Prospective analysis of the association of infection with CagA bearing strains of Helicobacter pylori and coronary heart disease.

OBJECTIVE: To see whether it was possible to replicate in a prospective study the association recently reported between infection with the more virulent (type 1) cytotoxin associated gene A (CagA) antigen carrying strains of Helicobacter pylori and increased risk of coronary heart disease. DESIGN AND SETTING: Nested case-control study in a clinical outcomes trial. SUBJECTS: Participants in the West of Scotland coronary prevention study. METHODS: H pylori CagA serological status was determined in plasma samples of 201 subjects (cases) who subsequently had a coronary event during follow up and in 414 subjects (controls) matched for age and smoking who remained event-free, using a semiquantitative commercial enzyme linked immunosorbent assay (ELISA) kit against the p120 antigen of CagA. RESULTS: 105 (52%) in the case group and 176 (43%) in the control group were seropositive (odds ratio (OR) 1.49, 95% confidence interval (CI) 1.06 to 2.10, p = 0.022). The association remained significant after adjustment for blood pressure, body mass index, plasma concentrations of low density lipoprotein and high density lipoprotein cholesterol, history of hypertension and diabetes, statin treatment, and socioeconomic status (OR 1.51, 95% CI 1.06 to 2.16, p = 0.023). Baseline inflammatory markers (white cell count, C reactive protein, fibrinogen) were not significantly increased in either H pylori CagA positive cases or controls. CONCLUSIONS: The findings provide support from a prospective study for the hypothesis that there is an association between infection with CagA bearing strains of H pylori and coronary heart disease. The mechanism(s) underlying the association remain to be elucidated.

Significant association of cagA positive Helicobacter pylori strains with risk of premature myocardial infarction.

OBJECTIVE: To investigate whether genetic diversity of Helicobacter pylori influences its association with coronary heart disease, and specifically whether the risk is confined to infection with the more virulent strains bearing the cytotoxin associated gene-A (cagA) antigen. DESIGN AND SETTING: Case-control study in hospital admitting unselected patients with myocardial infarction. METHODS AND SUBJECTS: Serological status for cagA and H pylori were determined in 342 cases of acute myocardial infarction and 214 population based control subjects free of clinical coronary heart disease. RESULTS: 38.0% of cases and 30.8% of controls were cagA seropositive (odds ratio 1.38, 95% confidence interval (CI) 0.94 to 2.01, p = 0.08). In subjects < 65 years old (153 cases, 153 controls), cagA seropositivity was associated with a 1.80-fold increase (95% CI 1.07 to 3.03, p = 0.02) in myocardial infarction risk, which increased further to 2.25-fold (95% CI 1.12 to 4.53, p = 0.01) in subjects < 55 years. There was no significant association of cagA status with classical coronary heart disease risk factors. H pylori seropositivity was present in 60.2% of cases and 53.7% of controls (odds ratio 1.12, 95% CI 0.83 to 1.51, p = 0.43). H pylori seropositivity was not increased in young cases and did not show any interaction with age. CONCLUSIONS: The association of chronic H pylori infection with risk of myocardial infarction appears to be restricted to cagA bearing strains. The association is age dependent and stronger in younger subjects. Genetic heterogeneity of H pylori may explain some of the discordant findings with regard to the association of H pylori with coronary heart disease.

Production and evaluation of guidelines for the management of inflammatory bowel disease: the Leicester experience.

Consensus guidelines for the management of patients with inflammatory bowel disease were produced by gastroenterologists, gastrointestinal surgeons and a cross-section of general practitioners (GPs) from Leicestershire in order to develop a seamless pattern of care with a common approach to diagnosis and treatment. It was hoped that the guidelines would encourage a movement towards care in the community for many patients with stable disease and so speed up new consultation rates. The study then assessed the impact of these guidelines on the referral letters of GPs to hospital consultants, the prediction of disease and adherence to them on re-referring patients after discharge. The guidelines were distributed to all 487 GPs in the Leicester Health Authority area and the gastroenterology teams within the hospitals. The value of the guidelines was assessed by an audit of referral letters, the length of time from referral letter to out-patient appointment, both before and after the launch of the guidelines, adherence to the guidelines on re-referral, and monitoring the outcome of the discharged patients. Whilst the guidelines may have helped GPs to manage stable patients in the community, the content of referral letters and the diagnostic abilities of GPs were not seen to improve since the launch of the guidelines. However, only 5% of stable patients who were discharged from one clinic were re-referred for inflammatory bowel disease.

