The incidence of neoplasia in patients with autoimmune metaplastic atrophic gastritis: a renewed call for surveillance

Research progress on the application of single-cell sequencing in autoimmune diseases

Autoimmune diseases (AIDs) are caused by immune tolerance deficiency or abnormal immune regulation, leading to damage to host organs. The complicated pathogenesis and varied clinical symptoms of AIDs pose great challenges in diagnosing and monitoring this disease. Regrettably, the etiological factors and pathogenesis of AIDs are still not completely understood. It is noteworthy that the development of single-cell RNA sequencing (scRNA-seq) technology provides a new tool for analyzing the transcriptome of AIDs. In this essay, we have summarized the development of scRNA-seq technology, and made a relatively systematic review of the current research progress of scRNA-seq technology in the field of AIDs, providing a reference to preferably understand the pathogenesis, diagnosis, and treatment of AIDs.

Autoimmune gastritis and stomach cancer: assessing the risks

The purpose of this publication is to systematize available data on the risks of developing stomach cancer in patients with a chronic autoimmune gastritis with a demonstration of the clinical case of a patient with a chronic autoimmune gastritis and a neuroendocrine gastric tumor of the type 1. Discussion: the article discusses the risks of stomach cancer in patients with chronic autoimmune gastritis. A mechanism for the formation of a neuroendocrine gastric tumor of the type 1, associated with autoimmune gastritis, is given. A clinical example of a patient with a long history of dyspepsia, the presence of concomitant changes in the results of laboratory tests, describes an algorithm for diagnosis of autoimmune gastritis and associated neuroendocrine tumors. The risks of the development in patients with autoimmune gastritis of formidable complications as an adenocarcinoma of the stomach are considered. Conclusion: Chronic autoimmune gastritis is a precancerous diseases of the stomach, with the progressive atrophy of the gastric body mucosa, and associated with an increased risk of developing neuroendocrine gastric tumor of the type 1 and adenocarcinoma of the stomach. Patients with autoimmune gastritis need dynamic outpatient observation, with endoscopic control and assessment of the degree and stage of gastritis in OLGA system, with immunogistochemistry to evaluate the risks of stomach cancer and timely implementation of the necessary measures of carcinoprection.

How to improve the diagnosis of neoplastic transformation of gastric hyperplastic polyps in the context of autoimmune gastritis?: A case report and lierature review

RATIONALE

Gastric hyperplastic polyp (GHP) commonly arises in the abnormal background mucosa, which makes it easy to be misdiagnosed and missed, and has a potential risk of malignant transformation over time. Here, we present a case of neoplastic transformation of GHP in a context of autoimmune gastritis (AIG).

PATIENT CONCERNS

In 2020, a 67-year-old woman was admitted for endoscopic review 6 years after gastric polyp resection, the histological diagnosis of gastric polyp was neoplastic transformation of GHP as before. The patient had undergone multiple polypectomies at the same part. Then histological examination revealed that partial epithelial hyperplasia and dysplasia, and the neoplastic areas were interlaced with normal mucosa.

DIAGNOSES AND INTERVENTIONS

We further found that the background diagnosis was AIG. These results supported the diagnosis of neoplastic transformation of GHP in a context of AIG. With the doubt of missed diagnose, we retrospectively analyzed the medical history in 2014, 2015 and 2016, confirmed the presence of AIG. Unfortunately, serological tests and special treatment were not performed.

OUTCOMES

The correct diagnosis was eventually confirmed in 2020, which enables patients to receive normal treatment and monitoring, and avoids further deterioration of the disease.

LESSONS

The purpose of this case report is to increase clinical awareness of neoplastic transformation of GHP in a context of AIG, and hope promise for early diagnosis and treatment.

The immune microenvironment in gastric adenocarcinoma

Like most solid tumours, the microenvironment of epithelial-derived gastric adenocarcinoma (GAC) consists of a variety of stromal cell types, including fibroblasts, and neuronal, endothelial and immune cells. In this article, we review the role of the immune microenvironment in the progression of chronic inflammation to GAC, primarily the immune microenvironment driven by the gram-negative bacterial species Helicobacter pylori. The infection-driven nature of most GACs has renewed awareness of the immune microenvironment and its effect on tumour development and progression. About 75-90% of GACs are associated with prior H. pylori infection and 5-10% with Epstein-Barr virus infection. Although 50% of the world's population is infected with H. pylori, only 1-3% will progress to GAC, with progression the result of a combination of the H. pylori strain, host susceptibility and composition of the chronic inflammatory response. Other environmental risk factors include exposure to a high-salt diet and nitrates. Genetically, chromosome instability occurs in ~50% of GACs and 21% of GACs are microsatellite instability-high tumours. Here, we review the timeline and pathogenesis of the events triggered by H. pylori that can create an immunosuppressive microenvironment by modulating the host's innate and adaptive immune responses, and subsequently favour GAC development.

