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

Production of IL-12 in gastritis relates to infection with Helicobacter pylori

Increased production of proinflammatory cytokines, including tumour necrosis factor-alpha (TNF-alpha), IL-1beta, IL-6 and IL-8, has been demonstrated in Helicobacter pylori-associated gastric mucosal inflammation. IL-12, a newly characterized cytokine, is thought to be a key mediator in host responses to bacterial infections. The aim of this study was to investigate differences in cytokine patterns between H. pylori-positive and -negative gastritis and normal mucosa. Secretion of IL-12, TNF-alpha, IL-1beta, IL-6, IL-8 and IL-10 was measured in 176 patients with chronic gastritis in whole biopsy cultures. Gastritis was graded for chronic inflammation or acute inflammatory activity, respectively, according to the Sydney system. Biopsies with similar scores were matched for analysis from H. pylori-infected and non-infected patients. Secretion of IL-12 was significantly increased in H. pylori-associated gastritis in comparison with H. pylori-negative gastritis (P < 0.0001). In contrast, secretion of TNF-alpha, IL-1beta, IL-6, and IL-8 correlated with the degree of inflammation but was not different between H. pylori-positive and -negative patients. Moreover, IL-10 secretion was found to be higher in H. pylori-positive than in H. pylori-negative patients. IL-12 may play a specific role in H. pylori-associated gastric disease, whereas production of the proinflammatory cytokines TNF-alpha, IL-1beta, IL-6 and IL-8 does not seem to be restricted to H. pylori-induced inflammation. The contra-inflammatory cytokine IL-10 may be a contributor to the chronicity of H. pylori-associated gastritis by impairing clearance of the pathogen.

CDR3 sequences of MALT lymphoma show homology with those of autoreactive B-cell lines

We have examined the CDR3 sequence and adjacent regions of immunoglobulin genes from B-cell lymphoma of mucosa-associated lymphoid tissue (MALT). Twenty-nine sequences (15 sequences from 13 low-grade MALT lymphomas, marginal zone B-cell lymphomas; 7 sequences from 6 high-grade MALT lymphomas; 7 sequences from 7 diffuse large cell lymphomas) were obtained after cloning of the polymerase chain reaction-amplified segments. In the low-grade MALT, high-grade MALT and diffuse large cell lymphomas, the mean length of the CDR3 region was 47.6+/-10.31 (range 21 to 60), 38.71+/-10.37 (range 27 to 57) and 40.86+/-3.34 (range 39 to 48) nucleotides, respectively. The length of the CDR3 region was significantly greater in the low-grade MALT lymphoma group than in the other two groups. CDR3 sequences in lymphoma cell clones of 14 cases showed 60 to 81% homology with autoantibody-associated lymphocyte clones including rheumatoid factor. The incidences of these autoantibody-associated lymphocyte clones were higher in the high-grade MALT (4/6) and diffuse large lymphomas (5/7) than in the low-grade MALT lymphoma (5/13). Cases with more than 70% homology at the nucleotide level were found to have 71 to 82% homology with autoantibodies at the protein level in the low-grade MALT lymphomas (2/13), and 67% homology in the high-grade MALT lymphomas (2/7). These results indicate that MALT lymphomas may be derived from the malignant transformation of autoreactive B-cells.

A systematic review of Helicobacter pylori eradication therapy--the impact of antimicrobial resistance on eradication rates

BACKGROUND

We systematically reviewed all available data in the literature to determine the overall eradication rates of currently advised Helicobacter pylori eradication regimens and to resolve conflicting evidence on the impact of antimicrobial resistance on the eradication rates.

METHODS

A comprehensive search of all published trials on H. pylori eradication therapy was carried out via an electronic database search, hand-searching and checking reference lists of pharmaceutical companies and other reviews. Full papers and abstracts in the English language which study currently advised eradication regimes were included.

RESULTS

770 study-arms were analysed. Mean eradication rates for bismuth based triple, proton pump inhibitor triple, quadruple and ranitidine bismuth citrate combination therapies vary from 65 to 92%. In case of nitroimidazole resistance, a drop in efficacy of up to 50% was found for bismuth-based triple and proton pump inhibitor-based triple therapies. For quadruple therapy, a significant difference in efficacy was found in the equal-effects analysis; however, this could not be confirmed in the random-effects analysis. In case of clarithromycin resistance, a mean drop in efficacy of 56% was found for one- and two-week clarithromycin containing proton pump inhibitor-triple therapies and of 58% for two-week ranitidine bismuth citrate combined with clarithromycin therapies. For ranitidine bismuth citrate combined with clarithromycin and nitroimidazole, no difference in efficacy was found in case of nitroimidazole or clarithromycin resistance, but data are still scarce.

CONCLUSIONS

The cure rate with most regimens dropped significantly, in case of nitroimidazole-resistant strains, compared to nitroimidazole-susceptible strains. In case of clarithromycin resistance, the efficacy of most regimens is also decreased; however, data are still scarce. These data should allow physicians to make a better choice of an appropriate therapy for their patients.

Antibiotic treatment of gastric lymphoma of mucosa-associated lymphoid tissue. An uncontrolled trial

BACKGROUND

Gastric lymphoma of mucosa-associated lymphoid tissue (MALT) is related to Helicobacter pylori infection and may depend on this infection for growth.

OBJECTIVE

To determine the response of gastric MALT lymphoma to antibiotic treatment.

DESIGN

Prospective, uncontrolled treatment trial.

SETTING

University hospital referral center and three collaborating university and community hospitals.

PATIENTS

34 patients with stage I or stage II N1 gastric MALT lymphoma.

INTERVENTION

Two of three oral antibiotic regimens--1) amoxicillin, 750 mg three times daily, and clarithromycin, 500 mg three times daily; 2)tetracycline, 500 mg four times daily, and clarithromycin, 500 mg three times daily; or 3) tetracycline, 500 mg four times daily, and metronidazole, 500 mg three times daily--were administered sequentially (usually in the order written) for 21 days at baseline and at 8 weeks, along with a proton-pump inhibitor (lansoprazole or omeprazole) and bismuth subsalicylate.

MEASUREMENTS

Complete remission was defined as the absence of histopathologic evidence of lymphoma on endoscopic biopsy. Partial remission was defined as a reduction in endoscopic tumor stage or 50% reduction in the size of large tumors.