Coeliac disease presenting with intraperitoneal haemorrhage.

A 42-year-old man, who was previously fit and well, presented in haemorrhagic shock due to a spontaneous left mesocolonic haematoma and intraperitoneal bleed. His INR was noted to be raised on admission. Later investigations showed him to have villous atrophy on biopsy of the second part of his duodenum and a positive anti-reticulin antibody. His duodenal biopsy and INR normalized on a gluten-free diet. Coeliac disease may present with a single vitamin deficiency with potentially catastrophic results.

Detection and typing of the virulence determinants cagA and vacA of Helicobacter pylori directly from biopsy DNA: are in vitro strains representative of in vivo strains?

BACKGROUND: The relationship of Helicobacter pylori genotypes to gastrointestinal disease has relied on cultured isolates. This assumes that cultured strains are representative of in vivo strains. OBJECTIVE: To detect and type the cagA status and the vacA genotypes directly from biopsy DNA without the need for culture, and to further define the relationship between H. pylori genotypes and gastroduodenal pathology. METHODS: Fifty-two Caucasian patients undergoing routine endoscopy for dyspepsia had additional biopsies taken from four gastric sites and one duodenal site for biopsy DNA preparation. An antral sample was taken for biopsy culture. All recruited patients were H. pylori-positive on rapid urease test for Campylobacter-like organisms (CLO test) and/or histology. By polymerase chain reaction (PCR), the cagA status and the vacA s and m types were detected directly from biopsy DNA. RESULTS: H. pylori isolates were cultured from 28/52 patients in whom infection was detected by PCR. Two isolate types differed from biopsy types. Fifty of the 52 patients, strains were typable from all four gastric sites and in 51/52 the same strain predominated throughout. The cancer strains were all cagA-positive/vacA s1 type. There was a correlation between cagA positivity and vacA s1 (41/43). There was no difference between the cagA-positive/vacA s1 strains and the presence or absence of ulcers. There were only 5/52 vacA s2 m2 and four were in the non-ulcer dyspeptic group. CONCLUSION: cagA status and the vacA genotyping was successful with tissue samples taken directly from gastric and duodenal biopsies. Discrepancies between isolate and biopsy strain types stress the need for caution when interpreting in vitro strain types and suggest that direct PCR of biopsies is the preferred typing technique. The cagA status and the s1 vacA allele are unreliable as single markers in determining the risk of developing peptic ulcer disease.

Helicobacter pylori cagA status, vacA genotypes and ulcer disease.

OBJECTIVE: Helicobacter pylori is the causative organism of peptic ulcer disease and has two putative virulence determinants: the cagA gene which encodes a protein of unknown function in 60% of strains, and the vacA gene, which is present in all strains, although active cytotoxin is produced in only about 50% of these. The relationship between genotypes of both cagA and vacA and resultant gastroduodenal pathology is unclear. The objective of this study was to correlate vacA genotype and cagA status with gastroduodenal pathology. METHODS: One hundred and six dyspeptic patients were studied (average age 56 years, range 19-86 years, 56 men) referred for routine endoscopy. Macroscopic evidence of gastroduodenal disease was noted and antral biopsies taken for culture and genotyping of H. pylori. The polymerase chain reaction (PCR) was used to detect the cagA and vacA genes of H. pylori using specific primers. RESULTS: Seventy eight of the 106 (73.6%) patients were cagA positive. Of those who had peptic ulcer disease 29/32 (90.6%) were cagA positive. The presence of the cagA gene was significantly associated with peptic ulcer disease (P = 0.006). The presence of the vacA s1 genotype was also significantly associated with peptic ulcer disease (P = 0.01). The presence of the cagA gene was significantly associated with the vacA s1 genotype (P < 0.001). There was no significant difference in the distribution of the s1/m1 and s1/m2 strains between ulcer and non-ulcer patients. CONCLUSION: There is a significant association of the cagA gene and vacA s1 signal sequence with gastroduodenal ulcer disease. The relationship of the various other vacA genotypes to gastroduodenal ulcer disease is less clear.

