Relevance of CagA positivity to clinical course of Helicobacter pylori infection in children

Association of cagA+ Helicobacter pylori strains with high urease activity and dyspepsia in Mexican adults

INTRODUCTION AND AIMS

Helicobacter pylori (H. pylori) is associated with a higher risk of peptic ulcer and gastric cancer. The sole presence of the bacterium is not a determinant of clinical outcome, but rather the interaction of strain type and host factors determines the risk of disease. Our aim was to study the association between bacterial load, strain type, and gastric symptoms in H. pylori-positive subjects.

MATERIALS AND METHODS

In a community survey, a diagnostic ¹³C-urea breath test for H. pylori was performed on 302 volunteers that were not taking antibiotics, antacids, or proton pump inhibitors one month prior to the test. The breath test produced 25 H. pylori-positive subjects, between 25-74 years of age, who then took a gastric symptoms survey and were tested for the presence of the cagA genotype in gastric juice, using the Entero-test®. Bacterial load was determined as a measure of urease activity, utilizing the delta over baseline value, obtained in the ¹³C-urea breath test.

RESULTS

A total of 48% of the H. pylori-positive subjects were cagA+. A positive association was found between cagA status and high gastric urease activity (P<.0001) and the latter was significantly associated with the presence of symptoms (P<.0001).

CONCLUSION

Gastric urease activity was strongly associated with dyspeptic symptoms and cagA+ H. pylori. Elevated ¹³C-delta over baseline values could be used as indicators of a higher risk for gastric disease.

Relationship between ureB Sequence Diversity, Urease Activity and Genotypic Variations of Different Helicobacter pylori Strains in Patients with Gastric Disorders

Association of the severity of Helicobacter pylori induced diseases with virulence entity of the colonized strains was proven in some studies. Urease has been demonstrated as a potent virulence factor for H. pylori. The main aim of this study was investigation of the relationships of ureB sequence diversity, urease activity and virulence genotypes of different H. pylori strains with histopathological changes of gastric tissue in infected patients suffering from different gastric disorders. Analysis of the virulence genotypes in the isolated strains indicated significant associations between the presence of severe active gastritis and cagA+ (P = 0.039) or cagA/iceA1 genotypes (P = 0.026), and intestinal metaplasia and vacA m1 (P = 0.008) or vacA s1/m2 (P = 0.001) genotypes. Our results showed a 2.4-fold increased risk of peptic ulcer (95% CI: 0.483-11.93), compared with gastritis, in the infected patients who had dupA positive strains; however this association was not statistically significant. The results of urease activity showed a significant mean difference between the isolated strains from patients with PUD and NUD (P = 0.034). This activity was relatively higher among patients with intestinal metaplasia. Also a significant associa-tion was found between the lack of cagA and increased urease activity among the isolated strains (P = 0.036). While the greatest sequencevariation of ureB was detected in a strain from a patient with intestinal metaplasia, the sole determined amino acid change in UreB sequence (Ala201Thr, 30%), showed no influence on urease activity. In conclusion, the supposed role of H. pylori urease to form peptic ulcer and advancing of intestinal metaplasia was postulated in this study. Higher urease activity in the colonizing H. pylori strains that present specific virulence factors was indicated as a risk factor for promotion of histopathological changes of gastric tissue that advance gastric malignancy.

Helicobacter pylori infection is associated with advanced colorectal neoplasia

OBJECTIVE

The aim of this article was to evaluate the prevalence of Helicobacter pylori infection in patients diagnosed with advanced colorectal neoplasia undergoing a colonoscopy compared to patients without neoplasia.

MATERIAL AND METHODS

This cross-sectional study investigated the association of neoplastic lesions diagnosed on colonoscopy with H. pylori infection in a consecutive series of subjects who had undergone a pancolonoscopy in a single academic medical center. All patients were tested by ELISA and the immunoblot technique for serum anti-H. pylori and CagA protein IgG antibodies. Multivariate analyses were adjusted for potential-relevant confounders, including age, sex, smoking, childhood socioeconomic status, and family history of colorectal cancer.