RESULTS

34 patients were followed for a mean (+/-SD) of 41 +/- 16 months (range, 18 to 70 months) after antibiotic treatment. Of 28 H. pylori-positive patients, 14 (50% [95% CI, 31% to 69%]) achieved complete remission, 8 (29%) achieved partial remission (treatment eventually failed in 4 of the 8), and 10 (36% [CI, 19% to 56%]) did not respond to treatment. Treatment failed in all 6 (100% [CI, 54% to 100%]) H. pylori-negative patients. Patients with endoscopic appearance of gastritis (stage I T1 disease) were most likely to achieve complete remission within 18 months. Tumors in the distal stomach were associated with more favorable response than tumors in the proximal stomach.

CONCLUSIONS

A subset of H. pylori-positive gastric MALT lymphomas, including infiltrative tumors, may respond to antibiotics. The likelihood of early complete remission seems to be greatest for superficial and distal tumors.

Isolation of a Helicobacter pylori protein, FldA, associated with mucosa-associated lymphoid tissue lymphoma of the stomach

BACKGROUND & AIMS

The growth of gastric mucosa-associated lymphoid tissue lymphoma (MALToma) seems to depend on the stimulation of Helicobacter pylori. We attempted to identify specific antigen(s) from H. pylori strains associated with MALToma.

METHODS

Membranous and secreted proteins of H. pylori were compared on sodium dodecyl sulfate-polyacrylamide gel electrophoresis by Western blot using sera from patients with MALToma.

RESULTS

A 19-kilodalton protein was seen in all strains isolated from patients with MALToma but uncommonly in other strains. The protein was purified and sequenced. Amino acid sequence comparison showed it was an FldA homologue, a putative flavodoxin protein. DNA sequencing in 26 strains revealed that a nucleotide G insertion at position 481 of the fldA gene was more frequently observed in strains associated with MALToma than other strains (9/9 vs. 6/17; P = 0.002). The mutation caused a short truncation. A recombinant protein with this truncation was expressed and tested. Sera of 12 (70.6%) of 17 patients with MALToma were positive for the antibody to the recombinant protein, and 7 (16.7%) of 42 control patients were positive (12/17 vs. 7/42; P < 0.0001).

CONCLUSIONS

Truncated FldA of H. pylori is associated with gastric MALToma. It may be involved in the pathogenesis of gastric MALToma. Antibody to this antigen could be used as a serological marker of the disease.

Serum antibody responses to Helicobacter pylori and the cagA marker in patients with mucosa-associated lymphoid tissue lymphoma

The lymphoma of the mucosa-associated lymphoid tissue (MALT) of the stomach has been linked to Helicobacter pylori infection, but the mechanisms involved in B-cell proliferation remain elusive. In a search for putative H. pylori-specific monoclonal immunoglobulin production, an H. pylori strain was isolated from 10 patients with MALT lymphoma and used to detect the specific serum antibody response to the homologous strain by immunoblotting. Moreover, the antigenicity of the different strains was compared by using each of the 10 sera. We found that the different strains induced highly variable patterns of systemic immunoglobulin G antibody response, although several bacterial antigens, such as the 60-kDa urease B, were often recognized by the different sera. The cagA marker was detected in the strains by PCR with specific primers and by dot blot analysis, and the CagA protein was found in the sera of 4 of the 10 patients by immunoblotting. In conclusion, MALT lymphoma patients, like other patients with H. pylori gastritis, exhibit a polymorphic systemic antibody response, despite an apparently similar antigenic profile. The CagA marker of pathogenicity is not associated with this disease.

Effect of an aluminum hydroxide-magnesium hydroxide combination drug on adhesion, IL-8 inducibility, and expression of HSP60 by Helicobacter pylori

BACKGROUND

Co-magaldrox (Maalox) is used world-wide as an antacid and as a cytoprotective agent for gastritis and peptic ulcer diseases. We examined the effects of co-magaldrox on Helicobacter pylori.

METHODS

Adhesion of H. pylori to human gastric epithelial cells (MKN45) was evaluated by flow cytometry. Morphologic changes in H. pylori caused by co-magaldrox were determined by scanning electron microscopy. Induction of interleukin-8 (IL-8) from MKN45 cells was examined with enzyme-linked immunosorbent assay, and the intracellular and extracellular expression of heat-shock protein 60 (HSP60) was analyzed with sodium dodecyl sulphate-polyacrylamide gel electrophoresis and flow cytometry.

RESULTS

Adhesion of H. pylori to MKN 45 cells was significantly inhibited by 1.25%-5% comagaldrox. H. pylori aggregated with co-magaldrox according to an electron microscopic examination. IL-8 secretion from MKN45 cells after H. pylori infection was also inhibited by co-magaldrox. Extracellular expression of HSP60 on the surface of H. pylori was decreased after treatment with comagaldrox, whereas the intracellular synthesis of HSP60 was not. HSP60-induced IL-8 secretion was significantly inhibited by co-magaldrox in a dose-dependent manner.

CONCLUSIONS

These results show that co-magaldrox suppressed the expression of the following virulence factors: adhesion, IL-8 inducibility, and expression of extracellular HSP60. Therefore, co-magaldrox is a potent anti-H. pylori and cytoprotective drug.

The Apoptosis Inhibitor Gene API2 and a Novel 18q Gene,MLT, Are Recurrently Rearranged in the t(11;18)(q21;q21) Associated With Mucosa-Associated Lymphoid Tissue Lymphomas

Marginal zone cell lymphomas of the mucosa-associated lymphoid tissue (MALT) are the most common subtype of lymphoma arising at extranodal sites. The t(11;18)(q21;q21) appears to be the key genetic lesion and is found in approximately 50% of cytogenetically abnormal low-grade MALT lymphomas. We show that the API2 gene, encoding an inhibitor of apoptosis also known as c-IAP2, HIAP1, andMIHC, and a novel gene on 18q21 characterized by several Ig-like C2-type domains, named MLT, are recurrently rearranged in the t(11;18). In both MALT lymphomas analyzed, the breakpoint inAPI2 occurred in the intron separating the exons coding respectively for the baculovirus IAP repeat domains and the caspase recruitment domain. The breakpoints within MLT differed but the open reading frame was conserved in both cases. In one case, the translocation was accompanied by a cryptic deletion involving the 3′ part of API2. As a result, the reciprocal transcript was not present, strongly suggesting that the API2-MLT fusion is involved in the oncogenesis of MALT lymphoma.

