Regression of primary gastric lymphoma of mucosa-associated lymphoid tissue type after cure of Helicobacter pylori infection. MALT Lymphoma Study Group

Gastric low-grade mucosa-associated lymphoid tissue lymphomas: their histogenesis and high-grade transformation

Gastric low-grade mucosa-associated lymphoid tissue (MALT) lymphoma is a unique disease. A vast majority of lymphoma cells are centrocyte-like cells or resemble monocytoid B cells, and occasionally show plasmacytic differentiation. Immunophenotypical and immunogenotypical examinations have indicated that they are in the differentiation stage of memory B cells, whose normal counterparts are marginal zone lymphocytes or monocytoid B cells in the lymphoid tissues. It arises from chronic gastritis closely associated with Helicobacter pylori (H. pylori) infection. Mucosa-associated lymphoid tissue lymphomas of other organs are also based on acquired MALT associated with chronic inflammation or autoimmune diseases. Interestingly, the majority of gastric low-grade MALT lymphomas regress by the eradication of H. pylori. The lymphoma cells, however, are not derived from B cells reacting with H. pylori itself but from autoreactive B cells. Although the mechanism of their oncogenesis has not been clarified, previous data suggest that autoreactive B cells proliferate in response to H. pylori-specific T cells, presumably with some cytokines. The genetic instability of such B cells then induces chromosomal abnormalities including trisomy 3 and/or other genetic changes. These B cells have the ability of autonomic proliferation and, even so, they might be sensitive to T cell stimuli. Low-grade gastric lymphomas occasionally progress to high-grade malignancy. The high-grade component of MALT lymphomas are composed of large-sized lymphoma cells that are morphologically indistinguishable from nodal large B cell lymphomas. This high-grade transformation is associated with p53 abnormalities or Bcl-6 overexpression. Gastric MALT lymphoma may provide a useful model in understanding multistep lymphomagenesis.

Treatment of gastric MALT lymphoma by Helicobacter pylori eradication: a study controlled by endoscopic ultrasonography

OBJECTIVE

Previous studies have demonstrated a link between Helicobacter pylori infection and low grade B-cell gastric MALT lymphoma. The aim of this study was to evaluate the effect of Helicobacter pylori eradication in 17 patients with low grade B-cell gastric MALT lymphoma stage EI.

METHODS

For disease staging EUS and CT scan were systematically performed. Eight patients were excluded from the present series because stage EII disease was diagnosed. To demonstrate B-cell monoclonality, immunohistochemistry and polymerase chain reaction were used. H. pylori eradication was performed with triple therapy.

RESULTS

H. pylori was eradicated in all patients after first (n = 15) or second line (n = 2) treatment. Histologic regression of lymphoma was observed in all patients after a median period of 2 mo. Disappearance of monoclonality according to polymerase chain reaction took significantly longer (7 mo). At the end of the study, four of 16 patients still exhibited persistent monoclonal bands. Relapse of lymphoma occurred in two patients associated with H. pylori reinfection/recrudescence.

CONCLUSION

Eradication of H. pylori seems to be an effective therapy in patients with stage EI gastric MALT lymphoma, although long-term results are still uncertain. Endoscopic ultrasonography is useful for a more accurate staging of the disease. The clinical significance of detecting monoclonality by polymerase chain reaction remains to be determined.

How do clinicians practicing in the U.S. manage Helicobacter pylori-related gastrointestinal diseases? A comparison of primary care and specialist physicians

OBJECTIVES

We sought to examine the extent to which physicians recognize H. pylori as a causal agent in peptic ulcer disease or as a potential cofactor in other gastrointestinal diseases, and to observe how this knowledge has influenced diagnostic and therapeutic practices.

METHODS

We used a national mail survey in the U.S. between February and May of 1996, querying 5994 U.S. physicians (family/general practitioners [FPs], internists [IMs], and gastroenterologists) selected at random from three different membership databases of professional associations.

RESULTS

The response rate was 52%. More than 95% of physicians who treat symptoms empirically would prescribe acid suppressant therapy rather than anti-H. pylori therapy. Between 43% and 66% of physicians, varying in frequency by medical specialty, would treat the infection in H. pylori-positive patients with nonulcer dyspepsia. In confirmed peptic ulcer disease, between 88% and 100% of physicians would treat the H. pylori infection, depending on the physician group and whether or not the presentation of an ulcer was recurrent. Although 103 distinct anti-H. pylori regimens were reported, 89% of the gastroenterologists and 70% of the primary care physicians (PCPs) used combinations of antimicrobials with reported cure rates of at least 80%.

CONCLUSIONS

General knowledge regarding H. pylori-associated diseases was widespread among primary care physicians and gastroenterologists. However, anti-H. pylori therapies judged ineffective were reported as the first choice regimen by 5% of gastroenterologists and 18% of primary care physicians. Gastroenterologists appear to implement the latest scientific developments in the field rapidly whereas PCPs manifest a delayed response, due to either insufficient knowledge or to other factors influencing their approach to treatment.

Disappearance of gastric mucosa-associated lymphoid tissue in coeliac patients after gluten withdrawal

BACKGROUND

Mucosa-associated lymphoid tissue (MALT) develops in gastric mucosa in response to chronic antigenic stimulation, such as Helicobacter pylori infection. However, reactive lymphoid follicles have been found also in the stomach of H. pylori-negative coeliac patients, suggesting that other environmental factors may be involved in MALT genesis. The aim of our study was to evaluate the effects of gluten withdrawal in H. pylori-negative coeliac patients with gastric MALT.

METHODS

We studied 23 H. pylori-negative untreated coeliac patients with gastric MALT. All patients underwent determination of antigliadin (AGA) and antiendomysium antibodies (EMA) and upper endoscopy with multiple biopsies in duodenum, gastric corpus, and antrum. Lymphoid follicles and H. pylori status were assessed by histopathologic and enzymatic analysis. All patients were started on a gluten-free diet and were reevaluated after 12 months. To consider their adherence to the gluten-free diet we relied on direct patient questioning. Thirteen patients who had strictly adhered to the gluten-free diet constituted our study group. Ten patients who had not strictly adhered to gluten withdrawal from their diet constituted the control group.

RESULTS

Regression of MALT was obtained in 9 of 13 (69%) patients who strictly followed the gluten-free diet; in the control group MALT disappeared in 2 of 10 (20%) patients (P=0.0361).

