [2 amplified and 5 mutated cases]), ARID1A (6/19, 32%), and PIK3CA (4/19, 21%). In summary, AIG-associated GCs are often diagnosed at low stage in patients with longstanding misrecognized severe AIG; they often display a neuroendocrine component or differentiation, have relatively higher rates of MMR deficiency, and TMB high.

Trained Immunity and Trained Tolerance: The Case of Helicobacter pylori Infection

Trained immunity is a concept in immunology in which innate immune cells, such as monocytes and macrophages, exhibit enhanced responsiveness and memory-like characteristics following initial contact with a pathogenic stimulus that may promote a more effective immune defense following subsequent contact with the same pathogen. Helicobacter pylori, a bacterium that colonizes the stomach lining, is etiologically associated with various gastrointestinal diseases, including gastritis, peptic ulcer, gastric adenocarcinoma, MALT lymphoma, and extra gastric disorders. It has been demonstrated that repeated exposure to H. pylori can induce trained immunity in the innate immune cells of the gastric mucosa, which become more responsive and better able to respond to subsequent H. pylori infections. However, interactions between H. pylori and trained immunity are intricate and produce both beneficial and detrimental effects. H. pylori infection is characterized histologically as the presence of both an acute and chronic inflammatory response called acute-on-chronic inflammation, or gastritis. The clinical outcomes of ongoing inflammation include intestinal metaplasia, gastric atrophy, and dysplasia. These same mechanisms may also reduce immunotolerance and trigger autoimmune pathologies in the host. This review focuses on the relationship between trained immunity and H. pylori and underscores the dynamic interplay between the immune system and the pathogen in the context of gastric colonization and inflammation.

Gastric neuroendocrine neoplasms

Gastric neuroendocrine neoplasms (gNENs) display peculiar site-specific features among all NENs. Their incidence and prevalence have been rising in the past few decades. gNENs comprise gastric neuroendocrine carcinomas (gNECs) and gastric neuroendocrine tumours (gNETs), the latter further classified into three types. Type I anatype II gNETs are gastrin-dependent and develop in chronic atrophic gastritis and as part of Zollinger-Ellison syndrome within a multiple endocrine neoplasia type 1 syndrome (MEN1), respectively. Type III or sporadic gNETs develop in the absence of hypergastrinaemia and in the context of a near-normal or inflamed gastric mucosa. gNECs can also develop in the context of variable atrophic, relatively normal or inflamed gastric mucosa. Each gNEN type has different clinical characteristics and requires a different multidisciplinary approach in expert dedicated centres. Type I gNETs are managed mainly by endoscopy or surgery, whereas the treatment of type II gNETs largely depends on the management of the concomitant MEN1. Type III gNETs may require both locoregional approaches and systemic treatments; NECs are often metastatic and therefore require systemic treatment. Specific data regarding the systemic treatment of gNENs are lacking and are derived from the treatment of intestinal NETs and NECs. An enhanced understanding of molecular and clinical pathophysiology is needed to improve the management and outcomes of patients' gNETs.

Environmental pollutants and phosphoinositide signaling in autoimmunity

Environmental pollution stands as one of the most critical challenges affecting human health, with an estimated mortality rate linked to pollution-induced non-communicable diseases projected to range from 20% to 25%. These pollutants not only disrupt immune responses but can also trigger immunotoxicity. Phosphoinositide signaling, a pivotal regulator of immune responses, plays a central role in the development of autoimmune diseases and exhibits high sensitivity to environmental stressors. Among these stressors, environmental pollutants have become increasingly prevalent in our society, contributing to the initiation and exacerbation of autoimmune conditions. In this review, we summarize the intricate interplay between phosphoinositide signaling and autoimmune diseases within the context of environmental pollutants and contaminants. We provide an up-to-date overview of stress-induced phosphoinositide signaling, discuss 14 selected examples categorized into three groups of environmental pollutants and their connections to immune diseases, and shed light on the associated phosphoinositide signaling pathways. Through these discussions, this review advances our understanding of how phosphoinositide signaling influences the coordinated immune response to environmental stressors at a biological level. Furthermore, it offers valuable insights into potential research directions and therapeutic targets aimed at mitigating the impact of environmental pollutants on the pathogenesis of autoimmune diseases. SYNOPSIS: Phosphoinositide signaling at the intersection of environmental pollutants and autoimmunity provides novel insights for managing autoimmune diseases aggravated by pollutants.

Impact of autoimmune gastritis on chronic urticaria in paediatric patients - pathophysiological point of views

We would like to provide an updated comprehensive perspective and identify the components linked to chronic spontaneous urticaria (CSU) without specific triggers in autoimmune atrophic gastritis (AAG). AAG is an organ-specific autoimmune disease that affects the corpus-fundus gastric mucosa. Although we lack a unified explanation of the underlying pathways, when considering all paediatric patients reported in the literature, alterations result in gastric neuroendocrine enterochromaffin-like (ECL) cell proliferation and paracrine release of histamine. Several mechanisms have been proposed for the pathogenesis of CSU, with much evidence pointing towards AAG and ECL cell responses, which may be implicated as potential factors contributing to CSU. The excessive production/release of histamine into the bloodstream could cause or trigger exacerbations of CSU in AAG, independent of Helicobacter pylori; thus, the release of histamine from ECL cells may be the primary modulator.

CONCLUSION

Considering the understanding of these interactions, recognising the respective roles of AAG in the pathogenesis of CSU may strongly impact the diagnostic workup and management of unexplained/refractory CSU and may inform future research and interventions in the paediatric population.

WHAT IS KNOWN

• Autoimmune atrophic gastritis is a chronic immune-mediated inflammatory disease characterised by the destruction of the oxyntic mucosa in the gastric body and fundus, mucosal atrophy, and metaplastic changes. • Autoimmune atrophic gastritis in paediatric patients is important because of the poor outcome and risk of malignancy and possibly underestimated entities primarily reported in single-case reports.

WHAT IS NEW

• Upper gastrointestinal inflammatory disorders, independent of H. pylori, have been implicated as potential inducing factors in the development of chronic spontaneous urticaria. • If a paediatric patient presents with symptoms such as anaemia, reduced vitamin B12 levels, recurrent urticaria with no other detectable aetiology, positive anti-parietal cell antibodies, and elevated gastrin levels, autoimmune atrophic gastritis should be considered a possible cause of chronic urticaria.