RESULTS

Two hundred and seventy-three patients were included in the study: 75% (84/112), diagnosed with neoplastic colorectal lesions and 48% (77/161) without neoplastic lesions, were found to be seropositive for H. pylori infection (p < 0.001). H. pylori infection was found in 66/77 (86 %) patients with advanced neoplasia, 18/35 (51%) patients with nonadvanced neoplasia, and 48% (77/161) patients without neoplasia (p < 0.001). In the adjusted analysis, H. pylori infection was found to be associated with advanced colorectal neoplasia (odds ratio, OR 9.57; 95% CI 4.31-21.2; p < 0.001) and CRC (OR 7.98;95% CI 3.16-20.16; p < 0.001). There was no association in patients who were CagA positive.

CONCLUSION

H. pylori infection is associated with the development of advanced colorectal neoplasia. More studies are needed to confirm our findings.

Frequency of Helicobacter pylori and cytotoxine associated gene A antibodies in patients with cardiac syndrome X

Background:

Cardiac syndrome X (CSX) is a condition in which patients have the pain of angina despite normal coronary angiogram. Recently, Helicobacter pylori (H. pylori) bacteria has been associated with CSX. However, there is no obvious data about the frequency of its virulent strain (cytotoxine associated gene A: CagA) in patients with CSX. We surveyed the frequency of H. pylori and CagA antibodies in patients with cardiac syndrome X and healthy controls.

Materials and Methods:

Plasma samples from 100 CSX patients (61 females and 39 males; mean age: 51.8 ± 12.3 years) and 100 healthy controls (61 females and 39 males; mean age: 48.9 ± 6.3 years) were tested for the presence of IgG antibody to H. pylori using enzyme linked immunosorbent assay (ELISA) method. Also, infected patients were determined by the presence of IgG antibody to CagA by ELISA method. Statistical analysis was carried out using chi-square test and independent samples T-test.

Results:

Ninety two percent (92/100) of patients were anti-H. pylori positive (anti-H. pylori+), while only 56.0% (56/100) of control group were anti-H. pylori+ (P<0.01). However, prevalence of anti-CagA positive (anti- CagA+) in H. pylori infected- CSX patients and control groups were 59.8% (55/92) and 60.7% (34/56), respectively (P>0.05).

Conclusion:

Thus, due to the high frequency of anti-H. pylori in CSX patients, and the probable causative effect of chronic infection in vascular diseases, it is suggested that H. pylori has a probable role in the pathogenesis of CSX.

Iron, zinc, and copper nutritional status in children infected with Helicobacter pylori

OBJECTIVE

: Helicobacter pylori colonizes the gastric mucosa of about half of the world's population and it has been related to extragastrointestinal diseases. The present study sought to evaluate the association between H pylori infection and iron, zinc, and copper nutritional status in symptomatic children.

PATIENTS AND METHODS

: A cross-sectional study was carried out in 395 children (4-16 years) with upper gastrointestinal symptoms, who were tested for H pylori infection by the C-urea breath test. Iron status was determined by hemoglobin, serum ferritin, and serum transferrin receptors. Copper and zinc serum concentrations were also evaluated. Epidemiological data, dietary assessment, and anthropometric indicators were analyzed as potential confounding factors.

RESULTS

: Prevalence of H pylori infection was 24.3%. Anemia and iron deficiency (ID) were found in 12.0% and 14.3% of the H pylori-positive and 8.9% and 11.0% of the H pylori-negative children, respectively. There was no association between H pylori infection and anemia (odds ratio = 1.54 [95% confidence interval [CI] 0.73%-3.24%]) or ID (odds ratio = 1.35 [95% CI 0.67-2.70]). Crude beta coefficients showed that H pylori has no significant effect on hemoglobin, serum ferritin, serum transferrin receptors, copper, and zinc concentrations. However, adjusted results suggested that H pylori-infected children had an increase of 9.74 microg/dL (95% CI 2.12-17.37 microg/dL) in copper concentrations.

