High incidence of autoimmune gastritis in patients misdiagnosed with two or more failures of H. pylori eradication

Risk Factors Analysis and Predictive Model Construction for Autoimmune Gastritis: A Nationwide Multicenter Case-Control Study in China

OBJECTIVE

Here, we ascertained the clinical characteristics of Chinese patients with autoimmune gastritis (AIG) and determined the correlation of dietary and lifestyle factors with AIG occurrence and development to establish a noninvasive predictive model for AIG.

METHODS

In this case-control study, we enrolled 479 patients from seven independent centers nationwide in China; of them, 279 had AIG, 112 had chronic atrophic gastritis mostly in the antrum, and 88 had chronic nonatrophic gastritis. Their clinical and lifestyle data were systematically collected and analyzed. Finally, a multivariate logistic regression disease prediction model was then established and validated.

RESULTS

Most of the 279 patients with AIG were middle-aged, older, and female. In the predictive model of AIG, the larger amount of cooking oil used per meal and comorbid autoimmune thyroid disease was considered risk factors, and a diet rich in vitamin B12 was considered a protective factor. We plotted a receiver operating characteristic (ROC) curve of the model in the discovery and validation cohorts, and the areas under the ROC curves were 0.72 and 0.74, respectively. In addition, dietary structure, eating habits, sleep quality, and smoking status were noted to be correlated with the occurrence of gastrointestinal symptoms and complications, as well as histopathological grades of AIG.

CONCLUSION

Dietary and lifestyle factors may predict AIG risk in Chinese populations and were related to AIG prognosis.

Gastric cancer in patients with Helicobacter pylori-negative autoimmune gastritis

Although Helicobacter pylori (H. pylori) is implicated in the development of most cases of gastric cancer with autoimmune gastritis, cases of gastric cancer have been reported in patients testing negative for H. pylori. Here, we aimed to outline the current research status of the factors involved in the development of gastric cancer in H. pylori-negative autoimmune gastritis. Predictive pathological conditions for the development of gastric cancer in H. pylori-negative autoimmune gastritis are postulated to be: (1) Severe atrophy; (2) Hypergastrinemia; (3) Bile reflux; and (4) Low acidity, which are directly related to the pathophysiology of autoimmune gastritis, as well as smoking and family history, which are not related to autoimmune gastritis. In autoimmune gastritis, where there is a possibility of spontaneous disappearance of H. pylori in advanced atrophy, it is difficult to assess H. pylori. Since H. pylori infection begins in the antrum and subsequently progresses to the proximal stomach, it is interpreted as H. pylori-negative autoimmune gastritis if histologically consistent with autoimmune gastritis in the body with spared antrum, and negative for other H. pylori tests. However, it is essential to examine whether the currently prevailing histological interpretation used to evaluate H. pylori infection status is appropriate.

Enhanced activity of autoimmune gastritis following Helicobacter pylori eradication therapy

The relationship between autoimmune gastritis (AIG) and Helicobacter pylori (H. pylori) gastritis remains unclear, particularly whether there is any interaction. Herein, we report a case of early-stage AIG diagnosed in an elderly patient with highly active H. pylori gastritis, who subsequently underwent eradication therapy. We were able to follow the changes in these two types of gastritis immediately before and after eradication therapy, through observation over a period of 5 years and 5 months. Despite the previous state of predominant H. pylori gastritis, eradication therapy led to rapid exacerbation of atrophic changes, which was especially evident in endoscopic findings. In addition, the anti-parietal cell antibody titer increased constantly from 1:320 to 1:1280. We concluded that AIG activity was enhanced compared to that before eradication therapy. This course suggests the following two possibilities: early-stage AIG may have progressed steadily regardless of H. pylori gastritis status, or its activity may have been suppressed until the time of eradication therapy.

Parietal Cell Antibody Levels Among Chronic Gastritis Patients in a Country With Low Helicobacter pylori Infection: Epidemiology, Histopathological Features, and H. pylori Infection

BACKGROUND

Despite the low prevalence of Helicobacter pylori in Indonesia, the high incidence of gastritis, predominantly atrophic gastritis, suggests that factors such as autoimmune gastritis (AIG) contribute to this unusual pattern. This study aims to investigate the epidemiology of AIG, histopathology, and its association with H. pylori status in Indonesia.

