CXCR4 PET/MRI for follow-up of gastric mucosa-associated lymphoid tissue lymphoma after first-line Helicobacter pylori eradication.

Posttreatment evaluation of gastric mucosa-associated lymphoid tissue (MALT) lymphoma currently relies on esophagogastroduodenoscopy with histological assessment of biopsies. Overexpression of the G protein-coupled C-X-C chemokine receptor type 4 (CXCR4) has been previously observed in MALT lymphoma. The aim of this prospective study was to evaluate positron emission tomography (PET) with the novel CXCR4 tracer [68Ga]Pentixafor as a potential alternative to follow up biopsies for assessment of residual disease (noncomplete remission [CR]) after first-line Helicobacter pylori eradication. Forty-six post-H pylori eradication [68Ga]Pentixafor-PET/magnetic resonance imaging (MRI) examinations of 26 gastric MALT lymphoma patients, and 20 [68Ga]Pentixafor-PET/MRI examinations of 20 control group patients without lymphoma, were analyzed. In the MALT lymphoma group, time-matched gastric biopsies were used as reference standard and showed CR in 6 cases. Pooled examination-based accuracy, sensitivity, specificity, and positive and negative predictive values of [68Ga]Pentixafor-PET for detection of residual gastric MALT lymphoma at follow-up were 97.0%, 95.0%, 100.0%, 100.0%, and 92.9%, respectively. Maximum and mean PET standardized uptake values showed moderate correlation with immunohistochemistry-based CXCR4+ cell counts, with correlation coefficients of r = 0.51 and r = 0.52 (P = .008 and P = .006). In summary, CXCR4 imaging with [68Ga]Pentixafor-PET may represent a promising test for assessment of residual gastric MALT lymphomas after H pylori eradication.

Helicobacter pylori-Associated Extranodal Marginal Zone Lymphoma of Mucosa-Associated Tissue in Children: A Multicenter Case Series.

OBJECTIVE: Data regarding Helicobacter pylori (H. pylori)-associated mucosa-associated lymphoid tissue (MALT) lymphoma in children are lacking. We aimed to characterize the diagnosis, management, and outcome of H. pylori-associated MALT lymphoma in pediatric patients. STUDY DESIGN: A retrospective multicenter case series of the pediatric patients with H. pylori-associated MALT lymphoma who were diagnosed during 2010-2022. RESULTS: Five children, of them three females, were identified. The mean age at diagnosis was 14.6 ± 2.4 years. The clinical presentation included abdominal pain (5/5), nausea (3/5), weight loss, night sweats, recurrent fever (1/5), and iron deficiency anemia (2/5). Endoscopic findings in both the stomach antrum and body included a fragile and hyperemic mucosa, large ulcers, extensive nodularity, and exudate. All the biopsies from the gastric mucosa were consistent with MALT lymphoma, and positive for H. pylori (by Giemsa stain). All the patients received triple therapy (amoxicillin, nitroimidazole, or a macrolide, and a proton pump inhibitor, for 14 days), and achieved H. pylori eradication. All had complete resolution of histological findings at the last follow-up. In one patient, the histology of MALT lymphoma persisted 12 months after H. pylori eradication, and only the 18-month-biopsy was free of residual disease. CONCLUSIONS: In this series of pediatric MALT lymphoma, complete resolution of disease occurred in all the patients, yet histological remission was delayed in one. This supports the importance of endoscopic follow-up.

Clinicopathologic characteristics and treatment of marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma).

Extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) accounts for 7% to 8% of newly diagnosed lymphomas. Because of its association with infectious causes, such as Helicobacter pylori (HP) or Chlamydophila psittaci (CP), and autoimmune diseases, it has become the paradigm of an antigen-driven malignancy. MALT lymphoma usually displays an indolent course, and watch-and-wait strategies are justified initially in a certain percentage of patients. In patients with gastric MALT lymphoma or ocular adnexal MALT lymphoma, antibiotic therapy against HP or CP, respectively, is the first-line management of choice, resulting in lymphoma response rates from 75% to 80% after HP eradication and from 33% to 65% after antibiotic therapy for CP. In patients who have localized disease that is refractory to antibiotics, radiation is widely applied in various centers with excellent local control, whereas systemic therapies are increasingly being applied, at least in Europe, because of the potentially systemic nature of the disease. Therefore, the objective of this review is to briefly summarize the clinicopathologic characteristics of this distinct type of lymphoma along with current data on management strategies.

