Helicobacter pylori infection and gastric lymphoma

Acute pancreatitis revealing duodenal papilla MALT lymphoma: a case report and review of the literature

Mucosa-associated lymphoid tissue (MALT) lymphoma is a rare subtype of non-Hodgkin lymphoma, predominantly found in the gastrointestinal tract, particularly the stomach. However, its localization at the ampulla of Vater is exceptionally rare and presents considerable diagnostic challenges. This atypical presentation can easily mimic more common conditions, such as ampullary tumors or pancreaticobiliary disorders, making accurate diagnosis and management particularly complex. We present the case of a 70-year-old woman who initially presented with obstructive jaundice and acute pancreatitis, ultimately revealing a diagnosis of MALT lymphoma at the duodenal papilla. She was managed with combination of Helicobacter pylori eradication therapy followed by chemotherapy. This case emphasizes the importance of considering lymphoproliferative disorders in the differential diagnosis of biliary obstruction and pancreatitis, highlighting the need for heightened awareness among clinicians. Through this unique case, we aim to contribute to the limited literature on MALT lymphoma at the ampulla of Vater, illustrating both the complexities of diagnosis and the potential for successful management strategies in rare gastrointestinal lymphomas.

Pathogenicity and virulence of Helicobacter pylori: A paradigm of chronic infection

Infection with Helicobacter pylori is one of the most common infections of mankind. Infection typically occurs in childhood and persists for the lifetime of the host unless eradicated with antimicrobials. The organism colonizes the stomach and causes gastritis. Most infected individuals are asymptomatic, but infection also causes gastric and duodenal ulceration, and gastric cancer. H. pylori possesses an arsenal of virulence factors, including a potent urease enzyme for protection from acid, flagella that mediate motility, an abundance of outer membrane proteins that can mediate attachment, several immunomodulatory proteins, and an ability to adapt to specific conditions in individual human stomachs. The presence of a type 4 secretion system that injects effector molecules into gastric cells and subverts host cell signalling is associated with virulence. In this review we discuss the interplay of H. pylori colonization and virulence factors with host and environmental factors to determine disease outcome in infected individuals.

Dental plaque as an extra-gastric reservoir of Helicobacter pylori: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis (SRMA) aimed to determine whether the presence of H. pylori in dental plaque is associated with gastric H. pylori infection.

DESIGN

Search for the relevant literature was done in various databases: PubMed, Embase, Web of Science and Cochrane till September 21, 2023. The studies were screened for outcome of interest i.e. gastric H. pylori infection and exposure of interest i.e. H. pylori positivity in dental plaque. The pooled results of the study outcomes were evaluated using Odds Ratio (OR), accompanied by a 95 % confidence interval (CI). To evaluate the heterogeneity among studies, I2 statistics were utilized, with an I2 exceeding 50 % indicating a significant to high variation. In cases where I2 was greater than 50 %, a random-effects model (specifically, the Der Simonian and Laird method) was employed.

RESULTS

Data from 27 observational studies and 2408 participants were included. The pooled OR of the H. pylori positivity in dental plaque among the patients with H. pylori positivity in stomach was 3.80 (95 % CI 2.24; 6.43), with high heterogeneity (I2= 69 %, p<0.01). Sensitivity analysis after removing the outliers reduced the heterogeneity significantly (I2=22 %, p=0.16). Meta-regression revealed that the strength of association did not vary according to the year of study or the sample size included in the studies. Overall certainty of the evidence was low.

CONCLUSIONS

The present meta-analysis showed that the presence of gastric H. pylori infection was higher among patients with H. pylori in dental plaque compared to patients without H. pylori in dental plaque. Presence of H. pylori infection in dental plaque can have implications in the management of H. pylori infection as dental plaque can serve as a reservoir from which the microorganism can recolonize the gastric mucosa.

Clinicopathological Characteristics of Extranodal Marginal Zone Lymphoma of the Mucosa Associated Lymphoid Tissue (MALT-Lymphoma) of the Intestine: A Single Center Analysis

Extranodal marginal zone B-cell lymphoma of the mucosa associated lymphoid tissue (MALT-lymphoma) is an indolent B-cell lymphoma with a distinct affinity for mucosal structures. Most commonly arising in the stomach, only roughly 2% of MALT-lymphomas occur in the colon or the intestine. In view of this, we have retrospectively assessed all patients with MALT-lymphoma involving the intestine for clinicopathological characteristics. Data of all patients with MALT-lymphoma and intestinal involvement (i.e. both primary and secondary), treated and followed at the Medical University of Vienna between 1999 and 2021 were retrospectively collected from hospital records and analyzed. Differences in baseline and therapy characteristics, as well as survival between primary and secondary, and between intestinal and gastric MALT-lymphoma (as the most common subgroup of patients) were investigated. In total, 42 patients were identified; 24/484 (5%) were classified as primary and 18 (3.7%) as secondary intestinal MALT-lymphomas. The most common primary intestinal location was the colon (10/24) and the most frequent primary site in the 18 cases with secondary intestinal MALT-lymphomas was the stomach (14/18). A total of 28/42 (66.7%) patients presented with LUGANO stage I, 7/42 (16.7%) with stage II/IIE and 7/42 (16.7%) with stage IV disease. Translocation t (11; 18) (q21; q21) was positive in 47% of patients with secondary and 25% of primary intestinal MALT-lymphomas. Median OS in for intestinal MALT-lymphoma was 301 months (95% CI n.a.) with 89.1% alive at 5 years and 77.2% alive at 10 years. Median PFS in the entire cohort was 50.4 months (95% CI 38.4-62.4 months), with an overall response rate and disease control rate of 73% and 97.3%, respectively. No difference in OS and PFS between primary and secondary intestinal, as well as between intestinal and gastric MALT-lymphoma was detected. Our data suggest that dissemination within the GI tract does not seem to be an adverse prognostic feature and highlights the preferred use of the Lugano staging system in such patients, which also summarizes multiple lesions within the GI-tract as Stage I.

The RIG-I-like receptor signaling pathway triggered by Staphylococcus aureus promotes breast cancer metastasis

Host microbes are increasingly recognized as key components in various types of cancer, although their exact impact remains unclear. This study investigated the functional significance of Staphylococcus aureus (S. aureus) in breast cancer tumorigenesis and progression. We found that S. aureus invasion resulted in a compromised DNA damage response process, as evidenced by the absence of G1-phase arrest and apoptosis in breast cells in the background of double strand breaks production and the activation of the ataxia-telangiectasia mutated (ATM)-p53 signaling pathway. The high-throughput mRNA sequencing, bioinformatics analysis and pharmacological studies revealed that S. aureus facilitates breast cell metastasis through the innate immune pathway, particularly in cancer cells. During metastasis, S. aureus initially induced the expression of RIG-I-like receptors (RIG-I in normal breast cells, RIG-I and MDA5 in breast cancer cells), which in turn activated NF-κB p65 expression. We further showed that NF-κB p65 activated the CCL5-CCR5 pathway, contributing to breast cell metastasis. Our study provides novel evidence that the innate immune system, triggered by bacterial infection, plays a role in bacterial-driven cancer metastasis.

Helicobacter pylori Seroprevalence in Rheumatoid Arthritis Patients with Interstitial Lung Disease

Background

Rheumatoid arthritis (RA) is complicated with interstitial lung disease (ILD). Gastroesophageal reflux disease is prevented by Helicobacter pylori infection and is a predisposing factor for idiopathic pulmonary fibrosis. However, the prevalence of H. pylori infection in RA patients with ILD has not been sufficiently investigated.

Objective

In this study, we analyzed anti-H. pylori antibodies in RA patients with ILD.

Design

Case-control observational study.

Methods

Anti-H. pylori antibodies were analyzed in the sera of RA patients using a commercially available enzyme-linked immunosorbent assay kit.

Results

The positivity of anti-H. pylori antibodies in RA with ILD (n = 30 [18.0%], P = .0227), usual interstitial pneumonia (n = 10 [14.3%], P = .0212), and airway disease (n = 30 [18.0%], P = .0227) was significantly lower than that of RA without chronic lung disease (n = 78 [27.5%]). The positivity of anti-H. pylori antibodies was also lower in RA with chronic lung disease (n = 68 [18.2%], P = .0059). Multiple logistic regression analyses showed that the presence of anti-H. pylori antibodies was independently and protectively associated with chronic lung disease in RA.