METHODS

A cross-sectional study was conducted in various regions in Indonesia between 2014 and 2017; 380 eligible sera and gastric biopsies were available when this study was conducted. As many as 138 sera samples were included in this study based on the initial examination by the updated Sydney system. The diagnosis of AIG was confirmed by serologic testing for parietal-cell antibodies (PCA) and detailed histopathological assessment with sparing of antrum histopathological features.

RESULTS

Among the included samples in this study, 78.99% (109/138) were PCA positive (≥ 10 RU/mL) and 0.72% (1/138) were considered to be diagnosed as AIG (spared from antrum histopathological features). The majority of PCA positive cases were H. pylori positive (61/109; 55.96%) with a significant correlation (p < 0.05, R = 0.31). Additionally, a significant association was found between H. pylori infection and PCA level with gastric histopathological features (p < 0.05).

CONCLUSION

This study demonstrates that the incidence of gastritis without H. pylori infection in Indonesia is not attributable to AIG, as only a single AIG-positive case was found. These findings underscore the important role of H. pylori as a pathogenic factor in chronic gastritis and highlight its mechanisms in triggering immune responses and driving disease progression and histopathological changes.

Intragastric bacterial infection and endoscopic findings in Helicobacter pylori-negative patients

In the present study, the authors examined the association between gastric bacterial infection and gastric endoscopic findings in Helicobacter pylori (H. pylori)-negative patients. The subjects were 105 H. pylori-negative patients. The mean age was 72.8 ± 9.1 years. Endoscopy and gastric juice culture were performed. The presence or absence of endoscopic findings was checked according to the Kyoto classification of gastritis. Culture was positive in 69 patients (65.7%), with Streptococcus α-hemolytic being the most common (51 patients), followed by Neisseria sp. (43 patients). According to the univariate analysis, there was a significant difference between the results of culture and background factors in the use of gastric antisecretory drugs and between the results of culture and various endoscopic findings in atrophic gastritis, intestinal metaplasia, regular arrangement of collecting venule, mucosal swelling, sticky mucus, hyperplastic polyps, hematin, and gastric cobblestone-like lesions. Furthermore, multivariate analysis revealed significant differences in background factors such as the use of gastric antisecretory drugs and endoscopic findings only in patients with mucosal swelling. Endoscopic findings of non-H. pylori bacteria-positive gastritis differed from endoscopic findings of H. pylori-infected gastritis in several respects. In conclusion, our results suggest that non-H. pylori bacteria may infect the stomach and cause gastric inflammation, especially in patients who long term use gastric antisecretory drugs.

Characterization of cytotoxic Citrobacter braakii isolated from human stomach

Citrobacter braakii (C. braakii) is an anaerobic, gram-negative bacterium that has been isolated from the environment, food, and humans. Infection by C. braakii has been associated with acute mucosal inflammation in the intestine, respiratory tract, and urinary tract. However, the pathogenesis of C. braakii in the gastric mucosa has not yet been clarified. In this study, the bacterium was detected in 35.5% (61/172) of patients with chronic gastritis (CG) and was closely associated with the severity of mucosal inflammation. Citrobacter braakii P1 isolated from a patient with CG exhibited urease activity and acid resistance. It contained multiple secretion systems, including a complete type I secretion system (T1SS), T5aSS and T6SS. We then predicted the potential pilus-related adhesins. Citrobacter braakii P1 diffusely adhered to AGS cells and significantly increased lactate dehydrogenase (LDH) release; the adhesion rate and LDH release were much lower in HEp-2 cells. Strain P1 also induced markedly increased mRNA and protein expression of IL-8 and TNF-α in AGS cells, and the fold increase was much higher than that in HEp-2 cells. Our results demonstrate proinflammatory and cytotoxic role of C. braakii in gastric epithelial cells, indicating the bacterium is potentially involved in inducing gastric mucosa inflammation.