Innate Immune Molecule NLRC5 Protects Mice From Helicobacter-induced Formation of Gastric Lymphoid Tissue.

BACKGROUND & AIMS: Helicobacter pylori induces strong inflammatory responses that are directed at clearing the infection, but if not controlled, these responses can be harmful to the host. We investigated the immune-regulatory effects of the innate immune molecule, nucleotide-binding oligomerization domain-like receptors (NLR) family CARD domain-containing 5 (NLRC5), in patients and mice with Helicobacter infection. METHODS: We obtained gastric biopsies from 30 patients in Australia. We performed studies with mice that lack NLRC5 in the myeloid linage (Nlrc5møKO) and mice without Nlrc5 gene disruption (controls). Some mice were gavaged with H pylori SS1 or Helicobacter felis; 3 months later, stomachs, spleens, and sera were collected, along with macrophages derived from bone marrow. Human and mouse gastric tissues and mouse macrophages were analyzed by histology, immunohistochemistry, immunoblots, and quantitative polymerase chain reaction. THP-1 cells (human macrophages, controls) and NLRC5-/- THP-1 cells (generated by CRISPR-Cas9 gene editing) were incubated with Helicobacter and gene expression and production of cytokines were analyzed. RESULTS: Levels of NLRC5 messenger RNA were significantly increased in gastric tissues from patients with H pylori infection, compared with patients without infection (P < .01), and correlated with gastritis severity (P < .05). H pylori bacteria induced significantly higher levels of chemokine and cytokine production by NLRC5-/- THP-1 macrophages than by control THP-1 cells (P < .05). After 3 months of infection with H felis, Nlrc5mø-KO mice developed gastric hyperplasia (P < .0001), splenomegaly (P < .0001), and increased serum antibody titers (P < .01), whereas control mice did not. Nlrc5mø-KO mice with chronic H felis infection had increased numbers of gastric B-cell follicles expressing CD19 (P < .0001); these follicles had features of mucosa-associated lymphoid tissue lymphoma. We identified B-cell-activating factor as a protein that promoted B-cell hyperproliferation in Nlrc5mø-KO mice. CONCLUSIONS: NLRC5 is a negative regulator of gastric inflammation and mucosal lymphoid formation in response to Helicobacter infection. Aberrant NLRC5 signaling in macrophages can promote B-cell lymphomagenesis during chronic Helicobacter infection.

Involvement of non-Helicobacter pylori helicobacter infections in Helicobacter pylori-negative gastric MALT lymphoma pathogenesis and efficacy of eradication therapy.

BACKGROUND: Eradication therapy is known to be effective against Helicobacter pylori-positive gastric MALT lymphoma but predicting the efficacy of eradication therapy against Helicobacter pylori-negative gastric MALT lymphoma is difficult. Recent reports have shown that non-Helicobacter pylori helicobacter infections induce gastric MALT lymphoma, and we aimed to clarify whether non-Helicobacter pylori helicobacter infections are associated with the efficacy of eradication therapy. METHODS: We analyzed eradication therapy as a first-line treatment for 182 cases of gastric MALT lymphoma, classified according to Helicobacter pylori infection and API2-MALT1 mutation status. We also evaluated the non-Helicobacter pylori helicobacter infection status in 29 Helicobacter pylori-negative cases via PCR with DNA extracted from paraffin-embedded biopsy tissues. Finally, we analyzed the relationship between non-Helicobacter pylori helicobacter infection status and eradication therapy outcome. RESULTS: The API2-MALT1 mutation was observed in 13/182 patients (7.1%), none of whom were cured by eradication therapy. Helicobacter pylori-negative cases had a significantly higher non-Helicobacter pylori helicobacter infection rate than Helicobacter pylori-positive cases (16/29, 55% vs. 3/29, 10%; P < 0.05). Among the Helicobacter pylori-negative cases, non-Helicobacter pylori helicobacter-positive cases had a significantly higher complete response rate than non-Helicobacter pylori helicobacter-negative cases (12/16, 75% vs. 3/13, 23%; P < 0.05). CONCLUSION: Helicobacter pylori-negative and API2-MALT1-negative gastric MALT lymphoma cases exhibited a high rate of non-Helicobacter pylori helicobacter infections, which may have contributed to the success of eradication therapy. Therefore, we recommend eradication therapy as a first-line treatment for non-Helicobacter pylori helicobacter-positive gastric MALT lymphoma.