Conclusion

The seroprevalence of H. pylori was lower in RA with ILD. H. pylori infection prevented ILD in patients with RA by protecting them from gastroesophageal reflux disease.

From modern pathogenetic insights and molecular understanding to new deescalating therapeutic strategies in gastric MALT-lymphoma

Based on new insights into the aetiology and pathogenesis of gastric marginal-zone B-cell lymphoma of MALT (MALT-lymphoma) and its histomorphological and molecular characteristics, important progress in our understanding of the disease and its clinical management has been made during the last decades. A landmark in this development was the identification of Helicobacter pylori as the decisive pathogenetic factor for gastric MALT lymphoma. We, here, give an overview about the history and the current knowledge of the histology, genetics, and molecular characteristics and pathogenesis of gastric MALT lymphoma. We then focus on how these findings have fundamentally changed its clinical management over the last three decades with consequent deescalating therapeutic strategies.

O-GlcNAcylation: Crosstalk between Hemostasis, Inflammation, and Cancer

O-linked β-N-acetylglucosamine (O-GlcNAc, O-GlcNAcylation) is a post-translational modification of serine/threonine residues of proteins. Alterations in O-GlcNAcylation have been implicated in several types of cancer, regulation of tumor progression, inflammation, and thrombosis through its interaction with signaling pathways. We aim to explore the relationship between O-GlcNAcylation and hemostasis, inflammation, and cancer, which could serve as potential prognostic tools or clinical predictions for cancer patients' healthcare and as an approach to combat cancer. We found that cancer is characterized by high glucose demand and consumption, a chronic inflammatory state, a state of hypercoagulability, and platelet hyperaggregability that favors thrombosis; the latter is a major cause of death in these patients. Furthermore, we review transcription factors and pathways associated with O-GlcNAcylation, thrombosis, inflammation, and cancer, such as the PI3K/Akt/c-Myc pathway, the nuclear factor kappa B pathway, and the PI3K/AKT/mTOR pathway. We also review infectious agents associated with cancer and chronic inflammation and potential inhibitors of cancer cell development. We conclude that it is necessary to approach both the diagnosis and treatment of cancer as a network in which multiple signaling pathways are integrated, and to search for a combination of potential drugs that regulate this signaling network.

Should All Patients With Stage IE Gastric Mucosa-Associated Lymphoid Tissue Lymphoma Receive Antibiotic Eradication Therapy for Helicobacter pylori?

PURPOSE

H. pylori eradication therapy (HPE) can lead to tumor regression in H. pylori-positive (HPP) gastric mucosa-associated lymphoid tissue (MALT) lymphoma. However, some patients do not have detectable H. pylori (HP) infection (H. pylori-negative [HPN]) and the guidelines differ in their initial approach to HPN patients. The National Comprehensive Cancer Network (NCCN) recommends proceeding to radiation therapy, whereas European Society for Medical Oncology suggests HPE for every patient, even those who are HPN. To address this issue, we evaluated the effectiveness of HPE in limited-stage gastric MALT lymphoma.

MATERIALS AND METHODS

We retrospectively reviewed patients newly diagnosed with stage IE gastric MALT lymphoma between January 2002 and December 2022. The primary outcome was the complete remission (CR) rate defined as no macroscopic findings of lymphoma and negative gastric biopsy at the follow-up gastric endoscopy.

RESULTS

Fifty-two patients were reviewed, and HP infection was detected in 19 (36.5%) patients-14 by immunostaining, three by serology, and one each by stool antigen and urea breath test. All 19 HPP and eight of the 33 HPN patients received HPE treatment. The CR rate was 63% (12/19) in HPP patients and 13% (1/8) in HPN patients (P = .033). After a median follow-up of 89.7 months, only two of the 12 HPP patients achieving CR have relapsed; the one HPN patient who received HPE remains in CR at 12+ months.

CONCLUSION

For limited-stage HPP gastric MALT lymphoma, HPE is an effective and durable first-line treatment and should be used. For HPN patients, the CR rate with HPE is very low in our experience and is thus in support of the NCCN guideline.

Two cases demonstrate an association between Tropheryma whipplei and pulmonary marginal zone lymphoma

BACKGROUND

Marginal zone lymphomas of mucosa-associated lymphatic tissues (MZL of MALT) are a group of indolent B-cell neoplasms, which are thought to arise from chronic antigenic stimulation of B-cells either due to underlying chronic infection or autoimmune disease. Little is known about potential causative pathogens in pulmonary MZL (PMZL), although some data suggests a potential role of Achromobacter (A.) xylosoxidans.

METHODS

An index case of chronic pulmonary colonisation with Tropheryma (T.) whipplei and subsequent development of PMZL was identified by T. whipplei specific PCR and metagenomic next genome sequencing (mNGS). This case prompted a retrospectively conducted analysis of T. whipplei-specific PCRs in lung tissue from PMZL patients (n = 22), other pulmonary lymphomas, and normal controls. Positive results were confirmed by mNGS. A systematic search for T. whipplei and A. xylosoxidans in our in-house mNGS dataset comprising autopsy lungs, lung biopsies and lung resection specimens (n = 181) was subsequently performed.

RESULTS

A 69-year-old patient presented with weight loss and persistent pulmonary consolidation. Subsequent mNGS analysis detected T. whipplei in the resected lung specimen. An antibiotic regimen eventually eliminated the bacterium. However, the consolidation persisted, and the diagnosis of PMZL was made in a second lung resection specimen. A second case of T. whipplei-associated PMZL was subsequently detected in the retrospectively analysed PMZL cohort. Both cases showed comparatively few mutations and no mutations in genes encoding for NF-κB pathway components, suggesting that T. whipplei infection may substitute for mutations in these PMZL. None of the samples in our in-house dataset tested positive for T. whipplei. In contrast, A. xylosoxidans was frequently found in both autopsy lungs and lung biopsy / resection specimens that were not affected by PMZL (> 50%).

CONCLUSIONS

Our data suggests that T. whipplei colonisation of lungs may trigger PMZL as a potential driver. Systematic analyses with larger cohorts should be conducted to further support this hypothesis. The frequent detection of A. xylosoxidans in lung tissue suggests that it is a common component of the pulmonary microbiome and therefore less likely to trigger lymphomas.

Evidence of Helicobacter pylori heterogeneity in human stomachs by susceptibility testing and characterization of mutations in drug-resistant isolates

Heterogeneity of Helicobacter pylori communities contributes to its pathogenicity and diverse clinical outcomes. We conducted drug-susceptibility tests using four antibiotics, clarithromycin (CLR), amoxicillin (AMX), metronidazole and sitafloxacin, to examine H. pylori population diversity. We also analyzed genes associated with resistance to CLR and AMX. We examined multiple isolates from 42 Japanese patients, including 28 patients in whom primary eradication with CLR and AMX had failed, and 14 treatment-naïve patients. We identified some patients with coexistence of drug resistant- and sensitive-isolates (drug-heteroR/S-patients). More than 60% of patients were drug-heteroR/S to all four drugs, indicating extensive heterogeneity. For the four drugs except AMX, the rates of drug-heteroR/S-patients were higher in treatment-naïve patients than in primary eradication-failure patients. In primary eradication-failure patients, isolates multi-resistant to all four drugs existed among other isolates. In primary eradication-failure drug-heteroR/S-patients, CLR- and AMX-resistant isolates were preferentially distributed to the corpus and antrum with different minimum inhibitory concentrations, respectively. We found two mutations in PBP1A, G591K and A480V, and analyzed these in recombinants to directly demonstrate their association with AMX resistance. Assessment of multiple isolates from different stomach regions will improve accurate assessment of H. pylori colonization status in the stomach.

The Effect of Mind-Body Intervention on Lymphocyte Doubling Time and Treatment-Free Survival in Treatment-Naïve Chronic Lymphocytic Leukemia Patients

INTRODUCTION

Mind-body intervention (MBI) serves as a supportive aid in oncology. We hypothesized that MBI could impact the progression of chronic lymphocytic leukemia (CLL) in the "watch and wait" (w&w) phase.