Autoimmune gastritis

Diagnosis of autoimmune gastritis (AIG) is often challenging because of the absence of typical symptoms. Clinical guidelines are lacking, which results in inadequate treatment and poor cancer screening. This work presents an overview of current management options and aims at raising awareness for this disease. The paper also describes a clinical case of the full-scale course of AIG with all its complications. Autoimmune gastritis is mostly considered as a disease of elderly with vitamin B12 deficiency and pernicious anaemia. Today it is recognized that AIG is found with a similar prevalence in all age groups, with iron deficiency being a frequent symptom. Conventional therapy consists of adequate iron and vitamin B12 supplementation, as well as symptomatic approaches. The associated risk for gastric adenocarcinoma and gastric neuroendocrine tumours requires regular endoscopic follow-up. New treatments aiming to reduce gastric atrophy and cancer risk are currently under development. Thus, treatment of autoimmune gastritis should focus on optimizing supplementation of vitamin and macronutrient deficiencies, symptomatic therapy that improves quality of life, and include cancer prevention measures. Clinical studies should address the possibility to arrest the inflammation process and to prevent progression of AIG. The author of the article suggests that itopride hydrochloride and rebamipide will be used for symptomatic and pathogenetic therapy. The problem facing gastroenterologists today is to develop domestic guidelines for the management and screening endoscopic intervals of patients with AIG.

Efficacy and safety of a 14-day modified concomitant therapy for refractory Helicobacter pylori infection: a pilot study

BACKGROUND AND AIM

After three treatment failures, Helicobacter pylori infection is deemed refractory as antibiotic treatment options become significantly limited. This study evaluated the efficacy and safety of a 14-day modified concomitant therapy for managing refractory H. pylori infection.

METHODS

Patients who had failed to respond to three or more rounds of H. pylori therapies were recruited for this study. They received a 14-day modified concomitant therapy, including esomeprazole 40 mg, amoxicillin 1000 mg, and furazolidone 100 mg twice daily and tetracycline 500 mg four times daily. Demographic data, adverse events, and patient compliance were recorded. The presence of H. pylori was reevaluated 6 weeks following treatment. Eradication rate was assessed as the primary outcome.

RESULTS

Overall, 59 participants received the 14-day modified concomitant therapy. In the intention-to-treat and per-protocol analyses, the eradication rate was 84.7% (50/59) and 89.3% (50/56), respectively. H. pylori was successfully isolated from 75.0% (12/16) of patients. The resistance rate of H. pylori to metronidazole, levofloxacin, and clarithromycin was 91.7% (11/12), 58.3% (7/12), and 50.0% (6/12), respectively. Resistance to amoxicillin, furazolidone, or tetracycline was not observed. The frequency of adverse events was 35.6% (21/59), with no serious adverse events reported.

CONCLUSION

The 14-day modified concomitant therapy appears to be appropriate for refractory H. pylori infection and is particularly promising for the Chinese population. A randomized controlled trial is warranted to verify its efficacy, especially in the current environment of increasing antibiotic resistance.

Case report: A pediatric case of repeated false-positive urea breath test for Helicobacter pylori without decreased gastric acid secretion

The urea breath test (UBT) is often used to diagnose Helicobacter pylori infection and for its eradication. However, this text can give positive results even for other urease-active bacteria other than H. pylori. Even after the successful eradication of H. pylori, the presence of other urease-active bacteria in the gut and oral cavity can lead to positive UBT results in patients with decreased gastric acid secretion. Herein, a 15-year-old boy was diagnosed with H. pylori infection through the testing and treatment program for H. pylori for third-year junior high-school students in Saga Prefecture initiated in 2016. He underwent triple therapy comprising vonoprazan; however, UBT was found to be positive even after therapy. The results remained positive even after fourth-line eradication therapy. Stool antigen, PCR using gastric fluid, microscopy, culture, and rapid urease tests were all negative. Pepsinogen levels were normal, and none of the findings suggested autoimmune gastritis. Gastric microflora analysis revealed oral flora showing urease activity. UBT is considered useful for determining the successful eradication of H. pylori; however, it may give false-positive results for both H. pylori infection and eradication judgment. Although the patient did not have autoimmune gastritis or decreased gastric acid secretion, it is presumed that oral commensal bacteria showing urease activity inhabited the stomach, resulting in the persistently positive UBT results. In conclusion, repeated false-positive UBT results for H. pylori may occur even without gastric acid hyposecretion. If H. pylori eradication is unsuccessful based on UBT, additional test by stool H. pylori antigen tests should be considered.