Identification of Autoantigens in Pediatric Gastric Juices

Purpose

This study aimed to investigate the presence of autoantigens in the gastric juices of children.

Methods

Gastric juice and serum samples were obtained from 53 children <15 years of age who underwent gastric endoscopy. Among these, 8, 22, and 23 participants were in the age groups 0-5, 6-10, and 11-15 years, respectively. These samples were analyzed using two-dimensional electrophoresis (2-DE), immunoblot analysis, and matrix-assisted laser desorption ionization-time of-flight mass spectrometry. Furthermore, we reviewed the histopathological findings and urease test results and compared them with the results of 2-DE and immunoblot analysis.

Results

There were no statistically significant differences in urease test positivity, grades of chronic gastritis, active gastritis, or Helicobacter pylori infiltration of the antrum and body among the three age groups. Three distinct patterns of gastric juice were observed on 2-DE. Pattern I was the most common, and pattern III was not observed below the age of 5 years. Histopathological findings were significantly different among active gastritis (p=0.037) and H. pylori infiltration (p=0.060) in the gastric body. The immunoblots showed large spots at an approximate pH of 3-4 and molecular weights of 31-45 kDa. These distinct, large positive spots were identified as gastric lipase and pepsin A and C.

Conclusion

Three enzymes, which are normally secreted under acidic conditions were identified as autoantigens. Further investigation of the pathophysiology and function of autoantigens in the stomach is required.

Critical influence of cytokines and immune cells in autoimmune gastritis

Gastric cancer (GC) is a type of the most common cancers. Autoimmune gastritis (AIG) and infection with Helicobacter pylori (HP) are the risk factors of triggering GC. With the emphasis on the treatment of HP, the incidence and prevalence of HP infection in population is decreasing. However, AIG lacks accurate diagnosis and treatment methods, which occupies high cancer risk factors. AIG is controlled by the immune environment of the stomach, including immune cells, inflammatory cells, and infiltrating intercellular material. Various immune cells or cytokines play a central role in the process of regulating gastric parietal cells. Abnormal expression levels of cytokines involved in immunity are bound to face the risk of tumorigenesis. Therefore, it is particularly important for preventing or treating AIG and avoiding the risk of gastric cancer to clarify the confirmed action mode of immune cells and cytokines in the gastric system. Herein, we briefly reviewed the role of the immune environment under AIG, focussing on describing these double-edged effects between immune cells and cytokines, and pointing out potential research challenges.

Research status and hotspots of autoimmune gastritis: A bibliometric analysis

BACKGROUND

As an emerging potential risk factor for gastric cancer, autoimmune gastritis (AIG) has garnered increasing attention from researchers.

AIM

To analyze the research overview and popular topics in the field of AIG using bibliometrics.

METHODS

Relevant publications on AIG in the Web of Science Core Collection were collated, and data visualization and analysis of the number of publications, countries, institutions, journals, authors, keywords, and citations were performed using software such as VOSviewer, CiteSpace, and Scimago Graphic.

RESULTS

In total, 316 relevant articles were included in the analysis. From 2015 to 2022, the number of publications increased annually. The countries, institutions, authors, and journals with the highest number of publications in this field were Italy, Monash University, Toh BH, and Internal Medicine. The main keywords used in this field of research were pathogenesis, Helicobacter pylori, autoantibody, parietal cell antibody, atrophic gastritis, classification, diagnosis, autoimmune disease, risk, cancer, gastric cancer, vitamin B12 deficiency, and pernicious anemia. The following directions may be popular for future research: (1) The role of Helicobacter pylori in the pathogenesis of AIG; (2) diagnostic criteria for AIG and reference values for serum antibodies; (3) comorbidity mechanisms between AIG and other autoimmune diseases; (4) specific risks of AIG complicating gastric and other cancers; and (5) the role of vitamin B12 supplementation in patients with early-stage AIG.

CONCLUSION

This bibliometric analysis reported on popular topics and emerging trends in AIG, with diagnosis and prognosis being research hotspots in this field.

Mining Autoimmune-Disorder-Linked Molecular-Mimicry Candidates in Clostridioides difficile and Prospects of Mimic-Based Vaccine Design: An In Silico Approach

Molecular mimicry, a phenomenon in which microbial or environmental antigens resemble host antigens, has been proposed as a potential trigger for autoimmune responses. In this study, we employed a bioinformatics approach to investigate the role of molecular mimicry in Clostridioides difficile-caused infections and the induction of autoimmune disorders due to this phenomenon. Comparing proteomes of host and pathogen, we identified 23 proteins that exhibited significant sequence homology and were linked to autoimmune disorders. The disorders included rheumatoid arthritis, psoriasis, Alzheimer's disease, etc., while infections included viral and bacterial infections like HIV, HCV, and tuberculosis. The structure of the homologous proteins was superposed, and RMSD was calculated to find the maximum deviation, while accounting for rigid and flexible regions. Two sequence mimics (antigenic, non-allergenic, and immunogenic) of ≥10 amino acids from these proteins were used to design a vaccine construct to explore the possibility of eliciting an immune response. Docking analysis of the top vaccine construct C2 showed favorable interactions with HLA and TLR-4 receptor, indicating potential efficacy. The B-cell and T-helper cell activity was also simulated, showing promising results for effective immunization against C. difficile infections. This study highlights the potential of C. difficile to trigger autoimmunity through molecular mimicry and vaccine design based on sequence mimics that trigger a defensive response.

Autoimmune Gastritis with a Long-term Course of Type B Gastritis: A Report of Two Cases

Autoimmune gastritis (AIG) typically exhibits the characteristics of type A gastritis and has been classified as a separate disease from type B gastritis that corresponds to Helicobacter pylori gastritis. However, many reports have suggested the involvement of H. pylori infection in the pathogenesis of AIG. In our two cases, the patients' previous gastritis exhibited a clear pattern in which H. pylori gastritis had progressed over many years, but ultimately transitioned to AIG with its spontaneous disappearance. These findings suggest that some cases of AIG might originate from long-standing H. pylori gastritis.

