Multicenter study of autoimmune gastritis in Japan: Clinical and endoscopic characteristics

Multiple gastric neuroendocrine tumors in a patient with parietal cell dysfunction and adenosine triphosphatase H+/K+ transporting subunit alpha gene variant

A 47-year-old woman presented with multiple gastric tumors, each up to 10 mm in diameter, in the gastric body and fundus without mucosal atrophy. White spots and numerous transparent, light-brownish, small, and rounded spots were observed in the background gastric mucosa. Biopsy specimens obtained from the tumors revealed gastric neuroendocrine tumors. The patient exhibited hypergastrinemia and achlorhydria and tested negative for serum parietal cell antibody, intrinsic factor antibody, and Helicobacter pylori infection. Moreover, no additional lesions were detected on imaging. These findings were inconsistent with Rindi's classification. The tumor was resected via endoscopic submucosal resection. Histopathological examination revealed gastric neuroendocrine tumors G2 infiltrating the submucosa with no atrophy of the gastric mucosa, dilated fundic glands, parietal cell protrusions, and hyperplasia of enterochromaffin-like cells. Immunohistochemically, the parietal cells were negative for both α- and β-subunits of H+/K+ ATPase, suggesting parietal cell dysfunction. A genomic variant was identified in adenosine triphosphatase H+/K+ transporting subunit alpha. After 7 years of treatment, there was no evidence of residual or metastatic lesions. Modification of adenosine triphosphatase H+/K+ transporting subunit alpha may be a significant factor in the pathogenesis of multiple gastric neuroendocrine tumors in the context of gastric parietal cell dysfunction.

Characteristic endoscopic findings in Helicobacter pylori diagnosis in clinical practice

INTRODUCTION

Helicobacter pylori is a major risk factor for gastric cancer. In addition to eradication therapy, early-phase detection of gastric cancer through screening programs using high-vision endoscopy is also widely known to reduce mortality. Although European and US guidelines recommend evaluation of atrophy and intestinal metaplasia by high-vision endoscopy and pathological findings, the guideline used in Japan - the Kyoto classification of gastritis - is based on endoscopic evaluation, and recommends the grading of risk factors. This system requires classification into three endoscopic groups: H. pylori-negative, previous H. pylori infection (inactive gastritis), and current H. pylori infection (active gastritis). Major endoscopic findings in active gastritis are diffuse redness, enlarged folds, nodularity, mucosal swelling, and sticky mucus, while those in H pylori-related gastritis - irrespective of active or inactive status - are atrophy, intestinal metaplasia, and xanthoma.

AREAS COVERED

This review describes the endoscopic characteristics of current H. pylori infection, and how characteristic endoscopic findings should be evaluated.

EXPERT OPINION

Although the correct evaluation of endoscopic findings related to H. pylori remains necessary, if findings of possible infection are observed, it is important to diagnose infection by detection methods with high sensitivity and specificity, including the stool antigen test and urea breath test.

A Novel Characteristic Gastric Mucus Named "Web-like Mucus" Potentially Induced by Vonoprazan

Background: In the absence of Helicobacter pylori (HP) infection, a characteristic gastric mucus adhesion may appear during the use of vonoprazan. We named this novel characteristic mucus "web-like mucus" (WLM). This study aimed to determine the incidence and risk factors for WLM. Methods: Between January 2017 and January 2022, 5665 patients were enrolled in this study. The patients were divided into a proton-pump inhibitor (PPI)-prescribed group (n = 2000), a vonoprazan-prescribed group (n = 268), and a no-PPI/vonoprazan-prescribed (n = 3397) group, and the presence of WLM was examined. After excluding four patients with autoimmune gastritis, the remaining 264 patients in the vonoprazan group were divided into WLM and non-WLM groups, and their clinical features were analyzed. Results: A total of 55 (21%) patients had WLM, all in the vonoprazan-prescribed group. There were no significant differences in factors such as, sex, age, chronic kidney disease, diabetes mellitus, HP eradication history, smoking, or alcohol consumption between the WLM and non-WLM groups. The median duration from the start of vonoprazan administration to the endoscopic detection of WLM was 2 (1-24) months. Conclusions: WLM appears to be a characteristic feature in patients treated with vonoprazan.

Endoscopic Grading and Sampling of Gastric Precancerous Lesions: A Comprehensive Literature Review

Gastric cancer remains a disease with an ominous prognosis, while early gastric cancer has a good-to-excellent prognosis, with 5-year survival rates of up to 92.6% after successful endoscopic resection. In this context, the accurate identification of patients with established gastric precancerous lesions, namely chronic atrophic gastritis and intestinal metaplasia, is the first step in a stepwise approach to minimize cancer risk. Although current guidelines advocate for the execution of random biopsies to stage the extent and severity of gastritis/intestinal metaplasia, modern biopsy protocols are still imperfect as they have limited reproducibility and are susceptible to sampling error. The advent of novel imaging-enhancing modalities, i.e., high-definition with virtual chromoendoscopy (CE), has revolutionized the inspection of gastric mucosa, leading to an endoscopy-based staging strategy for the management of these premalignant changes in the stomach. Nowadays, the incorporation of CE-targeted biopsies in everyday clinical practice offers not only the robust detection of premalignant lesions but also an improvement in quality, by reducing missed diagnoses along with mean biopsies and, thus, the procedural costs and the environmental footprint. In this review, we summarize the recent evidence regarding the endoscopic grading and sampling of gastric precancerous lesions.

Unveiling early stage autoimmune gastritis: novel endoscopic insights from two case reports

The predominant characteristic of autoimmune gastritis (AIG) is corpus-dominant advanced atrophy, which is mostly observed in the middle to late stages. More reports are needed on the endoscopic features of the early stage. In this report, we present two cases of early-stage AIG in which endoscopic examinations showed no atrophy of the gastric mucosa but displayed a transition of collecting venules from a regular to an irregular arrangement. In addition, yellowish-white cobblestone-like elevations were observed in the fundic gland region. Histologically, the observed manifestations included pseudohypertrophy and protrusion of parietal cells into the lumen, possibly along with hyperplasia of G cells, lymphocytic infiltration and potentially pseudopyloric gland metaplasia. Serologically, the anti-parietal cell antibody returned positive results, whereas the anti-intrinsic factor antibody yielded negative results. In this study, we summarized some endoscopic features of two patients, aiming to provide clues for endoscopists to detect early-stage AIG.