METHODS

We conducted a non-randomized, prospective controlled study between the years 2020 and 2022 on 76 treatment-naïve CLL patients in the w&w phase. Thirty-seven patients were included in the intervention arm and received MBI, while 39 patients were included in the control group. The primary and secondary endpoints were prolongation of lymphocyte doubling time (LDT) and treatment-free survival (TFS). LDT was compared at 0, 180, 360, and 540 days using paired t tests. TFS was compared between the intervention and control groups using the log-rank test. Cox proportional hazards models were used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for TFS in the intervention group compared to the control, stratified by the study covariates.

RESULTS

MBI prolonged LDT at all time points, including at day 360 (median of 2.47 years; CI 1.05-3.9; p = 0.001). TFS at 18 months was longer in the intervention group compared to the control group (HR 0.23; CI 0.06-0.79, p = 0.01).

CONCLUSIONS

MBI was associated with prolonged LDT and TFS in patients with CLL in the w&w phase. These results provide a basis for a larger randomized controlled trial.

Non-resolving pneumonia: primary pulmonary MALT lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphoma is an uncommon extranodal low-grade B-cell lymphoma. Pulmonary MALT lymphomas originate from bronchial MALT and are also referred to as bronchial-associated lymphoid tissue lymphomas. MALT lymphomas of the lung are slow-growing tumours and usually present as asymptomatic chronic alveolar opacities visible on chest radiographs or with non-specific pulmonary symptoms. Here we described a case of a male patient in his early 50s with cough and chest pain for 4 years. His CT chest scan showed consolidation in the lingula and left lower lobe. Histopathology of the specimen obtained from cryobiopsy of the lung lesion showed a dense monomorphic lymphoid infiltrate, and immunohistochemistry confirmed the diagnosis of MALT lymphoma. The prognosis of pulmonary MALT lymphomas is good with >80% 5-year survival rates. This case highlights that MALT lymphoma should be considered as a differential diagnosis while evaluating cases with non-resolving consolidation.

Helicobacter pylori enhances HLA-C expression in the human gastric adenocarcinoma cells AGS and can protect them from the cytotoxicity of natural killer cells

Helicobacter pylori (H. pylori) seems to play causative roles in gastric cancers. H. pylori has also been detected in established gastric cancers. How the presence of H. pylori modulates immune response to the cancer is unclear. The cytotoxicity of natural killer (NK) cells, toward infected or malignant cells, is controlled by the repertoire of activating and inhibitory receptors expressed on their surface. Here, we studied H. pylori-induced changes in the expression of ligands, of activating and inhibitory receptors of NK cells, in the gastric adenocarcinoma AGS cells, and their impacts on NK cell responses. AGS cells lacked or had low surface expression of the class I major histocompatibility complex (MHC-I) molecules HLA-E and HLA-C-ligands of the major NK cell inhibitory receptors NKG2A and killer-cell Ig-like receptor (KIR), respectively. However, AGS cells had high surface expression of ligands of activating receptors DNAM-1 and CD2, and of the adhesion molecules LFA-1. Consistently, AGS cells were sensitive to killing by NK cells despite the expression of inhibitory KIR on NK cells. Furthermore, H. pylori enhanced HLA-C surface expression on AGS cells. H. pylori infection enhanced HLA-C protein synthesis, which could explain H. pylori-induced HLA-C surface expression. H. pylori infection enhanced HLA-C surface expression also in the hepatoma Huh7 and HepG2 cells. Furthermore, H. pylori-induced HLA-C surface expression on AGS cells promoted inhibition of NK cells by KIR, and thereby protected AGS cells from NK cell cytotoxicity. These results suggest that H. pylori enhances HLA-C expression in host cells and protects them from the cytotoxic attack of NK cells expressing HLA-C-specific inhibitory receptors.

Efficacy and tolerability of Helicobacter pylori eradication regimes in South Kivu, Eastern of the Democratic Republic of Congo: A single center observational study

Background and Aims

Treating Helicobacter pylori infections has become a major challenge due to increased antibiotic resistance. The aim of this study was to investigate the efficacy and tolerability of the main standard regimens recommended for H. pylori eradication in Bukavu, Eastern of the Democratic Republic of Congo.

Methods

The study enrolled patients with evidence of H. pylori infection in histological examination or serology testing combined with a positive fecal antigen test. As first-line treatment, patients were randomized to either a 10-days (OAC-10) or a 14-days (OAC-14) regimen, employing a combination of omeprazole 20 mg, amoxicillin 1 g, and clarithromycin 500 mg twice daily. In case of failure, a second line regimen was evaluated and included two others protocols: OAC-10 regimen + levofloxacin 500 mg (OAC-10+) and the bismuth-based therapy (pantoprazole + bismuth salt + metronidazole + tetracycline) during 10 days. Our primary endpoint was H. pylori eradication and secondarily, the compliance and adverse effects were also evaluated.

Results

A total of 179 patients were enrolled. The eradication rate was 79.2% and 80.5% with the OAC-10 and OAC-14 regimen, respectively (p = 0.796). Adverse effects were significant higher in the OAC-14 group than in the OAC-10 group (36.5% vs. 57.8%; p < 0.001). On the other hand, the compliance rate was slightly higher in the OAC-10 group (97.9% vs. 91.6%, p = 0.052) while clinical improvement was almost similar in both groups. Regarding the second line regimen, the bismuth-based therapy (n = 18) seemed to show a better response with 100% of eradication rate and 100% of clinical improvement.

Conclusion

The classic 10-days triple therapy seems to be as effective as the 14-days regimen while having in addition a good tolerance. Apart from cost issues, the bismuth-based therapy seems to be a very good alternative in case of first-line treatment failure.

Large renal lymphoma in a patient with horseshoe kidney: A case report

Horseshoe kidney (HSK) is the most common renal fusion anomaly. It frequently consists of kidney fusion in the lower pole across the midline and occurs during embryogenesis. The incidence of malignancies in HSKs can be 3-4 times higher than that in normal kidneys. A 69-year-old man with a voluminous right kidney neoplasm in HSK and a single omolateral axillary lymphadenopathy underwent complete excision of right axillary lymphadenopathy and ultrasound-guided percutaneous biopsy of the right kidney expansive lesion. The diagnosis of non-Hodgkin's B cell lymphoma both in HSK and right axilla was made. We report this case to raise awareness among physicians regarding the importance of a correct clinical evaluation and diagnostic workup so as to avoid surgery, which is not easy and without complications, in patients with this kidney anomaly. Primary renal lymphoma should also be included among possible neoplasms of HSK. Renal biopsy should always be recommended in cases where atypical findings are obtained from imaging techniques and when its outcome can impact clinical decision-making. In the present case, biopsy was performed, and thus, nephrectomy was avoided and specific medical therapy was quickly started.

Primary central nervous system marginal zone lymphoma

Marginal zone lymphoma (MZL) is the most common indolent lymphoma primarily arising in the central nervous system (CNS). To date, 207 cases of primary CNS MZL (PCNSMZL) were published, mostly as single case reports or small case series. It most commonly presents as extra-axial dural-based masses, more frequently in middle-aged women, displaying an insidious onset, with a long history of symptoms preceding the diagnosis. PCNSMZL can be radiographically mistaken for meningioma. PCNSMZL consists of CD20+ , CD3- small B lymphocytes with varying degrees of plasmacytic differentiation and low proliferation index. Trisomy 3, but not MALT1 or IgH translocation, is a common genetic abnormality. Other recurrent genetic abnormalities involve TNFAIP3 and NOTCH2. Ethiopathogenesis was poorly investigated. Due to its rarity, standard of care remains to be defined; it exhibits an excellent prognosis after varied treatments, such as surgery, radiotherapy, chemotherapy or their combinations. Nevertheless, each treatment should be considered after an accurate analysis of overtreatment risk. Short follow-up is a major limitation in reported PCNSMZL cases, which restrains our knowledge on long-term results and iatrogenic sequels. This review was focussed on presentation, differential diagnoses, pathological findings, treatment options and clinical outcomes of PCNSMZL; recommendations for best clinical practice are provided.