Regression of Autoimmune Gastritis after Eradication of Helicobacter pylori

We report a case of autoimmune gastritis (AIG) in which gastric mucosal atrophy improved with Helicobacter pylori eradication. Based on endoscopic findings (advanced gastric atrophy with vascular visibility and diffuse redness in remnant oxyntic mucosa), a woman in her 40s was suspected of having AIG coexisting with an active H. pylori infection. This was confirmed by a positive anti-parietal cell antibody (PCA, 1:160), an elevated serum gastrin level (638 pg/mL), and positive anti-H. pylori antibody (Hp Ab, 15.5 U/mL) and H. pylori stool antigen tests. Seven months after eradication, reduced vascular visibility and disappearance of diffuse redness on endoscopy and reduced PCA (1:40) and Hp Ab (5.1 U/mL) titers were observed, although histopathological findings (basal-predominant lymphocytic infiltration, destruction of parietal and chief cells, pseudopyloric metaplasia, and enterochromaffin-like cell hyperplasia) were consistent with AIG. Endoscopy 26 months after eradication showed further improvement in atrophic findings in the gastric corpus and histopathological recovery of parietal and chief cells in fundic glands. Serum gastrin levels returned to normal (64 pg/mL), and the PCA titer fell further (1:20).

When malignancy hits twice – synchronous gastric carcinoma and non-Hodgkin-B-cell lymphoma in a patient with common variable immunodeficiency

Patients with common variable immunodeficiency (CVID) generally bear a higher risk of non Hodgkin B-cell lymphomas and solid tumors, in particular gastric adenocarcinoma.

Here we report a case of a 58-year-old male CVID patient who developed both malignancies within a very short period, as documented by two subsequent esophagogastroduodenoscopies performed within 4 months. While the first upper gastrointestinal endoscopy for routine surveillance purposes was uneventful, the second one after developing unexplained weight loss revealed two new neoplastic lesions in the stomach. The histological evaluation revealed a poorly differentiated adenocarcinoma infiltrating the muscularis propria forcing gastrectomy as well as a high-grade B-non-Hodgkin-lymphoma with detection of a MYC- and BCL6-translocation, necessitating chemotherapy with R-CHOP.

This case emphasizes the necessity of high awareness for gastric neoplasia in patients with CVID and highlights the need of a standardized yet not established endoscopic surveillance protocol for this vulnerable group.

Rapid Progression of Autoimmune Gastritis after Helicobacter pylori Eradication Therapy: A Case Report

We herein report a case of autoimmune gastritis (AIG) with rapid progression after Helicobacter pylori eradication therapy. The patient's previous gastritis had followed the course of type B gastritis before eradication therapy for many years. Immediately after eradication, we diagnosed her with AIG and carefully followed changes in the endoscopic and histopathological findings and serum markers. All of these clinical findings showed significant atrophic progression in the corporal area for approximately three years. We concluded that H. pylori eradication therapy exacerbated AIG in this case.

Helicobacter pylori Infection and Chronic Immune Thrombocytopenia

Approximately half of the world’s population is infected with Helicobacter pylori, which causes gastric disease. Recent systematic reviews and meta-analyses have reported that H. pylori may also have extragastric manifestations such as hematologic diseases, including chronic immune thrombocytopenia (cITP). However, the molecular mechanisms by which H. pylori induces cITP remain unclear, and may involve the host immune response, bacterial strain diversity, and delivery of bacterial molecules to the host blood vessels. This review discusses the important pathophysiological mechanisms by which H. pylori potentially contributes to the development of cITP in infected patients.

Autoimmune Atrophic Gastritis: The Role of miRNA in Relation to Helicobacter Pylori Infection

Introduction

MicroRNAs (miRNAs) have been proposed as diagnostic markers, biomarkers of neoplastic progression, and possible therapeutic targets in several immune-mediated diseases. We aimed to analyze the expression profile of selected miRNAs (miR21, miR142, miR223, miR155) in patients with autoimmune atrophic gastritis (AAG), patients with non-autoimmune multifocal atrophic gastritis (MAG), and healthy control subjects (HC).

Materials and methods

A total of 103 patients with AAG were consecutively recruited for this study among those attending our gastroenterology outpatient clinic. Participating patients were divided into two groups: primary, not Helicobacter pylori (HP)-associated related AAG (n=57, P-AAG) and HP-associated AAG (n=46, HP-AAG); this subgroup included HP-positive patients, patients with previously reported HP infection, and patients harboring antral atrophy, considered as a stigma of HP infection. We also included 20 sex-age-matched MAG patients and 10 HC. Upper endoscopy with gastric biopsies were performed on each AAG and MAG patient. Circulating levels of miR21-5p, miR142-3p, miR223-3p, and miR155-5p were measured by RT-PCR in all groups.

Results

MiR-21 was over-expressed in P-AAG (p=0.02), HP-AAG (p = 0.04), and MAG (p=0.03) compared with HC. By contrast, miR-142 was more expressed in HC than in HP-AAG (p=0.04) and MAG (p=0.03). MiR-155 showed no significant differences among the four subgroups, while, unexpectedly, miR-223 was overexpressed in HC compared to P-AAG (p=0.01), HP-AAG (p=0.003), and MAG (p<0.001), and was higher in P-AAG than in MAG (p=0.05).

Conclusions

MiR-21 was over-expressed in patients with gastric precancerous conditions irrespective of etiology, while in the same subgroups miR-142 and miR-223 were under-expressed compared to healthy controls. Controlling miRNAs up- or downregulation could lead to a breakthrough in treating chronic autoimmune diseases and potentially interfere with the progression to cancer.

Endoscopic Features of Autoimmune Gastritis: Focus on Typical Images and Early Images

Autoimmune gastritis (AIG) is chronic atrophic gastritis caused by an autoimmune mechanism of unknown etiology and presents with various pathological conditions by causing an achlorhydria state through parietal cell damage. The most characteristic endoscopic finding in AIG is advanced corpus-dominant mucosal atrophy. A recent study that examined several cases in Japan revealed the presence of endoscopic features other than corpus-dominant advanced atrophy. Remnants of oxyntic mucosa and sticky adherent dense mucus were found in ≥30% of cases, and hyperplastic polyps were found in ≥20% of cases. In image-enhanced endoscopy (IEE), white globe appearance (WGA) was observed in 32% of AIG cases. Additionally, some reports have stated that the findings in AIG cases using IEE showed cast-off skin appearance (CSA) and foveola type mucosa; however, a consensus is yet to be achieved. These endoscopic results were found in cases of advanced-stage AIG. There have been few reports concerning early-stage AIG cases. In these few reports, all of the cases were pathologically diagnosed as early AIG. In all of the cases, the pathological findings almost always showed neither parietal cell destruction nor atrophy. Endoscopic findings such as “mosaic pattern with slight swelling of the areae gastricae”, “diffuse reddened and edematous gastric fundic gland mucosa”, and “pseudopolyp-like nodules” may be common characteristics of early images. In such early cases, high antibody titers, no atrophic changes, and few clinical abnormal findings were shown. Endoscopists are expected to update their knowledge regarding AIG diagnosis with the evolution of imaging equipment.