A case of nodular gastritis progression to autoimmune gastritis after 10 years of Helicobacter pylori eradication

A 61-year-old female patient underwent upper gastrointestinal endoscopy, which confirmed the presence of Helicobacter pylori (H. pylori)-positive nodular gastritis (NG). Routine upper gastrointestinal endoscopy after H. pylori eradication revealed atrophic changes of the corpus, having gradually progressed over the 10 years after successful eradication. Serological and biopsy specimen examination showed hypergastrinemia (1200 pg/mL), positive anti-parietal cell antibody (with a titer of more 160), and endocrine cell micronests after 11 years of H. pylori eradication. The patient was diagnosed with autoimmune gastritis (AIG) based on endoscopic, serological, and histological findings. This is the first report of AIG diagnosed in a patient with NG over a long period of time after H. pylori eradication.

Autoimmune Atrophic Gastritis: A Clinical Review

Autoimmune atrophic gastritis (AAG) is a chronic condition characterized by the presence of atrophy in the oxyntic mucosa due to anti-parietal cell antibodies. This review provides a comprehensive and up-to-date overview of autoimmune atrophic gastritis, reporting recent evidence on epidemiology, pathogenesis, diagnosis, clinical presentation, risk of malignancies, and management. The prevalence of AAG has been estimated at between 0.3% and 2.7% in the general population. The diagnosis of AAG is based on a combination of the serologic profile and the histological examination of gastric biopsies. Patients with AAG are often asymptomatic but can also have dyspeptic or reflux symptoms. The atrophy of the oxyntic mucosa leads to iron and vitamin B12 malabsorption, which may result in anemia and neurological affections. Autoimmune atrophic gastritis is associated with an increased risk of type I neuroendocrine tumors (NETs) and gastric cancer, with an incidence rate of 2.8% and 0.5% per person/year, respectively. Management is directed to reinstate vitamins and iron and to prevent malignancies with endoscopic surveillance. In conclusion, atrophic autoimmune gastritis is an infrequent condition, often asymptomatic and misdiagnosed, that requires an early diagnosis for appropriate vitamin supplementation and endoscopic follow-up for the early diagnosis of NETs and gastric cancer.

Characteristic endoscopic findings in early-stage autoimmune gastritis

Background and study aims Until recently, autoimmune gastritis (AIG) was usually diagnosed at late stages based on typical endoscopic findings, including corpus-dominant advanced atrophy. Early-stage AIG prior to complete gastric atrophy had rarely been diagnosed due to a lack of knowledge about its endoscopic characteristics. The present study sought to identify the endoscopic characteristics of early-stage AIG, enabling its early diagnosis. Patients and methods The clinical and endoscopic findings of 12 patients diagnosed with early-stage AIG between 2016 and 2021 were retrospectively evaluated. Patients were included if they were: (1) positive for serum anti-parietal cell antibody; (2) diagnosed with histological early-stage AIG; and (3) endoscopically positive for folds on the greater curvature of the gastric corpus. Results Two characteristic endoscopic findings of early-stage AIG were identified: longitudinal alignment of pseudopolyps (i.e., a bamboo joint-like appearance) and swelling of gastric areas with erythema (i.e., a salmon roe-like appearance). Conclusions Endoscopic findings characteristic of early-stage AIG include a bamboo joint-like appearance and a salmon roe-like appearance. Studies in large numbers of patients with long-term follow-up are needed to confirm these findings.

RE.GA.IN.: the Real-world Gastritis Initiative-updating the updates

At the end of the last century, a far-sighted 'working party' held in Sydney, Australia addressed the clinicopathological issues related to gastric inflammatory diseases. A few years later, an international conference held in Houston, Texas, USA critically updated the seminal Sydney classification. In line with these initiatives, Kyoto Global Consensus Report, flanked by the Maastricht-Florence conferences, added new clinical evidence to the gastritis clinicopathological puzzle.The most relevant topics related to the gastric inflammatory diseases have been addressed by the Real-world Gastritis Initiative (RE.GA.IN.), from disease definitions to the clinical diagnosis and prognosis. This paper reports the conclusions of the RE.GA.IN. consensus process, which culminated in Venice in November 2022 after more than 8 months of intense global scientific deliberations. A forum of gastritis scholars from five continents participated in the multidisciplinary RE.GA.IN. consensus. After lively debates on the most controversial aspects of the gastritis spectrum, the RE.GA.IN. Faculty amalgamated complementary knowledge to distil patient-centred, evidence-based statements to assist health professionals in their real-world clinical practice. The sections of this report focus on: the epidemiology of gastritis; Helicobacter pylori as dominant aetiology of environmental gastritis and as the most important determinant of the gastric oncogenetic field; the evolving knowledge on gastric autoimmunity; the clinicopathological relevance of gastric microbiota; the new diagnostic horizons of endoscopy; and the clinical priority of histologically reporting gastritis in terms of staging. The ultimate goal of RE.GA.IN. was and remains the promotion of further improvement in the clinical management of patients with gastritis.

Clinical experience sharing on gastric microneuroendocrine tumors: A case report

BACKGROUND

The majority of gastric neuroendocrine tumors (G-NENs) are present in various lesions under endoscopy, and they can be polypoid uplifts, submucosal tumors or papules, erosions, and ulcers. The lesions are mostly confined to the mucosal or submucosal layer, usually less than 2 cm, and exclusively localized to the gastric body or fundus. In type 1 G-NENs, about 22% of cases have no visible lesions under an endoscope, and such lesions can only be detected via biopsies (microcarcinoids).