DISCUSSION

Disappearance of reactive lymphoid follicles in the gastric mucosa of H. pylori-negative coeliac patients after gluten withdrawal suggests that antigens related to alimentary gluten may constitute persistent stimuli for development of gastric MALT in coeliac patients.

Epithelial attachment alters the outcome of Helicobacter pylori infection

Genetically defined in vivo models are needed to assess the importance of target cell attachment in bacterial pathogenesis. Gastric colonization by Helicobacter pylori in human populations is common and persistent, and has various outcomes including peptic ulcers and cancer. The impact of attachment on the course of infection was examined in transgenic mice expressing a human receptor for H. pylori in their gastric epithelium. Persistent infection by a clinical isolate occurred at comparable microbial densities in transgenic and nontransgenic littermates. However, microbial attachment in transgenic mice resulted in production of autoantibodies to Lewisx carbohydrate epitopes shared by bacteria and acid-secreting parietal cells, chronic gastritis, and parietal cell loss. This model should help identify bacterial and host genes that produce attachment-related pathology.

Gastric lymphoma of mucosa-associated lymphoid tissue and Helicobacter pylori

Although the majority of primary gastric lymphomas are of high-grade non-Hodgkin's type, a significant number are low-grade B cell lymphomas. The recognition that the majority of the latter have characteristic clinicopathological features that are different from those of their nodal counterparts has led to the suggestion that these lymphomas arise specifically from within organized extranodal lymphoid tissue; this tissue resembles that seen constitutively in the intestine (mostly located in the terminal ileum as Peyer's patches) and is termed mucosa-associated lymphoid tissue (MALT). The paradox of this proposal is that there is no MALT in the gastric mucosa in normal individuals from which a primary lymphoma can arise. However, it has been shown that organized lymphoid tissue with all the features of MALT can be acquired in the gastric mucosa, and this is seen most frequently, but not exclusively, in association with infection by Helicobacter pylori (H. pylori). Subsequent studies have confirmed a close association between H. pylori infection and gastric MALT lymphoma with the infection preceding the development of the lymphoma. In vitro studies have demonstrated that there is an immunologically based drive to tumor cell proliferation in low-grade gastric MALT lymphomas associated with the presence of H. pylori. Clinical studies have shown that, at least in early lesions, eradication of the organism can result in tumor regression in 60 to 92% of cases.

Antibody to a Helicobacter pylori species specific antigen in patients with adenocarcinoma of the stomach

This study attempted to identify a possible antibody response to Helicobacter pylori, which is associated with patients with adeno-carcinoma of the stomach. By using proteins of H. pylori as the antigen, pooled sera from gastric cancer and non-cancer patients were used as the first antibody for Western blot analysis. Antibody responses to a 26 kD secreted protein were observed in pooled cancer sera, but not in pooled sera from non-cancer patients. The protein was purified, while amino acid sequences revealed that it was a H. pylori species specific protein. The gene of this protein was cloned and a recombinant protein was expressed in E. coli. In addition, an antibody to the recombinant protein was tested in each individual patient using Western blot analysis. None of the forty non-gastric cancer patients were positive for the antibody to the recombinantly expressed 26 kD species specific protein. Meanwhile, six of the twenty four cancer patients tested positive (0/40 vs 6/24, p < 0.01). Results presented herein demonstrate that the species specific protein of H. pylori can be useful in detecting H. pylori associated with adenocarcinoma of the stomach.

Clonal Salivary Gland Infiltrates Associated With Myoepithelial Sialadenitis (Sjögren's Syndrome) Begin as Nonmalignant Antigen-Selected Expansions

Myoepithelial sialadenitis (MESA) is the reactive salivary gland lymphoid infiltrate that occurs in patients with Sjögren's syndrome. Although it is well established that mucosa-associated lymphoid tissue (MALT)-type lymphomas may develop from MESA, the issue of whether monoclonal B-cell populations in early MESA-associated lesions represent MALT lymphomas or more benign types of expansions has been very controversial. In addition, it is unknown whether antigen stimulation plays a role in the development or growth of MESA-associated clones. To investigate these issues, we have analyzed the Ig VH genes used by MESA-associated clones in sequential biopsies obtained from contralateral sites of seven different patients. In three cases, single clones were identified in the follow-up biopsies that were distinct from the single clones identified in the initial specimens, whereas in three other cases, the same clone was identified in both the initial and subsequent specimens. In the remaining case, two clones were identified in the second biopsy specimen, one of which was distinct from the initial clone. Of the 11 distinct clones identified in the 14 specimens that were analyzed, 8 were derived from a V1-69 VH gene segment, whereas the other 3 were derived from a V3-7 VH gene segment. In addition, the MESA clones also showed conserved amino acids sequence motifs in their third complementarity-determining regions (CDR3), some of which were encoded by N nucleotides. The marked VH gene restriction along with the similar CDR3 sequences suggests that MESA-associated clones even from different patients may bind the same or similar antigens and are selected for clonal expansion on that basis. The high rates of ongoing VH gene mutation observed in some of the cases futher suggest that the growth of early MESA clones is still dependent on antigen stimulation. In addition, our finding that different biopsies from the same patient may contain distinct clones indicates that some MESA-associated clones have not yet evolved to malignant lymphomas.

Clonal Salivary Gland Infiltrates Associated With Myoepithelial Sialadenitis (Sjögren's Syndrome) Begin as Nonmalignant Antigen-Selected Expansions

Myoepithelial sialadenitis (MESA) is the reactive salivary gland lymphoid infiltrate that occurs in patients with Sjögren's syndrome. Although it is well established that mucosa-associated lymphoid tissue (MALT)-type lymphomas may develop from MESA, the issue of whether monoclonal B-cell populations in early MESA-associated lesions represent MALT lymphomas or more benign types of expansions has been very controversial. In addition, it is unknown whether antigen stimulation plays a role in the development or growth of MESA-associated clones. To investigate these issues, we have analyzed the Ig VH genes used by MESA-associated clones in sequential biopsies obtained from contralateral sites of seven different patients. In three cases, single clones were identified in the follow-up biopsies that were distinct from the single clones identified in the initial specimens, whereas in three other cases, the same clone was identified in both the initial and subsequent specimens. In the remaining case, two clones were identified in the second biopsy specimen, one of which was distinct from the initial clone. Of the 11 distinct clones identified in the 14 specimens that were analyzed, 8 were derived from a V1-69 VH gene segment, whereas the other 3 were derived from a V3-7 VH gene segment. In addition, the MESA clones also showed conserved amino acids sequence motifs in their third complementarity-determining regions (CDR3), some of which were encoded by N nucleotides. The marked VH gene restriction along with the similar CDR3 sequences suggests that MESA-associated clones even from different patients may bind the same or similar antigens and are selected for clonal expansion on that basis. The high rates of ongoing VH gene mutation observed in some of the cases futher suggest that the growth of early MESA clones is still dependent on antigen stimulation. In addition, our finding that different biopsies from the same patient may contain distinct clones indicates that some MESA-associated clones have not yet evolved to malignant lymphomas.