CONCLUSIONS

: This study revealed that H pylori infection was not associated with iron deficiency, anemia, or zinc concentrations; however, a positive relation with copper status was found after adjusting for confounding factors. The contribution of H pylori infection to higher copper concentrations needs to be confirmed by additional studies.

Associations between Helicobacter pylori infection, co-morbid infections, gastrointestinal symptoms, and circulating cytokines in African children

BACKGROUND

Refugee children have complex medical needs and often have multiple infections. The relationship between infection, gastrointestinal symptoms, and systemic inflammation is poorly understood. We investigated these parameters in refugee children with a high prevalence of Helicobacter pylori, helminth, and malaria infection.

MATERIALS AND METHODS

African refugee children were recruited at resettlement health screening. Data were collected on demography, gastrointestinal symptoms, co-morbid infection, and serum for peripheral cytokine levels. Helicobacter pylori infection was diagnosed by a fecal-based immunoassay.

RESULTS

Data from 163 children were analyzed, of which 84.0% were positive for H. pylori. Infected children were significantly older (9.2 years +/- 3.7 vs 7.1 years +/- 3.9, p = .01). Half the cohort (84/163, 51.5%) described gastrointestinal symptoms but these were not strongly associated with co-morbid infections. Helicobacter pylori-infected children had significantly lower circulating log-interleukin-8 (IL-8) (odds ratio 0.61, 95% confidence interval (CI) 0.40, 0.94, p = .025). Helminth infections were common (75/163, 46%) and associated with elevated log-IL-5 (beta: 0.42, 95% CI 0.077, 0.76). Children with malaria (15/163, 9.2%) had elevated log-tumor necrosis factor-alpha (TNFalpha) and log-IL-10 (beta: 0.67, 95% CI 0.34, 1.0 and beta: 1.3, 95% CI 0.67, 1.9, respectively). IL-10 : IL-12 ratios were increased in H. pylori-infected children with malaria or helminth infections. Symptoms were generally not associated with levels of circulating peripheral cytokines irrespective of co-morbid infection diagnosis.

CONCLUSIONS

There is a high prevalence of asymptomatic H. pylori infection in recently resettled African refugee children. Gastrointestinal symptoms were not predictive of H. pylori nor of helminth infections. Serum cytokines, particularly IL-5, IL-10, and TNFalpha, were significantly elevated in children with malaria and helminth infections but not in those with H. pylori infection.

In situ expression of cagA and risk of gastroduodenal disease in Helicobacter pylori-infected children

BACKGROUND AND AIM

Gastroduodenal disease is more common among adults and children with cagA+ Helicobacter pylori infection, but disease severity varies among those infected with cagA+ strains. We examined whether cagA in situ expression can predict disease manifestations among H pylori-infected children.

PATIENTS AND METHODS

Fifty-one children were selected from 805 patients with abdominal symptoms who underwent esophagogastroduodenoscopy with gastric biopsies. Endoscopic and histologic gastritis were scored and H pylori colonization was quantified by Genta stain and in situ hybridization expression of 16S rRNA and cagA.

RESULTS

Endoscopy was either normal (n = 14) or demonstrated nodularity (n = 18), gastric ulcer (n = 8) or duodenal ulcer (n = 11). H pylori was present in 7, 18, 6, and 10 children, respectively. Expression of 16S rRNA and cagA were significantly higher in children with ulcer compared with normal children. The fraction of H pylori bacteria expressing cagA in situ was higher in children with ulcer compared to those with endoscopic nodularity (P < 0.05).

CONCLUSIONS

Thus, cagA in situ expression is increased in H pylori-infected children with peptic ulcers and may play a role in the pathogenesis of peptic ulcer disease during childhood. Determination of in situ expression of cagA complements traditional isolation and in vitro testing of single-colony isolates.