Gastric MALT lymphoma: from concept to cure

Gastric MALT lymphomas are clinically and histologically quite distinct from comparable low-grade B-cell lymphomas of lymph nodes. Their histology suggests that immunological mechanisms might be operative in their growth. Given that there is normally no lymphoid tissue in gastric mucosa and that Helicobacter pylori (H. pylori), the only common bacterial antigen in the stomach, results in the accumulation of gastric MALT, the possibility that this organism is implicated in the pathogenesis of gastric lymphoma has been extensively investigated. It appears that most, but not necessarily all, gastric MALT lymphomas arise in MALT acquired in response to H. pylori infection and develop by stepwise accumulation of genetic abnormalities. Early molecular events in the evolution of gastric MALT lymphoma from 'acquired' MALT include trisomy 3, t(11;18)(q21;q21), genetic damage leading to genetic instability, as indicated by the so-called replication error repair (RER) phenotype, and both p53 and c-myc mutations. At this stage in their development, the growth of the lymphomas is driven by contact between the neoplastic B cells and H. pylori specific intra-tumoral T cells. Eradication of H. pylori causes the tumour to enter a latent phase resulting in clinical regression. Later events, such as t(1;14)(p22;q32), appear to be linked to a capacity for autonomous growth, loss of sensitivity to H. pylori and dissemination of the lymphoma beyond the stomach and gastric lymph nodes. Cloning of the breakpoint in t(1;14) has allowed the identification of a new tumour suppresser gene, bc110. High grade transformation of MALT lymphoma has been associated with p53 inactivation, deletions of p16 and t(8;14).

Surgery plus chemotherapy or chemotherapy alone for primary intermediate- and high-grade gastric non-Hodgkin's lymphoma: the Royal Marsden Hospital experience

Primary gastric lymphomas (PGL) have traditionally been treated with surgery followed by chemotherapy or radiotherapy. Surgery was thought to improve staging, optimise local disease control and reduce risk of perforation or bleeding, but recent studies question its role. In this study, patients with intermediate- or high-grade PGL who received chemotherapy from 1985 to 1996 at the Royal Marsden Hospital were identified using a prospectively accrued database. A total of 37 patients (6 with low-grade mucosa-associated lymphoid tissue lymphoma (MALT-L), 9 with high-grade MALT-L, 20 with diffuse large B-cell (DLBC) lymphoma and 2 other histologies), 17 of whom had localised disease, were treated with either surgery plus chemotherapy or chemotherapy alone. 5-year overall survival for localised and advanced PGL was 94 and 50%, respectively, with no differences between the two treatments over a 53 months median follow-up. No perforations or serious bleeding occurred. Surgery is associated with important morbidity and we detected no benefit of surgery prior to chemotherapy in this limited series of patients.

The Apoptosis Inhibitor Gene API2 and a Novel 18q Gene,MLT, Are Recurrently Rearranged in the t(11;18)(q21;q21) Associated With Mucosa-Associated Lymphoid Tissue Lymphomas

Marginal zone cell lymphomas of the mucosa-associated lymphoid tissue (MALT) are the most common subtype of lymphoma arising at extranodal sites. The t(11;18)(q21;q21) appears to be the key genetic lesion and is found in approximately 50% of cytogenetically abnormal low-grade MALT lymphomas. We show that the API2 gene, encoding an inhibitor of apoptosis also known as c-IAP2, HIAP1, andMIHC, and a novel gene on 18q21 characterized by several Ig-like C2-type domains, named MLT, are recurrently rearranged in the t(11;18). In both MALT lymphomas analyzed, the breakpoint inAPI2 occurred in the intron separating the exons coding respectively for the baculovirus IAP repeat domains and the caspase recruitment domain. The breakpoints within MLT differed but the open reading frame was conserved in both cases. In one case, the translocation was accompanied by a cryptic deletion involving the 3′ part of API2. As a result, the reciprocal transcript was not present, strongly suggesting that the API2-MLT fusion is involved in the oncogenesis of MALT lymphoma.

Oral immunization with urease and Escherichia coli heat-labile enterotoxin is safe and immunogenic in Helicobacter pylori-infected adults

BACKGROUND & AIMS

Oral immunization with Helicobacter pylori urease can cure Helicobacter infection in animals. As a step toward therapeutic immunization in humans, the safety and immunogenicity of oral immunization with recombinant H. pylori urease were tested in H. pylori-infected adults.

METHODS

Twenty-six H. pylori-infected volunteers were randomized in a double-blind study to four weekly oral doses of 180, 60, or 20 mg of urease with 5 microg heat-labile enterotoxin of Escherichia coli (LT), LT alone, or placebo. Side effects and immune responses were evaluated weekly after immunization, and gastric biopsy specimens were obtained after 1 month and 6 months for histology and quantitative cultures.

RESULTS

Diarrhea was noted in 16 of 24 (66%) of the volunteers who completed the study. Antiurease serum immunoglobulin A titers increased 1. 58-fold +/- 0.37-fold and 3.66-fold +/- 1.5-fold (mean +/- SEM) after immunization with 60 and 180 mg urease, respectively, whereas no change occurred in the placebo +/- LT groups (P = 0.005). Circulating antiurease immunoglobulin A-producing cells increased in volunteers exposed to urease compared with placebo (38.9 +/- 13. 6/10(6) vs. 5.4 +/- 3.1; P = 0.018). Eradication of H. pylori infection was not observed, but urease immunization induced a significant decrease in gastric H. pylori density.

CONCLUSIONS

H. pylori urease with LT is well tolerated and immunogenic in H. pylori-infected individuals. An improved vaccine formulation may induce curative immunity.

PCR-based clonality analysis: a reliable method for the diagnosis and follow-up monitoring of conservatively treated gastric B-cell MALT lymphomas?

AIMS

We evaluated polymerase chain reaction (PCR) amplification of specific immunoglobulin heavy chain (IgH) gene rearrangements as a means of demonstrating monoclonality during follow-up of conservatively treated gastric MALT lymphoma, and compared the reproducibility of PCR on sequential frozen and paraffin-embedded endoscopic biopsies. We established an association between clonality detected by PCR and the histological observations.