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.

Gastric adenocarcinoma of fundic gland type with autoimmune gastritis

An 87-year-old man with dysphagia presented to our hospital. He was diagnosed with autoimmune gastritis (AIG) with severe atrophy and hypergastrinemia. The patient was positive for parietal cell antibody (PCA) and anti-intrinsic factor antibody (IFA), without evidence of H. pylori infection. A flat elevated tumor was detected in the middle corpus, and therapeutic endoscopic submucosal dissection was performed. Histopathological examination revealed atypical cells mimicking the fundic glands, which were positive for pepsinogen-I and partially positive for MUC6 and H + /K + -ATPase, proliferating to the deep layer. The final diagnosis was gastric adenocarcinoma of the fundic gland type (GAFG). AIG is expected to be difficult to develop GAFG because the basal gastric glands are highly atrophic due to the production of PCA. However, some chief cells may remain and could have the potential to develop into malignancy during AIG progression. Therefore, careful observation is required in patients with AIG when considering the occurrence of GAFG.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Utility of Kyoto Classification of Gastritis in subjects with a high-negative titer of anti-Helicobacter pylori antibody during a medical check-up

Subjects with a high-negative titer (3-9.9 U/ml) of serum anti-Helicobacter pylori (H. pylori) antibody represent a heterogeneous group of currently H. pylori-infected, H. pylori-uninfected, and previously H. pylori-infected cases. We investigated the characteristics of subjects with a high-negative titer during a medical check-up and the utility of H. pylori infection score, the sum of scores of endoscopic findings based on the Kyoto Classification of Gastritis, for diagnosing H. pylori infection. Subjects with ¹³C-urea breath test-positive or H. pylori stool antigen test-positive were diagnosed as currently H. pylori-infected. Although around half of subjects with a high-negative titer were after eradication therapy (48.6%), currently H. pylori-infected were considerably confirmed (11.7%). H. pylori infection score showed a high value of area under the receiver operating characteristic curve [0.92; 95% confidence interval (CI), 0.84-1.00] with the most suitable cut-off value of 1.0 (sensitivity: 0.92; specificity: 0.90). Multivariate logistic regression analysis revealed that H. pylori infection score was an independent factor associated with increased prevalence of H. pylori infection (odds ratio, 9.53; 95% CI, 2.64-34.40; p<0.001). Currently H. pylori-infected subjects were considerably included among the subjects with a high-negative titer, and the Kyoto Classification of Gastritis was useful to predict current H. pylori infection.

Multiple Pseudopolyps Presenting as Reddish Nodules Are a Characteristic Endoscopic Finding in Patients with Early-stage Autoimmune Gastritis

We herein report two cases of autoimmune gastritis without complete atrophy of the corpus. Both were positive for anti-parietal cell antibodies. Endoscopic examinations indicated that atrophic changes were predominant in the lesser curvature of the corpus in both cases. In one, the greater curvature was covered with pseudopolyp-like nodules, whereas the greater curvature of the other showed multiple similar nodules and mildly atrophic mucosa. Histopathological examinations of these nodules showed focal and patchy atrophy and preserved fundic glands with parietal cell pseudohypertrophy. Follow-up endoscopy and a repeated biopsy demonstrated the development of gastric atrophy on the greater curvature in both cases.

Distinct Features of Autoimmune Gastritis in Patients with Open-Type Chronic Gastritis in Japan

In Asia, the incidences of Helicobacter pylori infection and gastric cancer are high, but their association with autoimmune gastritis (AIG) is unclear. This was a retrospective cohort study of patients endoscopically diagnosed with chronic gastritis between 2005 and 2017. AIG was diagnosed according to anti-parietal cell antibody positivity. Laboratory, histological findings, and gastric cancer incidence were compared between AIG and non-AIG patients. The AIG group had more females and a higher rate of thyroid disease. Serum levels of gastrin were significantly higher in AIG patients (mean 1412 and 353 pg/mL, p < 0.001). The endoscopic findings included a significantly higher percentage of corpus-dominant atrophy in AIG (31.67%) than in non-AIG (7.04%) patients (p < 0.001). Clusters of ECL cells were observed in 28% of AIG patients and 7% of non-AIG patients (p = 0.032). The cumulative incidence of gastric cancer at 5 and 10 years was 0% and 0.03% in the AIG group and 0.03% and 0.05% in the non-AIG group, and no significant difference in gastric cancer incidence was observed. Despite significant differences in gastrin levels between AIG and non-AIG patients, there was no evidence of an impact of AIG on the incidence of gastric cancer.