CASE SUMMARY

A 67-year-old female patient with appetite loss for more than half a year and personal history of hyperthyroidism was admitted to our hospital. After admission, a random multi-point biopsy was performed on the gastric body, fundus, angle, and antrum through gastroscopy. Pathological examination showed chronic severe atrophic gastritis in the fundus and body of the stomach. The small curvature of the gastric body, the anterior wall of the gastric body, and the posterior wall of the gastric body displayed proliferation of intestinal chromaffin cells. The curvature of the gastric body showed neuroendocrine tumor G1 (carcinoid), while the antrum and angle of the stomach showed mild atrophic gastritis with mild intestinal metaplasia. Immunohistochemical examination showed that the greater curvature of the gastric body was Syn (+), CgA (+), and Ki-67 (+, approximately 1%), which is consistent with neuroendocrine tumors (grade 1). Regular gastroscopy and biopsy should be performed every one to two years to monitor G-NENs.

CONCLUSION

In the case under study, the patient did not have any visible raised lesions under a gastroscope, and the lesions were found only after a random biopsy. This article combines the endoscopic manifestations and clinical features of the lesions in this case to improve the diagnosis of G-NENs.

Marked intestinal trans-differentiation by autoimmune gastritis along with ectopic pancreatic and pulmonary trans-differentiation

BACKGROUND

Autoimmune gastritis (AIG) is a prevalent chronic inflammatory disease with oncogenic potential that causes destruction of parietal cells and severe mucosal atrophy. We aimed to explore the distinctive gene expression profiles, activated signaling pathways, and their underlying mechanisms.

METHODS

A comprehensive gene expression analysis was conducted using biopsy specimens from AIG, Helicobacter pylori-associated gastritis (HPG), and non-inflammatory normal stomachs. Gastric cancer cell lines were cultured under acidic (pH 6.5) conditions to evaluate changes in gene expression.

RESULTS

Gastric mucosa with AIG had a unique gene expression profile compared with that with HPG and normal mucosa, such as extensively low expression of ATP4A and high expression of GAST and PAPPA2, which are involved in neuroendocrine tumorigenesis. Additionally, the mucosa with AIG and HPG showed the downregulation of stomach-specific genes and upregulation of small intestine-specific genes; however, intestinal trans-differentiation was much more prominent in AIG samples, likely in a CDX-dependent manner. Furthermore, AIG induced ectopic expression of pancreatic digestion-related genes, PNLIP, CEL, CTRB1, and CTRC; and a master regulator gene of the lung, NKX2-1/TTF1 with alveolar fluid secretion-related genes, SFTPB and SFTPC. Mechanistically, acidic conditions led to the downregulation of master regulator and stemness control genes of small intestine, suggesting that increased environmental pH may cause abnormal intestinal differentiation in the stomach.

CONCLUSIONS

AIG induces diverse trans-differentiation in the gastric mucosa, characterized by the transactivation of genes specific to the small intestine, pancreas, and lung. Increased environmental pH owing to AIG may cause abnormal differentiation of the gastric mucosa.

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.

Increased Prevalence of Autoimmune Gastritis in Patients with a Gastric Precancerous Lesion

Background: Autoimmune gastritis (AIG), characterized with the presence of anti-parietal-cell antibodies (APCA), is a risk factor for gastric cancer. However, AIG may go underdiagnosed, especially in the case of H. pylori infection and the presence of gastric precancerous lesions (GPL), due to the ambiguous pathology and delayed symptom onset. Aim: Investigate the prevalence and characteristics of AIG in GPL patients. Methods: Prevalence of AIG was determined with the presence of APCA in patients with GPL (n = 256) and the control group (n = 70). Pathological characteristics and levels of gastrin 17 (G17), pepsinogen (PG) I and II and anti-Helicobacter pylori IgG were assessed in GPL cases, and the severity of intestinal metaplasia and gastric atrophy was scored by expert pathologists. Results: APCA positivity was observed in 18% of cases vs. 7% of controls (p = 0.033). Only 3/256 patients were previously diagnosed with AIG. The presence of APCA was associated with corpus-limited and extended GPL. A receiver operating curve analysis demonstrated that the G17 and PGI/II ratio could identify APCA-positive patients within GPL cases (AUC: 0.884). Conclusions: The prevalence of AIG is higher in patients with GPL but goes undiagnosed. Using G17 and PG I/II as diagnostic markers can help to identify patients with AIG and improve surveillance programs for patients with GPL.

Clinical characteristics and long-term prognosis of type 1 gastric neuroendocrine tumors in a large Japanese national cohort

OBJECTIVES

Optimal management of type 1 gastric neuroendocrine tumors (T1-GNETs) remains unknown, with few reports on their long-term prognosis. This study investigated the clinical characteristics and long-term prognosis of T1-GNETs.

METHODS

We reviewed the medical records of patients diagnosed with T1-GNET during 1991-2019 at 40 institutions in Japan.

RESULTS

Among 172 patients, endoscopic resection (ER), endoscopic surveillance, and surgery were performed in 84, 61, and 27, respectively, including 27, 77, and 2 patients with pT1a-M, pT1b-SM, and pT2 tumors, respectively. The median tumor diameter was 5 (range 0.8-55) mm. Four (2.9%) patients had lymph node metastasis (LNM); none had liver metastasis. LNM rates were significantly higher in tumors with lymphovascular invasion (LVI) (15.8%; 3/19) than in those without (1.1%; 1/92) (P = 0.016). For tumors <10 mm, LVI and LNM rates were 18.4% (14/76) and 2.2% (2/90), respectively, which were not significantly different from those of tumors 10-20 mm (LVI 13.3%; 2/15, P = 0.211; and LNM 0%; 0/17, P = 1.0). However, these rates were significantly lower than those of tumors >20 mm (LVI 60%; 3/5, P = 0.021; and LNM 40%; 2/5, P = 0.039). No tumor recurrence or cause-specific death occurred during the median follow-up of 10.1 (1-25) years. The 10-year overall survival rate was 97%.

CONCLUSIONS

Type 1 gastric neuroendocrine tumors showed indolent nature and favorable long-term prognoses. LVI could be useful in indicating the need for additional treatments. ER for risk prediction of LNM should be considered for tumors <10 mm and may be feasible for tumors 10-20 mm.

TRIAL REGISTRATION

The study protocol was registered in the University Hospital Medical Information Network (UMIN) under the identifier UMIN000029927.