METHODS AND RESULTS

Sixty-nine pairs of sequential frozen and paraffin-embedded endoscopic biopsies from 21 conservatively treated patients were graded according to the Wotherspoon-Isaacson histological scoring system, which provides a measure of diagnostic confidence on a scale 0-5. PCR amplification of the IgH gene was performed using FR3/JH and FR2/JH primers. 68/69 paired samples (98.5%) showed identical mono- or polyclonal PCR amplification patterns. Forty-seven out of 48 pairs of samples sharing similar histological features produced identical amplification patterns in both fresh and paraffin-embedded tissues. In comparison with the histological grading, monoclonality was detected in 64.2% and 41.6% of samples scored 5 and 4, respectively. Conversely, among 64 samples scored 0-3, a monoclonal pattern was observed only in two samples, one of which was from a patient who relapsed 9 months later.

CONCLUSIONS

PCR-based clonality analysis by demonstration of specific IgH gene rearrangement can be easily and reliably performed on both frozen and paraffin-embedded endoscopic biopsies. In conjunction with histological observation, this method can be used as a complementary tool to monitor MALT lymphoma regression during conservative treatment.

Controversies and consensus in the diagnosis, work-up and treatment of gastric lymphoma: an international survey

BACKGROUND

Variations in diagnostic criteria and staging procedures in cancer patients have important consequences for patient selection and often preclude meaningful comparison of published series. In gastric lymphoma, these effects will play a role, since diagnostic criteria are controversial. Moreover, staging procedures and therapeutic choices are influenced by insights from different clinical specialisms.

METHODS

To review the management of gastric lymphoma, formatted questionnaires were mailed to leading institutes with a special interest in this field in Europe, the United States and Japan.

RESULTS

Nineteen centers agreed to contribute. Minimum histological criteria varied among pathologists with a notable influence of the classification system used in the different countries. Detailed evaluation of the lymphoma distribution in the gastric wall and routine staging of the GI-tract differed between groups leaded by medical oncologists and gastroenterologists. This results in basically different patient selections and bias in treatment outcome. Similar effects were recorded for the role of gastric resection and radiotherapy.

CONCLUSIONS

This study gives insight in the basis of the decisions that result in different approaches in the management of gastric MALT-NHL and in the effects for patient selection and treatment results and may help in the design of future clinical trials.

Results and prognostic factors in stage I(E)-II(E) primary gastric lymphoma after gastrectomy

BACKGROUND

Infrequency of gastric lymphomas and lack of homogeneity of studies dealing with them preclude accurate management schemes. Helicobacter pylori (HP) and Isaacson's classification are new factors to consider. Our aim was to analyze these and other prognostic factors in a homogeneous series.

STUDY DESIGN

Fifty-four patients (mean age 62.4 years) treated by gastrectomy for primary gastric non-Hodgkin's lymphoma in stages IE or IIE were retrospectively reviewed. Twenty-seven patients received postoperative chemotherapy. HP and histologic features were studied using new slides from the paraffin-embedded gastrectomy specimens.

RESULTS

Postoperative morbidity and mortality rates were 19% and 5.6%, respectively. Five-year survival was 83%. Classification showed low-grade tumors in 59% and high-grade tumors in 41%. HP was positive in 64% of the patients. A poorer survival was associated with high-grade tumors (p = 0.02) and serosa involvement (p = 0.02). We did not find any significant difference between patients treated either by partial or total gastrectomy (p = 0.2), or receiving chemotherapy or not (p = 0.9). Nor did we appreciate any differences concerning margin involvement (p = 0.9).

CONCLUSIONS

Most primary gastric lymphoma patients have gastric HP. Serosa involvement and high-grade tumors adversely influence survival but gastrectomy type, resection margin invasion, and postoperative chemotherapy did not appear to have any influence.

[Radiotherapy for gastrointestinal lymphomas: indications and techniques]

Gastrointestinal lymphomas are almost exclusively of a non-Hodgkin's type. The Western form is characterized by a higher incidence of stomach location (50%), a MALT type (mucosa associated lymphoid tissue) (40%), a B-cell type (90%), and a high grade (55%). Chronic infection with Helicobacter pylori is an important risk factor. Mediterranean lymphomas form a particular clinical and pathological entity with diffuse involvement of the small bowel and are frequently being associated with a chronic malabsorption disorder. Eradication of Helicobacter pylori in early gastric lymphomas, and the use of tetracyclines in early Mediterranean lymphomas, have been shown to induce durable remissions. For more advanced gastric lymphomas, treatment usually consists of anthracyclin-based chemotherapy followed by involved field radiotherapy. Surgery is usually reserved for complications such as perforation or bleeding, or in some selected cases for salvage after failure of non-surgical therapy. For intestinal lymphomas, surgical resection whenever feasible, followed by anthracyclin-based chemotherapy is the most common treatment. Radiotherapy is usually reserved for consolidation in some clinical situations. The most commonly found prognostic factors are stage, grade, and tumor bulk. Treatment results vary with the presence of adverse prognostic factors and the used treatment combination. In general, patients with favorable disease receiving combined therapy have a 5-year relapse free survival (RFS) approaching 90%, whereas those with unfavorable disease have a RFS of 40-50%.

Helicobacter pylori non-cytotoxic genotype enhances mucosal gastrin and mast cell tryptase

AIMS

To determine the association, if any, between H pylori genotype and the gastric mucosal variations in the levels of gastrin, somatostatin, tryptase, and histamine.

METHODS

49 patients affected by duodenal ulcer and 48 by non-ulcer dyspepsia were studied. To identify the H pylori genotype, the presence of the cagA gene and vacA alleles m1, m2, s1, and s2 were analysed by polymerase chain reaction. Gastrin, somatostatin, tryptase, and histamine were measured in antral mucosal biopsies.

RESULTS

57 patients were infected with H pylori (30 with duodenal ulcer and 27 with non-ulcer dyspepsia). Gastrin and tryptase were increased in patients with H pylori infection, although the variations were statistically significant only for gastrin; somatostatin and histamine were not influenced by H pylori infection. In patients with non-ulcer dyspepsia the absence of the cagA gene and the presence of vacA alleles s2 and m2 were associated with higher values of tryptase and to a lesser extent of gastrin. These associations were not found in patients with duodenal ulcer.

