Autoimmune gastritis in autoimmune thyroid disease

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.

Vitamin B12 levels in thyroid disorders: A systematic review and meta-analysis

Background and aims

Numerous studies have found an association between vitamin deficiency and thyroid disorders (TD). The presence of anti-parietal cell antibodies is indicative of reduced ability to absorb vitamin B12. Thus, this study reviewed the existing studies with the objective of assessing differences in the serum levels of vitamin B12 among patients with and without TD, the frequency of vitamin B12 deficiency in patients with TD, and the presence of anti-parietal cell antibodies in patients with TD.

Methods

A meta-analysis of random-effects model was conducted to calculate pooled frequencies, mean differences (MD), and their respective 95% confidence intervals (CI). We identified 64 studies that met our inclusion criteria (n = 28597).

Results

We found that patients with hypothyroidism had lower vitamin B12 levels than healthy participants (MD: -60.67 pg/mL; 95% CI: -107.31 to -14.03 pg/mL; p = 0.01). No significant differences in vitamin B12 levels were observed between healthy participants and patients with hyperthyroidism (p = 0.78), autoimmune thyroid disease (AITD) (p = 0.22), or subclinical hypothyroidism (SH) (p = 0.79). The frequencies of vitamin B12 deficiency among patients with hypothyroidism, hyperthyroidism, SH, and AITD were 27%, 6%, 27%, and 18%, respectively.

Conclusions

Patients with hypothyroidism had lower levels of vitamin B12 than healthy participants. No significant differences were observed between vitamin B12 levels and hyperthyroidism, AITD, or SH.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=324422, identifier (CRD42022324422).

Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report

Helicobacter pyloriInfection is formally recognised as an infectious disease, an entity that is now included in the International Classification of Diseases 11th Revision. This in principle leads to the recommendation that all infected patients should receive treatment. In the context of the wide clinical spectrum associated with Helicobacter pylori gastritis, specific issues persist and require regular updates for optimised management.The identification of distinct clinical scenarios, proper testing and adoption of effective strategies for prevention of gastric cancer and other complications are addressed. H. pylori treatment is challenged by the continuously rising antibiotic resistance and demands for susceptibility testing with consideration of novel molecular technologies and careful selection of first line and rescue therapies. The role of H. pylori and antibiotic therapies and their impact on the gut microbiota are also considered.Progress made in the management of H. pylori infection is covered in the present sixth edition of the Maastricht/Florence 2021 Consensus Report, key aspects related to the clinical role of H. pylori infection were re-evaluated and updated. Forty-one experts from 29 countries representing a global community, examined the new data related to H. pylori infection in five working groups: (1) indications/associations, (2) diagnosis, (3) treatment, (4) prevention/gastric cancer and (5) H. pylori and the gut microbiota. The results of the individual working groups were presented for a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in various clinical fields.

[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.

Mucocutaneous Manifestations in Autoimmune Gastritis: A Prospective Case-Control Study

INTRODUCTION

Autoimmune gastritis (AIG) is associated with nutritional deficiencies, autoimmune diseases, and gastric malignancies. The aims of the study were to test the hypothesis that mucocutaneous (MC) manifestations occur more often in patients with vs without AIG and to delineate patterns of MC manifestations in AIG.

METHODS

A single-center, prospective 2:1 case-control study was conducted. Cases were patients with the diagnosis of AIG based on consistent serologic and histologic findings. Controls had a normal gastric biopsy. MC manifestations were independently evaluated by 3 experienced dermatologists. We conducted a multivariable logistic regression model adjusted for age, sex, Helicobacter pylori, tobacco use, and alcohol consumption to estimate the association between AIG (vs no AIG) and MC manifestations (adjusted odds ratio; 95% confidence interval).

RESULTS

We prospectively enrolled 60 cases and 30 controls (mean age 53.5 ± 15.8 vs 53.4 ± 14.5 years; 75% vs 73.3% women). The pooled prevalence of MC immune-mediated diseases was higher in patients with vs without AIG (66.7% vs 23.3%; adjusted odds ratio 12.01 [95% confidence interval: 3.51-41.13]). In patients with AIG, seropositive vs seronegative anti-intrinsic factor antibodies more often had concomitant immunological diseases with MC manifestations (100% vs 58.5%; P = 0.016). The most common MC immune-mediated diseases in AIG were Sjögren syndrome (n = 5, 8.3%), alopecia areata (n = 5, 8.3%), and vitiligo (n = 4, 6.7%). Nutritional deficiency-related MC findings, mainly xerosis, lingual, and nail disorders, were also more common in AIG.