Gastric neuroendocrine tumors in a BRCA2 germline mutation carrier: A case report

BACKGROUND

The molecular changes present in gastric neuroendocrine tumors (NETs) include a loss of heterozygosity or mutation of MEN1, CDKN1B gene mutation, P27 heterozygous mutation, and ATP4A gene missense mutation. We identified and are the first to report a case of type 1 histamine-producing enterochromaffin-like cell NETs (ECL-cell NETs) with a BRCA2 gene germline mutation.

CASE SUMMARY

The patient had a history of iron-deficient anemia for 5 years, and gastroscopic examination indicated multiple gastric tumors. Then, the patient underwent distal gastrectomy. Microscopically, multifocal tumor cells were found in the mucosa and submucosa; tumor cells were organoid and arranged in nests and cords, and the stroma was rich in sinusoids. The surrounding gastric mucosa showed atrophy with mild intestinal metaplasia or pseudopyloric gland metaplasia. Neuroendocrine cells could be seen with diffuse linear, nodular, and adenomatous hyperplasia. Immunohistochemically, the tumor cells diffusely expressed cytokeratin, chromogranin, synaptophysin, and CD56. Whole-genome high-throughput molecular sequencing revealed a pathogenic germline mutation in the BRCA2 gene, a heterozygous germline frameshift mutation in exon 11, c.6443_6444del (p.S2148Yfs*2). The final diagnosis was gastric type 1 ECL-cell NETs with a BRCA2 gene germline mutation, accompanied by autoimmune gastritis.

CONCLUSION

This is the first report of a case of type 1 gastric ECL-cell NETs with a pathogenic germline mutation of the BRCA2 gene. The findings of this report will expand the germline mutation spectrum of gastric NETs and increase the understanding of the molecular changes present in these tumors for their improved diagnosis in the future.

Clinicopathological characteristics of autoimmune gastritis: A single-center retrospective study

BACKGROUND AND AIM

Autoimmune gastritis (AIG) is a prominent risk factor for pernicious anemia (PA) and gastric neoplasia. This study aimed to investigate the clinicopathological characteristics of AIG patients in China, with a focus on those who had positive anti-intrinsic factor antibodies (AIFA).

METHODS

A total of 103 AIG patients who were diagnosed between January 2018 and August 2022 were reviewed in a large academic tertiary teaching hospital. Patients were divided into two groups based on the presence or absence of AIFA, and their serologic and histopathological characteristics were analyzed.

RESULTS

The mean age of the 103 AIG patients was 54.16±11.92 years (range 23-79), with 69 (66.99%) being women. AIFA were present in 28.16% of patients. Patients with AIFA-positive had a higher risk of PA than those with AIFA-negative, as demonstrated by a larger mean corpuscular volume (MCV), lower hemoglobin level, and lower vitamin B-12 level (P<0.05). There were no statistically significant differences in gastric histopathology, gastrin level, and pepsinogen level when patients were divided into AIFA-positive and AIFA-negative group. Of the 103 cases, 34 (33.01%) were concomitant with other autoimmune diseases, with autoimmune thyroid diseases being the most common (25.24%, 26/103). Thyroid peroxidase antibody, which accounted for 45.45% (25/55), was the most prevalent thyroid antibody, followed by anti-thyroglobulin antibody (34.55%, 19/55), thyroid stimulating antibody (12.73%, 7/55), and thyrotropin receptor antibody (3.64%, 2/55).

CONCLUSION

This study highlights the increased risk of severe anemia in AIFA-positive AIG patients, particularly for PA. Clinicians should consider the presence of AIFA as a warning sign for PA and prioritize early diagnosis and appropriate treatment to prevent serious complications.

Update in Molecular Aspects and Diagnosis of Autoimmune Gastritis

Recent studies have advanced our understanding of the pathophysiology of autoimmune gastritis, particularly its molecular aspects. The most noteworthy recent advancement lies in the identification of several candidate genes implicated in the pathogenesis of pernicious anemia through genome-wide association studies. These genes include PTPN22, PNPT1, HLA-DQB1, and IL2RA. Recent studies have also directed attention towards other genes such as ATP4A, ATP4B, AIRE, SLC26A7, SLC26A9, and BACH2 polymorphism. In-depth investigations have been conducted on lymphocytes and cytokines, including T helper 17 cells, interleukin (IL)-17A, IL-17E, IL-17F, IL-21, IL-19, tumor necrosis factor-α, IL-15, transforming growth factor-β1, IL-13, and diminished levels of IL-27. Animal studies have explored the involvement of roseolovirus and H. pylori in relation to the onset of the disease and the process of carcinogenesis, respectively. Recent studies have comprehensively examined the involvement of autoantibodies, serum pepsinogen, and esophagogastroduodenoscopy in the diagnosis of autoimmune gastritis. The current focus lies on individuals demonstrating atypical presentations of the disease, including those diagnosed in childhood, those yielding negative results for autoantibodies, and those lacking the typical endoscopic characteristics of mucosal atrophy. Here, we discuss the recent developments in this field, focusing on genetic predisposition, epigenetic modifications, lymphocytes, cytokines, oxidative stress, infectious agents, proteins, microRNAs, autoantibodies, serum pepsinogen, gastrin, esophagogastroduodenoscopy and microscopic findings, and the risk of gastric neoplasm.

Histopathologic diagnosis of ultra-early autoimmune gastritis: A case report

We describe an ultra-early stage of autoimmune gastritis (AIG) that occurs prior to the well-known early-stage AIG. The key pathology is the shortening of the second layer with degenerated parietal cells. In the management of patients with autoimmune diseases, AIG should be considered even if the endoscopy findings are normal.

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.