Endoscopic features and clinical importance of autoimmune gastritis

Autoimmune gastritis (AIG) is a special type of chronic gastritis characterized by autoimmune disorders caused by cellular immunity, resulting in the destruction of parietal cells and production of antiparietal cell antibodies. Endoscopic findings of AIG are mainly characterized by corpus-dominant advanced atrophy. The antral area is generally considered to have no or mild atrophy; however, there are cases wherein the gastric mucosa is red or faded due to past infection with Helicobacter pylori or bile reflux. Currently, there are no diagnostic criteria for AIG in Japan, and it is important to make a diagnosis based on the presence of gastric autoantibodies and characteristic endoscopic and histological findings. AIG is associated with gastric cancer, neuroendocrine tumors (NETs), and other autoimmune diseases, such as thyroid diseases, anemia, and neurological symptoms due to impaired absorption of iron and vitamin B₁₂ , and thus requires systemic treatment. The significance of diagnosing AIG is to include patients as a high-risk group for the development of gastric cancer and gastric NETs, provide an opportunity to detect autoimmune endocrine diseases, and initiate therapeutic intervention before anemia and neurological symptoms develop. It is important to pay close attention to the occurrence of AIG comorbidities not only at the time of AIG diagnosis but also during follow-up after detection.

Gut Microbial Antigenic Mimicry in Autoimmunity

The gut microbiota plays a major role in the developmental biology and homeostasis of cells belonging to the adaptive and innate arms of the immune system. Alterations in its composition, which are known to be regulated by both genetic and environmental factors, can either promote or suppress the pathogenic processes underlying the development of various autoimmune diseases, including inflammatory bowel disease, multiple sclerosis, systemic lupus erythematosus, type 1 diabetes and rheumatoid arthritis, to just name a few. Cross-recognition of gut microbial antigens by autoreactive T cells as well as gut microbe-driven alterations in the activation and homeostasis of effector and regulatory T cells have been implicated in this process. Here, we summarize our current understanding of the positive and negative associations between alterations in the composition of the gut microbiota and the development of various autoimmune disorders, with a special emphasis on antigenic mimicry.

Pernicious Anemia: The Hematological Presentation of a Multifaceted Disorder Caused by Cobalamin Deficiency

Pernicious anemia is still a neglected disorder in many medical contexts and is underdiagnosed in many patients. Pernicious anemia is linked to but different from autoimmune gastritis. Pernicious anemia occurs in a later stage of autoimmune atrophic gastritis when gastric intrinsic factor deficiency and consequent vitamin B₁₂ deficiency may occur. The multifaceted nature of pernicious anemia is related to the important role of cobalamin, which, when deficient, may lead to several dysfunctions, and thus, the proteiform clinical presentations of pernicious anemia. Indeed, pernicious anemia may lead to potentially serious long-term complications related to micronutrient deficiencies and their consequences and the development of gastric cancer and type 1 gastric neuroendocrine tumors. When not recognized in a timely manner or when pernicious anemia is diagnosed with delay, these complications may be potentially life-threatening and sometimes irreversible. The current review aimed to focus on epidemiology, pathogenesis, and clinical presentations of pernicious anemia in an attempt to look beyond borders of medical specialties. It aimed to focus on micronutrient deficiencies besides the well-known vitamin B₁₂ deficiency, the diagnostic approach for pernicious anemia, its long-term complications and optimal clinical management, and endoscopic surveillance of patients with pernicious anemia.

Helicobacter Pylori and Autoimmune Diseases: Involving Multiple Systems

The modern Gastroenterology have witnessed an essential stride since Helicobacter pylori was first found in the stomach and then its pathogenic effect was discovered. According to the researches conducted during the nearly 40 years, it has been found that this bacterium is associated with a natural history of many upper gastrointestinal diseases. Epidemiological data show an increased incidence of autoimmune disorders with or after infection with specific microorganisms. The researches have revealed that H. pylori is a potential trigger of gastric autoimmunity, and it may be associated with other autoimmune diseases, both innate and acquired. This paper reviews the current support or opposition about H. pylori as the role of potential triggers of autoimmune diseases, including inflammatory bowel disease, autoimmune thyroiditis, type 1 diabetes mellitus, autoimmune liver diseases, rheumatoid arthritis, idiopathic thrombocytopenic purpura, systemic lupus erythematosus, as well as Sjogren’s syndrome, chronic urticaria and psoriasis, and tried to explain the possible mechanisms.

CRESSP: a comprehensive pipeline for prediction of immunopathogenic SARS-CoV-2 epitopes using structural properties of proteins

The development of autoimmune diseases following SARS-CoV-2 infection, including multisystem inflammatory syndrome, has been reported, and several mechanisms have been suggested, including molecular mimicry. We developed a scalable, comparative immunoinformatics pipeline called cross-reactive-epitope-search-using-structural-properties-of-proteins (CRESSP) to identify cross-reactive epitopes between a collection of SARS-CoV-2 proteomes and the human proteome using the structural properties of the proteins. Overall, by searching 4 911 245 proteins from 196 352 SARS-CoV-2 genomes, we identified 133 and 648 human proteins harboring potential cross-reactive B-cell and CD8+ T-cell epitopes, respectively. To demonstrate the robustness of our pipeline, we predicted the cross-reactive epitopes of coronavirus spike proteins, which were recognized by known cross-neutralizing antibodies. Using single-cell expression data, we identified PARP14 as a potential target of intermolecular epitope spreading between the virus and human proteins. Finally, we developed a web application (https://ahs2202.github.io/3M/) to interactively visualize our results. We also made our pipeline available as an open-source CRESSP package (https://pypi.org/project/cressp/), which can analyze any two proteomes of interest to identify potentially cross-reactive epitopes between the proteomes. Overall, our immunoinformatic resources provide a foundation for the investigation of molecular mimicry in the pathogenesis of autoimmune and chronic inflammatory diseases following COVID-19.