CONCLUSIONS

The cagA negative s2m2 strain of H pylori may be less dangerous for the gastric mucosa than other H pylori strains since it enhances tryptase production by gastric mucosal mast cells; this enzyme is thought to stimulate tissue turnover and favour wound healing.

Differences in endoscopic and clinicopathological features of primary and secondary gastric non-Hodgkin's lymphoma. German Gastrointestinal Lymphoma Study Group

BACKGROUND

Lymphomatous neoplasia of the stomach is initially seen either as primary gastric B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) or as nodal non-Hodgkin s lymphoma (NHL) secondarily involving the GI tract. One hundred seventy-six patients with primary gastric NHL (low grade, n = 65; high grade, n = 111) and 29 with secondary gastric NHL (low grade, n = 19; high grade, n = 10) were studied to evaluate whether differences in pathogenesis are associated with distinct clinical and endoscopic features.

METHODS

Clinical features, tumor size, localization, and growth pattern were analyzed by means of esophagogastroduodenoscopy; grading was determined with histologic examination.

RESULTS

The analysis of various clinical symptoms and endoscopic findings revealed a relationship between the occurrence of abdominal pain, vomiting, and unifocal growth pattern with an affiliation to the group with primary gastric NHL (p < 0.001), whereas tumor localization in the gastric fundus was predominantly found in secondary gastric NHL (p < 0.001). An equation has been generated that may help to predict affiliation to primary or secondary gastric NHL with an accuracy of 96%.

CONCLUSIONS

Our results indicate that careful pretreatment analysis of clinical and endoscopic findings may be helpful in the diagnosis of primary or secondary gastric involvement by NHL, although reliable discrimination still requires histologic verification.

AIDS Primary Central Nervous System Lymphoma: Molecular Analysis of the Expressed VH Genes and Possible Implications for Lymphomagenesis

AIDS-associated primary central nervous system lymphomas are late events that have an extremely poor prognosis. Despite different hypotheses, the brain localization of these B cell lymphomas remains an enigma. To better define the cell origin of the lymphomas and the possible role of the B cell receptor (BCR) in the brain localization and/or in the oncogenic transformation, we analyzed the V region genes of the Ig heavy chain expressed by lymphoma cells in five randomly selected patients. After amplifying the rearranged VHDJH DNA by PCR, cloning, and sequencing of the amplified products, we observed that: 1) of the five lymphomas analyzed, four were clearly monoclonal; 2) there was no preferential use of one peculiar VH family or one peculiar segment of gene; 3) the mutation analysis showed that an Ag-driven process occurred in at least two cases, probably before the oncogenic event; and 4) there was no intraclonal variability, suggesting that the hypermutation mechanism is no longer efficient in these lymphoma B cells. Taken together, our results suggest that distinct Ags could be recognized by the BCR of the lymphoma cells in different patients and that, if the Ags are responsible for the brain localization of these B cells bearing mutated BCR, other factors must be involved in B cell transformations in primary central nervous system lymphoma.

Eradication of Helicobacter pylori infection did not lead to cure of duodenal mucosa-associated lymphoid tissue lymphoma

Duodenal mucosa-associated lymphoid tissue (MALT) lymphoma is very rare, and little is known about its clinical course or association with Helicobacter pylori infection. This report describes the case of a 76-year-old man with a polypoid mass in the duodenal bulb, diagnosed as low-grade MALT lymphoma. H. pylori infection in the duodenal mucosa was confirmed by histology with silver stain. Endoscopic examination showed that the gross lesion regressed after the eradication of H. pylori despite its histopathologic persistence. Ten months later, however, cervical and intraperitoneal lymphadenopathy and bone marrow involvement was observed, and the pathologic diagnosis of the cervical lymph node was identical with that of the duodenal lesion.

The role of Helicobacter pylori in primary gastric MALT lymphoma

AIMS

Helicobacter pylori has been claimed to be an important aetiological factor which raises the risk of mucosa-associated tissue lymphoid (MALT) lymphoma. However, some studies on gastric MALT lymphoma revealed a low rate of H. pylori infection suggesting that not all gastric lymphomas are related to H. pylori infection. The aim of this study was to verify the H. pylori infection frequency in a series of patients with primary gastric MALT lymphomas and to examine the relationship between H. pylori and the pathological features of those lymphomas.

METHODS AND RESULTS

Thirty-one cases of resected gastric lymphoma were analysed: 10 cases (32%) were low-grade MALT lymphomas and 21 cases (68%) were high-grade MALT lymphomas. Helicobacter pylori was found in only 18 of 31 (58%) cases. Helicobacter pylori infection was significantly correlated with the grade and depth of invasion of MALT lymphoma since 63% of superficial low-grade MALT lymphomas were positive for H. pylori compared with 38% of advanced high-grade MALT lymphomas (P = 0.02).

CONCLUSION

We confirmed the relationship between H. pylori infection and a subset of gastric MALT lymphoma. Our results also showed that not all low- and high-grade gastric MALT lymphomas are H. pylori-dependent. This suggests that H. pylori infection may play a promoter role in the development of MALT lymphoma, but its presence is not mandatory for the progression of the lymphoma in view of its low frequency in advanced high-grade MALT lymphoma.

Helicobacter pylori, hyperammonemia and subclinical portosystemic encephalopathy: effects of eradication

BACKGROUND/AIMS

An involvement of Helicobacter pylori in the development of hepatic encephalopathy in cirrhotic patients has been proposed, but data confirming such an association are lacking. This prospective study aimed to assess whether ammonia levels and indicators of subclinical portosystemic encephalopathy were influenced by H. pylori status in a series of 62 cirrhotic patients. The effects of H. pylori eradication on such parameters were also investigated.

METHODS

Fasting blood ammonia levels, mental state, number connection test, flapping tremor, and EEG tracings were recorded at baseline, and in H. pylori-positive patients (as diagnosed by rapid urease test and 14C-urea breath test) these parameters were reassessed 2 months following eradication therapy.