Helicobacter pylori

Helicobacter pylori infection causes peptic ulcer disease, gastric adenocarcinoma, gastric lymphoma, and probably nonulcer dyspepsia. Although the prevalence of infection is declining over time, the organism still infects approximately one half of the world's population. Only a minority will ever suffer serious consequences from their infection. This article reviews current knowledge about H. pylori and presents some of the dilemmas surrounding clinical and public health approaches to this widespread pathogen.

How do practicing clinicians manage Helicobacter pylori-related gastrointestinal diseases in Germany? A survey of gastroenterologists and family practitioners

BACKGROUND

Since the bacterium H. pylori was identified in 1982, overwhelming evidence has implicated it as the causal factor in the occurrence and relapse of peptic ulcer disease. The major objective of this study was to examine the extent to which physicians recognize H. pylori as a causal agent in peptic ulcer disease or as potential cofactor in other gastrointestinal diseases, and the extent to which this knowledge has influenced diagnostic and therapeutic practices.

MATERIALS AND METHODS

Using a national mail survey in Germany in September 1995, 1197 family practitioners and 1197 gastroenterologists were selected for the study.

RESULTS

Of the surveyed physicians, 756 (32%) responded. Family practitioners treated almost 50% of their patients with initial presentation of suspected ulcer disease without ordering further diagnostic tests. More than 25% of the family practitioners and 14% of the gastroenterologists reported that they do not treat diagnosed H. pylori infection in the first presentation of duodenal ulcer. At the time we conducted the study, 22% of responding family practitioners and 5% of responding gastroenterologists treated the first presentation of H. pylori-positive ulcer disease with regimens determined to be ineffective according to the available literature.

CONCLUSIONS

Gastroenterologists preferred to treat H. pylori infection when the associated disease was one for which a causal relationship had been more clearly established, while family practitioners showed less discrimination. In order to provide optimal therapy aimed at minimizing the course and consequences of H. pylori-related diseases, researchers in the field must ensure continuous dissemination of current knowledge.

Anti-Helicobacter pylori specific antibody immunohistochemistry improves the diagnostic accuracy of Helicobacter pylori in biopsy specimen from patients treated with triple therapy

OBJECTIVE

To investigate the effectiveness of immunohistochemical technique to detect Helicobacter pylori (H. pylori) in patients treated with triple therapy.

METHODS

Forty patients (18 men, 22 women, mean age 43 years) with active antral gastritis, H. pylori positive at urease test, culture, and histology, were treated for 1 wk with omeprazole, amoxicillin, and metronidazole. Gastritis was scored according to Sydney criteria. Two months after the end of therapy, endoscopy, urease test, culture, and histology were repeated.

RESULTS

Culture and histology were negative in 32 (80%) of treated cases. Biopsy specimens of the eradicated group were stained with immunohistochemical technique using an anti-H. pylori specific polyclonal antibody. In 12 of 32 (37.5%) patients, clusters of round or vibrio-shaped bacteria, unidentified at histology, were stained by the specific anti-H. pylori antibody. After triple therapy, at histology all patients were found with improved gastritis. In six patients however, mucosal-associated lymphoid tissue (MALT) appearance, present before therapy, persisted after therapy. In five of six patients with MALT, immunostaining with anti-H. pylori antibody was positive.

CONCLUSIONS

The immunohistochemical technique is more accurate than classical methods in identifying H. pylori after specific therapy. This method should, therefore, be used in all studies that aim to achieve eradication. Whether the H. pylori identified at immunohistochemistry is able to reactivate and induce recrudescence of infection remains to be clarified.

Classification of primary gastric lymphomas according to histologic features

Histologic features of low-grade gastric lymphomas of mucosa-associated lymphoid tissue (MALT) have been extensively described, and transformation to a large cell (high-grade) lymphoma can occur. We characterize high-grade gastric lymphoma histologically in an attempt to distinguish between MALT-type and non-MALT-type lesions. We studied a series of 60 gastric lymphomas and characterized them clinically, histopathologically, and immunophenotypically. Low-grade gastric lymphomas were classified according to established criteria. High-grade lymphomas were classified in three groups based on the presence or absence of a low-grade component and lymphoepithelial lesions (LELs): 1) high-grade MALT lymphomas appearing in low-grade MALT lymphomas (LG/HG MALT lymphoma); 2) large cell lymphoma with LELs composed of large cells (high-grade LELs) but without a low-grade component (HG MALT lymphoma); and 3) diffuse large cell lymphoma without a low-grade MALT lymphoma component or LELs (DLCL). Twenty-two lymphomas were classified as low-grade MALT lymphomas, 16 as LG/HG MALT lymphomas, 10 as HG MALT lymphomas, and 12 as DLCL. B-cell immunophenotype was confirmed in all 55 cases in which immunophenotyping was performed. Low-grade LELs were seen in all low-grade MALT lymphomas, and CD20(L26) expression confirmed B-cell phenotype in the LELs in 20 of 20 cases. Clinical follow-up was available for 56 patients (range, 1-264 months; mean, 57 months). Actuarial analysis of disease-specific survival and relapse-free survival showed that clinical stage was highly statistically significant (P < 0.0001), whereas histologic type and grade approached statistical significance. Multivariate analysis showed that clinical stage was the only significant factor in relapse-free and disease-specific survival.