Epidemiological investigation of Helicobacter pylori infection in elderly people in Beijing

BACKGROUND

The Helicobacter pylori (H. pylori) infection rate in China is approximately 50%. H. pylori is a pathogenic factor of peptic ulcer and chronic gastritis. In addition, H. pylori infection may also be associated with a variety of cardiovascular diseases in elderly people, such as arteriosclerosis, coronary heart disease, and cerebral infarction, having deleterious effect on their health. With the aging of the population, the disease characteristics of the elderly population have been increasingly valued by the whole society. We conducted an epidemiological survey of H. pylori infection among elderly people in Beijing to provide a basis for health management of H. pylori infection.

AIM

To understand the epidemiological characteristics of H. pylori infection in elderly people in Beijing.

METHODS

A total of 1090 elderly people aged more than 60 years from different parts of Beijing (urban and rural areas) were selected using the random cluster sampling method. Structured questionnaires were completed during home visits and the 13C-urea breath test was conducted for H. pylori detection.

RESULTS

The prevalence of H. pylori infection was 46.5% (507/1090). The infection rate in men was 51.8%, which was significantly higher than that in women (42.5%; P < 0.05). The H. pylori infection rate in illiterate people was significantly higher than that in literate persons (53.5% vs 44.8%, P < 0.05). The total infection rate of H. pylori gradually increased with age and the difference was statistically significant (P < 0.01). The H. pylori infection rate in smokers was significantly higher than that in non-smokers and those who had quit smoking (P < 0.05).

CONCLUSION

The prevalence of H. pylori infection among elderly people is 46.5% and the infection rate gradually increases with age. Sex, education level, age, and smoking were determined to be H. pylori infection risk factors. The relationship of H. pylori infection with region, occupation, drinking, and diet structure needs to be further studied.

Rewiring of Microbiota Networks in Erosive Inflammation of the Stomach and Small Bowel

The development of non-invasive, inexpensive, and effective early diagnosis tests for gastric and small-bowel lesions is an urgent requirement. The introduction of magnetically guided capsule endoscopy (MGCE) has aided examination of the small bowel for diagnoses. However, the distribution of the fecal microbiome in abnormal erosions of the stomach and small bowel remains unclear. Herein, alternations in the fecal microbiome in three groups [normal, small-bowel inflammation, and chronic gastritis (CG)] were analyzed by metagenomics and our well-developed method [individual-specific edge-network analysis (iENA)]. In addition to the dominant microbiota identified by the conventional differential analysis, iENA could recognize novel network biomarkers of microbiome communities, such as the genus Bacteroide in CG and small-bowel inflammation. Combined with differential network analysis, the network-hub microbiota within rewired microbiota networks revealed high-ranked iENA microbiota markers, which were disease specific and had particular pathogenic functions. Our findings illuminate the components of the fecal microbiome and the importance of specific bacteria in CG and small-bowel erosions, and could be employed to develop preventive and non-invasive therapeutic strategies.

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

BACKGROUND AND AIM

In Japan, the prevalence of autoimmune gastritis (AIG) is assumed to be very low. With the recent rapid decrease in Helicobacter pylori (Hp) prevalence, reports on AIG are increasing. This multicenter registry study aimed to clarify the characteristics of AIG, especially its endoscopic appearance.

METHODS

A total of 245 patients with AIG from 11 institutions in Japan from January 2010 to October 2016 were included, and their clinical and endoscopic findings were evaluated.