Helicobacter pylori, helminth infections and growth: a cross-sectional study in a high prevalence population

AIM

Helicobacter pylori (H. pylori) infection is usually acquired in childhood and may adversely affect growth, although data are inconsistent. This study investigated growth parameters in a paediatric cohort with a high prevalence of H. pylori and helminth infection.

METHODS

A cross-sectional study of African refugee children (<16 years) recruited at their initial health assessment following resettlement in Australia. Detailed demographic, infection and anthropometric data were obtained. H. pylori infection was diagnosed by monoclonal faecal antigen enzyme immunoassay testing (MFAT). Growth restriction was defined as children with any anthropometric measures below the fifth centile for age and gender.

RESULTS

H. pylori infection was detected in 149/182 (81.9%). Children with H. pylori infection were older (mean 8.5 years, standard deviation (SD) 4.2 years vs. 5.8 years, SD 4.5 years, p < 0.001). No gender differences were observed. After adjustment for age, H. pylori did not adversely affect body mass index or other anthropometric measurements. Helminth infections were common (41.8%) but not associated with reduced growth or with H. pylori infection.

CONCLUSION

H. pylori and helminth infections are prevalent in African refugee children but neither is associated with growth restriction. Longitudinal growth velocity studies are necessary to identify any long-term consequences of H. pylori on childhood growth.

Helicobacter pylori is not associated with anaemia in Latin America: results from Argentina, Brazil, Bolivia, Cuba, Mexico and Venezuela

OBJECTIVE

To investigate the association between Helicobacter pylori infection and anaemia.

DESIGN

Six cross-sectional studies. H. pylori infection was assessed by the [13C]urea breath test using MS or IR analysis. Hb was measured for all countries. Ferritin and transferrin receptors were measured for Argentina, Bolivia, Mexico, and Venezuela.

SETTING

Health services in Argentina, Brazil and Mexico or public schools in Bolivia, Cuba and Venezuela.

SUBJECTS

In Argentina, 307 children aged 4-17 years referred to a gastroenterology unit; in Bolivia, 424 randomly selected schoolchildren aged 5-8 years; in Brazil, 1007 adults (157 men, 850 women) aged 18-45 years attending thirty-one primary health-care units; in Cuba, 996 randomly selected schoolchildren aged 6-14 years; in Mexico, seventy-one pregnant women in their first trimester attending public health clinics; in Venezuela, 418 children aged 4-13 years attending public schools.

RESULTS

The lowest prevalence of H. pylori found was among children in Argentina (25.1%) and the highest in Bolivia (74.0%). In Bolivia, Cuba and Venezuela children showed similar prevalence of H. pylori infection as in Brazilian and Mexican adults (range 47.5% to 81.8%). Overall anaemia prevalence was 11.3% in Argentina, 15.4% in Bolivia, 20.6% in Brazil, 10.5% in Cuba and 8.9% in Venezuela. Adjusted analyses allowing for confounding variables showed no association between H. pylori colonization and anaemia in any study. Hb, ferritin and transferrin receptor levels were also not associated with H. pylori infection in any country.

CONCLUSIONS

The present study showed no evidence to support the hypothesis that H. pylori contributes to anaemia in children, adolescents, adults or pregnant women in six Latin American countries.

Results from the pediatric European register for treatment of Helicobacter pylori (PERTH)

BACKGROUND AND AIM

Data on the eradication treatment for childhood Helicobacter pylori are scanty. A register was established on the European Society for Pediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) website to collect data on treatment performed by European pediatricians to ascertain what is practiced in the field.

SUBJECTS

From January 2001 to December 2002, information on 597 children were entered by 23 European Centers, but only data of 518 treated children were completed and analyzed (86.7%, 262 male subjects, median age 9 years, range 1-14). According to their nationality, 226 children were from Southern Europe, 132 from Eastern Europe, 68 from Western Europe, and 4 from northern Europe, 68 from North Africa, and 20 from Asia. At endoscopy, 454 children had gastritis and 64 had ulcer (12.3%). Antibiotic sensitivity, tested in 361 cases, revealed 18% clarithromycin-resistant and 19% metronidazole-resistant H. pylori strains.