RESULTS

In this series of non-advanced cirrhotic patients, the prevalence of H. pylori infection was 52%. No significant differences were observed between H. pylori+ and H. pylori- cases with respect to fasting venous blood ammonia concentration (47+/-24 vs. 43+/-22 micromol/l) or to the remaining parameters assessing portosystemic encephalopathy. In addition, H. pylori eradication failed to induce any significant variation in either fasting blood ammonia levels (from 45+/-23 to 48+/-26 micromol/l) or neurologic disturbances.

CONCLUSION

These results indicate that H. pylori infection is not a major contributing factor to either fasting blood ammonia levels or parameters assessing subclinical portosystemic encephalopathy in patients with non-advanced liver cirrhosis.

Mucosa-associated lymphoid tissue lymphoma of the stomach: long term outcome after local treatment

BACKGROUND

Although antibiotic therapy is emerging as effective initial treatment for patients with gastric lymphoma of mucosa-associated lymphoid tissue (MALT), there is a subset of patients for whom antibiotics are ineffective or inappropriate. Surgical resection can be curative, but total gastrectomy may be required for the eradication of all disease. To identify the optimal nonantibiotic therapy for early stage gastric MALT lymphoma, the authors retrospectively evaluated the Massachusetts General Hospital experience with gastric MALT lymphoma.

METHODS

Disease patterns and treatment outcomes were retrospectively analyzed in data from 21 consecutive patients with gastric MALT lymphoma who were treated between 1978 and 1995 at the Massachusetts General Hospital.

RESULTS

Sixteen patients were Stage IE, and 5 were in higher stages. Treatment consisted of resection with or without radiation or chemotherapy (14 patients), radiation alone (4 patients), or radiation plus chemotherapy (2 patients). Thirteen Stage IE patients received local therapy only. The 10-year actuarial relapse free survival rate for Stage IE patients was 93%, with 1 relapse among 15 treated patients. Because the patient who relapsed was treated successfully with chemotherapy, the 10-year cancer free survival was 100%. Overall survival for Stage IE patients was 93% at 5 years and 58% at 10 years, with no deaths from lymphoma.

CONCLUSIONS

These data indicate that a high probability of long term remission can be achieved with only local treatment of patients with Stage I gastric MALT lymphoma. Preliminary results suggest that radiation therapy is well tolerated and effective and may well be the optimal nonantibiotic treatment for patients with localized gastric MALT lymphoma.

Long-term follow-up of duodenal ulcer in children before and after eradication of Helicobacter pylori

BACKGROUND

Helicobacter pylori is a well-known cause of chronic antral gastritis and plays an important role in the pathogenesis of peptic ulcer disease in adults. However, because of the relatively low incidence of duodenal ulcer in childhood, few studies have been directed specifically at the relation between the treatment of H. pylori infection and duodenal ulcer in children. An evaluation in a larger patient population is necessary to draw a conclusion.

METHODS

Twenty-six children with duodenal ulcer and H. pylori antral gastritis received triple therapy (amoxicillin, bismuth, and metronidazole) to investigate whether eradication of the organisms can promote healing and prevent relapse of the ulcers in children. Endoscopic examinations were performed before, 2 months, and 12 months after the beginning of treatment.

RESULTS

H. pylori infection was eradicated in 25 (96%) of the 26 patients who underwent upper endoscopic follow-up. Clinical improvement and ulcer healing were achieved in 24 (92%) of 26 children. During a mean follow-up of nearly 2 years, the annual ulcer relapse rate was estimated to be 9%.

CONCLUSIONS

Triple therapy is the treatment of choice for endoscopically proven duodenal ulcer and histologically proven H. pylori antral gastritis in children. It strongly supports a causal relation between H. pylori and duodenal ulcer disease in children.

Low sensitivity of computed tomography in the staging of gastric lymphomas of mucosa-associated lymphoid tissue: impact on prospective trials and ordinary clinical practice

The natural history and management of gastric lymphomas of mucosa-associated lymphoid tissue (MALTomas) are not completely understood. Most stage I cases are now entered into prospective trials to confirm the excellent results obtained with conservative treatment, whereas current therapeutic policies are based on accumulated experience. The limits of staging work-ups may have a significant impact on prospective trials and ordinary clinical practice. The authors explore the sensitivity of computed tomography scanning in detecting perigastric adenopathy in 20 patients with gastric MALToma treated by gastrectomy. Clinical staging identified 17 patients as having stage I MALTomas and three patients as having stage II1 MALTomas. Histopathologic staging showed that 8 of 17 patients formerly diagnosed with stage I MALToma had perigastric nodal involvement, whereas the three patients with clinical stage II1 were confirmed as such. Computed tomography scanning has low sensitivity in detecting perigastric lymphadenopathy in gastric MALTomas. This leads to understaging, with a significant impact on therapeutic decision, and distorts newly acquired knowledge about the disease's natural history and management, introducing a bias in prospective clinical trials. Endoscopic ultrasonography should be tested as a staging procedure both in prospective trials and in ordinary clinical practice.

Helicobacter pylori in gastric biopsies of Taiwanese patients with gastroduodenal diseases

This study was designed to study the in vivo prevalence and the heterogeneity of H. pylori in patients with gastroduodenal diseases in central Taiwan. H. pylori infection was detected in 74.1% (575/776) of the symptomatic population studied. The prevalence of H. pylori infection increased from 11.1% in those between the ages of one to 20, to 82.9% in those between the ages of 41 and 50, and to 84% in those between the ages of 51 and 60. There was no significant difference in the prevalence of H. pylori infection between men and women. Among different blood types, the prevalence and relative risk of H. pylori infection was significantly higher in blood group O patients (90.3%) than in blood group A (41%), blood group B (27.4%), or blood group AB (62%) patients. Metronidazole resistance was found in 6.7% of the primary isolates. The prevalence of metronidazole-resistant H. pylori strains was higher in women (7.69%) than in men (6.25%), but this difference was not significant. A total of 88% of H. pylori strains were cagA-positive. CagA gene-positive strains were present in 90.1% of duodenal ulcers, 90% of duodenal ulcers combined with gastric ulcer, 85.8% of gastric ulcers, and 69.2% of gastritis patients, and was significantly higher in peptic ulcer disease groups than in the gastritis group. In conclusion, there was a low incidence (6.7%) of metronidazole-resistant H. pylori strains and a high prevalence (88%) of H. pylori cagA-positive strains in central Taiwan. This study also demonstrated a significant in vivo correlation between active H. pylori infection and blood group O-positive patients, and showed a significant association between cagA gene-positive H. pylori strains and the development of peptic ulcers.