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.

Bacterial Infection and Non-Hodgkin B-Cell Lymphoma: Interactions between Pathogen, Host and the Tumor Environment.

Non-Hodgkin B-cell lymphomas (NHL) are a heterogeneous group of lymphoid neoplasms with complex etiopathology, rich symptomatology, and a variety of clinical courses, therefore requiring different therapeutic approaches. The hypothesis that an infectious agent may initiate chronic inflammation and facilitate B lymphocyte transformation and lymphogenesis has been raised in recent years. Viruses, like EBV, HTLV-1, HIV, HCV and parasites, like Plasmodium falciparum, have been linked to the development of lymphomas. The association of chronic Helicobacter pylori (H. pylori) infection with mucosa-associated lymphoid tissue (MALT) lymphoma, Borrelia burgdorferi with cutaneous MALT lymphoma and Chlamydophila psittaci with ocular adnexal MALT lymphoma is well documented. Recent studies have indicated that other infectious agents may also be relevant in B-cell lymphogenesis such as Coxiella burnettii, Campylobacter jejuni, Achromobacter xylosoxidans, and Escherichia coli. The aim of the present review is to provide a summary of the current literature on infectious bacterial agents associated with B-cell NHL and to discuss its role in lymphogenesis, taking into account the interaction between infectious agents, host factors, and the tumor environment.

MALT Lymphoma as a Model of Chronic Inflammation-Induced Gastric Tumor Development.

Mucosa-associated lymphoid tissue (MALT) lymphoma, or extranodal marginal zone lymphoma of MALT, is an indolent B-cell non-Hodgkin lymphoma linked with preexisting chronic inflammation. The stomach is the most commonly affected organ and the MALT lymphoma pathogenesis is clearly associated with Helicobacter pylori gastroduodenitis. Inflammation induces the lymphoid infiltrates in extranodal sites, where the lymphoma then subsequently develops. Genetic aberrations arise through the release of reactive oxygen species (ROS), H. pylori-induced endonucleases, and other effects. The involvement of nuclear factor kappa B (NF-κB) pathway activation, a critical regulator of pro-inflammatory responses, further highlights the role of inflammation in gastric MALT lymphoma. The NF-κB pathway regulates key elements of normal lymphocyte function, including the transcription of proliferation-promoting and anti-apoptotic genes. Aberrant constitutive activation of NF-κB signaling can lead to autoimmunity and malignancy. NF-κB pathway activation can happen through both the canonical and non-canonical pathways and can be caused by multiple genetic aberrations such as t(11;18)(q12;q21), t(1;14)(p22;q32), and t(14;18)(q32;q21) translocations, chronic inflammation and even directly by H. pylori-associated mechanisms. Gastric MALT lymphoma is considered one of the best models of how inflammation initiates genetic events that lead to oncogenesis, determines tumor biology, dictates clinical behavior and leads to viable therapeutic targets. The purpose of this review is to present gastric MALT lymphoma as an outstanding example of the close pathogenetic link between chronic inflammation and tumor development and to describe how this information can be integrated into daily clinical practice.

Primary gastric lymphoma: A report of 16 pediatric cases treated at a single institute and review of the literature.