Report of the 1997 Asia Pacific Consensus Conference on the management of Helicobacter pylori infection

While European and United States guidelines for the management of Helicobacter pylori infection have been developed, there are no guidelines for the Asian Pacific. International experts and recognised local authorities met in Singapore in 1997 to develop appropriate guidelines, taking into account the high background prevalence of infection, high incidence rates of gastric cancer and resource limitations. Recommendations were made based on randomised controlled trials or where this was not possible, they were based on the current best available evidence or on good clinical practice. A number of acceptable diagnostic tests for infection are available throughout the region. The non-endoscopic methods of choice are the urea breath test or a locally validated antibody test. If endoscopy was to be performed, a biopsy urease test was recommended as the test of first choice, with histology recommended only if this was negative. Post treatment testing was not recommended for all patients; a urea breath test was considered the test of choice if available. All gastric and duodenal ulcer patients who are infected with H. pylori should be treated for H. pylori whether the ulcer is active or in remission. Patients requiring long term non-steroidal anti-inflammatory drug therapy who have a current or recent history of dyspepsia, patients with early gastric cancer or low grade gastric mucosa associated lymphoid tissue lymphoma, and patients with a family history of gastric cancer should be treated. However, it was concluded that there wasn't sufficient evidence that cure of H. pylori infection reduces the risk or prevents the development of gastric adenocarcinoma. Many patients with dyspepsia in the region will request or require early upper endoscopy because of an inherent fear of gastric cancer. However, where endoscopy is not available or is too costly, alternative acceptable approaches were recommended in high risk cancer regions. While evidence is inconclusive to support treatment of H. pylori infection in non-ulcer dyspepsia, it was agreed that treatment be offered to patients with documented infection on a case-by-case basis. Treatment regimens need to attain an eradication rate of 90% or greater by per protocol analysis and 80% or greater by intention-to-treat analysis. A number of 7-day regimens were recommended based on available evidence. These regimens were considered likely to maximize the chances of successful eradication with one course of treatment, thereby reducing the risk of acquired antibiotic resistance and leading to long term cost savings.

Randomized comparison of 1-hour topical method vs. amoxycillin plus omeprazole for eradication of Helicobacter pylori in duodenal ulcer patients

BACKGROUND

A novel 1-h topical method eradicated Helicobacter pylori in 96% of dyspeptic patients. The eradication rate of amoxycillin/omeprazole therapy varies from 0 to 93%.

AIM

To compare both methods in patients with endoscopically proven duodenal ulcer.

METHODS

Eighty patients (59 males, 21 females; median age 43 years) were randomized into two therapeutic groups. The first group (group A) was treated with a 6-week course of ranitidine 300 mg/day, then omeprazole 20 mg b.d. with pronase 36000 units/day for 2 days, followed by 1-h topical therapy with a solution of bismuth, metronidazole, amoxycillin and pronase. The second group (group B) consisted of patients treated with omeprazole 20 mg b.d. and amoxycillin 2 g/day for 2 weeks, followed by a 4-week course of ranitidine 300 mg/day. Eradication of H. pylori was assessed by urease test, histology, a polymerase chain reaction and a 13C-urea breath test, all of which were performed 4 weeks after discontinuation of the antibacterial treatment.

RESULTS

Eradication rates in groups A and B were 2.5% and 35% in an intention-to-treat analysis, respectively. Side-effects were encountered in 40.5% and 12.5% of subjects in groups A and B, respectively. Treatment tolerance was rated as poor by 54% of patients in group A and 2.5% of patients in group B.

CONCLUSIONS

Both treatment regimens, the 1-h topical method and amoxycillin with omeprazole, have low eradication rates in patients with duodenal ulcer. In addition, the topical treatment is characterized by a high rate of side-effects and poor tolerance. Based on the results of our study, neither method can be recommended for eradication of H. pylori in patients with duodenal ulcer.

Helicobacter pylori

Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori has been found in the stomachs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori. In developed countries, the prevalence of infection is lower. There appears to be no substantial reservoir of H. pylori aside from the human stomach. Transmission can occur by iatrogenic, fecal-oral, and oral-oral routes. H. pylori is able to colonize and persist in a unique biological niche within the gastric lumen. All fresh isolates of H. pylori express significant urease activity, which appears essential to the survival and pathogenesis of the bacterium. A variety of tests to diagnose H. pylori infection are now available. Histological examination of gastric tissue, culture, rapid urease testing, DNA probes, and PCR analysis, when used to test gastric tissue, all require endoscopy. In contrast, breath tests, serology, gastric juice PCR, and urinary excretion of [15N]ammonia are noninvasive tests that do not require endoscopy. In this review, we highlight advances in the detection of the presence of the organism and methods of differentiating among types of H. pylori, and we provide a background for appropriate chemotherapy of the infection.

What role does Helicobacter pylori eradication play in gastric MALT and gastric MALT lymphoma?

The concept of mucosa-associated lymphoid tissue (MALT) has been introduced to differentiate biological functions from behavior of nonnodal vs. nodal lymphoid tissues. Lymphomas arising from MALT also behave differently than typical nodal lymphomas. In contrast to other tissues, MALT in the stomach is almost exclusively a result of Helicobacter pylori infection. Thus, MALT is part of the host defense against the pathogen H. pylori. Consequently, lymphomas arising from gastric MALT may be a clonal evolution starting from the infection. In low-grade gastric MALT lymphoma, cure of the infection may induce complete histological remission in the majority of patients. Investigators have recently reported that complete remission rate is between 70% and 80%. In an extended analysis, we have treated 84 patients with low-grade gastric MALT lymphoma in stage El, using a dual regimen to eradicate H. pylori. Complete remission was observed in 68 (80%) patients; a partial remission was found in 4 patients. In contrast, 12 patients showed no change and were referred to alternative treatment. In patients in complete remission, a polymerase chain reaction assay for the rearranged immunoglobulin heavy-chain gene remained positive in many cases. Together with data from the literature, these data suggest that the majority of patients with low-grade gastric MALT lymphomas in stage El respond to eradication of H. pylori. Longer follow-up investigations are necessary to determine if remissions indicate a cure from the disease.