Free recombination within Helicobacter pylori

Sequences of three gene fragments (flaA, flaB, and vacA) from Helicobacter pylori strains isolated from patients in Germany, Canada, and South Africa were analyzed for diversity and for linkage equilibrium by using the Homoplasy Test and compatibility matrices. Horizontal genetic exchange in H. pylori is so frequent that different loci and polymorphisms within each locus are all at linkage equilibrium. These results indicate that H. pylori is panmictic. Comparisons with sequences from Escherichia coli, Neisseria meningitidis, and Drosophila melanogaster showed that recombination in H. pylori was much more frequent than in other species. In contrast, when multiple family members infected with H. pylori were investigated, some strains were indistinguishable at all three loci. Thus, H. pylori is clonal over short time periods after natural transmission.

Serological evidence of an association between chlamydial infections and malignant lymphomas

Chronic infections may predispose to malignant growth. Recently, serological markers of chronic Chlamydia pneumoniae infection have been associated with lung cancer. Our aim was to study the possible association between chronic chlamydial infections and malignant lymphomas. The present case-control study involved 72 patients with lymphoma (31 females and 41 males) and matched controls. 53 patients had non-Hodgkin's lymphoma (NHL) and 19 had Hodgkin's disease. The sera, collected at the time of diagnosis, were tested for IgG antibodies and immune complexes to C. pneumoniae and C. trachomatis by a microimmunofluorescence method and ELISA and for IgG antibodies and immune complexes to Helicobacter pylori by ELISA. The serological markers suggesting chronic chlamydial infection were associated with malignant lymphoma. The association was most evident for the presence of C. pneumoniae-specific immune complexes in NHL (OR = 7.3, 95% CI 2.2-25) and appeared to be limited to men. No association between H. pylori antibodies or immune complexes and malignant lymphomas could be demonstrated. Our study provides seroepidemiological evidence of an association between chronic chlamydial infections and lymphomas.

Evaluation and management of the "new" lymphoma entities: mantle cell lymphoma, lymphoma of mucosa-associated lymphoid tissue, anaplastic large-cell lymphoma, and primary mediastinal B-cell lymphoma

Non-Hodgkin's lymphomas (NHL) represent a major health problem worldwide, and incidence has been on the rise continuously for the last few decades. It is estimated that approximately 55,000 new cases of NHL will be diagnosed in the United States in 1998 and that slightly fewer than 25,000 patients will die of treatment failure or recurrent disease. The rising incidence of NHL is related not only to the acquired immunodeficiency syndrome epidemic but to also a steady increase in the number of cases diagnosed in older patients without immunosuppression. The new pathologic classification of NHL (revised European-American lymphoma classification, REAL) developed by the International Lymphoma Study Group (ILSG) is already resulting in more accurate disease-specific epidemiologic and clinical investigations. These studies have brought a new awareness of the existence and the relative prevalence of discrete NHL subtypes that appear to predominate among patients in different populations according to age, sex, geographic distribution, and predisposing conditions. This developing database has also the potential to result in the discovery of specific environmental causes, predisposing genetic factors, and therapeutic approaches. Some of the entities defined in the REAL classification, such as follicular lymphomas, diffuse B large-cell lymphomas, and T-cell lymphoblastic lymphomas, were already well described in the older classification systems (Kiel and Working Formulation). Others, such as mantle cell lymphoma, (MCL) anaplastic large-cell lymphoma (ALCL), lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), and primary mediastinal B-cell lymphoma (PMBCL) are relatively new members of the family, and accurate data on their clinicopathologic features and natural histories have only recently begun to emerge. This review presents in detail the most recent data on the clinical presentation of, diagnostic evaluation of, and treatment options for the most common of the new NHL entities: MCL, MALT lymphoma, CD30+ (Ki-1+) ALCL, and PMBCL. These four entities combined represent approximately 20% of all cases of NHL and exemplify well the broad clinicopathologic spectrum of NHL and the diagnostic and therapeutic challenges facing those who care for patients affected by these conditions.

Development of a PCR-restriction fragment length polymorphism assay using the nucleotide sequence of the Helicobacter hepaticus urease structural genes ureAB

Infection with Helicobacter hepaticus causes chronic active hepatitis in certain strains of mice and is associated with hepatocellular carcinoma in A/JCr mice. Like the gastric helicobacters, H. pylori and H. mustelae, H. hepaticus possesses a high level of urease activity. However, the H. hepaticus urease structural gene sequences have not been previously determined, and the role of the urease enzyme in colonization and in pathogenesis is not known. PCR was used to amplify a portion of the urease structural genes from H. hepaticus genomic DNA. Amplified DNA fragments were cloned, and the nucleotide sequence was determined. The deduced amino acid sequence of the partial H. hepaticus ureA gene product was found to exhibit 60% identity and 75% similarity to the predicted H. pylori UreA. The deduced amino acid sequence of a partial H. hepaticus ureB gene product exhibited 75% identity and 87% similarity to the predicted H. pylori UreB. Diversity among H. hepaticus isolates was evaluated by means of a restriction fragment length polymorphism (RFLP) assay. The 1.6-kb fragments within the ureAB open reading frames, amplified from 11 independent isolates, were digested with the restriction endonuclease HhaI. Three distinct RFLP patterns were observed. Identical RFLP profiles were noted in sequential isolates of one strain of H. hepaticus during an 18 month in vivo colonization study, suggesting that the urease genes of H. hepaticus are stable. The urease genes among H. hepaticus strains were also well conserved, showing 98.8 to 99% nucleotide sequence identity among three isolates analyzed. These findings indicate that H. hepaticus has urease structural genes which are homologous to those of the gastric Helicobacter species and that these gene sequences can be used in a PCR and RFLP assay for diagnosis of this important murine pathogen.

Frequency of vacA genotypes and cytotoxin activity in Helicobacter pylori associated with low-grade gastric mucosa-associated lymphoid tissue lymphoma

The vacA genotypes s1,m1 and s1,m2 were detected in 44 and 30% of Helicobacter pylori isolates, respectively, from patients with gastric mucosa-associated lymphoid tissue lymphoma, compared to 26 and 56% of isolates, respectively, from individuals with gastritis. The vacA s1 genotype was significantly associated with, but not predictive of, the presence of vacuolating cytotoxin activity.