H pylori-Negative MALT-Associated Extranodal Marginal Zone Lymphoma: A Comprehensive Case Report and Literature Review

Extranodal marginal zone B-cell lymphoma (ENMZL) of mucosa-associated lymphoid tissue (MALT), a rare subtype of B-cell lymphoma, is typically associated with Helicobacter pylori (H pylori) infection, especially in gastric cases. However, this article presents 2 unique cases of H pylori-negative colonic ENMZL, challenging the conventional understanding of the disease. The first case involves an 80-year-old male diagnosed with Stage 1E ENMZL in the descending colon, and the second describes a 74-year-old male with sigmoid colon ENMZL. Both cases lacked H pylori infection, adding complexity to their management. Accompanying these case studies is a comprehensive literature review, delving into the epidemiology, pathology, clinical features, diagnosis, and treatment of H pylori-negative ENMZL, with a focus on gastrointestinal involvement. This review highlights the importance of considering H pylori-negative cases in ENMZL diagnosis and management, illustrating the need for further research and individualized treatment approaches in this uncommon lymphoma subtype.

Cancers Attributable to Infections in the US in 2017: A Meta-Analysis

Importance

Infections are largely modifiable causes of cancer. However, there remains untapped potential for preventing and treating carcinogenic infections in the US.

Objective

To estimate the percentage and number of incident cancers attributable to infections in the US among adults and children for the most recent year cancer incidence data were available (2017).

Data Sources

A literature search from 1946 onward was performed in MEDLINE on January 6, 2023, to obtain the data required to calculate population attributable fractions for 31 infection-cancer pairs. National Health and Nutrition Examination Survey data were used to estimate the population prevalence of hepatitis B and C viruses and Helicobacter pylori.

Study Selection

Studies conducted in the US or other Western countries were selected according to specific infection-cancer criteria.

Data Extraction and Synthesis

Data from 128 studies were meta-analyzed to obtain the magnitude of an infection-cancer association or prevalence of the infection within cancer cells.

Main Outcomes and Measures

The proportion of cancer incidence attributable to 8 infections.

Results

Of the 1 666 102 cancers diagnosed in 2017 among individuals aged 20 years or older in the US, 71 485 (4.3%; 95% CI, 3.1%-5.3%) were attributable to infections. Human papillomavirus (n = 38 230) was responsible for the most cancers, followed by H pylori (n = 10 624), hepatitis C virus (n = 9006), Epstein-Barr virus (n = 7581), hepatitis B virus (n = 2310), Merkel cell polyomavirus (n = 2000), Kaposi sarcoma-associated herpesvirus (n = 1075), and human T-cell lymphotropic virus type 1 (n = 659). Cancers with the most infection-attributable cases were cervical (human papillomavirus; n = 12 829), gastric (H pylori and Epstein-Barr virus; n = 12 565), oropharynx (human papillomavirus; n = 12 430), and hepatocellular carcinoma (hepatitis B and C viruses; n = 10 017). The burden of infection-attributable cancers as a proportion of total cancer incidence ranged from 9.6% (95% CI, 9.2%-10.0%) for women aged 20 to 34 years to 3.2% (95% CI, 2.4%-3.8%) for women aged 65 years or older and from 6.1% (95% CI, 5.2%-7.0%) for men aged 20 to 34 years to 3.3% (95% CI, 1.9%-4.4%) for men aged 65 years or older. Among those aged 19 years or younger, 2.2% (95% CI, 1.3%-3.0%) of cancers diagnosed in 2017 were attributable to Epstein-Barr virus.

Conclusions and Relevance

Infections were estimated to be responsible for 4.3% of cancers diagnosed among adults in the US in 2017 and, therefore, represent an important target for cancer prevention efforts.

Helicobacter pylori Infections in Children

In the context of epidemiology, host response, disease presentation, diagnosis, and treatment management, the manifestation of Helicobacter pylori (H. pylori) infection diverges between children and adults. H. pylori infection stands out as one of the most prevalent bacterial infections globally, and its prevalence in both children and adults is decreasing in many developing countries but some still struggle with a high prevalence of pediatric H. pylori infection and its consequences. The majority of infected children are asymptomatic and pediatric studies do not support the involvement of H. pylori in functional disorders such as recurrent abdominal pain. The pathophysiology of H. pylori infection relies on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors. This interaction gives rise to diverse gastritis phenotypes, which subsequently influence the potential development of various gastroduodenal pathologies. In clinical settings, the diagnosis of this infection in childhood requires an upper gastrointestinal endoscopic exam with mucosal biopsy samples for histology and culture, or Polymerase Chain Reaction (PCR) at the very least. When warranted, eradication treatment should be given when good compliance is expected, and there should be systematic use of a treatment adapted to the antimicrobial susceptibility profile. To combat the burgeoning threat of multidrug resistance, vigilant surveillance of resistance patterns and strategic antibiotic management are paramount.

Bacteria in cancer initiation, promotion and progression

Cancer cells originate from a series of acquired genetic mutations that can drive their uncontrolled cell proliferation and immune evasion. Environmental factors, including the microorganisms that colonize the human body, can shift the metabolism, growth pattern and function of neoplastic cells and shape the tumour microenvironment. Dysbiosis of the gut microbiome is now recognized as a hallmark of cancer by the scientific community. However, only a few microorganisms have been identified that directly initiate tumorigenesis or skew the immune system to generate a tumour-permissive milieu. Over the past two decades, research on the human microbiome and its functionalities within and across individuals has revealed microbiota-focused strategies for health and disease. Here, we review the evolving understanding of the mechanisms by which the microbiota acts in cancer initiation, promotion and progression. We explore the roles of bacteria in gastrointestinal tract malignancies and cancers of the lung, breast and prostate. Finally, we discuss the promises and limitations of targeting or harnessing bacteria in personalized cancer prevention, diagnostics and treatment.

The link between Helicobacter pylori infection and gallbladder and biliary tract diseases: A review

Helicobacter pylori is a gram-negative pathogen commonly associated with peptic ulcer disease and gastric cancer. H. pylori infection has also been reported in cholelithiasis, cholecystitis, gallbladder polyps, and biliary tract cancers. However, the association between H. pylori and gallbladder and biliary tract pathologies remains unclear due to the paucity of literature. In response to the current literature gap, we aim to review and provide an updated summary of the association between H. pylori with gallbladder and biliary tract diseases and its impact on their clinical management. Relevant peer-reviewed studies were retrieved from Medline, PubMed, Embase, and Cochrane databases. We found that H. pylori infection was associated with cholelithiasis, chronic cholecystitis, biliary tract cancer, primary sclerosing cholangitis, and primary biliary cholangitis but not with gallbladder polyps. While causal links have been reported, prospective longitudinal studies are required to conclude the association between H. pylori and gallbladder pathologies. Clinicians should be aware of the implications that H. pylori infection has on the management of these diseases.

Biofilm and Cancer: Interactions and Future Directions for Cancer Therapy

There is a growing body of evidence supporting the significant role of bacterial biofilms in the pathogenesis of various human diseases, including cancer. Biofilms are polymicrobial communities enclosed within an extracellular matrix composed of polysaccharides, proteins, extracellular DNA, and lipids. This complex matrix provides protection against antibiotics and host immune responses, enabling the microorganisms to establish persistent infections. Moreover, biofilms induce anti-inflammatory responses and metabolic changes in the host, further facilitating their survival. Many of these changes are comparable to those observed in cancer cells. This review will cover recent research on the role of bacterial biofilms in carcinogenesis, especially in colorectal (CRC) and gastric cancers, emphasizing the shared physical and chemical characteristics of biofilms and cancer. This review will also discuss the interactions between bacteria and the tumor microenvironment, which can facilitate oncogene expression and cancer progression. This information will provide insight into developing new therapies to identify and treat biofilm-associated cancers, such as utilizing bacteria as delivery vectors, using bacteria to upregulate immune function, or more selectively targeting biofilms and cancer for their shared traits.