Diagnostic criteria and endoscopic and histological findings of autoimmune gastritis in Japan

The Japanese diagnostic criteria for autoimmune gastritis (AIG) were established by the "Study Group on the establishment of diagnostic criteria for type A gastritis," which is related to a workshop associated with the Japan Gastroenterological Endoscopy Society (JGES) and the Committee of AIG Research Group (CARP). The criteria were set as follows: the cases of confirmed diagnosis are patients in whom either the endoscopic or histological findings, or both, meet the requirements for AIG and who are confirmed to be positive for gastric autoantibodies (either anti-parietal cell or anti-intrinsic factor antibodies, or both). The presentation of endoscopic findings of early-stage AIG in the diagnostic criteria was withheld owing to the need for further accumulation and characterization of endoscopic clinical data. Therefore, diagnosis of early-stage AIG only requires histological confirmation and gastric autoantibody positivity. Suspected cases are patients in whom either the endoscopic or histological findings, or both, meet only the requirements for AIG. Histological findings only meet the requirements for early stage. AIG has been underdiagnosed in the past, but our study group's newly proposed diagnostic criteria will enable a more accurate and early diagnosis of AIG. The criteria can be used to stratify patients into various high-risk groups for gastric tumors and pernicious anemia. They would allow the establishment of an appropriate surveillance system in the coming years. Nevertheless, issues such as establishing the endoscopic findings of early-stage AIG and obtaining Japanese insurance coverage for gastric autoantibody tests require attention.

Incidence of Gastric Neoplasms Arising from Autoimmune Metaplastic Atrophic Gastritis: A Systematic Review and Case Reports

Autoimmune metaplastic atrophic gastritis (AMAG) is associated with an increased risk of gastric neoplasms. This study aimed to systematically analyze the incidence rate of gastric cancer (GC), low-grade dysplasia (LGD) and type-1 gastric neuroendocrine tumor (gNETs) development in AMAG adults. Studies on AMAG patients reporting the incidence of gastric neoplasms was identified through a systematic search in PUBMED and EMBASE. Study quality was assessed using the Joanna Briggs Institute quality assessment tool. Incidence rates of GC, LGD and type-1 gNETs were examined by meta-analysis. Thirteen studies met eligibility criteria. Incidence rate of gastric cancer calculated from the pooled data was 0.14% per person-year in both single-center studies and national registration studies. Meta-analysis showed a relative risk of 11.05 (95% CI: 6.39-19.11) for gastric cancer development in AMAG patients. The calculated pooled gastric LGD and type-1 gNETs incidence rates were 0.52% and 0.83% per person-year, respectively. As for experience from our center, we presented three distinctive cases of gastric neoplasm arising from the background of AMAG. This study underscores the potential for malignant transformation of precancerous lesions and reiterates the importance of careful esophagogastroduodenoscopy screening.

Examining the Diagnosis and Treatment Experiences of People Living With Autoimmune Gastritis and Pernicious Anemia

There is limited research evaluating the diagnosis and treatment of patients with autoimmune gastritis (AIG) and pernicious anemia (PA). We used a 2-phase data collection process to examine the literature and individual patient accounts. Phase one comprised a systematically conducted literature review focusing on diagnosis and treatment, relationships with healthcare practitioners and health-related quality of life (HRQOL). Phase two involved analysis of individual accounts via posts in online patient forums. We identified 6 main themes: the diagnosis journey, seeking treatment, patient-provider relationships, HRQOL, patient disempowerment, and the "expert patient." Our findings confirm significant knowledge gaps concerning AIG/PA across the healthcare community. These have a cascading effect starting with delays in diagnosis and poor treatment protocols and often lead to complete withdrawal from care seeking. The establishment of standard consensus guidelines and improved clinical awareness should be urgently addressed. Interventions that better help patients understand their illness are also needed to improve psychological health. Without these changes disengagement from health systems, and poor health outcomes, will continue for this population group.

Gastric lesions in patients with autoimmune metaplastic atrophic gastritis: a retrospective study in a single center

OBJECTIVES

The presence of autoimmune metaplastic atrophic gastritis (AMAG) may lead to an increased risk of associated gastric neoplastic lesions. This study aims to investigate the prevalence of gastric neoplasia in AMAG patients and to explore the possibility of PGI/II ratio as a predictor for AMAG diagnosis.

PATIENTS AND METHODS

Retrospective audit of 135 patients diagnosed with AMAG on endoscopic gastric biopsy between January 2017 and December 2020 at Beijing Friendship Hospital. The study was registered in Chinese Clinical Trial Registry (ChiCTR2000041163).

RESULTS

A total of 135 patients (the mean age 61.9 ± 10.9 years,109 female) had histologically confirmed AMAG. 31.1% (42/135) had AMAG without neoplasia on the initial biopsy; 37% (50/135) had multiple type 1 gastric neuroendocrine tumors (g-NETs), 36 grade 1 and 14 grade 2, the median diameter was 5 mm (range 1-25); 31.9% (43/135) had multiple gastric hyperplastic polyps (GHPs), including 15 cases of GHPs with neoplastic transformation, the median diameter was 14.5 mm (range 3-50). 3.7% (5/135) had single gastric low-grade dysplasia/adenoma, the median diameter was 5 mm (range 3-15). 5.9% (8/135) had single or double gastric high-grade dysplasia or adenocarcinoma, the median diameter was 15 mm (range 8-43). 40.7% (55/135) had pepsinogen (PG) I< 10 ng/ml, 45.9% (62/135) had PG I/II ratio ≤1 and each group had a median of PG I/II ratio <1.

CONCLUSIONS

Lower serum PG I level and PGI/II ratio may be a predictor to indicate the diagnosis of AMAG. It's necessary to perform regular endoscopic surveillance for AMAG patients to recognize associated gastric neoplasia timely.

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.

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.

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.

[Clinical management of autoimmune gastritis]

Autoimmune gastritis (AIG) is a chronic immune-mediated inflammation of the gastric corpus/fundus mucosa leading to progressive atrophy of the oxyntic gastric glands (AOM) and their consecutive loss of function. Possible clinical consequences of AIG include iron deficiency anemia, pernicious anemia, gastric neuroendocrine tumors (gNET), and gastric adenocarcinoma. This article provides a review of interdisciplinary aspects of the diagnosis and treatment of AIG.

Evaluation of screening tests for autoimmune gastritis in histopathologically confirmed Japanese patients, and re-evaluation of histopathological classification

Background

The aims of the present study are to evaluate non-invasive screening tests for autoimmune gastritis (AIG) and re-evaluate histopathological classification.