DISCUSSION

This is the first comparative study specifically designed to evaluate MC manifestations in AIG. We demonstrated that AIG is more frequently associated with both immune- and nutritional deficiency-related MC manifestations, which might have both diagnostic and therapeutic clinical implications.

Low Pepsinogen I/II Ratio and High Gastrin-17 Levels Typify Chronic Atrophic Autoimmune Gastritis Patients With Gastric Neuroendocrine Tumors

Chronic atrophic autoimmune gastritis (CAAG) can lead to the development of gastric neuroendocrine tumors (gNETs) and can be accompanied by other autoimmune diseases. This study aimed to determine, in CAAG patients, the association of gNET development, the prevalence of autoimmune diseases other than CAAG, the association of autoimmunity, and gNET development with pepsinogen I, II, gastrin-17, and Helicobacter pylori infection analysis.

Anti-gastric parietal cell antibodies for autoimmune gastritis screening in juvenile autoimmune thyroid disease

OBJECTIVE

Patients with autoimmune thyroid disease (ATD) have a higher prevalence of autoimmune gastritis (AIG) compared with the general population. The association between ATD and AIG is poorly characterized in the pediatric age. We reviewed the prevalence of anti-gastric parietal cell antibodies (PCA) in young patients with ATD to evaluate its usefulness as a marker for AIG screening.

METHODS

We evaluated 220 children and adolescents (11.28 ± 6.37 years) with ATD (186 with autoimmune thyroiditis (AT) and 34 with Graves' disease (GD). At ATD diagnosis and annually thereafter, blood counts and PCA levels were measured. In patients positive for PCA, plasma gastrin, chromogranin A, vitamin B₁₂, iron and ferritin levels and H. pylori antigen were measured. PCA-positive patients > 18 years were invited to undergo a gastroscopic exam.

RESULTS

PCA positivity was detected in ten (4.5%) subjects (5F/5M; 12.6 ± 3.4 years). The prevalence of PCA positivity was not significantly different in the comparison of GD and AT patients (p = 0.9). PCA positivity was detected after 2.7 ± 2.7 years of follow-up in AT and 4.4 ± 4.0 years in GD (p = 0.4). Autoantibody positivity was more prevalent in female patients, in both AT and GD (p = 0.02 and p = 0.03, respectively). At detection of PCA positivity, five out of ten PCA-positive patients had iron deficiency, four vitamin B₁₂ deficiency, two anemia, three hypergastrinemia and two elevated chromogranin values. Two patients had H. pylori infection. Gastroscopy was performed in the five ATD patients and in all patients, AIG was confirmed.

CONCLUSION

In the juvenile population, ATD and AIG may also be associated. PCA screening is useful to detect subjects at risk for this condition. Due to the longer life expectancy of the pediatric population and considering the relatively high risk of malignant transformation, early surveillance monitoring is mandatory for children and adolescents with ATD.

Thyro-entero-gastric autoimmunity: Pathophysiology and implications for patient management

The association between autoimmune atrophic gastritis and thyroid disorders has been observed since the early 1960s and the expression "thyrogastric syndrome" was coined to indicate the presence of thyroid autoantibodies or autoimmune thyroid disease in patients with pernicious anemia, a late clinical stage of autoimmune atrophic gastritis. More recently, it was confirmed that autoimmune thyroid disorders, in particular Hashimoto's thyroiditis, may be frequently associated with other organ-specific, immune-mediated disorders, such as autoimmune atrophic gastritis or celiac disease. The association of Hashimoto's thyroiditis with autoimmune atrophic gastritis or celiac disease in adult patients is currently considered part of the polyglandular autoimmune syndromes which include several autoimmune disorders associated with an autoaggressive impairment of endocrine glands. From a clinical point of view, the thyro-entero-gastric autoimmunity may lead to potentially serious consequences like anemia, micronutrients deficiencies, and drugs malabsorption, as well as to an increased risk for malignancies. These alterations may frequently present in an underhand manner, with consequent diagnostic and treatment delays. Many aspects of the association between thyroid, gastric and intestinal autoimmune diseases still await clarification. The present review focuses on the embryological, genetic and pathophysiological aspects of thyro-entero-gastric autoimmunity. In particular, the current diagnostic criteria of autoimmune thyroid disease, autoimmune atrophic gastritis, and celiac disease are reviewed, along with the evidences for their association in poly-autoimmunity syndromes. The benefits of proactive screening of autoimmune thyroid disorders in patients with autoimmune gastritis or enteropathy and viceversa are also discussed.

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

Objectives

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

Methods

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

Results

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

Conclusions

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

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.

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

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

Anti-parietal cell antibodies in patients with autoimmune thyroid diseases

BACKGROUND

Autoimmune thyroid disease (ATD) patients may have a higher prevalence of anti-parietal cell antibodies (APCA) than normal population.