The significance of cagA and vacA subtypes of Helicobacter pylori in the pathogenesis of inflammation and peptic ulceration.

AIMS: To assess the significance of cagA and vacA subtypes of Helicobacter pylori in relation to inflammation and density of bacterial colonisation in vivo within a dyspeptic UK population. METHODS: Dyspeptic patients who were Helicobacter pylori positive had antral samples taken for histology and culture. Gastroduodenal pathology was noted. The grade of bacterial density and inflammation was assessed using the Sydney system. Bacterial DNA was extracted and the vacA alleles and the cagA/gene typed using PCR. RESULTS: 120 patients were studied. There was high rate of cagA positive strains in this population. Bacterial density did not correlate with the presence of peptic ulceration. There was a significant association between cagA positive strains and increased inflammation and bacterial density. The vacA s1 type independently correlated with extensive chronic inflammation but there was no association with bacterial density. The vacA m type did not correlate with extent of inflammation or bacterial density. CONCLUSIONS: The results suggest that cagA is important in the pathogenesis of inflammation and peptic ulceration. These findings are in keeping with the hypothesis that cagA acts as a marker for a cag pathogenicity island which encodes several genes involved in inflammation. The vacA s1 allele correlates with inflammation independently of cagA, possibly through its enhanced ability to produce the vacuolating cytotoxin.

Histology of chronic gastritis with and without duodenitis in patients with Helicobacter pylori infection.

AIM: To compare the histological characteristics of Helicobacter pylori positive chronic gastritis in patients with and without associated duodenitis. METHODS: Gastric mucosal biopsy specimens were obtained from patients undergoing endoscopy for dyspepsia. Severity of gastritis and density of H pylori infection were graded according to the Sydney system. RESULTS: Of the 69 patients studied, 15 had normal histology, 22 had chronic gastritis only (77.3% H pylori positive), 21 had duodenitis (90.5% H pylori positive), and 11 had other diagnoses. In the H pylori positive patients, the median gastritis score was higher in the duodenitis group (6, range 3-9) than in the chronic gastritis only group (5, range 2-8), because of greater neutrophil activity scores in patients with duodenitis (median score 2 v 1). There were no differences in the density of H pylori infection, inflammation, atrophy, or intestinal metaplasia between patients with chronic gastritis only and those with duodenitis. CONCLUSIONS: These results suggest that H pylori positive patients with duodenitis have a more severe form of gastritis than those without associated duodenal inflammation. This is because of increased neutrophil activity, which seems to be independent of the density of H pylori infection.

Production of a monoclonal antibody against the 128 kDa (CagA) protein of Helicobacter pylori.

Helicobacter pylori is recognised as an important factor in gastroduodenal pathology. The 128 kDa CagA protein has been established as a useful marker of H. pylori strains associated with more severe forms of disease. A mouse monoclonal antibody raised against the CagA protein has been produced and characterised as belonging to the IgG1 subtype. It identified the protein in all clinical isolates (10/10) from this laboratory and in two NCTC reference strains (NCTC 11637 and NCTC 11961). No cross-reacting proteins were detected in H. pylori L2, a well characterised strain known not to contain the cagA gene, or in four Helicobacter sp. from non-human sources (H. canis, H. mustelidae, H. muridarum and H. acinonyx). The monoclonal antibody was used to develop an antigen capture ELISA system for detecting the presence of antibodies to the CagA protein in human serum samples.

Selection criteria for preoperative endoscopic retrograde cholangiopancreatography in the laparoscopic era.