A systematic review and meta-analysis on the relative and attributable risk of Helicobacter pylori infection and cardia and non-cardia gastric cancer

INTRODUCTION

This study aimed to update the association between Helicobacter pylori (H. pylori) infection and gastric cancer (GC).

METHODS

We searched PubMed, Embase, and Cochrane Library from 1990 to December 2021 to identify prospective studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were summarized to validate the relationship between H. pylori infection and GC.

RESULTS

Including 27 studies, findings indicated a strong link between H. pylori and non-cardia gastric cancer (NCGC) in both Europe/North America (OR=5.37, 95%CI:4.39-6.57) and Asia (OR = 2.50, 95%CI:1.89-3.32), and a positive association with cardia gastric cancer (CGC) in Asia (OR = 1.74, 95%CI:1.38-2.19), but an inverse association in European/American populations (OR = 0.64, 95%CI: 0.51 to 0.79). Furthermore, the strength of association was greater in studies that detected H. pylori by immunoblotting versus ELISA, and also in studies testing for H. pylori detection further back in time prior to cancer diagnosis (Ptrend<0.05). Approximately 79% of NCGC in Asia and 87% in Europe/North America, along with 62% of CGC in Asia, could be attributable to H. pylori infection.

CONCLUSIONS

The meta-analysis supports the significant attributable risk of H. pylori infection for GC and underscores the potential impact of targeting H. pylori in GC prevention programs.

PROSPERO REGISTRATION

CRD42021274120.

Helicobacter pylori and Its Role in Gastric Cancer

Gastric cancer is a challenging public health concern worldwide and remains a leading cause of cancer-related mortality. The primary risk factor implicated in gastric cancer development is infection with Helicobacter pylori. H. pylori induces chronic inflammation affecting the gastric epithelium, which can lead to DNA damage and the promotion of precancerous lesions. Disease manifestations associated with H. pylori are attributed to virulence factors with multiple activities, and its capacity to subvert host immunity. One of the most significant H. pylori virulence determinants is the cagPAI gene cluster, which encodes a type IV secretion system and the CagA toxin. This secretion system allows H. pylori to inject the CagA oncoprotein into host cells, causing multiple cellular perturbations. Despite the high prevalence of H. pylori infection, only a small percentage of affected individuals develop significant clinical outcomes, while most remain asymptomatic. Therefore, understanding how H. pylori triggers carcinogenesis and its immune evasion mechanisms is critical in preventing gastric cancer and mitigating the burden of this life-threatening disease. This review aims to provide an overview of our current understanding of H. pylori infection, its association with gastric cancer and other gastric diseases, and how it subverts the host immune system to establish persistent infection.

Infection with Neoehrlichia mikurensis promotes the development of malignant B-cell lymphomas

The tick-borne pathogen Neoehrlichia (N.) mikurensis is implicated in persistent infection of the vascular endothelium. B cells are crucial for the host defence to this infection. Chronic stimulation of B cells may result in B-cell transformation and lymphoma. Five patients with malignant B-cell lymphoma and concomitant N. mikurensis infection were investigated regarding clinical picture, lymphoma subtype, B-cell lymphoma immunophenotype and IGHV (variable region of the immunoglobulin heavy) gene repertoire. Three of the five patients improved markedly and ceased lymphoma treatment after doxycycline treatment to eliminate N. mikurensis. Sequencing the B-cell lymphoma IGHV genes revealed preferred usage of the IGHV1 (IGHV1-2, and -69) and IGHV3 (IGHV3-15, -21, -23) families. In conclusion, N. mikurensis infection may drive the development of malignant B-cell lymphomas. Eradication of the pathogen appears to induce remission with apparent curing of the lymphoma in some cases.

Estimating the prevalence of Epstein-Barr virus in primary gastric lymphoma: a systematic review and meta-analysis

The stomach is a common site for extranodal non-Hodgkin's lymphoma. While Helicobacter pylori (H. pylori) is the main established risk factor for primary gastric lymphoma, a fraction could be aetiologically associated with Epstein-Barr virus (EBV), a known haematolymphoid carcinogen. We systematically searched five databases from 1 January 1990 until 31 May 2022 for studies reporting EBV prevalence in gastric lymphoma tumour tissue by in-situ hybridisation (ISH) for EBV-encoded small RNA (PROSPERO CRD42020164473). We included representative series of more than five gastric lymphoma cases. Pooled prevalence and corresponding 95% confidence intervals (CI) of EBV in gastric tumour cells were calculated for two major gastric B-cell lymphoma types, mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B-cell lymphoma (DLBCL). When available, we also extracted data on H. pylori prevalence and survival by EBV status. We found ten studies including 194 cases of gastric MALT lymphoma and 11 studies including 643 cases of gastric DLBCL. EBV prevalence was 2.2% (95% CI: 0.5-13.3) in gastric MALT lymphoma and 11.0% (95% CI: 5.2-20.0) in gastric DLBCL. In a subset of studies, the prevalence of H. pylori was higher in gastric MALT lymphoma (51/69) compared to gastric DLBCL (62/102). Overall, our findings suggest that EBV is rarely seen in MALT lymphoma but is associated with around 10% of gastric DLBCL, similar to the proportion observed at other primary sites. EBV-related lymphoma adds a small number of cases to the burden of cancer that could be prevented by the future development of a vaccine against EBV.

Diffuse large B-cell lymphoma and red cell autoimmunity: clinical role and pathogenesis

Diffuse large B-cell lymphoma (DLBCL) is the most common form of B-cell non-Hodgkin lymphoma (B-NHL) with significant morbidity and mortality despite advancements in treatment. Lymphoma and autoimmune disease both result from breakdowns in normal cell regulatory pathways, and epidemiological studies have confirmed both that B-NHL is more likely to develop in the setting of autoimmune diseases and vice versa. Red cell immunity, as evidenced by direct antiglobulin test (DAT) positivity, has been linked to DLBCL and more recently the pathogenic causes of this association have begun to be better understood using molecular techniques. This project aimed to explore the relationship between red cell autoimmunity and DLBCL. DAT positivity was more common in DLBCL as compared to healthy controls (20.4% vs 3.7%, p=0.0005). Univariate analysis found a non-significant trend towards poorer overall survival in the DAT positive (DAT+) compared to the DAT negative (DAT-) groups (p=0.087). High throughput sequencing was used to compare mutations in DLBCL from DAT+ and DAT- patients. The most frequently mutated genes in 15 patient samples were KMT2D (n=13), MYOM2 (n=9), EP300 (n=8), SPEN (n=7), and ADAMTSL3 (n=7), which were mutated in both DAT+ and DAT- groups. BIRC3 (n=3), FOXO1 (n=3) and CARD11 (n=2) were found to be mutated only in samples from the DAT+ group. These gene mutations may be involved in disease development and progression, and potentially represent targets for future therapy. The immunoglobulin genotype IGHV4-34 is seen more frequently in DLBCL clones than in normal B cells and has intrinsic autoreactivity to self-antigens on red cells, which is largely mediated by two motifs within the first framework region (FR1); Q⁶W⁷ and A²⁴V²⁵Y.²⁶ These motifs form a hydrophobic patch which determines red cell antigen binding and are frequently mutated away from self-reactivity in normal B cells. If this does not occur this may provide constant B cell receptor signalling which encourages lymphoma development, a theory known as antigen driven lymphomagenesis. As with previous studies, IGHV4-34 was over-represented (15.6%) in our DLBCL cohort. Furthermore, of 6 IGHV4-34-expressing DLBCL samples five had unmutated hydrophobic patch mutations providing further evidence for antigen-driven lymphomagenesis. Mutation analysis of these five samples demonstrated high frequency of mutations in several genes, including CREBBP and NCOR2. Further research could explore if mutations in CREBBP and NCOR2 work in conjunction with the preserved QW and AVY motifs to promote lymphomagenesis in IGHV4-34-expressing B cells, and if so, could guide future targeted therapy.