Gastrointestinal tract is the most common extranodal site for childhood non-Hodgkin lymphomas (NHLs). However, primary gastric lymphoma (PGL) is very rare. We report our experience with PGL. Between 1972 and 2019, patients with PGL among 1696 NHL cases were evaluated retrospectively. Patient characteristics, treatments, and survival rates were recorded. We also reviewed the cases reported in literature. There were 16 PGL (11 males, five females) cases with a median age of 10 years. Most frequent complaints, similarly to the literature, were pain and vomiting. Hematemesis/melena and anemia were present in 20% of patients. Most common tumor location was antrum. Histopathological subtypes were Burkitt and non-Burkitt B-cell lymphoma in 43.75% and marginal zone lymphoma (MZL) in 6.25% of cases while mucosa-associated lymphoid tissue (MALT) and low-grade lymphomas constitute 15.3% of cases reported in the literature. In our series, Helicobacter pylori (H. pylori) was analyzed in only the case with MZL and found to be positive. However, H. pylori positivity was reported in 75% of the cases in the literature. H. pylori eradication, chemotherapy, and radiotherapy were applied in one, 14, and five patients. Subtotal gastrectomy with gastroduodenostomy/jejunostomy was performed in three patients. Gastrojejunostomy was done without tumor resection in two patients. Nine patients lived without disease for a median of 59 (12-252) months. Five-year EFS and OS were 69.6% and 64.3%, respectively. PGL constitutes 0.94% of our NHL cases. Interestingly, most of the cases in the literature were from Turkey. While adult PGL is mostly MALT lymphoma, most pediatric cases had high-grade histopathology. Although surgery and radiotherapy were applied earlier, chemotherapy alone is sufficient.

Heterogeneity of clinical management of low-grade gastric lymphoma of mucosa-associated lymphoid tissue. An audit of 198 patients in Spain.

INTRODUCTION: Cure of Helicobacter pylori infection in patients with gastric lymphoma of mucosa-associated lymphoid tissue (MALT) leads to long-term clinical remission in the initial stages. As it is a rare disease, its management in clinical practice remains largely unknown and heterogeneity of care remains a concern. The aim was to audit the management and evolution of a large series of low-grade gastric MALT lymphomas from thirteen Spanish hospitals. MATERIALS AND METHODS: Multicentre retrospective study including data on the diagnosis and follow-up of patients with gastric low-grade MALT lymphoma from January 1998 to December 2013. Clinical, biological and pathological data were analyzed and survival curves were drawn. RESULTS: One-hundred and ninety-eight patients were included. Helicobacter pylori was present in 132 (69%) patients and 103 (82%) in tumors confined to the stomach (stage EI) and was eradicated in 92% of patients. Chemotherapy was given in 90 (45%) patients and 43 (33%) with stage EI. Marked heterogeneity in the use of diagnostic methods and chemotherapy was observed. Five-year overall survival was 86% (89% in EI). Survival was similar in EI patients receiving aggressive treatment and in those receiving only antibiotics (p=0.577). DISCUSSION: Gastric MALT lymphoma has an excellent prognosis. We observed, however, a marked heterogeneity in the use of diagnostic methods or chemotherapy in early-stage patients.

Validation of the Marginal Zone Lymphoma International Prognostic Index.

The Marginal Zone Lymphoma International Prognostic Index (MALT-IPI) was recently developed for use in patients with mucosa-associated lymphoid tissue (MALT) lymphoma based on age, serum lactate dehydrogenase level, and Ann Arbor stage. In this study, we aimed to validate the MALT-IPI. A total of 455 MALT lymphoma patients were included in this study from between January 2005 and February 2017. Event-free survival (EFS), progression-free survival (PFS), cause-specific survival (CSS), and overall survival (OS) were the primary outcomes. Of the 455 patients, MALT-IPI low-, intermediate-, and high-risk groups included 309 (67.9%), 126 (27.7%), and 20 (4.4%) individuals, respectively. When comparing the low-risk group (L MALT-IPI) with the intermediate-high-risk group (I-H MALT-IPI), EFS, PFS, CSS, and OS were significantly different (p = 0.000, p = 0.000, p = 0.027, and p = 0.037). The International Prognostic Index and the Follicular Lymphoma International Prognostic Index failed to predict the prognosis of MALT lymphoma. Use of the MALT-IPI significantly differentiated L MALT-IPI from I-H MALT-IPI with respect to EFS, PFS, CSS, and OS. MALT-IPI is a valuable tool for the prediction of MALT lymphoma prognosis.

Helicobacter pylori (HP) infection alone, but not HP-induced atrophic gastritis, increases the risk of gastric lymphoma: a case-control study in Japan.