RESULTS

Mean age was 67.2 ± 11.4 years, and 63.7% of the participants were women. The most common approach to diagnose AIG was endoscopic examination. Repeated incorrect treatment for Hp infection, due to a false-positive result in 13 C-urea breath test, ranked third among the basis for diagnosis of AIG. Associated gastric lesions were type 1 neuroendocrine tumor (11.4%), adenocarcinoma (9.8%), and hyperplastic polyps (21.1%). Corpus pan-atrophy was the most common appearance (90.1%); however, remnant oxyntic mucosa was found in 31.5% of the patients (flat, localized type, 48.6%). Sticky adherent dense mucus and scattered minute whitish protrusions were also observed in approximately 30% of the patients. Despite the prevailing presumption of the antral mucosa remaining normal, 42.3% of the patients presented with various extents of atrophy, and patchy redness and circular wrinkle-like patterns were both observed in approximately 20% of the patients.

CONCLUSIONS

The present study showed some prominent clinical characteristics and endoscopic findings of AIG. We believe that our study will facilitate the diagnosis of potential AIG.

Effect of Citric Acid on Accuracy of 13C-Urea Breath Test after Helicobacter pylori Eradication Therapy in a Region with a High Prevalence of Atrophic Gastritis

Background/Aims

The validity of ¹³C-urea breath test (¹³C-UBT) for Helicobacter pylori detection is influenced by atrophic gastritis. The aim of this study was to evaluate the effect of citric acid on the accuracy of ¹³C-Urea breath test after H. pylori eradication therapy in a region where atrophic gastritis is common.

Methods

In this prospective study, H. pylori-positive patients received ¹³C-UBT after H. pylori eradication regimen. They were classified into citric acid group and control group. To determine diagnostic accuracy of ¹³C-UBT, patients were offered invasive methods.

Results

A total of 1,207 who successfully took H. pylori-eradication regimen received UBT. They were assigned into the citric acid group (n=562) and the control group (n=645). The mean ¹³C-UBT value of the citric acid group was 10.3±26.4‰, which was significantly (p<0.001) higher than that of that control group (5.1‰±12.6‰). Of these patients 122 patients were evaluated by endoscopic biopsy methods. Based on invasive tests, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of ¹³C-UBT for the citric acid group were 83.3%, 91.7%, 81.3%, 55.0%, and 97.5%, respectively. Those of the control group were 87.7%, 90.9%, 88.2%, 62.5%, and 97.8%, respectively. They were not significantly different between the two groups. Although the presence of gastric atrophy and intestinal metaplasia (IM) decreased the accuracy, the decrease was not significant.

Conclusions

In a country with high prevalence of atrophic gastritis or IM, false positivity remained common despite the use of citric acid in ¹³C-UBT.

Natural history of autoimmune atrophic gastritis: a prospective, single centre, long-term experience

BACKGROUND

Autoimmune atrophic gastritis (AAG) is an immune-mediated disorder characterised by destruction of gastric oxyntic mucosa AIM: To explore gastric histopathological evolution in a cohort of AAG patients over a prolonged follow-up METHODS: Single centre prospective study enrolling consecutive patients with histologically confirmed AAG between 2000 and 2018. All AAG patients undergoing endoscopic follow-up every 1-3 years were classified as having stages 1, 2 or 3 according to atrophy severity (mild, moderate and severe). AAG patients with either glandular or neuroendocrine dysplasia/neoplasia were classified as having stage 4. Disease stage progression, and changes in serum anti-parietal cell antibody (PCA), chromogranin A and gastrin-17 were assessed.

RESULTS

In total, 282 AAG patients (mean age 60.3 years; F:M ratio 2.4:1; median follow-up 3 years, interquartile range 1-7) were enrolled. All patients with stages 1 or 2 progressed to stage 2 or 3 over time with a steady trend (P = .243) and regression from a severe to a milder stage was never noticed. Disease progression of patients with stages 1 or 2 occurred within the first 3 years. PCA positivity rate did not change over time. Stage 3 patients had higher gastrin-17 levels compared to patients with stages 1 and 2 (median 606 vs 295 pg/mL; P < .001). In stage 3, the hazard ratio for the risk of developing stage 4 was 6.6 (95% CI 1.5-29; P = .001).