Methods

We screened candidates of AIG in JCHO Shiga Hospital between May 2012 and January 2020. The screening criteria were as follows: endoscopic O-p atrophy with Updated Kimura–Takemoto classification, 3 + pepsinogen (PG) test, low serum vitamin B₁₂ or elevated serum gastrin with positive anti-parietal cell (PC) or intrinsic factor antibodies. We evaluated the screening criteria in the patients who were histopathologically confirmed as AIG, and re-evaluated histopathological staging in clinical aspects.

Results

Twenty-two of 28 (78.6%) patients who met the screening criteria were histopathologically confirmed as AIG. Common clinical findings in the AIG patients were 10 × or greater anti-PC antibody, elevated serum gastrin greater than 172 pg/mL and endoscopic atrophy O-1 or greater. The areas under the curve of PG I, PG II and PG I/II ratio were 0.81, 0.29 and 0.98, respectively. Among histopathologically confirmed AIG patients, 4 and 18 patients were histopathologically classified into florid and end stages, respectively, while no patients into early stage. We could not find a significant difference between florid and end stages in the screening items studied.

Conclusions

Florid and end stages in histopathological classification are both advanced-stage AIG in clinical aspects. Our screening criteria without biopsy are applicable to screen clinically-advanced AIG with 78.6% positive predictive value. PG I and PG I/II ratio may be useful to screen AIG. However, we may need other criteria to screen early stage of AIG.

An Evaluation of Endoscopic Images from Over 15 Years Prior to the Diagnosis of Autoimmune Gastritis: A Report of Three Patients

We herein describe three patients whose endoscopic images from over 15 years prior to their diagnosis of autoimmune gastritis (AIG) were available for review. All patients had corpus-dominant atrophic gastritis at the time of the diagnosis of AIG. Previous endoscopic images without severe atrophy showed erythema restricted to the fundic mucosa. These findings are suggestive of ongoing gastritis in patients with AIG. Initial endoscopy in Patient 2 showed multiple hyperplastic polyps that decreased in size and number over the course of 15 years. In this patient, circular wrinkle-like patterns and remnant oxyntic mucosa were visible after the atrophy had become quite prominent.

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.

Early autoimmune gastritis presenting with a normal endoscopic appearance

This report describes a patient with early-stage autoimmune gastritis (AIG) presenting with a normal endoscopic appearance. A 66-year-old man with autoimmune thyroiditis was suspected of having AIG because of a previous history of vitamin B12 deficiency when receiving steroid therapy for interstitial pneumonia 5 years earlier. At presentation, he tested positive for anti-parietal cell antibody (1:320) and anti-intrinsic factor antibody, but not for vitamin B12 deficiency. His gastrin level was elevated (338 pg/mL), but his pepsinogen (PG) I level (56.1 ng/mL) and PGI/PGII ratio (7.6) were normal. Endoscopically, neither atrophic nor inflammatory changes were observed. Histopathologic examination, however, showed mild atrophic changes with dense lymphocytic infiltration in the deep lamina propria and focal destruction of parietal cells in the greater curvature of the corpus. PGI-positive/MUC6-positive pseudo-pyloric metaplasia was observed in the area from which H⁺/K⁺-ATPase-positive parietal cells had disappeared. Chromogranin A immunostaining showed linear hyperplasia of enterochromaffin-like cells. By contrast, atrophic changes were not evident in the lesser curvature of the corpus, except for mild lymphocytic infiltration around and into the fundic glands. These serological and histopathological findings suggested that the patient had early-stage AIG with a normal endoscopic appearance.

Autoimmune gastritis induces aberrant DNA methylation reflecting its carcinogenic potential

BACKGROUND

Autoimmune gastritis (AIG) is a chronic inflammatory condition in gastric mucosa and is associated with increased cancer risk, though not as high as that by Helicobacter pylori (H. pylori)-associated gastritis (HPG). Although aberrant DNA methylation is induced by HPG and the level correlates with the risk of gastric cancer, DNA methylation induction by AIG is unknown.

METHODS

Gastric mucosa samples from the corpus were collected from 12 people with AIG without H. pylori infection, 10 people with HPG, and eight healthy volunteers. Genome-wide DNA methylation analysis was conducted using Infinium Methylation EPIC array. Gene expression was analyzed by quantitative RT-PCR.

RESULTS

The AIG samples had extensive aberrant DNA methylation but presented unique methylation profiles against the HPG samples after correction of leucocyte fractions. Comparison between the AIG and HPG samples showed that AIG induced methylation, but less than HPG, in overall CpG sites and also in promoter CpG islands. Promoter CpG islands of tumor-suppressor genes in the pathway of cell cycle, cell adhesion, p53, and WNT were highly methylated in the AIG samples, but more so in the HPG samples. The expression levels of IL1B and IL8, secreted by macrophage, were significantly lower in the AIG samples than in the HPG samples, suggesting that a difference in inflammatory response affected the degree and patterns of aberrant DNA methylation.

CONCLUSIONS

AIG induced aberrant DNA methylation in gastric mucosa. However, the degree of DNA methylation was less than that by HPG, which reflected carcinogenic risk.

The role of advanced endoscopy in the management of inflammatory digestive diseases (upper gastrointestinal tract)

The Japan Gastroenterological Endoscopy Society held four serial symposia between 2019 and 2020 on the state-of-the-art of issues related to upper GI inflammatory diseases. This review discusses some of the topics addressed in these symposia. The papers regarding nonerosive reflux disease, recent improvements in intraesophageal pH-impedance monitoring and endoscopic diagnosis using image-enhanced endoscopy have been published. Many publications have addressed its usefulness in endoscopic treatment of gastroesophageal reflux disease such as anti-reflux mucosectomy. In the management of eosinophilic esophagitis, since the symptoms are subjective, objective indicators have been sought, and ultrasonography and high-resolution manometry may be useful tools for evaluation. The natural course of this condition, especially of asymptomatic cases, is not well clarified. Some newly developed anti-acid or anti-inflammatory medicines are now under investigation. With regard to autoimmune gastritis, because of widespread medical examinations, diagnosis of asymptomatic cases has been increasing. Recently, its endoscopic characteristics have become clear and the natural history of these conditions is being elucidated. The Kyoto Classification of Gastritis has been reported to be useful not only for Helicobacter pylori diagnosis but also for identification of risks of gastric cancer. Its usefulness is now recognized in Asia and Europe.