RESULTS

Treatment was performed for 1 week in 388 and for 2 weeks in 130 children. Antibiotics were associated with proton pump inhibitors (PPI) in 345 and with bismuth in 121 children. Triple therapy was given to 485 children, dual therapy to 26, quadruple to 7. Follow-up data, by (13)C-Urea-Breath Test or histology or both, were available for 480 children. Overall eradication rate was 65.6%, significantly higher in children with ulcer (79.7%) than without (63.9%, p = .001). When given as first treatment, bismuth-containing triple therapies were more efficacious than PPI-containing ones (77% versus 64%, p = .02, OR 1.88, 95% CI 1.1-3.3). Twenty-seven different treatment regimens were used, but only six were administered to at least 18 children (range 18-157). There was no difference between treatments given for 1 or 2 weeks, or given as first or second therapies.

CONCLUSION

European pediatricians entering data in the register used 27 different regimens. Bismuth-containing therapies resulted in higher eradication rate. Omeprazole-containing triple therapies were the most used although their efficacy was low. Therapies recommended for adults do not appear to be suitable for children.

The humoral immuneresponse to Helicobacter pylori infection in children with gastrointestinal symptoms

The prevalence of Helicobacter pylori is high in Eastern Europe. The purpose of this study was to estimate the prevalence of H. pylori in symptomatic Lithuanian children and to identify the infection by clinicopathological and serological analyses. One hundred sixteen symptomatic children (age 8-16) with gastritis and duodenal ulcer were included. Biopsies were histologically assessed according to the Sydney-System. Serum IgG antibodies against H. pylori were detected by an enzyme-linked immunosorbent assay (ELISA), using low molecular mass antigen. The western blot technique was used to detect serum antibodies against the cytotoxin-associated protein (CagA) using whole cell antigen. Histologically the prevalence of H. pylori infection was 79% and not influenced by demographic factors. Mucosal inflammation and atrophy were associated with a H. pylori infection. Intestinal metaplasia was found in eight children, suggesting early H. pylori acquisition in life. Increased levels of IgG antibodies were detected in 57% of children. The prevalence of IgG antibodies was significantly higher in patients with duodenal ulcer compared to children with gastritis. Forty-four (67%) H. pylori-seropositive children had antibodies against CagA. Low molecular weight-ELISA and whole cell-western blot results were significantly associated with histopathology, the presence of duodenal ulcer and the CagA status. A high number of false seronegative cases were due to poor immunological responses in children and poor locally validated tests. The prevalence of H. pylori infection in Lithuanian children is higher compared to Western Europe. The infection is acquired in early life. Diagnosing H. pylori infection, serology is helpful, but endoscopy/histology remains as gold standard.

Association of CagA+ Helicobacter pylori infection with aortic atheroma

BACKGROUND

To investigate possible association between infection with CagA(+) strains of Helicobacter pylori and aortic atheroma diagnosed by transesophageal echocardiography.

METHODS AND RESULTS

One hundred and eighty-eight consecutive subjects prospectively examined for presence of aortic atheroma (localized intimal thickening of >/=3mm) by transesophageal echocardiography were tested for serum IgG antibodies against H. pylori (enzyme-linked immunosorbent assay) and CagA protein (Western blot assay). The association between infection with H. pylori, CagA status of the infecting H. pylori strains, and aortic atherosclerosis was evaluated after adjusting for coronary artery disease risk factors. There was a linear trend for presence of atheroma in subjects with CagA-positive H. pylori infection (51/81, 63%) compared to subjects with CagA-negative H. pylori infection (21/45, 46.7%) and uninfected subjects (18/62, 29%) (p=0.003). H. pylori seropositivity was not associated with aortic atheroma (OR 2.9; 95% CI, 0.8-10.3; p=0.11) when CagA status is not taken into account. On multivariate analysis, parameters associated with risk of aortic atheroma were CagA-positive H. pylori seropositivity (OR 4.4; 95% CI, 1.4-14.7; p=0.01), older age (OR 1.2; 95% CI, 0.9-14.7; p=0.01), having ever smoked cigarettes (OR 3.6; 95% CI, 1.3-10.0; p<0.001), and elevated serum triglyceride level (OR 3.4; 95% CI, 1.3-9.4; p=0.02).