Regression of superficial gastric MALT lymphoma with unsuccessful eradication therapy for Helicobacter pylori infection

A 51-year-old man had a reddish flat granular lesion in the stomach on endoscopic examination. Histology of biopsied specimen confirmed the diagnosis of low-grade B-cell gastric lymphoma of mucosa-associated lymphoid tissue (gastric MALT lymphoma) and simultaneous infection with Helicobacter pylori. He was given antibiotic treatment. Five weeks later, endoscopy and histology of biopsied specimen showed eradication of H. pylori, and the tumor had regressed. Six months later, H. pylori reemerged, but the tumor had not recurred. After the second antibiotic therapy, H. pylori has been eradicated. The lymphoma has been in remission for 14 months.

Gastric B-cell clonal expansion and Helicobacter pylori infection in patients with autoimmune diseases and with dyspepsia. A follow-up study

BACKGROUND

It is not clear whether gastric B-cell clonal expansion, a possible precursor of mucosa-associated lymphatic tissue (MALT) lymphoma, is exclusively linked to Helicobacter pylori infection and virulence.

METHODS

In this study we followed up, for up to 33 months, 16 VDJ polymerase chain reaction-positive patients (4 with dyspepsia, 9 with Sjögren's syndrome, and 3 with other autoimmune diseases). Of these, 12 were H. pylori-positive. In addition, in H. pylori-positive patients we tested whether the serum anti-cag-A (a potential marker of virulence) was preferentially associated with B-cell clonality.

RESULTS

In all but one patient clonality appeared temporally unrelated to H. pylori infection. The prevalence of anti-cagA was not higher in H. pylori/VDJ-positive patients than in controls.

CONCLUSIONS

These data indicate that, in addition to H. pylori, gastric B-cell clonality may be sustained by other agents/mechanisms. Anti-cag-A does not appear to be involved in the pathogenesis of clonality.

What are the host factors that place an individual at risk for Helicobacter pylori-associated disease?

Helicobacter pylori infection is associated with duodenal and gastric ulcer disease, gastric cancer, and gastric mucosa-associated lymphoid tissue lymphoma. Although more than half the world's population harbors H. pylori, only a proportion will develop clinically significant disease. The specific clinical outcome of an individual can be examined as the modulation of host factors by H. pylori infection. Host acid-secretory status and sensitivity to gastrin can be modulated by H. pylori infection. Once H. pylori has established itself in the stomach, virtually everyone develops gastritis, and variations in gastritis patterns have been associated with different gastric acid responses to H. pylori infection. The patterns of gastritis are important because they seem to determine disease outcome. Blood group antigens have been implicated in studies of ulcer disease. Receptors to Lewis antigens in gastric mucosa indicate that host mucosal factors influence H. pylori attachment. Conversely, H. pylori strains express Lewis antigen-like molecules, suggesting an autoimmune component for some H. pylori-associated diseases. HLA genotypes may influence the host response to H. pylori infection, and those of H. pylori-infected individuals have been correlated with histological features. The clinical outcome of H. pylori infection is most likely a result of complex interactions among host, bacterial, and environmental factors. The mechanisms by which these diverse factors influence the pathogenesis of different clinical outcomes remain under investigation.

Who should be treated for Helicobacter pylori infection? A review of consensus conferences and guidelines

The publication of the National Institutes of Health Consensus Development Conference guidelines on management of Helicobacter pylori infection in 1994 set a precedence. At present, at least eight European countries have produced national guidelines, and, more recently, the European Helicobacter pylori Study Group also outlined guidelines based on the strength of available evidence. It is generally agreed that H. pylori should be eradicated in peptic ulcer disease. In nonsteroidal anti-inflammatory drug (NSAID)-related ulcers, most countries that considered the issue suggested discontinuing NSAIDs when possible and eradicating H. pylori. The prophylactic eradication of H. pylori was not recommended. A number of panels felt that there was not enough evidence available to recommend eradication of H. pylori in functional dyspepsia, whereas other groups felt that nonulcer dyspepsia, particularly after investigation and with severe or recurrent symptoms, was an indication for eradication therapy. Other conditions (i.e., gastroesophageal reflux disease [GERD] and mucosa-associated lymphoid tissue [MALT] lymphoma) have emerged in this short time as possible indications for H. pylori eradication. There is no evidence that H. pylori infection has a role in the pathogenesis of GERD, but there is evidence suggesting that patients with H. pylori infection who require long-term acid suppression may be at risk of developing atrophic gastritis. The European Helicobacter pylori Study Group has suggested that eradication therapy should be offered to infected family members of patients with gastric cancer. It also recommended that eradication therapy was "strongly recommended" on the basis of "supportive" evidence in gastritis with severe abnormalities and after early resection of early gastric cancer. An "uncertain" recommendation with "equivocal" evidence was given for asymptomatic subjects, extra-alimentary tract disease, the prevention of gastric cancer in the absence of risk factors, and in pediatric patients with recurrent abdominal pain. Despite considerable advances, further research studies are needed to provide definite direction for the treatment of many conditions.

What other regimens are under investigation to treat Helicobacter pylori infection?

The most common infection in the world, Helicobacter pylori infection, is very specific, and present experience in treating infectious diseases is not applicable in general for this infection. Animal models (e.g., mouse and ferret) are thus far inadequate as reliable screening models. Old-fashioned trial-and-error treatment of infected humans is still the screening model and the gold standard in the evaluation of regimens aimed at eradication of H. pylori. A variety of studies on treatment of H. pylori infection have been performed with varying results. This pooled analysis of the following therapeutic combinations: proton pump inhibitor (PPI) plus two antibiotics or antimicrobials, quadruple therapies, and nonantibiotic regimens is an attempt to make a fair comparison of tested therapeutic strategies aimed at eradicating H. pylori. Data from treatment groups including specified drug combinations are pooled, regardless of dose or duration. Search methods are: MEDLINE 1984-1996, Digestive Disease Week 1988-1996, United European Gastroenterology Week 1992-1996, European Helicobacter pylori Study Group 1988-1996, Asia Pacific Congress 1996, H. pylori International Workshop Hong Kong 1996, and miscellaneous. Eradication rates (efficacy) are presented as intention-to-treat data (i.e., worst-case analysis). Separate subanalyses with regard to study quality, dose, and duration are performed for some groups. A general cost-efficacy analysis is performed based on pooled efficacy data. Convenience data are presented as total number of tablets, total number of intake occasions, and duration of therapy. Drugs evaluated in the analysis are bismuthdicitrate, tetracycline, amoxicillin, nitroimidazoles, macrolides, H2-receptor antagonists, PPIs, sucralfate, and sofalcone. The most effective and convenient drug combinations are the PPI-based triple therapies. No significant difference was observed between the three PPIs. The cure rate did not improve after addition of bismuth. Cost-effectiveness is closely associated with efficacy.