OBJECTIVE

To study the prevalence of APCA in a cohort of ATD patients to know its association with patient's clinical profile and gastrointestinal complaints.

METHODS

APCA was sought for by indirect immunofluorescence test in 243 ATD patients: 136 (55.9%) with Graves' disease and 107 (44.0%) with Hashimoto's thyroiditis. A structured questionnaire for gastrointestinal symptoms, previous history of thrombosis, arthralgia and other autoimmune diseases in the patients and their families was applied. Positive and negative APCA individuals were compared. Positive patients were invited to perform upper gastrointestinal endoscopy and biopsy of duodenum segments. Sera from 100 healthy individuals from the same geographic area were used as controls.

RESULTS

APCA was present in 20.1% (49/243) of ATD patients: 21.3% (29/136) in the Graves' sample and 18.6% (20/107) in the Hashimoto's sample (p = 0.61). Patients with positive APCA had more anemia (p = 0.03; OR = 2.89; 95% CI = 1.03-8.07) and less heartburn (p = 0.01; OR = 0.4; 95% CI = 0.20-0.83). Among the group of 49 APCA-positive patients, 24 agreed with upper endoscopy and it was found that 54.1% had atrophic gastritis.

CONCLUSIONS

There is a high prevalence of positive APCA in ATD patients. APCA are more common in those with anemia and less common in those with complaints of heartburn. Almost half of positive APCA patients had atrophic gastritis.

Luminescent Immunoprecipitation System (LIPS) for Detection of Autoantibodies Against ATP4A and ATP4B Subunits of Gastric Proton Pump H+,K+-ATPase in Atrophic Body Gastritis Patients

OBJECTIVES

Circulating autoantibodies targeting the H+/K+-ATPase proton pump of gastric parietal cells are considered markers of autoimmune gastritis, whose diagnostic accuracy in atrophic body gastritis, the pathological lesion of autoimmune gastritis, remains unknown. This study aimed to assess autoantibodies against ATP4A and ATP4B subunits of parietal cells H+, K+-ATPase in atrophic body gastritis patients and controls.

METHODS

One-hundred and four cases with atrophic body gastritis and 205 controls were assessed for serological autoantibodies specific for ATP4A or ATP4B subunits using luminescent immunoprecipitation system (LIPS). Recombinant luciferase-reporter-fused-antigens were expressed by in vitro transcription-translation (ATP4A) or after transfection in Expi293F cells (ATP4B), incubated with test sera, and immune complexes recovered using protein-A-sepharose. LIPS assays were compared with a commercial enzyme immunoassay (EIA) for parietal cell autoantibodies.

RESULTS

ATP4A and ATP4B autoantibody titers were higher in cases compared to controls (P<0.0001). The area under the receiver-operating characteristic curve was 0.98 (95% CI 0.965-0.996) for ATP4A, and 0.99 (95% CI 0.979-1.000) for ATP4B, both higher as compared with that of EIA: 0.86 (95% CI 0.809-0.896), P<0.0001. Sensitivity-specificity were 100-89% for ATP4A and 100-90% for ATP4B assay. Compared with LIPS, EIA for parietal cell autoantibodies showed a lower sensitivity (72%, P<0.0001) at a similar specificity (92%, P=0.558).

CONCLUSIONS

Positivity to both, ATP4A and ATP4B autoantibodies is closely associated with atrophic body gastritis. Both assays had the highest sensitivity, at the cost of diagnostic accuracy (89 and 90% specificity), outperforming traditional EIA. Once validated, these LIPS assays should be valuable screening tools for detecting biomarkers of damaged atrophic oxyntic mucosa.

Hashimoto's Thyroiditis and Autoimmune Gastritis

The term "thyrogastric syndrome" defines the association between autoimmune thyroid disease and chronic autoimmune gastritis (CAG), and it was first described in the early 1960s. More recently, this association has been included in polyglandular autoimmune syndrome type IIIb, in which autoimmune thyroiditis represents the pivotal disorder. Hashimoto's thyroiditis (HT) is the most frequent autoimmune disease, and it has been reported to be associated with gastric disorders in 10-40% of patients while about 40% of patients with autoimmune gastritis also present HT. Some intriguing similarities have been described about the pathogenic mechanism of these two disorders, involving a complex interaction among genetic, embryological, immunologic, and environmental factors. CAG is characterized by a partial or total disappearance of parietal cells implying the impairment of both hydrochloric acid and intrinsic factor production. The clinical outcome of this gastric damage is the occurrence of a hypochlorhydric-dependent iron-deficient anemia, followed by pernicious anemia concomitant with the progression to a severe gastric atrophy. Malabsorption of levothyroxine may occur as well. We have briefly summarized in this minireview the most recent achievements on this peculiar association of diseases that, in the last years, have been increasingly diagnosed.