CONCLUSIONS

After controlling for H. pylori infection and coronary artery disease risk factors, infection with a CagA-positive strain of H. pylori was independently associated with aortic atherosclerosis. This study suggests a gradient of atherosclerosis between uninfected individuals and patients with CagA-positive H. pylori infection and should prompt research into the role of CagA-positive H. pylori infection in the inflammatory atherosclerotic process.

Dual vs. triple therapy for childhood Helicobacter pylori gastritis: a double-blind randomized multicentre trial

BACKGROUND

Data on the efficacy of eradication treatment for Helicobacter pylori gastritis in children are scarce.

AIM

To evaluate the efficacy of triple therapy with lansoprazole plus amoxicillin and tinidazole vs. dual therapy with amoxicillin and tinidazole in a double-blind randomized multicentre trial, and the usefulness of eradication in terms of long-term symptom resolution.

SUBJECTS

We enrolled 43 consecutive children undergoing endoscopy for upper gastrointestinal dyspepsia with H. pylori gastritis. They underwent a 13C-urea breath test, completed a 2-week symptom diary card, and were randomized. Treatment was given in a Redidose box (Redidose Company Ltd., Brighton, UK) containing either lansoprazole-amoxicillin-tinidazole (triple therapy) or placebo plus amoxicillin-tinidazole (dual therapy) for 1 week. The completion of a 2-week symptom diary card and the performance of a breath test were repeated 6 weeks and 6 months after the end of therapy. One to two years later, a structured telephone interview was conducted with 36 of the children.

RESULTS

According to the breath test, 6 weeks after the end of therapy H. pylori was eradicated in 15 of 22 children on triple therapy [68.2%; 95% confidence interval (CI) = 45-88] and in 15 of 21 children on dual therapy (71%; 95% CI = 48-89; not significant), and 6 months after the end of therapy it was eradicated in 16 of 22 children on triple therapy (72.7%) and in 15 of 21 children on dual therapy. Six months after therapy, symptoms were analysed in 11 H. pylori-positive and 31 H. pylori-negative children, and it was found that dyspeptic symptoms had disappeared or improved in both groups, with no difference between them. One to two years later, 36 children were interviewed. Epigastric pain had recurred in three of 26 H. pylori-negative and in seven of 10 H. pylori-positive children (p = .001); in three of the latter, pain was severe and required additional treatment.

CONCLUSION

One-week triple or dual therapy with two antibiotics achieved similar eradication rates. Soon after treatment, symptoms disappeared or improved in most children irrespective of eradication, but epigastric pain recurred in the majority of the still-infected children within 2 years.

The cagA status of Helicobacter pylori isolates from dyspeptic children in Turkey

There are inconsistent reports regarding cytotoxin-associated gene A (cagA) status of Helicobacter pylori isolates and the severity of the mucosal lesions in children. The aim of this study was to determine the prevalence of cagA(+) strains and to evaluate its correlation with clinic and endoscopic findings. We examined 45 H. pylori strains that were grown on brain-heart infusion agar supplemented with 7% horse blood. Following 72 h of incubation colonies were harvested and bacterial DNA was extracted. Polymerase chain reaction primers F1 and B1 were used to amplify a 348-bp internal fragment of cagA. The prevalence of cagA in Turkish pediatric patients was 55.6%. No association was found between cagA status and the severity of gastro-duodenal lesions.