For what conditions is there evidence-based justification for treatment of Helicobacter pylori infection?

Evidence-based medicine combines clinical expertise and the best available evidence from systematic research to aid decision making in patient care. Levels of evidence can be graded from I to V, with level I, the strongest, coming from large randomized controlled trials (RCTs). When a definitive RCT has not been performed, or is impracticable or inappropriate, lesser grades of evidence are used. There is level I evidence supporting the treatment of Helicobacter pylori infection in patients with duodenal or gastric ulcers. Prospective RCTs have shown that cure of the infection is associated with ultimate cure of the ulcer diathesis. Therefore, this is a "grade A" recommendation for treatment. In nonulcer dyspepsia, numerous RCTs have yielded conflicting results regarding the benefits of treatment. Although there are methodological problems with many reported studies, there is some evidence (level II at best) to support treatment--a grade B recommendation. In early gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma, the best available evidence supporting treatment of H. pylori infection is of low quality, i.e., levels III and V. Although these carry only grade C treatment recommendations, treatment is safe and carries at least some evidence of efficacy. It is therefore indicated based on the current best available evidence. No evidence exists to support treating the infection in patients receiving long-term proton pump inhibitors for gastroesophageal reflux disease or in patients with any of the nongastrointestinal conditions that have been tentatively linked to H. pylori.

Helicobacter pylori

Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori has been found in the stomachs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori. In developed countries, the prevalence of infection is lower. There appears to be no substantial reservoir of H. pylori aside from the human stomach. Transmission can occur by iatrogenic, fecal-oral, and oral-oral routes. H. pylori is able to colonize and persist in a unique biological niche within the gastric lumen. All fresh isolates of H. pylori express significant urease activity, which appears essential to the survival and pathogenesis of the bacterium. A variety of tests to diagnose H. pylori infection are now available. Histological examination of gastric tissue, culture, rapid urease testing, DNA probes, and PCR analysis, when used to test gastric tissue, all require endoscopy. In contrast, breath tests, serology, gastric juice PCR, and urinary excretion of [15N]ammonia are noninvasive tests that do not require endoscopy. In this review, we highlight advances in the detection of the presence of the organism and methods of differentiating among types of H. pylori, and we provide a background for appropriate chemotherapy of the infection.

Endoscopic ultrasonography for the initial staging and follow-up in patients with low-grade gastric lymphoma of mucosa-associated lymphoid tissue treated medically

BACKGROUND

Endoscopic ultrasonography is an appropriate procedure to assess the depth of tumoral infiltration in primary gastric lymphoma. The aims of the present study were to characterize the endoscopic ultrasonographic aspects of low-grade gastric lymphoma of mucosa-associated lymphoid tissue and to determine the value of this procedure in medical treatment assessment.

METHODS

Between 1991 and 1996, 15 patients with low-grade gastric lymphoma of mucosa-associated lymphoid tissue were treated with oral cyclophosphamide and/or anti-Helicobacter pylori treatment. Endoscopic ultrasonography was carried out at the time of the diagnosis in all patients, 8 of whom (4 in complete remission and 4 with a stable or progressive disease) had at least one endoscopic ultrasonography examination within the treatment period (median follow-up 17 months).

RESULTS

The initial procedure showed an increased gastric wall thickness from 6 to 12 mm in 8 patients, equal to 5 mm in 5 patients, and normal in 2 patients. The thickening was predominantly of the mucosa alone and/or the submucosa but never extended beyond the muscularis propria. No lymph node was found. Gastric wall thickness returned to normal in the 4 patients in complete remission and remained thick in 3 of the 4 patients with a stable or progressive disease. Of these 3 patients, at least one set of biopsy samples, carried out during follow-up, showed the absence of lymphoma, but histology performed subsequently found evidence of disease.

CONCLUSIONS

Endoscopic ultrasonography differentiates superficial from infiltrative types of gastric lymphoma of mucosa-associated lymphoid tissue, which may have a prognostic significance and confirms remission or persistence of the disease with medical treatment during follow-up. When the gastric wall remains thick, even if histology is negative, repeated biopsies should be performed to detect evolving disease or relapse.

Cure of Helicobacter pylori infection and duration of remission of low-grade gastric mucosa-associated lymphoid tissue lymphoma

BACKGROUND

Low-grade B-cell lymphomas arising in mucosa-associated lymphoid tissue (MALT) are most frequently localized in the gastrointestinal tract. More than 90% of gastric MALT lymphomas are diagnosed in patients with chronic, Helicobacter pylori-associated gastritis. High remission rates for these lymphomas have been observed after the cure of H. pylori infection. Data are lacking, however, with regard to the duration of the remissions. To address this question of remission duration, we have followed 50 patients in whom H. pylori infections were eradicated, and we determined whether the patients in complete remission displayed evidence of residual monoclonal B cells during follow-up.

METHODS

Patients were treated with amoxycillin and omeprazole for 2 weeks in an attempt to cure H. pylori infections. Follow-up included endoscopic investigations with biopsy sampling. Monoclonal B cells in biopsy specimens were detected by means of a polymerase chain reaction (PCR)-based assay.

RESULTS

H. pylori infections were cured in all 50 patients. The median follow-up for the 50 patients is currently 24 months (729 days; range, 135-1411 days). Forty patients achieved complete remission of their lymphomas, but five have subsequently relapsed. The median time of continuous complete remission for the 40 patients was 15.4 months (468 days; range, 0-1198 days). Among six patients whose Iymphomas did not respond to H. pylori eradication, four revealed high-grade lymphomas upon surgery. PCR indicated the presence of monoclonal B cells during follow-up in 22 of 31 assessable patients in complete remission.

CONCLUSIONS

Complete remissions of low-grade gastric MALT Iymphomas after the cure of H. pylori infection appear to be stable, although most patients display evidence of monoclonal B cells during follow-up. Whether these patients are truly cured of their Iymphomas remains to be determined.