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.

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.

Helicobacter pylori-Induced Inflammation: Possible Factors Modulating the Risk of Gastric Cancer

Chronic inflammation and long-term tissue injury are related to many malignancies, including gastric cancer (GC). Helicobacter pylori (H. pylori), classified as a class I carcinogen, induces chronic superficial gastritis followed by gastric carcinogenesis. Despite a high prevalence of H. pylori infection, only about 1–3% of people infected with this bacterium develop GC worldwide. Furthermore, the development of chronic gastritis in some, but not all, H. pylori-infected subjects remains unexplained. These conflicting findings indicate that clinical outcomes of aggressive inflammation (atrophic gastritis) to gastric carcinogenesis are influenced by several other factors (in addition to H. pylori infection), such as gut microbiota, co-existence of intestinal helminths, dietary habits, and host genetic factors. This review has five goals: (1) to assess our current understanding of the process of H. pylori-triggered inflammation and gastric precursor lesions; (2) to present a hypothesis on risk modulation by the gut microbiota and infestation with intestinal helminths; (3) to identify the dietary behavior of the people at risk of GC; (4) to check the inflammation-related genetic polymorphisms and role of exosomes together with other factors as initiators of precancerous lesions and gastric carcinoma; and (5) finally, to conclude and suggest a new direction for future research.

Two Different 1-Week Quadruple Therapies Given Back-to-Back Consecutive Therapy for Difficult-to-Treat Helicobacter pylori Infection: A Pilot Study

INTRODUCTION

We aim to evaluate the efficacy of 2 different 1-week quadruple therapies given back-to-back consecutive therapy in patients with difficult-to-treat Helicobacter pylori infection.

METHODS

Patients with proven H. pylori infection were recruited after >3 failed standard quadruple eradication. They received consecutive therapy consisting of esomeprazole 40 mg or rabeprazole 20 mg twice daily, amoxicillin 1,000 mg twice daily, tetracycline 500 mg 4 times daily, and furazolidone 100 mg 3 times daily for the first 7 days, followed by colloidal bismuth pectin 200 mg twice daily in place of furazolidone 100 mg for another 7 days. Eradication rates, treatment-emergent adverse events (TEAEs), and compliance were assessed.

RESULTS

Sixty-five patients were enrolled. The mean number of previous eradications was 3.6 (range: 3-7). The intention-to-treat and per-protocol eradication rates were 90.8% (59/65) and 95.1% (58/61). In total, 23.4% (15/64) of patients experienced drug-related TEAEs. No serious adverse events were observed. None of the patients required treatment for TEAEs, and 95.3% (61/64) showed good compliance. Overall, 51 patients (78.5%) were with the available antimicrobial susceptibility testing results. The resistance rates to clarithromycin, metronidazole, levofloxacin, and amoxicillin were 60.8% (31/51), 100% (51/51), 70.6% (36/51), and 2.0% (1/51), respectively. No resistance was detected to either furazolidone or tetracycline. However, in 54.9% of patients (28/51), H. pylori was resistant to 3 antibiotics (metronidazole, levofloxacin, and clarithromycin).

DISCUSSION

Consecutive therapy, including amoxicillin, tetracycline, and furazolidone, achieved a good eradication rate (>90%), with desirable compliance and tolerability in difficult-to-treat H. pylori infection.

Autoimmune Gastritis With Progression of Leukemic Non-Nodal Mantle Cell Lymphoma

The pathogenesis of autoimmune gastritis (AIG) remains unclear. In addition, it is difficult to follow the process of AIG onset endoscopically. Leukemic non-nodal mantle cell lymphoma (MCL) was newly added as a subtype of MCL in the fourth revised edition of the World Health Organization (WHO) classification (2017). Here, we report a case of AIG associated with the progression of leukemic non-nodal MCL. A 74-year-old woman who had been followed up in a nearby hospital for chronic B-cell lymphoproliferative disorder with no treatment for six years presented with fever and fatigue in the previous one month. The patient was admitted to our department and was diagnosed with leukemic non-nodal MCL. Positron emission tomography-computed tomography examination, which indicated no abnormalities in the six preceding years, revealed uptake in the bone marrow and spleen. Since MCL was progressing, esophagogastroduodenoscopy (EGD), which showed almost no abnormal findings in the gastric mucosa 13 preceding months, was conducted again to search for lesions involving gastrointestinal MCL. Lymphoma lesions were not found, but wide atrophic mucosal changes in the stomach were revealed mainly in the corpus, and patchy redness was also observed in the pylorus, consistent with AIG. The patient tested positive for an anti-gastric parietal cell antibody (×80), her gastrin level was significantly elevated (5,280 pg/mL), and her pepsinogen (PG) I/PG II was considerably less than 1.0 (>3.1). Although no pathological confirmation was obtained by biopsy, the patient was clinically diagnosed with AIG. In our patient, AIG was revealed to be associated with the progression of leukemic non-nodal MCL in this short period.

Endoscopic and Upper Gastrointestinal Barium X-ray Radiography Images of Early-stage Autoimmune Gastritis: A Report of Two Cases

We herein report two patients with early-stage autoimmune gastritis who did not exhibit complete atrophy. Endoscopic examinations showed no manifestations of severe atrophic gastritis, but revealed a mosaic pattern with slight swelling of the areae gastricae restricted to the corpus in both patients. In the patient in case 2, upper gastrointestinal barium X-ray radiography revealed a slightly protruded irregular areae gastricae throughout the gastric body, except for in the antrum. Our findings emphasize the need for clinicians to recognize that autoimmune gastritis might be present in the absence of severe atrophic gastritis; this can aid in the identification of the early stages of autoimmune gastritis.

Does Helicobacter pylori infection affect the structure of bacteria in the gastric mucosa and fluid in patients with chronic antral gastritis?