New Developments in Gastric Neuroendocrine Neoplasms

Purpose of Review

Gastric neuroendocrine neoplasms (g-NENs) are a rare type of stomach cancer. The three main subtypes have different pathogeneses, biological behaviours and clinical characteristics, so they require different management strategies. This article will provide an overview of g-NENs and highlight recent advances in the field.

Recent Findings

Molecular profiling has revealed differences between indolent and aggressive g-NENs, as well as a new somatic mutation responsible for some familial type I g-NENs. Novel biomarkers have been developed which will hopefully improve diagnosis, treatment, risk stratification and follow-up. Patient treatment is also changing, as evidence supports the use of less aggressive options (e.g. endoscopic surveillance or resection) in some patients with more indolent tumours.

Summary

g-NEN heterogeneity poses challenges in understanding and managing this rare disease. More basic science research is needed to investigate molecular pathogenesis, and future larger clinical studies will hopefully also further improve treatment and patient outcomes.

Two Distinct Etiologies of Gastric Cancer: Infection and Autoimmunity

Gastric cancer is a leading cause of mortality worldwide. The risk of developing gastric adenocarcinoma, which comprises >90% of gastric cancers, is multifactorial, but most associated with Helicobacter pylori infection. Autoimmune gastritis is a chronic autoinflammatory syndrome where self-reactive immune cells are activated by gastric epithelial cell autoantigens. This cause of gastritis is more so associated with the development of neuroendocrine tumors. However, in both autoimmune and infection-induced gastritis, high risk metaplastic lesions develop within the gastric mucosa. This warrants concern for carcinogenesis in both inflammatory settings. There are many similarities and differences in disease progression between these two etiologies of chronic gastritis. Both diseases have an increased risk of gastric adenocarcinoma development, but each have their own unique comorbidities. Autoimmune gastritis is a primary cause of pernicious anemia, whereas chronic infection typically causes gastrointestinal ulceration. Both immune responses are driven by T cells, primarily CD4⁺ T cells of the IFN-γ producing, Th1 phenotype. Neutrophilic infiltrates help clear H. pylori infection, but neutrophils are not necessarily recruited in the autoimmune setting. There have also been hypotheses that infection with H. pylori initiates autoimmune gastritis, but the literature is far from definitive with evidence of infection-independent autoimmune gastric disease. Gastric cancer incidence is increasing among young women in the United States, a population at higher risk of developing autoimmune disease, and H. pylori infection rates are falling. Therefore, a better understanding of these two chronic inflammatory diseases is needed to identify their roles in initiating gastric cancer.

Helicobacter pylori and its association with autoimmune diseases: systemic lupus erythematosus, rheumatoid arthritis and Sjögren syndrome

Helicobacter pylori (H. pylori) is a gram-negative bacterium that adapts to the gastric mucosa and provokes symptoms associated with gastritis. Chronic H. pylori infection in patients with a genetic predisposition can trigger autoimmune diseases due to the immune interaction of cellular and humoral responses. Infections are a triggering factor for systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and Sjögren syndrome (SS), although the association between H. pylori and these diseases is unclear. Therefore, we reviewed this interaction and its clinical importance.

Clue of Diagnosis for Autoimmune Gastritis

BACKGROUND

The diagnostic clues for autoimmune gastritis (AIG) can be classified into 2 categories: endoscopic findings and pathological diagnosis. We believe that research on the AIG detection rate by endoscopists could provide a better understanding of the diagnosis of AIG. This study aimed to clarify the ratio of the endoscopic and the pathological diagnoses of AIG.

METHODS

We retrospectively reviewed consecutive patients who underwent esophagogastroduodenoscopy (EGD). During their first EGD, the gastric mucosa with C2 atrophy or more was biopsied for pathological evaluation based on the updated Sydney system. A gastric biopsy was also performed after Helicobacter pylori eradication, obtaining specimens from at least 2 sites, the greater curvature of the corpus and the antrum. We enrolled patients who were positive for the anti-parietal cell antibody and were diagnosed with AIG, histologically and/or endoscopically. The detection rates of AIG were compared between endoscopic diagnosis and pathological diagnosis.

RESULTS

A total of 10,822 patients underwent EGD during the study period. Finally, 41 patients with AIG were enrolled, leading to an AIG prevalence of 0.38% in this study. As for the clue leading to AIG detection, 31.7% (13/41) were diagnosed through endoscopy (proximal-predominant atrophy), and 68.3% (28/41) were diagnosed pathologically. The AIG detection rate by endoscopists in the posteradication group was significantly lower than in the H. pylori-negative group (p < 0.05).

CONCLUSION

Endoscopists frequently overlooked AIG, especially in posteradication cases. Pathological assessment using the updated Sydney system after H. pylori eradication might be a promising strategy to detect AIG better.

Clinicopathological characteristics of early gastric cancer associated with autoimmune gastritis

Background

Autoimmune gastritis is known to be associated with neoplastic lesions but the relationship between autoimmunity and tumorigenesis have not been sufficiently clarified. The aim of this study is to assess the clinicopathological characteristics of gastric cancer cases associated with autoimmune gastritis.

Methods

A total of 24 patients diagnosed as early gastric cancer with autoimmune gastritis were registered. Chart reviews with the data including age, gender, state of Helicobacter pylori infection, comorbidity, and concomitant gastric diseases were conducted. As for the characteristics of gastric cancer, location, size, morphological type, histopathology, invasion depth, and the presence of metachronous or simultaneous lesion were assessed. These data from autoimmune gastritis group were compared with those from 301 patients of early gastric cancer as a control group.

Results

The gastric cancer associated with autoimmune gastritis was located in the upper, middle, and lower parts in 28.1%, 53.1%, and 18.8%, respectively. The morphological types are as follows: 0‐I, 9.4%; 0‐IIa, 28.1%; 0‐IIb, 15.6%; 0‐IIc, 46.9%; and 0‐III, 0.0%. The mean tumor size was 21.8 mm. While 90.6% were confined to the mucosa, 9.4% showed submucosal invasion. The histological classifications are as follows: tub1, 50.0%; tub2, 15.6%; pap, 21.9%; sig, 9.4%; and por, 3.1%. More numbers of female, protruded types, larger tumor size, papillary tumor, and that in the upper location were observed in autoimmune gastritis group compared to control group.