Management of Marginal Zone Lymphoma: A Canadian Perspective

Marginal zone lymphomas (MZL) are a rare, heterogenous group of lymphomas, accounting for 5-17% of indolent non-Hodgkin lymphomas in the western world. They can be further divided into three subtypes: extranodal MZL, splenic MZL, and nodal MZL. These subtypes differ in clinical presentation and behavior, which influences how they are managed. There is currently no standard of care for the treatment of MZL, owing to the difficulty in conducting phase 3 randomized trials in MZL, and the fact that there are limited data on the efficacy of therapy in individual subtypes. Treatment practices are thus largely borrowed from other indolent lymphomas and are based on patient and disease characteristics, as well as access to therapy. This review summarizes the Canadian treatment landscape for MZL and how these therapies may be sequenced in practice.

Management of Helicobacter pylori infection

Helicobacter pylori infection exhibits a wide disease spectrum ranging from asymptomatic gastritis, peptic ulcer disease, to gastric cancer. H. pylori can induce dysbiosis of gastric microbiota in the pathway of carcinogenesis and successful eradication can restore gastric homeostasis. Diagnostic testing and treatment for H. pylori infection is recommended in patients with active or past history of peptic ulcer, chronic dyspepsia, chronic non-steroidal anti-inflammatory drugs (NSAID) or aspirin use, precancerous gastric lesions, gastric cancer, mucosa-associated lymphoid tissue (MALT) lymphoma, family history of gastric cancer, family history of peptic ulcers, household family member having active H. pylori infection, iron deficiency anemia, idiopathic thrombocytopenic purpura, or vitamin B12 deficiency. Recommended first-line regimens for H. pylori eradication are classified according to clarithromycin resistance. In areas of high clarithromycin resistance (≥15%), we recommend 14-day concomitant therapy or 14-day bismuth quadruple therapy (BQT) as first-line regimen. In areas of low clarithromycin resistance (<15%), we recommend 14-day triple therapy or 14-day BQT as first-line treatment. Second-line regimens are 14-day levofloxacin triple therapy or 14-day BQT if BQT is not previously used. For patients with multiple treatment failure, antimicrobial susceptibility testing (AST) should be performed. If AST is not available, we recommend using antibiotics not previously used or for which resistance is unlikely, such as amoxicillin, tetracycline, bismuth, or furazolidone. High-dose potent proton pump inhibitor or vonoprazan is recommended to achieve adequate acid suppression. Probiotics can be used as an adjuvant treatment to reduce the side effects of antibiotics and enhance eradication rate.

Bacterial infection-driven lymphomagenesis

PURPOSE OF REVIEW

The first convincing evidence for a causal relationship between bacterial infection and lymphomagenesis came from the link between gastric lymphoma and chronic Helicobacter pylori gastritis. This review will summarize the current epidemiological, clinical, and biological evidence of a causative role of bacteria in the development of malignant lymphomas, particularly, the extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type.

RECENT FINDINGS

Other microorganisms have been associated with specific extranodal lymphoma sites with variable and not always definitive, evidence, including Chlamydia psittaci , Borrelia burgdorferi , Campylobacter jejuni and, most recently, Coxiella Burnetii . According to most plausible models, lymphoma growth is a consequence of continuous antigenic stimulation induced by chronic infection. However, some evidence of a direct oncogenic role of H. pylori has been provided, too.

SUMMARY

Lymphomas are not the result of a single cause but multifactorial diseases, influenced by a variety of genetic and environmental elements. Hence, ascertaining the specific contribution of bacterial infections is not always easy. Nevertheless, the eradication of the associated chronic infection may result in sustained lymphoma regression. Moreover, the association between infections and lymphoma may offer opportunities for reducing lymphoma incidence by preventing the predisposing infections or treating them early.

Higher dietary total antioxidant capacity is inversely associated with Helicobacter pylori infection among adults: A case-control study

INTRODUCTION

Antioxidants appear to hinder the actions of Helicobacter pylori (H. pylori). The aim of this research was to evaluate the association between dietary total antioxidant capacity (DTAC) and H. pylori infection.

METHODS

A case-control study was carried out among 200 patients with  H. pylori infection and 402 healthy subjects (18-55 years). Dietary data were collected using a validated 168-item quantitative food frequency questionnaire. DTAC was calculated based on the oxygen radical absorbance capacity of each food (except for coffee) reported by the US Department of Agriculture.

RESULTS

Compared with participants in the lowest tertile of DTAC, those in the highest tertile had a significantly lower odds ratio (OR) in the crude model (OR, 0.29; 95% CI, 0.14-0.61; p for trend = 0.001), model 1 (adjustment for age and sex) (OR, 0.37; 95% CI, 0.24-0.58; p for trend < 0.001), and model 2 (adjustment for model 1 plus body mass index, waist circumference, physical activity, smoking, dietary intake of energy and fat) (OR, 0.20; 95% CI, 0.10-0.40; p for trend ≤ 0.001).

CONCLUSIONS

A high DTAC is associated with a reduced risk of H. pylori infection in adults. Further studies are mandatory to elucidate the mechanisms and a dose-effect relationship.

Changing profile of Helicobacter pylori primary antibiotic resistance in Singapore over two decades

OBJECTIVES

Antibiotic resistance is a key reason for Helicobacter pylori (H. pylori) treatment failure and updated local data are important to guide the choice of empiric first-line therapy. Clarithromycin-based triple therapy (TT) is currently the first-line treatment in Singapore. Our primary aim was to determine the change in pattern of primary antibiotic resistance of H. pylori in Singapore as well as TT success rate.

METHODS

A registry of H. pylori isolates was tested for primary antibiotic resistance and were analyzed from year 2001 to 2020. Treatment outcome data based on 13C-urea breath test (13C-UBT) results of empiric first-line 2-week TT from 2019 to 2020 were also analyzed retrospectively.

RESULTS

A total of 387 H. pylori isolates were included. Rates of resistance to clarithromycin as well as tetracycline showed a downtrend in the last 5 years (clarithromycin: 2001-2002: 8.57%; 2007-2008: 14.14%; 2013-2014: 18.09%; 2019-2020: 13.71%; tetracycline: 2001-2002: 5.71%; 2007-2008: 7.07%; 2013-2014: 7.45%; 2019-2020: 0%). The resistance rate for amoxicillin remained low (2001-2002: 2.86%; 2007-2008: 5.05%; 2013-2014: 4.26%; 2019-2020: 7.26%). There was a steady increase in the rate of levofloxacin resistance (2001-2002: 5.71%; 2007-2008: 11.11%; 2013-2014: 15.96%; 2019-2020: 16.94%). From 2019 to 2020, the rate of successful TT was 91.67% (891/972).

CONCLUSION

The latest rate of clarithromycin resistance in 2019 to 2020 remained below the threshold of 15% and eradication rates remain high; thus, TT remains appropriate as an empiric first-line treatment in Singapore.

Extranodal Marginal Zone Lymphoma: Pathogenesis, Diagnosis and Treatment

Simple Summary

Extranodal marginal zone lymphoma (EMZL) is an indolent lymphoproliferative disease morphologically composed of small heterogeneous B lymphocytes. It generally occurs with a localized stage and can arise in various organs, the most frequent being the stomach, lung, and ocular adnexa. Depending on the presentation and the possible association with infectious agents, different therapeutic approaches are to be undertaken. The purpose of this review is to describe the biology underlying this pathology, the diagnostic, and therapeutic approach.

Abstract

Extranodal Marginal Zone Lymphoma (EMZL lymphoma) is an indolent B-cell lymphoma with a median age at diagnosis of about 60 years. It accounts for 7–8% of all B-cell lymphomas. It can occur in various extranodal sites, including stomach, lung, ocular adnexa, and skin; furthermore, the disseminated disease can be found in 25–50% of cases. Several infectious agents, such as Helicobacter pylori (H. Pylori) in the case of gastric Mucosa Associated Lymphoid Tissue (MALT) Lymphoma, can drive the pathogenesis of this cancer, through the autoantigenic stimulation of T cells, but there may also be other factors participating such autoimmune diseases. Initial staging should include total body computed tomography, bone marrow aspirate, and endoscopic investigation if indicated. Fluorescence in situ hybridization (FISH), should be performed to detect the presence of specific chromosomal translocations involving the MALT1 and BCL10 genes, which leads to the activation of the NF-κB signaling pathway. Depending on the location and dissemination of the disease, different therapeutic choices may include targeted therapy against the etiopathogenetic agent, radiotherapy, immunochemotherapy, and biological drugs. The purpose of this review is to illustrate the complex biology and the diagnosis of this disease and to better define new treatment strategies.