Gastric cancer - clinical and epidemiological aspects

Gastric cancer (GC) ranks fifth for cancer incidence and second for cancer deaths. Epidemiological data showed that survivors of Hodgkin's lymphoma and patients with pernicious anemia etiologically linked to autoimmune gastritis are at increased risk of GC. Screening of patients with autoimmune thyroid disease by means of pepsinogen (PG) I and PG I/II detected autoimmune gastritis with oxyntic gastric atrophy in one of four patients and may be recommended for GC prevention purposes. The International Agency for Research on Cancer reported a positive association between consumption of processed meet and increased GC risk. A new GC risk prediction model based on biological markers, age, gender, smoking status, family history of GC, and consumption of highly salted food showed good predictive performance, and might prompt individuals to modify their lifestyle habits, attend regular check-up visits or participate in screening programs. A novel GC classification based on gene expression of primary resected cancers correlated with clinicopathological features. Noncoding RNA for GC screening remains the focus of multiple studies. Patients with early GC undergoing endoscopic resection are more likely to develop metachronous lesions than patients undergoing surgery and endoscopic surveillance is warranted in this special cohort. The addition of gastrectomy to chemotherapy did not improve survival of patients with advanced GC and a single noncurable factor. Apatinib, a novel oral vascular endothelial growth factor receptor 2 tyrosine kinase inhibitor, improved the median overall survival of patients with advanced GC and progressive disease after two or more lines of prior chemotherapy of nearly 3 months.

Pepsinogens to Distinguish Patients With Gastric Intestinal Metaplasia and Helicobacter pylori Infection Among Populations at Risk for Gastric Cancer

OBJECTIVES

The objectives of this study were to investigate the serum pepsinogen test for the prediction of OLGIM (Operative Link on Gastric Intestinal Metaplasia Assessment) stages in first-degree relatives (FDR-GC) of patients with gastric cancer (GC) and autoimmune chronic atrophic gastritis (ACAG).

METHODS

In 67 consecutive patients with ACAG, 82 FDR-GC, and 53 controls (CTRL) without gastric disease (confirmed by biopsy), serum levels of pepsinogen 1 (PG1), pepsinogen 2 (PG2), G17, and the PG1/2 ratio were assessed by enzyme-linked immunosorbent assay kit. All ACAG patients had positive antiparietal cell antibody levels, estimated by indirect immunofluorescence. Biopsies taken in duplicate from the antrum, corpus, and fundus were stained with Giemsa for Helicobacter pylori detection. Endoscopic detection of metaplasia was confirmed by histological diagnosis. Histological classification of OLGIM stages was applied by using the criteria of severity and topography of intestinal metaplasia (IM).

RESULTS

The highest discrimination capacity for distinguishing ACAG from other groups of patients was the gastrin G17 test. The lowest mean for PG1 and PG2 serum levels was found in ACAG. In multivariate analysis by age, PG1 and PG1/PG2 were independent prognostic factors for metaplasia, and PG2 also for the presence of a histological H. pylori infection. The serum PG1 level was significantly lower in individuals with IM at OLGIM stage >2 than in those with IM at OLGIM stage <2, resulting in a useful method for the prediction of OLGIM stage. With the inclusion of patient age at diagnosis in the prediction of ≥2 vs. 0-1 OLGIM stages, the receiver operating characteristic (ROC) curve at 47.9 ng/ml PG1 level reached a significant area under the curve (AUC) value (0.978, P<0.001). We also observed a slight difference in PG2 serum levels between histological H. pylori-positive and H. pylori-negative subjects (ROC AUC: 0.599).

CONCLUSIONS

This study demonstrated an important increase in gastrin G17 serum level in autoimmune gastritis. PG1 serum level corrected by patient age can be used in the management of patients at risk for GC with a high predicted probability of having an OLGIM stage ≥2. Using a cutoff of 47.9 ng/ml, PG1 testing in FDR-GC and ACAG patients had a sensitivity of 95.83% and a specificity of 93.37. Although these results could be validated in a prospective study, the known importance of higher OLGIM stages in increasing the risk of GC development supports the rationale of proposing PG1 algorithm as a diagnostic tool for the selection of high-risk FDR-GC and ACAG patients at high-risk stages for subsequent detailed endoscopic examination to detect dysplasia and asymptomatic GC. In addition, serum PG1 and PG2 levels could stratify patients based on both H. pylori infection and OLGIM risk in consideration of the increased acknowledge regarding the role of H. pylori in the progression of gastritis to GC.