CONCLUSIONS

AAG is a steadily progressive disease, in which stages 1 and 2 always progress to stage 3. The risk of developing a complicated disease stage is greater in patients with more severe gastric lesions.

Autoimmune metaplastic atrophic gastritis and association with neuroendocrine tumors of the stomach

Autoimmune metaplastic atrophic gastritis (AMAG) previously called type A chronic gastritis is an immune-mediated chronic inflammatory disease characterized by the immune-mediated destruction of gastric parietal cells in the fundus and body of the stomach. AMAG is an uncommon disease that often presents with hematological manifestations and may lead to the development of gastric carcinoids. AMAG can be reliably diagnosed by antibody assays, functional serology, and histology. The understanding of the disease process is essential for the detection and management of hematological complications and gastric lesions. The prevalence of AMAG is on the rise and subsequently gastric carcinoids. However, this association is not well recognized in clinical practice, and management and diagnosis of AMAG and gastric carcinoids remain suboptimal. In the current review, we will discuss the pathophysiology, diagnosis and management of AMAG. A special focus is given to the association between AMAG and gastric carcinoids. We will also review the management options of type 1 gastric carcinoids.

Current status of first- and second-line Helicobacter pylori eradication therapy in the metropolitan area: a multicenter study with a large number of patients

BACKGROUND

The environment surrounding Helicobacter pylori eradication treatment is dramatically changing. Recently, vonoprazan, a first-in-class potassium-competitive acid blocker (P-CAB), was introduced onto the market in 2015. The aging of Japan's demographic structure is becoming pronounced. In this study, we examined the trend of the eradication rate of H. pylori in the metropolitan area and examined factors concerning successful eradication.

METHODS

We collected data from 20 hospitals in the Tokyo metropolitan area on patients who received first-line eradication therapy with a proton-pump inhibitor (PPI)/P-CAB, amoxicillin, and clarithromycin for 1 week and second-line eradication therapy with a PPI/P-CAB, amoxicillin, and metronidazole for 1 week from 2013 to 2018. The annual eradication rate and associated factors for successful eradication were analyzed.

RESULTS

We collected data of 4097 and 3572 patients in the first- and second-line eradication therapies, respectively. The eradication rate decreased from 2013 to 2014 and increased again from 2015 to 2018 with the first-line therapy [the eradication rates in 2013, 2014, 2015, 2016, 2017 and 2018 were 71.8%, 63.7%, 78.5%, 84.6%, 89.7 and 90.1%, respectively, in the per protocol (PP)]. The second-line eradication rates were 90.0%, 82.6%, 88.8%, 87.5%, 91.8% and 90.1% in 2013, 2014, 2015, 2016, 2017 and 2018, respectively, in PP. Vonoprazan was an independent factor for successful eradication in not only first-line, but also second-line eradication. Age over 75 years was an independent factor for eradication failure in both first- and second-line eradication therapies.

CONCLUSION

The eradication rate improved from 2015 to 2018 with the first-line therapy because of the introduction of vonoprazan in the market. The eradication rates with first- and second-line regimens in elderly patients were lower than those in younger patients.

Determinants of diagnostic delay in autoimmune atrophic gastritis

BACKGROUND

Autoimmune atrophic gastritis (AAG) is characterised by a wide clinical spectrum that could delay its diagnosis.

AIMS

To quantify the diagnostic delay in patients suffering from AAG and to explore possible risk factors for longer diagnostic delay.

METHODS

Consecutive patients with AAG evaluated at our gastroenterological outpatient clinic between 2009 and 2018 were included. Diagnostic delay was estimated as the time lapse occurring between the appearance of the first likely symptoms, laboratory alterations, and other clues indicative of AAG and the final diagnosis. Patient-dependent and physician-dependent diagnostic delays were also assessed. Multivariable regression models were fitted.