Conclusion

Early gastric cancer associated with autoimmune gastritis demonstrated different characteristics from those without autoimmune gastritis including variety of tumor morphologies and histological types with female dominancy.

Autoimmune gastritis, with or without pernicious anemia: epidemiology, risk factors, and clinical management

Autoimmune gastritis (AIG) is a chronic immune-mediated, inflammatory condition that involves the destruction of the gastric oxyntic mucosa through the autoimmune-mediated loss of parietal cells, with replacement by atrophic and metaplastic tissue. Diagnosing AIG is important, given the need for ongoing clinical management and vigilance with respect to downstream complications, the most serious of which is gastric adenocarcinoma. Other clinical consequences include gastric neuroendocrine tumors, consequences related to decreased gastric acid and decreased intrinsic factor due to parietal cell destruction and antibodies against intrinsic factor (e.g. micronutrient deficiencies), as well as concomitant autoimmune disorders. Considering the prevalence of AIG and the potential for severe clinical outcomes, it is important to engage in efforts to reduce practice pattern variability related to diagnosis and management. Accordingly, herein, we review of the epidemiology, pathogenesis, clinical presentation of AIG, including both gastric and extragastric manifestations, and provide an overview of clinical management.

Exploring the Oral Microbiome in Rheumatic Diseases, State of Art and Future Prospective in Personalized Medicine with an AI Approach

The oral microbiome is receiving growing interest from the scientific community, as the mouth is the gateway for numerous potential etiopathogenetic factors in different diseases. In addition, the progression of niches from the mouth to the gut, defined as "oral-gut microbiome axis", affects several pathologies, as rheumatic diseases. Notably, rheumatic disorders (RDs) are conditions causing chronic, often intermittent pain affecting the joints or connective tissue. In this review, we examine evidence which supports a role for the oral microbiome in the etiology and progression of various RDs, including rheumatoid arthritis (RA), Sjogren's syndrome (SS), and systemic lupus erythematosus (SLE). In addition, we address the most recent studies endorsing the oral microbiome as promising diagnostic biomarkers for RDs. Lastly, we introduce the concepts of artificial intelligence (AI), in particular, machine learning (ML) and their general application for understanding the link between oral microbiota and rheumatic diseases, speculating the application of a possible AI approach-based that can be applied to personalized medicine in the future.

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

Review: Extragastric diseases and Helicobacter pylori

The involvement of Helicobacter pylori infection in many extra-gastroduodenal manifestations remains a fascinating field of investigation. However, for several of these supposed associations, the potential pathogenic mechanism remains unclear. The present review highlights the main associations of H pylori with extra-gastroduodenal manifestations reported during the last year. We searched for the most relevant studies on this topic, published between April 2019 and March 2020, identified using the term "Helicobacter" in the MEDLINE/Pubmed database. Consistent data emerged from studies investigating metabolic syndrome and ischaemic cardiovascular diseases. Other reported fields of investigation were hepatology, especially focused on non-alcoholic steatohepatitis, neurology, including Parkinson's disease and Alzheimer's disease, as well as dermatology. Inflammatory bowel disease (IBD), that comprises Crohn's disease and ulcerative colitis, may originate from a dysregulation of the host's immune response to commensal bacteria in individuals with genetic predisposition. The reduction of biodiversity and other specific imbalances in the faecal microbiome composition of IBD patients compared to that of healthy controls support this hypothesis. In this context, an inverse correlation between H pylori infection and IBD prevalence has been confirmed. Similar results were found in patients with kidney diseases and allergic manifestations. There are indications of the possible involvement of H pylori infection in metabolic syndrome and ischaemic cardiovascular diseases. However, due to a series of factors linked to study designs and the multifactorial pathogenesis of some diseases, further studies are needed.

Autoimmune gastritis

Autoimmune gastritis (AIG) is an increasingly prevalent, organ-specific, immune-mediated disorder characterized by the destruction of gastric parietal cells, leading to the loss of intrinsic factor and reduced acid output. These alterations result in malabsorption of iron, vitamin B₁₂ (pernicious anaemia) and potentially other micronutrients. For several years, most studies have focused on pernicious anaemia only, generating confusion between the two entities. In AIG, the gastric proton pump, H⁺/K⁺ ATPase, is the major autoantigen recognized by autoreactive T cells. The T cell-dependent activation of B cells stimulates the production of anti-parietal cell antibodies, the serological hallmark of AIG. The role of Helicobacter pylori infection in activating or favouring the autoimmune process is still uncertain. Early histopathological alterations allowing a more precise and prompt recognition have recently been described. AIG is burdened by a substantial diagnostic delay as it can present with varied clinical signs including, among others, gastrointestinal symptoms and neuropsychiatric manifestations. In advanced stages, AIG might progress to neuroendocrine tumours and gastric adenocarcinoma. Management includes early detection through a proactive case-finding strategy, micronutrient supplementation and endoscopic surveillance. This Primer comprehensively describes the most important insights regarding the epidemiology, pathophysiology, diagnosis and management of AIG, focusing on the most controversial, outstanding issues and future directions.

Molecular mechanisms of postbiotics in colorectal cancer prevention and treatment

The occurrence of colorectal cancer (CRC) has been rising expeditiously and anticipated that 2.4 million new occasions of CRC will be detected yearly around the world until the year 2035. Due to some side-effects and complications of conventional CRC therapies, bioactive components such as microbial-derived biomolecules (postbiotics) have been attaining great significance by researchers for adjuvant therapy in CRC patients. The term 'postbiotics' encompasses an extensive range of complex micro- and macro-molecules (<50, 50-100, and 100< kDa) such as inactivated microbial cells, cell fractions or metabolites, which confer various physiological health benefits to the host when administered in adequate amounts. Postbiotics modulate the composition of the gut microbiota and the functionality of the immune system, as well as promote the CRC treatment effectiveness and reduces its side-effects in CRC patients due to possessing anti-oxidant, anti-proliferative, anti-inflammatory, and anti-cancer activities. Presently scientific literature confirms that postbiotics with their unique characteristics in terms of clinical (safe origin), technological (stability), and economic (low production costs) aspects can be used as promising tools for both prevent and adjuvant treat strategies in CRC patients without any serious undesirable side-effects. This review provides an overview of the concept and safety issues regarding postbiotics, with emphasis on their biological role in the prevention and treatment of CRC.