The TNF-Alpha Inducing Protein is Associated With Gastric Inflammation and Hyperplasia in a Murine Model of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that colonizes the human stomach leading to the development of chronic gastritis, peptic ulcers and gastric adenocarcinoma. A combination of host, environment and bacterial virulence factors contribute to disease development. The H. pylori TNFα inducing protein (Tipɑ) is a virulence factor shown to induce multiple pro-inflammatory cytokines in addition to TNFα in vitro. The goal of the present study was to elucidate the role of Tipα in promoting inflammation in vivo and to identify the molecular pathways associated with Tipα associated virulence. Mice were infected with wild-type Sydney strain (SS1) or a tipα mutant (Δtipα) for 1 month and 4 months. We also completed a second 4 months infection including a 1:1 SS1 to Δtipα co-infected group in addition to SS1 and Δtipα infected groups. The expression of TNFα, and KC were significantly higher in the SS1 infected group compared to both uninfected control (naïve) and Δtipα groups. Mice infected with Tipα expressing SS1 induced more severe histological gastritis and developed hyperplasia compared to Δtipα infected mice. Microarray analysis of gastric epithelial cells co-cultured with recombinant Tipα (rTipα) demonstrates up-regulation of the NFκB pathway. This data suggest Tipα plays an important role in H. pylori induced inflammation.

Helicobacter pylori Infection of Primary Human Monocytes Boosts Subsequent Immune Responses to LPS

Infection with Helicobacter pylori (H. pylori) affects almost half of the world's population and is a major cause of stomach cancer. Although immune cells react strongly to this gastric bacterium, H. pylori is still one of the rare pathogens that can evade elimination by the host and cause chronic inflammation. In the present study, we characterized the inflammatory response of primary human monocytes to repeated H. pylori infection and their responsiveness to an ensuing bacterial stimulus. We show that, although repeated stimulations with H. pylori do not result in an enhanced response, H. pylori-primed monocytes are hyper-responsive to an Escherichia coli-lipopolysaccharide (LPS) stimulation that takes place shortly after infection. This hyper-responsiveness to bacterial stimuli is observed upon infection with viable H. pylori only, while heat-killed H. pylori fails to boost both cytokine secretion and STAT activation in response to LPS. When the secondary challenge occurs several days after the primary infection with live bacteria, H. pylori-infected monocytes lose their hyper-responsiveness. The observation that H. pylori makes primary human monocytes more susceptible to subsequent/overlapping stimuli provides an important basis to better understand how H. pylori can maintain chronic inflammation and thus contribute to gastric cancer progression.

Effects of Helicobacter pylori infection in gastrointestinal tract malignant diseases: From the oral cavity to rectum

Helicobacter pylori (H. pylori) has infected approximately fifty percent of humans for a long period of time. However, improvements in the public health environment have led to a decreased chance of H. pylori infection. However, a high infection rate is noted in populations with a high incidence rate of gastric cancer (GC). The worldwide fraction of GC attributable to H. pylori is greater than 85%, and a high H. pylori prevalence is noted in gastric mucosa-associated lymphoid tissue lymphoma patients. These results indicate that the majority of GC cases can be prevented if H. pylori infection is eliminated. Because H. pylori exhibits oral-oral or fecal-oral transmission, the relationship between this microorganism and other digestive tract malignant diseases has also attracted attention. This review article provides an overview of H. pylori and the condition of the whole gastrointestinal tract environment to further understand the correlation between the pathogen and the host, thus allowing improved realization of disease presentation.

Prevalence and risk factors of Helicobacter pylori infection in military personnel: a systematic review and meta-analysis

BACKGROUND AND AIMS

Helicobacter pylori infection is prevalent and recognized as a major cause of gastrointestinal diseases in the world. Previous studies on the prevalence of H. pylori infection in military personnel have shown some conflicting results. This study aimed to estimate the pooled prevalence of H. pylori infection and evaluate its risk factors in military personnel.

METHODS

The PubMed, EMBASE, and Cochrane Library databases were searched. We pooled the prevalence of H. pylori infection in military personnel using a random-effect model. Metaregression analysis was used to explore the sources of heterogeneity. Pooled proportion of H. pylori infection with 95% confidence interval (CI) was calculated.

RESULTS

Sixteen studies were included. Meta-analysis showed that the overall prevalence of H. pylori infection was 32% (95% CI = 31-33) in military personnel. There was a significant heterogeneity. Metaregression analysis showed that study region (P = 0.0004) and publication year (P = 0.023) were the potential sources of heterogeneity. In the subgroup analysis by study region, the highest prevalence was found in Asia (50.2%; 95% CI = 49-51.4). In the subgroup analysis by diagnostic methods for H. pylori, the highest prevalence was found when urea breath test was employed (47.9%; 95% CI = 46.5-49.3). The most common risk factor for H. pylori infection was familial aggregation, followed by living environment and age.

CONCLUSION

H. pylori infection is common in military personnel. In future, we may require appropriate population screening for H. pylori infection by multiple diagnostic tests and increase the knowledge and awareness of the bacterial transmission among military personnel.

Prognostic significance of serum immunoglobulin paraprotein in mucosa-associated lymphoid tissue (MALT) lymphoma

To assess the prognostic significance of immunoglobulin (Ig) paraproteinaemia in mucosa-associated lymphoid tissue (MALT) lymphoma, 218 patients diagnosed with MALT lymphoma were enrolled in this study. Serum Ig paraprotein was detected in 42 of 218 patients (19.3%), mostly IgM-K (15, 35.7%), followed by IgM-L and IgG-L. Advanced age (p = 0.025), poor Eastern Cooperative Oncology Group performance status (p = 0.014), bone marrow involvement (p = 0.019), B symptoms (p = 0.039), advanced disease stage (III-IV) (p < 0.0001), elevated serum β2-microglobulin level (p < 0.0001), multiple extranodal sites of involvement (p < 0.0001), nodal involvement (p < 0.0001), systemic therapy (p < 0.0001) and higher MALT-lymphoma International Prognostic Index (MALT-IPI) scores (p = 0.001) were significantly associated with the presence of serum Ig paraprotein. Multivariate Cox regression analysis showed that Ig paraproteinaemia was an independent prognostic predictor for inferior progression-free survival (PFS) and overall survival. A new prognostic index based on MALT-IPI and Ig paraproteinaemia, as assessed using receiver operating characteristic curves and the area under the curve statistics, showed better discriminative ability than MALT-IPI in predicting PFS. In conclusion, Ig paraproteinaemia was a promising prognostic predictor for MALT lymphoma. Ig paraproteinaemia together with MALT-IPI might contribute to optimising therapeutic management in clinical practice.

HomA and HomB, outer membrane proteins of Helicobacter pylori down-regulate activation-induced cytidine deaminase (AID) and Ig switch germline transcription and thereby affect class switch recombination (CSR) of Ig genes in human B-cells

H. pylori is one of the major causes of chronic gastritis, peptic ulcer disease (PUD), gastric mucosa-associated lymphoid tissue lymphoma (MALT) and gastric carcinoma. H. pylori toxin VacA is responsible for host cell apoptosis, whereas CagA is known to aberrantly induce expression of activation-induced cytidine deaminase (AID) in gastric epithelial cells that causes mutations in oncogenes and tumour suppressor genes, leading to the transformation of normal cells into cancerous cells. Although, a significant amount of research has been conducted to understand the role of bacterial factors modulating deregulated host cell pathways, the interaction between H. pylori and immune cells of the marginal zone and its consequences are still not well understood. HomB and HomA, outer membrane proteins (OMPs) from H. pylori, which assist in the adhesion of bacteria to host cells, are found to be associated with H. pylori virulent strains and promote inflammation. Interestingly, we observed that the interaction of HomB/HomA OMPs with B-cells transiently downregulates AID expression and Ig switch germline transcription. Downregulation of AID leads to impairment of class switch recombination (CSR), resulting in significantly reduced switching to IgG and IgA antibodies. Besides, we examined the immune-suppressive response of B-cells and observed that the cells stimulated with HomA/B show upregulation in the levels of IL10, IL35, as well as PDL1, a T-cell inhibition marker. Our study suggests the potential role of OMPs in immune response modulation strategies used by the pathogen to evade the immune response. These results provide a better understanding of H. pylori pathogenesis and assist in identifying novel targets for therapy.