Relevance of pepsinogen, gastrin, and endoscopic atrophy in the diagnosis of autoimmune gastritis

Simple objective modalities are required for evaluating suspected autoimmune gastritis (AIG). This cross-sectional study aimed to examine whether pepsinogen, gastrin, and endoscopic findings can predict AIG. The diagnostic performance of endoscopic findings and serology in distinguishing AIG was evaluated. AIG was diagnosed in patients (N = 31) with anti-parietal cell antibody and/or intrinsic factor antibody positivity and histological findings consistent with AIG. Non-AIG patients (N = 301) were seronegative for anti-parietal cell antibodies. Receiver operating characteristic curve analysis of the entire cohort (N = 332) identified an endoscopic atrophic grade cutoff point of O3 on the Kimura–Takemoto classification (area under the curve [AUC]: 0.909), while those of pepsinogen-I, I/II ratio, and gastrin were 20.1 ng/mL (AUC: 0.932), 1.8 (AUC: 0.913), and 355 pg/mL (AUC: 0.912), respectively. In severe atrophy cases (≥ O3, N = 58, AIG/control; 27/31), the cutoff values of pepsinogen-I, I/II ratio, and gastrin were 9.8 ng/mL (AUC: 0.895), 1.8 (AUC: 0.86), and 355 pg/mL (AUC: 0.897), respectively. In conclusion, endoscopic atrophy is a predictor of AIG. High serum gastrin and low pepsinogen-I and I/II ratio are predictors even in the case of severe atrophy, suggesting their usefulness when the diagnosis of AIG is difficult or as serological screening tests.

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.

Five Autoimmune Gastritis Patients with Positive Findings of Serum Anti-parietal Cell Antibodies

Autoimmune gastritis is a corpus-dominant type of gastritis with positive serum anti-parietal cell antibodies (APCA) and/or anti-intrinsic factor antibodies. Serum APCA and pepsinogen (PG) assays were performed in subjects with corpus-dominant gastritis detected by endoscopy. Serum APCA was positive in five patients. All these patients were postmenopausal women (four Koreans and one Caucasian from the Russian Federation) with a mean age of 59.0±3.2 years. They displayed low PG I levels ranging from 8.1 to 18.8 ng/mL (mean, 11.4±4.8 ng/mL) and low PG I/II ratios ranging from 0.7 to 2.4 (mean, 1.2±0.7). Three of the patients were being treated for autoimmune thyroiditis. Multiple gastric neuroendocrine tumors were observed in two Helicobacter pylori (H. pylori)-naive patients with high serum gastrin levels exceeding 700 pg/mL and serum chromogranin A levels exceeding 1,000 ng/mL. In the remaining three patients, intestinal metaplasia was observed in the biopsied specimens from the antrum, suggesting a history of H. pylori infection. Our findings indicate the value of positive serum APCA findings, low serum PG I levels, and low serum PG I/II ratios in confirming autoimmune gastritis in patients showing corpus-dominant atrophy, regardless of their H. pylori infection status.

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.

Autoimmune Gastritis Treated With Mycophenolate Mofetil

Autoimmune gastritis is an inflammatory condition of the gastric mucosa. We report a 64-year-old woman with chronic abdominal pain of 3-year duration. Endoscopic and histologic evaluation revealed autoimmune pangastritis. The gastritis was partially responsive to steroids but attempts to taper failed, and the patient had no relief from mercaptopurine, adalimumab, budesonide, or hydroxychloroquine. The patient was treated with mycophenolate mofetil which resulted in resolution of symptoms. Endoscopic and histologic examination after mycophenolate therapy showed near complete resolution of active inflammation. To the best of our knowledge, this is the first report of symptomatic autoimmune gastritis successfully treated by mycophenolate mofetil.

Selective Resection of Type 1 Gastric Neuroendocrine Neoplasms and the Risk of Progression in an Endoscopic Surveillance Programme

BACKGROUND

Current guidance for type 1 gastric neuroendocrine neoplasms (gNENs) recommends either resection of all visible lesions or selective resection of gNENs >10 mm. We adopt a selective strategy targeting lesions approaching 10 mm for endoscopic mucosal resection (EMR) and provide surveillance for smaller lesions.

OBJECTIVES

This study aimed to describe the incidence of type 1 gNENs requiring endoscopic/surgical resection and the risk of disease progression (both considered significant disease) on endoscopic surveillance. The secondary objective was to assess the risk factors for disease progression during surveillance and the incidence of gastric dysplasia/adenoma/adenocarcinoma.

METHODS

We collected consecutive patients with type 1 gNENs and obtained demographic and clinical data through the electronic patient record.