Helicobacter pylori eradication for the treatment of low-grade gastric MALT lymphoma: follow-up together with sequential molecular studies

BACKGROUND

Helicobacter pylori infection is associated with low-grade gastric MALT lymphoma, and available data support that the eradication of the H. pylori can cause histological regression of the lymphoma.

PATIENTS AND METHODS

Nine patients with low-grade gastric MALT lymphoma were treated with amoxicillin, metronidazole, and omeprazole for 14 days in a prospective study. Patients were followed up with sequential endoscopy, mapping gastric biopsies, and molecular studies with PCR amplification of the IgH gene in order to assess the response to H. pylori eradication and the evolution of the histological molecular responses.

RESULTS

H. pylori was eradicated in all patients and reinfections were not demonstrated. After H. pylori eradication treatment, the lymphoma regressed both endoscopically and histologically in eight of the nine patients (88.8%). In four of the eight histologically cured patients, no clonal band was detected by PCR; in the remaining four patients; PCR identified a clonal band, which disappeared in all patients after a mean of 12 +/- 4 months. No clonal band was detected by the PCR analysis in any of the eight patients with histological regression after a median of 7 +/- 6 months (range 1-20). The seven followed-up patients have a persistent clinical and histological remission after a median of 14 +/- 5 months.

CONCLUSIONS

(1) Low-grade gastric MALT lymphoma can be histologically cured with eradication therapy for H. pylori. (2) After histological regression, PCR amplification of the IgH gene can identify an eventually persisting clonal population. (3) Sequential histological and molecular studies are essential for the assessment of the evolution of the lymphoma. (4) The clonal population tends to disappear, but its disappearance may be delayed for months. (5) Patients with histological regression but with a persistent clonal band should not be treated unless the lymphoma can be histologically demonstrated. All these observations suggest that gastric lymphoma can be effectively cured, but the ultimate fate of these patients is unknown until long-term follow-up studies are available.

Nongastrointestinal mucosa-associated lymphoid tissue (MALT) lymphomas: clinical and therapeutic features of 24 localized patients

BACKGROUND

Peripheral B-cell lymphoma of the marginal zone (MALT, low-grade), presenting as localized, extranodal disease, usually affects the elderly. The gastrointestinal tract is the most frequently involved extranodal location, representing 70% of all MALT lymphomas. Recently, numerous other extranodal sites involved by MALT lymphomas have also been described.

PATIENTS AND METHODS

From January 1990 to October 1995, 24 patients with untreated nongastrointestinal low-grade MALT lymphoma were submitted to treatments ranging from the local approach of radiotherapy and local alpha-interferon (alpha-IFN) administration to chemotherapy. The tumours were located in the lung (seven cases), conjunctiva (four cases), lachrymal gland and orbital soft tissue (four cases), salivary glands (three cases), skin (three cases), breast (two cases), and thyroid (one case). All patients had low-grade stage IE tumours.

RESULTS

Chemotherapy was administered in 11 patients (six with lung, three with salivary gland, one with breast, and one with thyroid locations); radiation therapy was employed in seven patients (three with lachrymal gland, three with skin, and one with breast locations); local alpha-IFN administration was administered in five patients (four with conjunctival, and one with lachrymal gland sites); and surgery was employed in one patient with a lung tumour. All patients achieved complete remissions; three local recurrences and two relapses in other sites were observed. The global five-year survival rate was 100% with a relapse-free survival rate of 79%.

CONCLUSIONS

These data confirm the significant efficacy of different therapeutic approaches to specific sites inbes obtaining a good remission rate for nongastrointestinal localized low-grade MALT lymphomas.

Regression of atypical lymphoid hyperplasia after eradication of Helicobacter pylori

A rare case of endoscopic and histological regression of a gastric lymphoid mucosal lesion after eradication of Helicobacter pylori is reported. A 72-year-old man was suspected of having a low-grade B-cell gastric mucosa-associated lymphoid tissue (MALT) lymphoma by endoscopic and histological findings. Histology of biopsy specimens showed massive infiltration of atypical lymphocytes and lymphoepithelial lesions. Immunohistochemical staining revealed kappa light chain expression in the infiltrated atypical lymphocytes to be twofold that of lambda light chain. The above diagnosis was thus highly suspected but not confirmed. Antibiotic therapy was given on the basis of evidence of H. pylori infection. Successful eradication of H. pylori resulted in remarkable improvement of endoscopic and histological findings. Follow-up studies were carried out 8 months after eradication, with no evidence of relapse. The eradication of H. pylori appears to be an effective alternative therapy for B-cell lymphoproliferative disease, although longer follow-up and further studies are needed before this treatment can be established.

Clinical features, treatment and outcome in a series of 93 patients with low-grade gastric MALT lymphoma

The purpose of this paper is to report the clinical characteristics and treatment outcome following different therapeutic approaches in a large series of patients with primary low-grade MALT lymphoma of the stomach. A total of ninety-three patients (median age 63 years) were reviewed. The patients were treated by different modalities (local treatment alone, combined treatment, chemotherapy, antibiotics alone); seven patients refused any treatment. The antibiotic-treated group of patients was prospectively followed with regular endoscopic biopsies, and their responses were histologically evaluated. The 5-years projected overall survival is 82% (95% C.I.; 67%-91%) in the series as a whole. Second tumors were observed in 21.5% of the patients in this series (95% CI 14%v to 31%). There was no apparent difference in overall survival and event-free survival between patients who received different treatments. In the antibiotic-treated group histologic regression of MALT lymphoma was documented in 67% of patients (95% CI 51% to 80%). In conclusion the indolent nature of the disease justifies a conservative approach. The use of antibiotics as first-line therapy may avert or at least postpone the indication for surgical resection in the majority of patients.

Isolation of a genetic locus associated with metronidazole resistance in Helicobacter pylori

We examined the molecular mechanism of metronidazole resistance by constructing a lambda-Zap II phagemid expression library with genomic DNA from a metronidazole-resistance strain of Helicobacter pylori. Twenty-two clones were found to have elevated MTZ resistances in XLOLR strain of E. coli. Phagemids belonging to the twenty two clones were extracted and then retransformed into the XLOLR strain of E. coli. After MTZ selection, five clones could confer metronidazole resistance consistently. According to Southern hybridization and DNA sequencing, the five clones contained a same locus, recA. In addition, transforming the five clones into BL21 strain of E. coli produced a higher resistance to MTZ. Interestingly, electroporation of one of the five phagemid clones into two MTZ sensitive H. pylori yielded MTZ resistant strains. Comparing amino acid sequence in MTZ resistant with sensitive isolates revealed two point mutations at this locus. Above results suggest that mutation in recA may be associated with metronidazole resistance of H. pylori.