Infection with Helicobacter pylori (H. pylori) is associated with an increased risk of gastric malignant lymphoma. The chronic inflammation of gastric mucosa by H. pylori infection induces lymphomagenesis. Although this chronic mucosal inflammation also results in atrophic gastritis, evidence supporting the possible significance of atrophic gastritis in gastric lymphomagenesis is scarce. Here, to evaluate the association between gastric mucosal atrophy and the risk of gastric lymphoma, we conducted a matched case-control study at Aichi Cancer Center focusing on the attribution of H. pylori infection status and pepsinogen (PG) serum levels. In total, 86 patients with gastric lymphoma (including 49 cases of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) and 24 cases of diffuse large B cell lymphoma (DLBCL)) and 1720 non-cancer controls were included. Odds ratios (ORs) and 95% confidence intervals (CIs) were assessed by conditional logistic regression analysis with adjustment for potential confounders. Results failed to show a statistically significant association between atrophic gastritis and the risk of gastric lymphoma. The adjusted ORs of positive atrophic gastritis relative to negative for overall gastric lymphoma, MALT lymphoma, DLBCL, and other lymphomas were 0.77 (95% CI 0.45-1.33), 0.65 (0.30-1.39), 1.03 (0.38-2.79), and 0.84 (0.22-3.29), respectively. In contrast, a positive association between overall gastric lymphoma and H. pylori infection was observed (OR = 2.14, 95% CI 1.30-3.54). A consistent association was observed for MALT lymphoma, DLBCL, and other lymphomas with ORs of 1.96 (1.00-3.86), 1.92 (0.74-4.95), and 5.80 (1.12-30.12), respectively. These findings suggest that H. pylori infection triggers gastric lymphoma but that epithelial changes due to atrophic gastritis do not inherently affect the development of gastric lymphoma.

A Unique Case of Primary Extranodal Marginal Zone Lymphoma of the Anal Canal.

Marginal zone lymphomas represent approximately 10-12% of all B-cell lymphomas. Extranodal marginal zone lymphomas (EMZL) or mucosa-associated lymphoid tissue (MALT) lymphomas are the most common subtype. Almost half of all MALT lymphomas arise in the gastrointestinal (GI) tract and, while the stomach is the most common site of GI involvement, the small and large intestines can also be involved. Rare cases of MALT lymphoma involving the rectum have been reported; however, to our knowledge, involvement of the anal canal has never been reported in the literature. Here, we describe a unique case of MALT lymphoma of the anal canal. Infectious agents have been implicated in the pathogenesis of MALT lymphomas, possibly through persistent antigenic stimulation of the area; however, in our case no such infection was documented.

Epidemiological characterization, genetic alterations of Helicobacter pylori infection in chronic gastric disorder and prognostic values of heterozygosity loss in chromosome 3p.

From the literature review, there seem to be no studies conducted on infection caused by Helicobacter pylori in patients with gastric MALT lymphoma in the KSA region. The present research is an attempt to understand the prevalence of patients infected with H. pylori in the selected region and the role of allelic imbalance of chromosome 3p regions to understand the clinical manifestations and features associated with MALT lymphomagenesis. The researcher analyzed the frequency of infection in patients from the region of Saudi Arabia by examining the data collected from hospitals and biopsy tissue samples as per the recommended protocol. The endoscopic diagnosis was performed to collect biopsy samples. Histology and AP-PCR DNA fingerprinting analyses were performed from the endoscopic gastric mucosal biopsies collected from patients with associated gastric MALT lymphoma. The existence of H. pylori was examined based on the results of gastric mucosal biopsies stained with hematoxylin-eosin (H&E) and Steiner's silver stains. MALT, MALT lymphoma tissue samples and H. pylori-positive chronic gastritis were examined for LOH at chromosome 3p24 using standard procedures and techniques. The findings of the paper revealed the H. pylori was found to be positive in 17% of the cases significantly high among the age group of 31-50 years. Patients with MALT, MALT lymphoma, and H. pylori-associated gastritis presented features such as lymphocyte accumulation, vacuolation, Peyer's patch appearance, and lymphatic follicles. H. pylori were found to appear as a dense colored accumulated mass in the gastric epithelial layer. The findings from AP-PCR generated DNA fingerprints revealed intense band including two prominent bands in MALT lymphoma. Among other loci, 3p24 was the only one locus that showed high percentages of LOH as reported earlier in all cancer-related cases. The findings of this research paper empower the fact that allelic imbalances play a vital role in the development of MALT lymphoma. However, future researches should be conducted to identify the chromosome regions of the AP-PCR generated DNA fingerprints of human gastric MALT lymphoma in order to confirm this proposition.