Detection and characterization of Helicobacter pylori from patients with gastroduodenal diseases

Polymerase chain reaction and cytotoxin assays were performed to identify as Helicobacter pylori type I (cagA+/tox+) or type II (cagA-/tox-) 56 (59.6%) strains from 94 patients. Of these patients 64 were affected by nonulcer dyspepsia (NUD), 10 by gastric ulcer (GU), 19 by duodenal ulcer (DU), and 1 by both GU and DU. H. pylori strains were tested for cagA using two sets of primers; target sequences were detected in 40-42/56 (71.4-75%) depending on the set of primers used, while cytotoxin-producing strains (tox +) were 26/56 (46.4%). Tox+ strains were isolated in 13/32 (40.6%), 2/7 (28.6%), and 11/17 (64.7%) in NUD, GU, and DU patients, respectively. However, the different percentage between cagA+ strains from NUD patients (13/32; 40.6%) and patients with ulcerative diseases (13/23; 54.2%) is not statistically significant (p = 0.462). Because the two sets of primers employed for amplification of cagA target sequences give different results, we concluded that cagA alone could not be taken as predictive factor for severity of gastroduodenal disease. It has been found that H. pylori type I is associated with duodenal ulcer disease.

MALT lymphoma of labial minor salivary gland in an immunocompetent child with a gastric Helicobacter pylori infection

We report a pediatric case of a mucosa-associated lymphoid tissue lymphoma of the labial minor salivary gland in an immunocompetent patient. Chronic gastritis with Helicobacter pylori was disclosed and managed with antibiotic therapy. With eradication of Helicobacter pylori there was complete remission of the lymphoma.

Localization in situ of costimulatory molecules and cytokines in B-cell non-Hodgkin's lymphoma

Costimulatory molecules are essential in cognate interactions between T and B lymphocytes. To study the prerequisites of functional interactions between malignant B cells and intermingled T cells in B-cell non-Hodgkin's lymphomas (B-NHL), we examined the expression of CD40, CD80 and CD86 and their ligands CD40 ligand (CD40L, CD154), CD28 and CTLA4 (CD152) using immunohistochemistry and confocal laser scanning microscopy. Almost all mucosa-associated lymphoid tissue (MALT) NHL were positive for CD40 and CD80 and in nine out of 14 cases were positive for CD86. The majority of follicle centre cell lymphomas (FCCL) expressed CD40, but were heterogeneous in their expression of CD80 and CD86. Most diffuse large cell lymphomas (DLCL) were CD80+, but lacked expression of CD86. These patterns reflect the differences in phenotype of normal marginal-zone B cells (as counterparts of MALT NHL) and germinal centre cells (as counterparts of FCCL and DLCL). Counter-receptors on T cells were detectable in 13 of 14 MALT NHL, 12 of 16 FCCL but only occasionally in DLCL (three of 12 cases). A subgroup of FCCL was identified with T-cell expression of CD40L, CD28 and CTLA4 simultaneously with strong expression of CD40 and CD86 on the tumour B cells. These results indicate that MALT NHL and a subset of FCCL are most optimally equipped for functional interactions with T cells. This may be supported by the demonstration of cytokine production - mainly in T cells - in MALT NHL [interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-10] and FCCL (IL-2, IFN-gamma) and to a lesser extent in DLCL.

Primary gastrointestinal non-Hodgkin's lymphoma in adults: a population-based clinical and histopathologic study

OBJECTIVES

To analyse the clinical course and the histopathology of primary gastrointestinal non-Hodgkin's lymphoma (GI-NHL) in adult patients and to investigate a possible impact of Helicobacter pylori.

DESIGN/SETTING

Retrospective study of all adult patients in Copenhagen county diagnosed during a 6-year period with NHL.

SUBJECTS

A total of 55 patients with GI-NHL diagnosed during the period from 1985 to the end of 1990.

RESULTS

Twenty-eight patients had primary lymphoma in the stomach, 14 in the small intestine, 11 in the large intestine and two patients had multifocal involvement. The dominant presenting symptoms were abdominal pain, weight loss, diarrhoea, constipation and fatigue. Acute emergency problems such as severe haemorrhage or perforation at initial presentation were unusual. According to the revised European-American lymphoma (REAL) classification, diffuse large B-cell lymphoma was the most frequent histologic subtype comprising 53% of the cases. Helicobacter pylori infection was documented in 15 of 25 evaluable patients (60%) with gastric lymphomas and was not associated with any specific histological subtype. Endoscopic procedures and barium X-rays were the diagnostic approaches with highest sensitivity. In total, 30 patients (58%) achieved complete remission, 10 (19%) achieved partial remission, and 12 (23%) did not respond to treatment. The overall 5 year survival rate was 0.36 without statistically significant difference between the histological subtypes. Likewise the presence of Helicobacter pylori did not affect survival.

CONCLUSION

Primary GI-NHL is a heterogeneous disease entity with considerable therapeutic controversies. No specific clinical or histological phenotype was associated with the presence of Helicobacter pylori.

Detection of Helicobacter pylori associated antigen and heat shock protein 60 on follicular dendritic cells in the germinal centres of low grade B cell lymphoma of gastric mucosa associated lymphoid tissue (MALT)

AIMS

To investigate the localisation of Helicobacter pylori antigens and the expression of human heat shock proteins (HSP) in stomachs affected by MALT lymphoma.

METHODS

Surgically resected stomachs from 24 patients with MALT lymphoma were immunostained with anti-H pylori rabbit antibodies (ORP-1 and ORP-2) and anti-human HSP60 mouse monoclonal antibodies (mAb) (LK-1 and LK-2).

RESULTS

Follicular dendritic cells of germinal centres in the stomachs affected by MALT lymphoma were immunostained with anti-H pylori polyclonal antibodies and with anti-human HSP60 mAb, as were the epithelial cells. None of the lymph node samples reacted.

CONCLUSIONS

Human HSP60, which cross reacts with anti-H pylori polyclonal antibodies, is often expressed on follicular dendritic cells in gastric MALT lymphoma tissues and may be aetiologically relevant to lymphomagenesis of MALT lymphoma.