High levels of Helicobacter pylori antigens and antibodies in patients with severe acne vulgaris

BACKGROUND

Helicobacter pylori (H pylori) may play a role in the pathogenesis of extra-intestinal disorders including dermatological diseases.

AIMS

This study aimed to assess the levels of H pylori antigen and antibody in patients with acne vulgaris (AV).

METHODS

This cross-sectional study compared the levels of fecal H pylori antigen and serum H pylori antibody in 100 patients with AV and 100 age and sex-matched healthy volunteers. Patients with AV were classified into mild, moderate, and severe according to the Global Acne Grading Scale. Levels of fecal H pylori antigen and serum H pylori antibodies were assessed using commercially available enzyme-linked immune-sorbent assay.

RESULTS

The patients with severe AV had significantly higher levels of fecal H pylori antigen as compared to the patients with mild AV, moderate AV, and healthy controls (P < .001). The patients with severe AV had significantly higher serum H pylori antibody as compared to the patients with mild AV, moderate AV, and healthy controls (P = .001). The levels of fecal H pylori antigen and serum H pylori antibody in the patients with mild AV were not significantly different from those in the patients with moderate AV (P = .49 and P = .05, respectively).

CONCLUSION

The patients with severe AV had higher levels of fecal H pylori antigen and serum H pylori antibody as compared to the patients with mild and moderate AV and with healthy controls. The indicators of H pylori infection were positively correlated with the severity and duration of AV.

Helicobacter pylori seropositivity is associated with antinuclear antibodies in US adults, NHANES 1999-2000

Infectious diseases, such as Helicobacter pylori, which produce systemic inflammation may be one key factor in the onset of autoimmunity. The association between H. pylori and antinuclear antibodies (ANA), a marker of autoimmunity, has been understudied. Data from the 1999–2000 National Health and Nutrition Examination Survey were used to evaluate the cross-sectional association between H. pylori seroprevalence and ANA positivity in US adults aged ≥20 years. ANA was measured in a 1:80 dilution of sera by indirect immunofluorescence using HEp-2 cells (positive ⩾3). H. pylori immunoglobulin G enzyme-linked immunosorbent assays were used to categorise individuals as seropositive or seronegative. H. pylori seropositivity and ANA positivity were common in the adult US population, with estimated prevalences of 33.3% and 9.9%, respectively. Both were associated with increasing age. H. pylori seropositivity was associated with higher odds of ANA (prevalence odds ratio = 1.89, 95% confidence interval = 1.08–3.33), adjusted for age, sex, race/ethnicity, educational attainment and body mass index. H. pylori infection may be one key factor in the loss of self-tolerance, contributing to immune dysfunction.

Increased Risk of Systemic Lupus Erythematosus in Patients With Helicobacter pylori Infection: A Nationwide Population-Based Cohort Study

Helicobacter pylori (HP) infection is associated with systemic lupus erythematosus (SLE), but the related results have been controversial. Therefore, this study investigated the association between HP infection and SLE by using a nationwide longitudinal population-based cohort. We identified 41,651 patients with HP infection and 83,302 matched controls between 2000 and 2013 from the Longitudinal Health Insurance Research Database of the National Taiwan Insurance Research Database. Age, gender, comorbidities, and medical visits were matched at a 1:2 ratio by using propensity score analysis. The adjusted hazard ratio (aHR) of SLE was calculated by multiple Cox regression. Furthermore, sensitivity test and stratified analysis were performed. The SLE incidence rate was 1.17 [95% confidence interval (CI): 0.89–1.54] per 100,000 person-months in the HP cohort, and the hazard ratio was 1.63 (95% CI: 1.12–2.37) in comparison with the propensity score-matched control cohort. After multivariate adjustment, patients with HP infection had a significantly high overall aHR (1.58; 95% CI: 1.08–2.30) of SLE. Stratified analysis revealed the aHR of 8.23 (95% CI: 1.77–38.32) in patients <30 years old, and the p for interaction between age and HP infection was 0.039. For age–sex subgroup analysis, the highest aHR was 12.74 (95% CI: 1.55–104.59) in young (aged <30 years) female patients with HP infection. HP infection is associated with a 1.63-fold increased SLE risk, particularly with female patients aged <30 years. Future research is required to elucidate the underlying mechanism of this association.

A genetic origin for acid-base imbalance triggers the mitochondrial damage that explains the autoimmune response and drives to gastric neuroendocrine tumours

BACKGROUND

Type I gastric neuroendocrine tumors (gNETs) arise from hypergastrinemia in patients with autoimmune chronic atrophic gastritis. According to the classical model, the gastric H+/K+ ATPase was the causative autoantigen recognized by CD4+ T cells in chronic autoimmune scenario that secretes IL-17 and correlates with parietal cell (PC) atrophy, which drives to gastric achlorhydria and increases the risk for gastric neoplasms. However, the mechanism by which the inflammatory response correlates with PC atrophy is not clearly defined.

METHODS

Recently, we found that the ATP4A^p.R703C mutation impaired PC function and gastric acidification, which drove familial gNET. Our group constructed a knock-in mouse model for the ATP4A mutation, which has served us to better understand the relation between impaired capability to export protons across the plasma membrane of PCs and tumor progression.

RESULTS

The ATP4A^p.R703C mutation drives gastric achlorhydria, but also deregulates the acid-base balance within PCs, affecting mitochondrial biogenesis. Mitochondrial malfunction activates ROS signaling, which triggers caspase-3-mediated apoptosis of parietal cells. In addition, when gastric euchlorhydria was restored, mitochondrial function is recovered. Infection by H. pylori promotes destabilization of the mitochondria of the PCs by a mechanism similar to that described for APT4A^p.R703C carriers.

CONCLUSIONS

A genetic origin that drives mitochondria alteration would initiate the gastric chronic inflammation instead of the classical IL-17 secretion-mediated mechanism explanation. Gastric euchlorhydria restoration is suggested to be indicated for mitochondrial recover. Our results open a new window to understand gastric neoplasms formation but also the inflammatory mechanisms and autoimmune disorders conducted by genetic origin that composes a premalignant scenario.