RESULTS

291 patients with AAG (mean age at diagnosis 61 ± 15 years; F:M ratio = 2.3:1) were included. The median overall diagnostic delay was 14 months (interquartile range [IQR] 4-41). Factors associated with longer median overall diagnostic delay were female sex (17 months, IQR 5-48), having a previous misdiagnosis (36 months, IQR 17-125) and a history of infertility/miscarriages (33 months, IQR 8-120), whereas a higher level of education was associated with longer patient-dependent diagnostic delay (4 months, IQR 1-12). First evaluation by a gastroenterologist was associated with a median longer diagnostic delay (6 months, IQR 2-15) compared to an internist (3 months, IQR 3-31) and a haematologist (1 month, IQR 0-2). Age, socioeconomic or marital status did not affect the diagnostic delay.

CONCLUSIONS

AAG is burdened by substantial diagnostic delay, especially in female patients, and due to lack of awareness, particularly among gastroenterologists. Uncommon vitamin B12 deficiency-related manifestations are overlooked and may prolong the diagnostic delay.

The prevalence of histologic atrophy and intestinal metaplasia in the corpus has decreased over 15 years in females in the Korean population

BACKGROUND

The aim of this study was to investigate the trends of atrophy and intestinal metaplasia (IM) in 2002 subjects without significant gastroduodenal diseases.

MATERIALS AND METHODS

A total of 2002 subjects were prospectively enrolled and divided into three periods (2003-2007, 2008-2012, and 2013-2018). Trends of H pylori and atrophy/IM scored by Updated Sydney System were analyzed according to sex, and multivariate logistic analysis was performed for the risk factors for atrophy/IM.

RESULTS

H pylori-negative and H pylori-positive subjects were 1220 (61.0%) and 782 (38.0%), respectively. H pylori positivity decreased from 149/303 (49.2%), 207/515 (40.2%) and 426/1184 (36.0%), in the three periods, respectively (P < 0.001). The prevalence of atrophy (P < 0.001) and IM in the corpus (P < 0.001) significantly decreased over 15 years in females, but not in males. The mean grade of atrophy and IM was higher in males (0.36 and 0.51) than in females (0.28 and 0.41) in the corpus (P = 0.027) and in the antrum (P = 0.006), respectively. Similarly, the mean grade of IM in males (0.34) was higher in females (0.19; P < 0.001) in the corpus. Multivariate analysis showed that old age, study period, and H pylori were statistically significant in atrophy of antrum and corpus, and IM in the corpus. In cases of IM of antrum, old age, H pylori, and smoking were statistically significant.

CONCLUSION

A significant decrease in atrophy and IM in the corpus in females over 15 years suggests sex- or gender-specific characteristics.

The changing face of chronic autoimmune atrophic gastritis: an updated comprehensive perspective

Chronic autoimmune atrophic gastritis (CAAG) is an organ-specific autoimmune disease, which affects the corpus-fundus gastric mucosa. Although it has been described for several years, the real pathophysiological mechanisms, the natural history and the possible neoplastic complications are not completely known. Atrophy of the gastric mucosa is the endpoint of the chronic processes, with the loss of glandular cells and their replacement by intestinal-type epithelium, pyloric-type glands, and fibrous tissue. As a consequence, hydrochloric acid, pepsin and intrinsic-factor is impaired resulting in pernicious anemia. The exact causal agent is not yet known, but both genetic and environmental factors seem to play a decisive role. Moreover, the clinical onset may assume different characteristics; differently from what previously observed, recent evidence has reported the onset of CAAG at a younger age, frequently with iron deficiency anemia or upper gastro-intestinal symptoms. The diagnosis of CAAG might be challenging and usually requires the combination of clinical, serological and histopathologic data; moreover, CAAG patients are often misdiagnosed as refractory to HP eradication therapy, probably because achlorhydria might allow urease-positive bacteria other than H pylori to colonize the stomach, causing positive 13C-urea breath test results. However, biopsy is the most reliable method to evaluate the presence of metaplastic atrophic gastritis. In order to assess the severity of gastric atrophy and intestinal metaplasia, OLGA and OLGIM staging systems have been proposed and seem to correlate with the risk of developing gastric adenocarcinoma. Indeed, CAAG represents a pre-neoplastic condition, as patients with CAAG are very likely to develop either type-1 gastric neuroendocrine tumors and gastric adenocarcinomas, as well as several other neoplastic diseases. To date, the need, the intervals and cost-effectiveness of endoscopic/histological surveillance for patients with CAAG/pernicious anemia are yet to be established.