RESULTS

In our cohort of 57 patients, 12 patients had EMR at index gastroscopy; 7 patients had surgery (4: large/multiple gNENs and 3: nodal metastases) (5.2% [3/57] risk of nodal metastases); and a patient with nodal and liver metastases (1.8% [1/57] risk of distant metastases). The prevalence of gastric adenocarcinoma in our study was 3.5% with an incidence rate of 9.59 per 1,000 persons per year. For patients undergoing surveillance, 29.5% (13/44) of patients progressed requiring resection. Serum gastrin was significantly higher in patients who progressed to resection (p value = 0.023).

CONCLUSION

We concluded that up to a third of patients with type 1 gNENs have significant disease requiring resection. Hence, endoscopic surveillance and resect strategy would benefit patients.

Identification of Gastritis Subtypes by Convolutional Neuronal Networks on Histological Images of Antrum and Corpus Biopsies

Background: Gastritis is a prevalent disease and commonly classified into autoimmune (A), bacterial (B), and chemical (C) type gastritis. While the former two subtypes are associated with an increased risk of developing gastric intestinal adenocarcinoma, the latter subtype is not. In this study, we evaluated the capability to classify common gastritis subtypes using convolutional neuronal networks on a small dataset of antrum and corpus biopsies. Methods: 1230 representative 500 × 500 µm images of 135 patients with type A, type B, and type C gastritis were extracted from scanned histological slides. Patients were allocated randomly into a training set (60%), a validation set (20%), and a test set (20%). One classifier for antrum and one classifier for corpus were trained and optimized. After optimization, the test set was analyzed using a joint result from both classifiers. Results: Overall accuracy in the test set was 84% and was particularly high for type B gastritis with a sensitivity of 100% and a specificity of 93%. Conclusions: Classification of gastritis subtypes is possible using convolutional neural networks on a small dataset of histopathological images of antrum and corpus biopsies. Deep learning strategies to support routine diagnostic pathology merit further evaluation.

Precancerous lesions of the stomach, gastric cancer and hereditary gastric cancer syndromes

Gastric cancer accounts for about 6% of cancers worldwide, being the fifth most frequently diagnosed malignancy and the third leading cause of cancer related death. Gastric carcinogenesis is a multistep and multifactorial process and is the result of the complex interplay between genetic susceptibility and environmental factors. The identification of predisposing conditions and of precancerous lesions is the basis for screening programs and early stage treatment. Furthermore, although most gastric cancers are sporadic, familial clustering is observed in up to 10% of patients. Among them, hereditary cases, related to known cancer susceptibility syndromes and/or genetic causes are thought to account for 1-3% of all gastric cancers. The pathology report of gastric resections specimens therefore requires a standardized approach as well as in depth knowledge of prognostic and treatment associated factors.

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.

Interleukin 27 Protects From Gastric Atrophy and Metaplasia During Chronic Autoimmune Gastritis

BACKGROUND & AIMS

The association between chronic inflammation and gastric carcinogenesis is well established, but it is not clear how immune cells and cytokines regulate this process. We investigated the role of interleukin 27 (IL27) in the development of gastric atrophy, hyperplasia, and metaplasia (preneoplastic lesions associated with inflammation-induced gastric cancer) in mice with autoimmune gastritis.

METHODS

We performed studies with TxA23 mice (control mice), which express a T-cell receptor against the H+/K+ adenosine triphosphatase α chain and develop autoimmune gastritis, and TxA23xEbi3-/- mice, which develop gastritis but do not express IL27. In some experiments, mice were given high-dose tamoxifen to induce parietal cell atrophy and spasmolytic polypeptide-expressing metaplasia (SPEM). Recombinant IL27 was administered to mice with mini osmotic pumps. Stomachs were collected and analyzed by histopathology and immunofluorescence; we used flow cytometry to measure IL27 and identify immune cells that secrete IL27 in the gastric mucosa. Single-cell RNA sequencing was performed on immune cells that infiltrated stomach tissues.

RESULTS

We identified IL27-secreting macrophages and dendritic cell in the corpus of mice with chronic gastritis (TxA23 mice). Mice deficient in IL27 developed more severe gastritis, atrophy, and SPEM than control mice. Administration of recombinant IL27 significantly reduced the severity of inflammation, atrophy, and SPEM in mice with gastritis. Single-cell RNA sequencing showed that IL27 acted almost exclusively on stomach-infiltrating CD4+ T cells to suppress expression of inflammatory genes.

CONCLUSIONS

In studies of mice with autoimmune gastritis, we found that IL27 is an inhibitor of gastritis and SPEM, suppressing CD4+ T-cell-mediated inflammation in the gastric mucosa.

Gastric cancer in autoimmune gastritis: A case-control study from the German centers of the staR project on gastric cancer research

Objectives

Patients with autoimmune gastritis (AIG) are reported to have an increased risk of developing gastric cancer (GC). In this study, we assess the characteristics and outcomes of GC patients with AIG in a multicenter case-control study.