Carbohydrate binding specificity of the neutrophil-activating protein of Helicobacter pylori

The possible interaction of the neutrophil-activating protein of Helicobacter pylori with target cell glycoconjugates was investigated by the binding of 125I-labeled recombinant protein to glycosphingolipids from human neutrophils in solid phase assays. Thereby, a distinct binding of the neutrophil-activating protein to four bands in the acid glycosphingolipid fraction from human neutrophils was detected, whereas no binding to the non-acid glycosphingolipids or polyglycosyl ceramides from these cells was obtained. When using glycosphingolipids not present in the cell membrane of human neutrophils, it was found that the neutrophil-activating protein also bound to sulfated glycosphingolipids as sulfatide and sulfated gangliotetraosyl ceramide. Comparison of the binding preferences of the protein to reference glycosphingolipids from other sources suggested that in human granulocytes, the neutrophil-activating protein of H. pylori preferentially recognizes glycoconjugates with a terminally unsubstituted NeuAcalpha3Galbeta4GlcNAcbeta3Galbeta4GlcNAcbeta sequence.

High prevalence of hepatitis C virus infection in patients with B-cell lymphoproliferative disorders in Italy

Starting from the observation that a number of consecutive patients with non-Hodgkin's lymphoma (NHL) resulted positive for hepatitis C virus (HCV) antibodies on routine testing, we set up a survey for HCV contact prevalence in all patients with lymphoproliferative disorders (LPD) followed in our institution. We searched for HCV antibodies by a third-generation ELISA technique, followed by a confirmation test (RIBA III); serum viral RNA and HCV genotype were investigated by a RT-PCR technique. We screened a total of 315 patients suffering from B-NHL (91), multiple myeloma (56), MGUS (48), chronic lymphocytic leukemia (57), Waldentrom's macroglobulinemia (13), Hodgkin's disease (HD)(43), and T-NHL (9). While only 1 of 52 patients with a non-B-LPD (HD or T-NHL) had signs of HCV contact (i.e., 1.9%, which is in the range of the normal population in the South of Italy), 59 of 263 patients with a B-LPD (22.4%) had HCV antibodies or RNA, or both, with no major differences among the various types of disorders, except for WM, in which the rate was higher (61.5%). The same prevalence was found for patients tested at diagnosis or during the follow-up, and in transfused or never-transfused patients. Only a few patients were aware of having a liver disease; one-half of HCV-positive patients never had transaminase increase. A review of data from Central and Northern Italy is included, showing similar findings; a report from Japan has confirmed such an association, while limited surveys in England have not revealed any correlation. These findings may have important biological and clinical implications.

Ongoing Ig Gene Hypermutation in Salivary Gland Mucosa-Associated Lymphoid Tissue-Type Lymphomas

Salivary gland mucosa-associated lymphoid tissue (MALT) type lymphomas are typically indolent B-cell neoplasms that are often associated with Sjogren's syndrome. To better define the cell of origin and evaluate whether antigen receptor stimulation may be playing a role in tumor growth, the Ig heavy and light chain variable genes (VH and VL) expressed by five salivary gland MALT lymphomas were cloned and sequenced. Comparison to known germline sequences indicated that three of the lymphoma VH genes were derived from 51p1, a member of the VH1 family, while the other two used different VH gene segments from the VH3 family, 22-2B and HG19. All five of the VL genes belonged to the VkIII family, with three derived from Humkv325 and the other two from the Vg and Humkv328 genes. Numerous point mutations relative to the proposed germline genes were present in all of the lymphoma VH and VL genes. In addition, the VH and VL genes from each lymphoma showed intraclonal sequence heterogeneity indicative of ongoing somatic hypermutation. Because the process of Ig gene hypermutation is thought to occur at the germinal center stage of B-cell development, these findings suggest the MALT lymphoma cell of origin may be a germinal center B cell. Selection against mutations that result in replacement of amino acids suggested that Ig stimulation may be important for lymphoma growth. The possibility that antigen receptor stimulation may be involved in the growth of salivary gland MALT lymphomas is further suggested by the noted restricted use of VH and VL gene segments.

Lack of serologic evidence for Helicobacter pylori infection in head and neck cancer

BACKGROUND

Several epidemiologic investigations have established a link between Helicobacter pylori infection and gastric malignancies. Because the stomach is in continuity with the oral cavity and the bacterium has been isolated from dental plaque and saliva, we hypothesized that H. pylori infection of the upper aerodigestive tract might result in mucosal disruption, allowing for subsequent transformation by known carcinogens such as tobacco and alcohol.

METHODS

To test this hypothesis, we assayed for the presence of IgG antibodies to H. pylori in the serum of 21 patients with squamous cell carcinoma of the head and neck (SCCHN) and 21 matched controls without a history of head and neck cancer.

RESULTS

The incidence of seropositivity in the SCCHN patients was 57% and in the controls, 62% (p > 0.05).

CONCLUSIONS

These data do not support an etiologic role for H. pylori infection in head and neck cancer.

Clinicopathological studies on coexisting gastric malignant lymphoma and gastric adenocarcinoma: report of four cases and review of the Japanese literature

Among 121 cases of primary gastric malignant lymphoma from 1962 to 1994 at the National Cancer Center Hospital, Tokyo, we found four cases (three males and one female) of adenocarcinoma coexisting in the stomach. The incidence of gastric malignant lymphoma together with gastric adenocarcinoma was 3.3%, suggesting that patients with lymphoma may have an increased incidence of gastric adenocarcinoma. A review of the Japanese literature revealed an additional 62 patients who developed coexisting gastric malignant lymphoma and adenocarcinoma. In the total series of 66 patients whose age and sex were recorded, there were 48 males with a mean age of 63.8 years and 18 females with a mean age of 58.6 years. Most adenocarcinomas were macroscopically early (76%) and of histologically differentiated type (75%). Conversely, 71% of lymphomas were of the advanced type macroscopically. The correct preoperative diagnoses were made in only 27% (16/59) of cases, when both tumors were located independently.