Gastric IL-1β, IL-8, and IL-17A expression in Moroccan patients infected with Helicobacter pylori may be a predictive signature of severe pathological stages

INTRODUCTION

Helicobacter pylori induces acute gastritis that can progress to serious diseases such as gastric cancer. H. pylori interacts with host cells within the gastric mucosa, resulting in activation of multiple innate immune signalling pathways, leading to pro-inflammatory cytokines production and immune cells recruitment. Various studies have shown that there are ethnic- and population-related differences in the expression of these cytokines. Although the H. pylori infection is a major public health problem in Morocco, to our knowledge, no study has been carried out in gastric cytokine expression from H. pylori-infected Moroccan patients. Thus we aimed to (i) determine the IL-1β, IL-8 and IL-17A gene expression in gastric biopsies from Moroccan patients infected with H. pylori, and (ii) to determine the cytokine signature of each pathological stages associated with this infection.

MATERIAL AND METHODS

71 patients with epigastralgic pain were included in this study. The H. pylori detection on gastric biopsies was performed by histopathological and PCR analysis. The IL-1β, IL-8 and IL-17A mRNA expression in the antrun and fundus biopsies was performed by RT-qPCR.

RESULTS

The histopathological and PCR analyses revealed that 87.32% of the patients were infected with H. pylori. IL-1β mRNA expression was significantly lower in the antral mucosa of H. pylori-infected patients (p = 0.0038) than in the uninfected while there was no significant difference in the expression of IL-8 and IL-17A mRNA. The expression of the three cytokines was higher in the fundic mucosa of H. pylori-infected patients than in the uninfected patients, but only IL-8 and IL-17A expression reached statistical significance (p = 0.042 and p = 0.0179 respectively). Furthermore, the multivariate predictive analysis highlighted a cytokine signature that may predict metaplasia during the infection progression that involves a specific down-regulation of IL17A and an up-regulation of IL1β in antral and fundic metaplasia respectively.

Prevalence of Autoimmune Gastritis in Individuals Undergoing Medical Checkups in Japan

Objective Based on both endoscopic findings and serum auto-antibody levels, we determined the prevalence of autoimmune gastritis (AIG), which has not been previously reported, in individuals who underwent health checkup examinations in Japan. Methods At total of 6,739 subjects (4,288 males, 2,451 females; mean age 52.1 years) underwent an upper gastrointestinal endoscopic examination as part of an annual medical checkup. Those suspected to have AIG based on endoscopic evidence of proximal-predominant gastric mucosal atrophy were further examined for the presence of anti-parietal cells and anti-intrinsic factor antibodies, with a final diagnosis of AIG made in cases found to be positive for either or both of those factors. Results Of the 6,739 examined subjects, 46 were suspected to have AIG based on the endoscopic findings, of whom 33 were finally diagnosed with AIG, for an overall prevalence 0.49% (females 0.65%, males 0.40%). Seven with AIG also had thyroid disease, including Hashimoto's and Basedow disease, while none with AIG showed anemia in blood test findings. The prevalence of AIG was not different regardless of the H. pylori infection status (negative, positive, post-eradicated). Conclusion In individuals who underwent an upper gastrointestinal endoscopic examination as part of an annual checkup in Japan, the prevalence of AIG was 0.49%. We concluded that it is not uncommon for asymptomatic and healthy individuals to have AIG, and propose that additional studies are needed to clarify its prevalence as well as to establish the criteria used for diagnosis.

Insights Into Pediatric Autoimmune Gastritis: Is There a Role for Helicobacter pylori Infection?

OBJECTIVES

Autoimmune gastritis (AIG) is a chronic inflammatory condition of the gastric mucosa, mainly described in adults presenting with pernicious anemia. It results from antibody-mediated destruction of parietal cells, but the precise initiating event is unknown. The pathogenicity of Helicobacter pylori (H pylori) has been suggested but not established. This study aimed to better characterize AIG in pediatric patients and to address the possible role of H pylori infection.

METHODS

Descriptive single-center study, retrospectively describing 20 patients with a diagnosis of AIG based on positivity for anti-parietal cell autoantibodies, in addition to analytical and/or histological findings of oxyntic mucosa atrophy.

RESULTS

In the majority (18/20), AIG diagnosis was suggested during investigation of refractory iron-deficient anemia. One patient had dyspepsia and none of the others had gastrointestinal symptoms. Fifty-five percent (11/20) were H pylori positive, but there were no significant differences regarding mean hemoglobin values at presentation (10.6 ± 2.5 vs 9.5 ± 1.0 g/dL, P > 0.05), analytical indicators of gastric atrophy (gastrin, 564.4 ± 184 vs 721.2 ± 220.6 pg/mL, P > 0.05), or in the presence or the grade of oxyntic mucosa atrophy.

CONCLUSIONS

Our findings highlight that AIG may have an age-dependent presentation; thus, we can consider a pediatric phenotype that in contrast to adults, is manifested by refractory iron-deficient anemia and associated with parietal cell autoantibody positivity, but not intrinsic factor autoantibodies. A correlation between H pylori and AIG was not evident in the current study and it is still unclear whether H pylori is a trigger for AIG.

Infections: a double-edge sword in autoimmunity

PURPOSE OF REVIEW

Infections play a role in the pathogenesis of autoimmune diseases (AID). Several bacterial and viral pathogens play a double role, as both inducers and inhibitors of AID. In this review, we will present current evidence and discuss different aspects of this notion.

RECENT FINDINGS

Infectors that both inhibit and induce AID include Helicobacter pylori, Klebsiella pneumoniae, hepatitis B virus, group B Coxsackieviruses, Epstein-Barr virus and Lymphocytic choriomeningitis virus. Numerous AID are affected by infections, including polyarteritis nodosa, inflammatory bowel disease, and type 1 diabetes. Some pathogens, such as group B Coxsackieviruses, may induce and inhibit the development of the same AID. This reveals a complex role of infections in autoimmunity pathogenesis.

SUMMARY

Elucidating the exact role of each pathogen on each specific AID is important, as this will enable evaluating the manipulation of these infections in the treatment of AID.