Helicobacter pylori virulence genotypes in Portuguese children and adults with gastroduodenal pathology

The aim of this study was to evaluate the prevalence of virulence genotypes, namely cagA, vacA and babA2, of Helicobacter pylori strains isolated from Portuguese adults and children presenting gastroduodenal pathology. One hundred thirty-six strains were studied, 82 isolated from adult patients (50 with nonulcerative gastritis and 32 with active peptic ulcer) and 58 isolated from children (54 with nonulcerative gastritis and 4 with duodenal ulcer). Genotyping of cagA, vacA and babA2 was assessed by polymerase chain reaction. Overall, Helicobacter pylori strains carrying more virulent genotypes were much more prevalent in adults than in children, particularly the type I ( vacAs1- and cagA-positive) and the triple-positive ( vacAs1-, cagA- and babA2-positive) strains ( P<0.001). A subpopulation of adults and children with nonulcerative gastritis was also studied, and differences in the prevalence of virulent genotypes were observed, either for individual genotypes ( P=0.017 for cagA, P=0.010 for vacAs1) or in combinations, i.e. the type I genotype ( P=0.005) and the triple-positive strains ( P=0.031). There was no difference between the two populations in the distribution of babA2 and m1/m2 genotypes. Considering the cohort effect in the epidemiology of Helicobacter pylori infection, these results suggest that different strains might circulate during different periods of time, or that, after infection in childhood, individual strains will undergo changes during the course of infection.

Helicobacter pylori genotypes in Israeli children: the significance of geography

BACKGROUND

There is substantial genetic variation among different isolates of Helicobacter pylori, which may affect the clinical outcome. The aims of this study were to find the common H. pylori genotypes in Israeli children and to look for a possible genotype-phenotype correlation.

METHODS

Ninety-eight H. pylori cultures were isolated from antral biopsy specimens of symptomatic Israeli children and were analyzed for vacA and iceA genotype and cagA and cagE status by polymerase chain reaction.

RESULTS

cagA and cagE genes were present in only 25.5% and 24.5%, respectively. The common vacA genotype was s2m2, which was found in 65%. Eleven specimens (11%) contained multiple vacA genotypes. iceA1 was found in 37% and iceA2 in 52% of cases. Both iceA alleles were found in 11%. Increased prevalence of iceA1 and cagE were observed in children with duodenal disease, although it did not reach significance.

CONCLUSIONS

The low prevalence of cagA and the high prevalence of vacA genotype s2m2 in Israeli pediatric patients are different from the genotype prevalence reported globally. However, similar findings have been reported in Egypt, indicating a possible geographic influence. There is a possible correlation between duodenal ulcer and cag E and ice A1 genotype, but the power of the study was too low to prove it.

Pediatric disorders of the stomach

Disorders of the stomach represent a significant portion of the practice of pediatric gastroenterology. Controversy still exists in the appropriate management of children with abdominal pain and vomiting and large gaps remain in our understanding of the physiology and pathophysiology of the stomach in children. Nevertheless, we have made significant progress in understanding Helicobacter pylori infection and gastric motility in the pediatric population.

Antral nodularity and positive CagA serology are distinct and relevant markers of severe gastric inflammation in children with Helicobacter pylori infection

BACKGROUND

The aim of this study was to assess whether the endoscopic finding of antral nodularity and serum IgG antibodies to CagA are associated with higher grades of gastric inflammation.

MATERIALS AND METHODS

The comprehensive data of two previously published trials were reanalysed. One hundred and fifty-three children (median age 9.5 years) who underwent gastroscopy were included. Biopsy specimens from the antrum and corpus were taken to assess Helicobacter pylori status, gastritis score and lymphoid follicles. During endoscopy, antral nodularity was noted. Serum samples were assayed for IgG antibodies to CagA.