[Gastric MALT lymphoma - from pathogenetic insights to consequent deescalation of therapy]

Gastric MALT- (mucosa-associated-lymphoid-tissue) lymphoma represents the most frequent gastrointestinal lymphoma. For decades, surgery and later on radiation and chemotherapy were regarded as established therapy. Some 30 years ago, the pathogenetic role of Helicobacter pylori infection for the development of gastric MALT-lymphoma became evident. During the following years, the pathogenetic insights were consequently implemented into clinical medicine. This lead to a radical change of the therapeutic approach to these lymphoma. Nowadays, Helicobacter pylori eradication is the internationally established therapy of first choice. It is followed by lymphoma regression in most cases. The long-term prognosis of patients after exclusive eradication therapy is excellent, even if endoscopic and/or histological residuals persist and a watch-and-wait strategy is favored.The pathogenetic insights und their clinical application implicated a consequent deescalation of therapy of gastric MALT-lymphoma. This review summarizes the single steps of this development and gives a recommendation for the actual management of patients with gastric MALT lymphoma.

Detrimental relevance of Helicobacter pylori infection with sarcopenia

BACKGROUND

Helicobacter pylori (H. pylori), Gram negative microaerophilic bacteria, is a well-known pathogen of many gastrointestinal diseases. But several emerging evidences suggest it role in numerous other extra-gastric diseases. The current study investigates the relationship between H. pylori infection and sarcopenia, a clinical condition characterized by the loss of mass and function of skeletal muscle. A total of 3453 eligible participants from the Third National Health and Nutrition Examination Survey (NHANES III), the United States, were enrolled. Based on the serum laboratory results, subjects were categorized into three groups: normal (without evidence of any H. pylori infection), anti-H. pylori IgG positive [H. pylori (+)], and concurrent anti-H. pylori IgG and anti-cytotoxin-associated gene A IgG positive [CagA (+)]. Sarcopenia was determined as having a skeletal muscle index (SMI) value that is more than 1 standard deviation away from the mean value of sex-specific, healthy young adults between 20 and 39 years old. Risk of sarcopenia and its components are compared between subgroups.

RESULTS

Odds ratios (OR) for confirmed diagnosis of sarcopenia were higher in H. pylori (+) (OR = 2.052, 95% CI 1.697-2.481, p < 0.001) and CagA (+) (OR = 1.585, 95% CI 1.278-1.965, p < 0.001) groups. Moreover, negative beta regression coefficient of SMI were shown in H. pylori (+) (β: - 0.023, p < 0.001) and CagA (+) (β: - 0.017, p < 0.001). Sub-analyses which categorized participants by gender revealed that absolute value of beta regression coefficient for SMI were higher in female in H. pylori (+) subgroup (β: - 1.745 in male and - 2.942 in female, p were both < 0.001), and the CagA (+) subgroup (β: - 1.407 in male and - 2.159 in female, p were both < 0.001).

CONCLUSIONS

Positive serum H. pylori infectious markers including anti-H. pylori antibody and CagA seropositivity are correlated with sarcopenia and low muscle quantity. Therefore, H. pylori eradication therapy may bring benefits to sarcopenia patients with concurrent active H. pylori infection.

A systematic review of primary gastric diffuse large B-cell lymphoma: Clinical diagnosis, staging, treatment and prognostic factors

Primary gastric lymphoma (PGL) is a rare clinical entity accounting for the majority of extra-nodal non-Hodgkin lymphoma (EN-NHL). The most common histological subtype is the primary gastric diffuse large B-cell lymphoma (PG-DLBCL) with a media age of 50-60 years old, mostly in male. Pathogenesis is often related to some bacterial infection such as Helicobacter pylori (H. pylori) infection. However, due to various available staging system, there is still no consensus on the staging of PG-DLBCL. The international prognostic index (IPI) is the most valuable used for the stratification of almost all subtype of NHL and as well as for PG-DLBCL. As for treatment strategies, surgery, chemotherapy, radiation therapy and antibiotic therapy in various combinations have been applied in clinical treatment. There are a few well-known prognostic factors and some of them may constitute prognostic models. Due to the increasing incidence of this neoplasm, it is necessary for clinicians to make deep insight of the diagnosis, staging, treatment and prognostic factors of PG-DLBCL.

Dysregulation of miRNAs in DLBCL: Causative Factor for Pathogenesis, Diagnosis and Prognosis

MicroRNA is a small non-coding RNA (sncRNA) involved in gene silencing and regulating post-transcriptional gene expression. miRNAs play an essential role in the pathogenesis of numerous diseases, including diabetes, cardiovascular diseases, viral diseases and cancer. Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin's lymphoma (NHL), arising from different stages of B-cell differentiation whose pathogenesis involves miRNAs. Various viral and non-viral vectors are used as a delivery vehicle for introducing specific miRNA inside the cell. Adenoviruses are linear, double-stranded DNA viruses with 35 kb genome size and are extensively used in gene therapy. Meanwhile, Adeno-associated viruses accommodate up to 4.8 kb foreign genetic material and are favorable for transferring miRNA due to small size of miRNA. The genetic material is integrated into the DNA of the host cell by retroviruses so that only dividing cells are infected and stable expression of miRNA is achieved. Over the years, remarkable progress was made to understand DLBCL biology using advanced genomics and epigenomics technologies enabling oncologists to uncover multiple genetic mutations in DLBCL patients. These genetic mutations are involved in epigenetic modification, ability to escape immunosurveillance, impaired BCL6 and NF-κβ signaling pathways and blocking terminal differentiation. These pathways have since been identified and used as therapeutic targets for the treatment of DLBCL. Recently miRNAs were also identified to act either as oncogenes or tumor suppressors in DLBCL pathology by altering the expression levels of some of the known DLBCL related oncogenes. i.e., miR-155, miR-17-92 and miR-21 act as oncogenes by altering the expression levels of MYC, SHIP and FOXO1, respectively, conversely; miR-34a, mir-144 and miR-181a act as tumor suppressors by altering the expression levels of SIRT1, BCL6 and CARD11, respectively. Hundreds of miRNAs have already been identified as biomarkers in the prognosis and diagnosis of DLBCL because of their significant roles in DLBCL pathogenesis. In conclusion, miRNAs in addition to their role as biomarkers of prognosis and diagnosis could also serve as potential therapeutic targets for treating DLBCL.

The Helicobacter pylori CagY Protein Drives Gastric Th1 and Th17 Inflammation and B Cell Proliferation in Gastric MALT Lymphoma

Background: the neoplastic B cells of the Helicobacter pylori-related low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma proliferate in response to H. pylori, however, the nature of the H. pylori antigen responsible for proliferation is still unknown. The purpose of the study was to dissect whether CagY might be the H. pylori antigen able to drive B cell proliferation. Methods: the B cells and the clonal progeny of T cells from the gastric mucosa of five patients with MALT lymphoma were compared with those of T cell clones obtained from five H. pylori–infected patients with chronic gastritis. The T cell clones were assessed for their specificity to H. pylori CagY, cytokine profile and helper function for B cell proliferation. Results: 22 of 158 CD4⁺ (13.9%) gastric clones from MALT lymphoma and three of 179 CD4⁺ (1.7%) clones from chronic gastritis recognized CagY. CagY predominantly drives Interferon-gamma (IFN-γ) and Interleukin-17 (IL-17) secretion by gastric CD4⁺ T cells from H. pylori-infected patients with low-grade gastric MALT lymphoma. All MALT lymphoma-derived clones dose dependently increased their B cell help, whereas clones from chronic gastritis lost helper activity at T-to-B-cell ratios greater than 1. Conclusion: the results obtained indicate that CagY drives both B cell proliferation and T cell activation in gastric MALT lymphomas.