This study aimed to evaluate the composition of the gastric microbiota in the gastric mucosa and gastric fluid of patients with chronic antral gastritis. Specifically, we sought to determine whether Helicobacter pylori (Hp) infection changes the bacterial community in the gastric mucosa or alters the microbiota in the gastric fluid. The bacterial community at another site in the stomach was also investigated. DNA was extracted from 160 samples collected from 40 patients with chronic antral gastritis (20 Hp-positive and 20 Hp-negative cases). Three tissue samples of the gastric mucosa (gastric angle, body, and antral mucosa) and one tube of gastric fluid were collected from every patient. A 16S rRNA amplification library was created, and high-throughput sequencing was performed. A profile of the community composition was obtained using bioinformatics methods, including cluster, taxonomy, and diversity analyses. Analysis of the gastric bacterial community revealed that the community compositions of the gastric mucosa and gastric fluid of patients without Hp are similar to but show differences from those of Hp-positive patients. The microbiota in Hp-positive patients exhibited reduced microbial diversity, and the gastric fluid of these patients contained a small proportion of Hp. The richness of Leptotrichia in mucosal samples was greater than that in gastric fluid samples from Hp-negative patients with chronic antral gastritis. Hp changes the growth of other microbiota in the mucosa and affects the microbiota in the gastric fluid of patients with chronic antral gastritis. In addition to Hp, the presence of other bacteria might be related to the development of chronic antral gastritis.

Autoimmune gastritis concomitant with gastric adenoma and subacute combined degeneration of the spinal cord

A 62-year-old woman was referred to our department for further investigation of anaemia. Blood test showed macrocytic anaemia. Oesophagogastroduodenoscopy (OGD) revealed proximal-predominant gastric atrophy and flat elevated lesion in the gastric body. Several days after OGD, she complained of gait disturbance and was diagnosed with subacute combined degeneration of the spinal cord. Furthermore, laboratory tests showed positive for both anti-parietal cell and anti-intrinsic factor antibodies, as well as increased serum gastrin level and decreased pepsinogen I level, which confirmed the diagnosis of autoimmune gastritis (AIG). Anaemia and neurological symptoms were improved after vitamin B₁₂ supplementation. Subsequently, the patient underwent gastric endoscopic submucosal dissection; histopathological examination revealed gastric adenoma. AIG can cause gastric neoplasms and vitamin B₁₂ deficiency, with the latter resulting in pernicious anaemia and neurological disorders. These diseases are treatable but potentially life-threatening. This case highlights the importance of early diagnosis of AIG and proper management of its comorbidities.

Gastric Hyperplastic Polyps after Argon Plasma Coagulation for Gastric Antral Vascular Ectasia in Patients with Liver Cirrhosis: A Case Suggesting the "Gastrin Link Theory"

We herein report a case of gastric hyperplastic polyps after argon plasma coagulation (APC) for gastric antral vascular ectasia (GAVE) in the antrum of a 65-year-old man with liver cirrhosis and hypergastrinemia induced by long-term proton pump inhibitor (PPI) use. Two years after APC therapy, endoscopy demonstrated multiple gastric polyps in the antrum and angle. A gastric polyp biopsy indicated foveolar epithelium hyperplasia, which was diagnosed as gastric hyperplastic polyps. One year after switching to an H2 blocker antagonist, endoscopy revealed that the polyps and GAVE had disappeared, with normal gastrin levels suggesting that PPI-induced hypergastrinemia had caused gastric hyperplastic polyps after APC therapy, and the polyps had disappeared after discontinuing PPIs.

Helicobacter pylori-negative Gastric Cancer

<i>Helicobacter pylori (H. pylori)</i>-negative gastric cancer is diagnosed when gastric malignancies are found in patients in <i>H. pylori</i>-naïve stomachs. There are four types of noncardiac <i>H. pylori</i>-negative gastric cancers. The signet ring cell-type poorly cohesive carcinoma is most common, followed by the chief cell-predominant type gastric adenocarcinoma of the fundic gland. Extremely well-differentiated adenocarcinoma of the corpus and well-differentiated pyloric gland cancers are rare outside Japan because of country-specific differences in diagnostic criteria. In endemic areas of <i>H. pylori</i> infection, strict criteria are required for diagnosing an <i>H. pylori</i>-naïve stomach. Both invasive and noninvasive <i>H. pylori</i> tests should show negative results in a subject without a history of <i>H. pylori</i> infection. Furthermore, the serum pepsinogen (PG) assay and endoscopic findings of the background gastric mucosa are required to discriminate subjects with past infections owing to spontaneous regression or unintended eradication of <i>H. pylori</i>. There should be no gastric corpus atrophy (PG I ≤70 ng/mL and PG I/II ≤3.0). Gastroscopy should reveal a regular arrangement of collecting venules without gastric xanthoma, metaplastic gastritis, or advanced atrophy over the angle. On biopsy, there should be no gastric atrophy, intestinal metaplasia, neutrophils, or <i>H. pylori</i> infiltration, and only a mild degree of mononuclear cell infiltration is permitted. The types and characteristics of noncardiac <i>H. pylori</i>-negative gastric cancers are summarized in this review, along with current diagnostic challenges found in Korea.

A case of early autoimmune gastritis with characteristic endoscopic findings

Significant atrophic gastritis in the fundic gland region is a well-known endoscopic finding observed in autoimmune gastritis (AIG). The endoscopic features of early AIG have not been reported. Iron deficiency, vitamin B₁₂ deficiency, anemia, or neurological symptoms may not be observed in the early stages of AIG, and it may thus be difficult to diagnose early AIG based on clinical findings. We treated a 50-year-old Japanese female whose condition was suspected to be early AIG. The endoscopic findings showed normal gastric pyloric gland mucosa, and diffuse reddened and edematous gastric fundic gland mucosa. Pathologically, local infiltration of lymphocytes and decrease of parietal cells was present in a deep part of the gastric fundic gland mucosa. Blood tests showed that the titer of parietal cell antibody (PCA) was 1:320 and the gastrin level was 820 pg/ml. We determined that the patient had AIG because she also had Hashimoto’s disease, the PCA titer was high, the serum gastrin level was slightly increased, and inflammation was observed only in the gastric body on the endoscopic images. To the best of our knowledge, this is the first case report of endoscopic findings that suggest early AIG, before atrophic changes were observed.