The Role of Host Genetic Polymorphisms in Helicobacter pylori Mediated Disease Outcome.

The clinical outcome of infection with the chronic gastric pathogen Helicobacter pylori is not the same for all individuals and also differs in different ethnic groups. Infection occurs in early life (<3 years of age), and while all infected persons mount an immune response and develop gastritis, the majority of individuals are asymptomatic. However, up to 10-15% develop duodenal ulceration, up to 1% develop gastric cancer (GC) and up to 0.1% can develop gastric mucosa-associated lymphoid tissue (MALT) lymphoma. The initial immune response fails to clear infection and H. pylori can persist for decades. H. pylori has been classified as a group one carcinogen by the WHO. Interestingly, development of duodenal ulceration protects against GC. Factors that determine the outcome of infection include the genotype of the infecting strains and the environment. Host genetic polymorphisms have also been identified as factors that play a role in mediating the clinical outcome of infection. Several studies present compelling evidence that polymorphisms in genes involved in the immune response such as pro and anti-inflammatory cytokines and pathogen recognition receptors (PRRs) play a role in modulating disease outcome. However, as the number of studies grows emerging confounding factors are small sample size and lack of appropriate controls, lack of consideration of environmental and bacterial factors and ethnicity of the population. This chapter is a review of current evidence that host genetic polymorphisms play a role in mediating persistent H. pylori infection and the consequences of the subsequent inflammatory response.

[Microbial regulation of tumor development and responses to tumor therapy]. / Mikrobielle Einflüsse in der Tumorentwicklung und Tumortherapie.

Viruses and bacteria play central roles in gastrointestinal tumor development. This includes well-characterized contributions of Helicobacter pylori to gastric carcinoma and MALT lymphoma and of Hepatitis B and C virus infections to hepatocellular cancer. However, recent studies have demonstrated a much broader role of the microbiota in the regulation of cancer development. As such, it was shown that barrier defects and alterations in microbial community structure contribute to colorectal and hepatocellular cancer. Moreover, intriguing studies have highlighted the microbiota as a central regulator of the efficacy of systemic anti-tumor therapies. Here, we provide an overview of recent observations on the role of the microbiota in tumor development and the regulation of therapeutic anti-tumor responses and discuss the implications of these findings for clinical diagnostics and treatment.

Patients with gastric MALT lymphoma revealing persisting endoscopic abnormalities after successful eradication of Helicobacter pylori can be safely managed by a watch-and-wait strategy.

BACKGROUND: In current guidelines, Helicobacter pylori eradication is recommended as first-line therapy in patients with gastric MALT lymphoma. This leads to complete lymphoma regression in the majority of patients. Those who show persisting histological residuals of lymphoma after eradication of the bacterium and normalization of endoscopic findings are managed by a watch-and-wait strategy. We aim to show that such an approach can be extended to patients with persisting endoscopic abnormalities. METHODS: Thirteen patients (7 female and 6 male; 62 years, range: 43 - 80) with gastric MALT lymphoma of stages I and II1 had received exclusive H. pylori eradication. Control endoscopies performed every 3 - 4 months during the first 2 years and 6 and 12 times monthly 2 - 5 and > 5 years after diagnosis, respectively, revealed successful eradication of H. pylori but persisting endoscopic abnormalities. Histologically, complete regression of the lymphoma or minor residuals were observed. RESULTS: Persisting endoscopic changes included thickened folds with or without superficial erosions, nodular mucosal surface with or without angiectasia, focal or diffuse atrophy, focal erythema, or a mixture of these findings. During a follow-up of 89.9 (12 - 329) months, the outcome of these patients was excellent with no single case of lymphoma progression. CONCLUSION: A watch-and-wait strategy can be recommended for patients with gastric MALT lymphoma showing persisting endoscopic abnormalities after eradication of H. pylori. There is no need for any oncological treatment provided that regular endoscopic-bioptic controls do not reveal any progressive changes. A standardized description of the endoscopic changes as well as a thorough bioptic technique should be included.

A New Animal Model of Gastric Lymphomagenesis: APRIL Transgenic Mice Infected by Helicobacter Species.