BACKGROUND: Indicators for cholangiography were originally designed to select patients at risk for common bile duct (CBD) stones for intraoperative cholangiography. OBJECTIVE: To refine these criteria to apply to the much more invasive procedure of preoperative endoscopic retrograde cholangiopancreatography (ERCP). DESIGN: Retrospective review of selection criteria for ERCP in consecutive patients referred over 18 months following the introduction of laparoscopic cholecystectomy. SETTING: Two ERCP units in adjacent teaching hospitals. PATIENTS: Three hundred seventeen patients with gallstones and in situ gallbladders. INTERVENTION: Common bile duct imaging at ERCP. MAIN OUTCOME MEASURES: Abnormalities justifying ERCP. RESULTS: Abnormalities justifying ERCP were found in 66% of patients. This group differed significantly from those with normal ducts, with more being referred with abnormal results of all liver function tests (P < .001), jaundice (P < = .001), a dilated CBD on ultrasound (P < .001), or CBD stones on ultrasound (P < .001). On the other hand, patients with normal ducts were significantly more likely to have been referred with pancreatitis (P = .003) or elevated results of individual liver function tests (P < .001). A logistic regression model using age, presence of jaundice at ERCP, levels of alkaline phosphatase and albumin, and ultrasonography showing dilated ducts or visible CBD stones was found to have a specificity of 75% and a sensitivity of 89%. Past pancreatitis or elevated results of individual liver function tests were not predictive factors. CONCLUSION: The use of such a model rather than individual criteria would improve the selection of patients for preoperative ERCP, optimizing its role in the laparoscopic era.

Factors predicting outcome after selective ERCP in the laparoscopic era.

This study assessed the outcome of 342 patients with in situ gallbladders undergoing ERCP for suspected choledocholithiasis. The result of ERCP was found to play a significant role (P < 0.0001) in determining whether patients were subsequently managed conservatively (n = 152) or underwent either laparoscopic (n = 110) or open (n = 80) surgery. Those undergoing laparoscopic surgery were noted to be younger (P = 0.0001) and were less likely to be jaundiced (P = 0.0015) or have CBD stones at ERCP (P = 0.0295). In 28 patients with CBD stones remaining after ERCP, pre- rather than postoperative timing of ERCP prevented a potential second operation. The current success rate of 85% in clearing CBD stones at ERCP cannot support a routine policy of intraoperative cholangiography followed by postoperative ERCP.

Helicobacter pylori serology in patients with coeliac disease and dermatitis herpetiformis.

AIMS: To investigate whether Helicobacter pylori infection or autoimmune gastritis is responsible for the reported increase in gastric pathology and abnormalities of gastric function in patients with coeliac disease and dermatitis herpetiformis (DH). METHODS: Serum H pylori IgG antibodies were assayed by enzyme linked immunosorbent assay and intrinsic factor antibodies by radioimmunoassay in 99 patients with coeliac disease and 58 patients with dermatitis herpetiformis from two geographic areas. RESULTS: H pylori positivity in patients with coeliac disease and dermatitis herpetiformis increased with age, reaching 50% and 70%, respectively, in patients over 50 years. The percentage H pylori seropositivity in coeliac disease did not differ from the percentage positivity observed in 250 similarly aged blood donors from the same geographic area (Leeds). Seropositivity in patients with dermatitis herpetiformis was not significantly different from the level of positivity observed in 98 age matched patients without dermatitis herpetiformis attending the same Edinburgh dermatology clinic. Only one patient with coeliac disease had positive intrinsic factor antibodies. H pylori seropositivity in Edinburgh control subjects under 30 years of age (41.9%) was significantly higher (p less than 0.03) than in Leeds controls (18%) of corresponding age. An increasing prevalence of H pylori seropositivity with age in coeliac disease and dermatitis herpetiformis paralleled that of the control groups. CONCLUSIONS: Gastritis in coeliac disease and dermatitis herpetiformis is largely caused by H pylori infection at a level that is no different from that of the general population. Any increase in the prevalence of gastritis in these two diseases might be caused by lymphocytic gastritis rather than pernicious anaemia.

Acute Helicobacter pylori infection: clinical features, local and systemic immune response, gastric mucosal histology, and gastric juice ascorbic acid concentrations.