RESULTS

The presence of antral nodularity (nod+) and positive CagA serology (CagA+) were each found in 32 of the 77 (41.5%) children who had evidence of H. pylori infection. Cross tabulation showed that 20 children (26%) were nod+/CagA+, 12 (15.5%) nod+/CagA-, 12 (15.5%) nod-/CagA+ and 33 (43%) nod-/CagA-. Gastritis score was significantly lower in nod-/CagA- children than in nod+/CagA- (p =.004), nod-/CagA+ (p =.002) and nod+/CagA+ (p <.001), both in the antrum and corpus. Completely normal gastric histology was only found in the nod-/CagA- subgroup of H. pylori-infected children (eight of 33, 24%). Regression analysis showed that antral nodularity and positive CagA serology were related to severe gastric inflammation independently of each other and age. Separate analysis showed that inflammation (p <.001), activity (p <.001) and H. pylori density (p =.002) scores were significantly lower in nod-/CagA- children compared with nod+/CagA+ children. The number of lymphoid follicles in the gastric mucosa was related to antral nodularity (p =.003) and positive CagA serology (p =.043), independently of each other.

CONCLUSIONS

Antral nodularity and positive CagA serology are distinct and relevant markers of severe gastric inflammation in children with H. pylori infection. The lack of both findings in the same child reflects low-grade or no gastritis.

Specific serum immunoglobulin G response to urease and CagA antigens of Helicobacter pylori in infected children and adults in a country with high prevalence of infection

Few studies have analyzed the immune response to Helicobacter pylori CagA and urease antigens across age groups in the same population. The aim of this study was to analyze the serologic immunoglobulin G (IgG) response to CagA and urease proteins in children and adults with gastrointestinal symptoms and belonging to the same population and similar socioeconomic levels. The serologic response was studied in 352 children and 293 adults with gastrointestinal symptoms. IgG antibodies against CagA and urease were tested by enzyme-linked immunosorbent assay methods using highly purified recombinant antigens. H. pylori infection was defined as a positive result in a serologic assay using whole-cell H. pylori extracts as the antigen. We found, in H. pylori-positive children, a seroprevalence of 46.9% to CagA and 16.2% to urease, whereas in H. pylori-positive adults, a seroprevalence of 78.9% to CagA and 59% to urease was found. In children, the magnitude of the response to CagA was significantly higher and the response to urease was significantly lower than those in adults. The kinetics of serologic response to CagA and to urease across age groups was contrastably different. Whereas CagA is a strong immunogen, urease is a poor immunogen during natural infection. These differences in the humoral response may be important for the short-term or long-term outcome of the infection. These results add to our knowledge of the epidemiology of H. pylori infection.

Genotypic, clinical, and demographic characteristics of children infected with Helicobacter pylori

Helicobacter pylori isolates vary between geographic regions. Certain H. pylori genotypes may be associated with disease outcome. Thirty-eight children underwent diagnostic upper endoscopy at four medical centers and were retrospectively analyzed to determine if H. pylori virulence genes were associated with endoscopic disease severity, histologic parameters, and host demographics. The H. pylori virulence genotype was analyzed by a reverse hybridization line probe assay and type-specific PCR. Endoscopic ulcers or erosions were found in 17 (45%) patients, with 13 (34%) of these patients having antral nodularity. Histological gastritis, of varying severity, was present in all children. Four patients harbored more than one H. pylori strain: one subject had both cagA(+) and cagA-negative strains, while three patients harbored either two different cagA-negative strains (two children) or two cagA(+) strains (one child). There were 28 (74%) cagA(+) isolates; 19 were associated with the vacA s1b genotype, 7 were associated with the vacA s1a genotype, 1 was associated with the vacA s1c genotype, and 1 was associated with the s2 genotype. Of 14 cagA-negative isolates, 6 were vacA s2 genotype, 4 were vacA s1b, 3 were vacA s1a, and 1 was vacA s1c. Nine of ten (90%) Hispanics had similar H. pylori strains (vacA s1b,m1), and all Asian-Canadian children were infected by strains with vacA s1c genotype. No correlation between H. pylori strain and endoscopic or histopathologic abnormalities was found. This study provides a baseline framework of North American children and their H. pylori strains, serving as a powerful epidemiological tool for prospective investigations to better understand the transmission and evolution of diverse disease outcomes.