APRIL is a member of the tumor necrosis factor cytokine family involved in the regulation of B-cell immunity. We present a study of the infection by Helicobacter species of transgenic (Tg) C57BL6 mice, ectopically expressing the human form of APRIL. Wild-type (WT) and APRIL Tg mice were infected with Helicobacter felis and Helicobacter pylori and compared with noninfected animals. Mice were euthanized 18 months after infection, and inflammatory responses and histologic alterations were analyzed. Flow cytometry results revealed that WT-infected mice had less leukocyte infiltration than APRIL Tg-infected mice. In WT-infected mice, infiltrates in gastric tissues were predominantly composed of T cells, mainly CD4+ for H. pylori and CD8+ for H. felis. In APRIL Tg-infected mice, leukocyte infiltrates were composed of B cells with few CD4+ T cells for both species. B cells expressed B surface markers compatible with a marginal zone origin. These results were confirmed by immunohistochemistry. B cells in particular were involved in lymphoepithelial lesions, a hallmark of gastric MALT lymphoma. Monoclonality was observed in a few infiltrates in the presence of lymphoepithelial lesions. These results confirm the importance of APRIL in the development of gastric lymphoid infiltrates induced by Helicobacter species in vivo. We believe that APRIL Tg mice infected by Helicobacter species may represent a novel animal model of gastric lymphomagenesis.

The spectrum of MALT lymphoma at different sites: biological and therapeutic relevance.

Extranodal marginal zone (MZ) B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. The best evidence of an etiopathogenetic link is provided by the association between Helicobacter pylori-positive gastritis and gastric MALT lymphoma. Indeed, successful eradication of this microorganism with antibiotics can be followed by gastric MALT lymphoma regression in most cases. Other microbial agents have been implicated in the pathogenesis of MZ lymphoma arising at different sites. Apart from gastric MALT lymphoma, antibiotic therapies have been adequately tested only in ocular adnexal MALT lymphomas where upfront doxycycline may be a reasonable and effective initial treatment of patients with Chlamydophila psittaci-positive lymphoma before considering more aggressive strategies. In all other instances, antibiotic treatment of nongastric lymphomas remains investigational. Indeed, there is no clear consensus for the treatment of patients with gastric MALT lymphoma requiring further treatment beyond H pylori eradication or with extensive disease. Both radiotherapy and systemic treatments with chemotherapy and anti-CD20 antibodies are efficacious and thus the experience of individual centers and each patient's preferences in terms of adverse effects are important parameters in the decision process.

Cholesterol-α-glucosyltransferase gene is present in most Helicobacter species including gastric non-Helicobacter pylori helicobacters obtained from Japanese patients.

BACKGROUND: Non-Helicobacter pylori helicobacters (NHPHs) besides H. pylori infect human stomachs and cause chronic gastritis and mucosa-associated lymphoid tissue lymphoma. Cholesteryl-α-glucosides have been identified as unique glycolipids present in H. pylori and some Helicobacter species. Cholesterol-α-glucosyltransferase (αCgT), a key enzyme for the biosynthesis of cholesteryl-α-glucosides, plays crucial roles in the pathogenicity of H. pylori. Therefore, it is important to examine αCgTs of NHPHs. MATERIALS AND METHODS: Six gastric NHPHs were isolated from Japanese patients and maintained in mouse stomachs. The αCgT genes were amplified by PCR and inverse PCR. We retrieved the αCgT genes of other Helicobacter species by BLAST searches in GenBank. RESULTS: αCgT genes were present in most Helicobacter species and in all Japanese isolates examined. However, we could find no candidate gene for αCgT in the whole genome of Helicobacter cinaedi and several enterohepatic species. Phylogenic analysis demonstrated that the αCgT genes of all Japanese isolates show high similarities to that of a zoonotic group of gastric NHPHs including Helicobacter suis, Helicobacter heilmannii, and Helicobacter ailurogastricus. Of 6 Japanese isolates, the αCgT genes of 4 isolates were identical to that of H. suis, and that of another 2 isolates were similar to that of H. heilmannii and H. ailurogastricus. CONCLUSIONS: All gastric NHPHs examined showed presence of αCgT genes, indicating that αCgT may be beneficial for these helicobacters to infect human and possibly animal stomachs. Our study indicated that NHPHs could be classified into 2 groups, NHPHs with αCgT genes and NHPHs without αCgT genes.