The symptomatology of a case of acute infection with Helicobacter pylori is described, together with the accompanying changes in gastric mucosal histology, local and systemic humoral immune response, and gastric ascorbic acid concentration. The patient was an endoscopist, previously negative for the carbon-14 urea breath test, who had a week of epigastric pain and then became asymptomatic. H pylori was detected by culture of antral biopsy specimens and was still present after 74 days. Five days after infection the histological findings showed acute neutrophilic gastritis; by day 74 changes of chronic gastritis were evident. The patient seroconverted by IgG enzyme linked immunosorbent assay by day 74, but a mucosal IgM and IgA response was evident as early as day 14. Infection was accompanied by a transient hypochlorhydria but a sustained fall in gastric juice ascorbic acid concentration.

Mucosal humoral immune response to Helicobacter pylori in patients with duodenitis.

The humoral immune response to Helicobacter pylori infection in the duodenum has been investigated by short-term in vitro culture, ELISA, and immunoblotting techniques. H. pylori IgA secretion by duodenal bulb biopsies was significantly increased (P less than 0.001) in patients with duodenitis. The IgA response to H. pylori in patients with duodenitis was restricted to the first part of the duodenum; second part duodenal biopsies secreting significantly (P less than 0.001) less IgA during culture in vitro. H. pylori IgG antibody secretion by cultured biopsies was also significantly increased (P less than 0.01) in patients with duodenitis and those with gastric H. pylori infection but without duodenitis. Immunoblotting of duodenal bulb culture supernatants showed positive recognition by the mucosal IgA response of H. pylori antigens in the region of 120, 90, 61, and 31-26 kDa in patients with duodenitis. Serologically, such patients showed little evidence of IgA H. pylori antibodies by immunoblotting. These results demonstrate that the inflammatory response in the duodenal mucosa of patients with duodenitis represents a specific highly localized humoral response to H. pylori.

Mucosal IgA recognition of Helicobacter pylori 120 kDa protein, peptic ulceration, and gastric pathology.

The gastric IgA response to Helicobacter pylori was examined in 100 dyspeptic patients by means of immunoblotting of supernatants from antral biopsy and gastric mononuclear cell cultures. 76 of 78 patients with chronic gastritis, 2 of 8 with reactive gastritis, and 1 of 14 subjects with normal mucosa showed positive responses. Of patients with chronic gastritis, 75%, 83%, 97% and 76%, respectively, showed responses to the 120 kDa, 90 kDa, 61 kDa, and 31 kDa proteins. None of the 19 patients with chronic gastritis who did not recognise the 120 kDa protein had peptic ulcers, whereas 25 of 57 with positive recognition had peptic ulcers (p less than 0.001). Mucosal recognition of the H pylori 120 kDa protein was also positively associated with the activity of gastritis (polymorph infiltration) (p less than 0.002) and with the extent of surface degeneration (p less than 0.01). These findings suggest that 120-kDa-positive strains of H pylori have pathogenic features associated with active gastritis and peptic ulceration. Infection with 120-kDa-negative strains may explain why peptic ulceration develops in only a proportion of subjects infected with H pylori.

Screening dyspepsia by serology to Helicobacter pylori.

Owing to limited endoscopy resources, various screening strategies for endoscopy have been proposed. Helicobacter pylori can be detected with high sensitivity and specificity by serology, and therefore we assessed the effects on diagnostic accuracy and endoscopic workload of a policy of screening clinic patients with dyspepsia before endoscopy by a strategy based on age, Helicobacter pylori serology, and use of non-steroidal anti-inflammatory drugs. 1153 patients were studied, of whom 842 were of known histological H pylori status (histology group) and 293 had serum assessed prospectively by in-house and commercial ELISAs for detection of IgG antibodies to H pylori. Overall, the screening strategy would have reduced endoscopy workload by 23.3% (95% confidence interval 20.9-25.8%) and would have had a sensitivity for detection of peptic ulcer of 97.4% (94.5-99.1%). No peptic ulcer or malignant disease was missed in the patients studied prospectively, but 6 of 192 peptic ulcers in the histology group would have been missed. A policy of screening young dyspeptic patients for H pylori by serology is more sensitive than symptom-based screening strategies, and may have an important role in reducing endoscopy workload.