Methods

Between April 2013 and May 2017, patients with GC, including cancers of the esophagogastric junction (EGJ) Siewert type II and III, were recruited. Patients with histological characteristics of AIG were identified and matched in a 1:2 fashion for age and gender to GC patients with no AIG. Presenting symptoms were documented using a self-administered questionnaire.

Results

Histological assessment of gastric mucosa was available for 572/759 GC patients. Overall, 28 (4.9%) of GC patients had AIG (67 ± 9 years, female-to-male ratio 1.3:1). In patients with AIG, GC was more likely to be localized in the proximal (i.e. EGJ, fundus, corpus) stomach (odds ratio (OR) 2.7, 95% confidence interval (CI) 1.0–7.1). In GC patients with AIG, pernicious anemia was the leading clinical sign (OR 22.0, 95% CI 2.6–187.2), and the most common indication for esophagogastroduodenoscopy (OR 29.0, 95% CI 7.2–116.4). GC patients with AIG were more likely to present without distant metastases (OR 6.2, 95% CI 1.3–28.8) and to be treated with curative intention (OR 3.0, 95% CI 1.0–9.0). The five-year survival rates with 95% CI in GC patients with and with no AIG were 84.7% (83.8–85.6) and 53.5% (50.9–56.1), respectively (OR 0.25, 95% CI 0.08–0.75, p = 0.001).

Conclusions

Pernicious anemia leads to earlier diagnosis of GC in AIG patients and contributes significantly to a better clinical outcome.

Differential Helicobacter pylori Plasticity in the Gastric Niche of Subjects at Increased Gastric Cancer Risk

Helicobacter pylori (H. pylori) represents an independent risk factor for Gastric Cancer (GC). First Degree Relatives (FDR) of GC subjects and Autoimmune Gastritis (AG) patients are both at increased risk for GC. H. pylori genetic heterogeneity within the gastric niche of FDR and AG individuals has been little explored. To understand whether they exploit an increased H. pylori stability and virulence, 14 AG, 25 FDR, 39 GC and 13 dyspeptic patients (D) were investigated by a cultural PCR-based approach characterizing single colonies-forming-units. We chose three loci within the Cytotoxin-associated gene-A Pathogenicity Island (CagPAI) (cagA,cagE,virB11), vacA, homA and homB as markers of virulence with reported association to GC. Inflammatory/precancerous lesions were staged according to Sydney System. When compared to D, FDR, similarly to GC patients, were associated to higher atrophy (OR = 6.29; 95% CI:1.23-31.96 in FDR; OR = 7.50; 95% CI:1.67-33.72 in GC) and a lower frequency of mixed infections (OR = 0.16; 95% CI:0.03-0.81 in FDR; OR = 0.10; 95% CI:0.02-0.48 in GC). FDR presented also an increased neutrophil infiltration (OR = 7.19; 95% CI:1.16-44.65). Both FDR and GC carried a higher proportion of CagPAI⁺vacAs1i1mx⁺homB⁺ profiles (OR = 2.71; 95% CI: 1.66-4.41 and OR = 3.43; 95% CI: 2.16-5.44, respectively). Conversely, AG patients presented a lower frequency of subtypes carrying a stable CagPAI and vacAs1i1mx. These results underline different H. pylori plasticity in FDR and AG individuals, and thus, a different host-bacterium interaction capacity that should be considered in the context of eradication therapies.

Polymorphism in Toll-Like Receptors and Helicobacter Pylori Motility in Autoimmune Atrophic Gastritis and Gastric Cancer

Autoimmune atrophic gastritis (AAG) is associated with an increased risk of certain types of gastric cancer (GC). Helicobacter pylori (H. pylori) infection may have a role in the induction and/or maintenance of AAG and GC. Toll-like receptors (TLR) are essential for H. pylori recognition and subsequent innate and adaptive immunity responses. This study therefore aimed to characterize TLR polymorphisms, and features of bacterial flagellin A in samples from patients with AAG (n = 67), GC (n = 114) and healthy donors (HD; n = 97). TLR5 rs5744174 C/C genotype was associated with GC, lower IgG anti H. pylori response and a higher H. pylori flagellin A abundance and motility. In a subset of patients with AAG, H. pylori strains showed a reduction of the flagellin A abundance and a moderate motility compared with strains from GC patients, a prerequisite for active colonization of the deeper layers of the mucosa, host immune response and inflammation. TLR9 rs5743836 T allele showed an association with serum gastrin G17. In conclusion, our study suggests that alterations of flaA protein, moderate motility in H. pylori and two polymorphisms in TLR5 and TLR9 may favor the onset of AAG and GC, at least in a subset of patients. These findings corroborate the function of pathogen–host cell interactions and responses, likely influencing the pathogenetic process.