Serum gastrin and pepsinogen I, II concentrations in children with Helicobacter pylori infection: the role of CagA and VacA

Helicobacter pylori infection and its related factors in junior high school students in Nagano Prefecture, Japan

BACKGROUND

There have been few reports on Helicobacter pylori (H. pylori) infection in asymptomatic Japanese children and adolescents. We hypothesized that the prevalence of H. pylori infection is very low among Japanese children and that clinical variables such as serum pepsinogen and iron levels are associated with H. pylori infection.

MATERIALS AND METHODS

We conducted a cross-sectional analysis of a sample of 454 junior high school students aged 12-15 years in four areas in Nagano Prefecture. A commercial ELISA kit (E-plate Eiken H. pylori antibody) was used to measure IgG antibody against H. pylori. Serum pepsinogen and iron levels were also measured using standard methods. A urea breath test was performed for seropositive students.

RESULTS

The overall prevalence of H. pylori was 3.1% (14/454). There were no significant differences in H. pylori prevalence among mountain, rural, and urban areas. The mean level of both serum pepsinogen (PG I) and PG II was significantly increased in the seropositive subjects compared with the seronegative subjects. When the cutoff values for adults (PG I: 70 ng/mL and PG I/II ratio: 3) were used, 4 of 14 subjects had PG I ≤70 ng/mL and PG I/II ratio ≤3. The results of a logistic regression analysis showed that low serum iron levels were significantly associated with H. pylori infection (P=.02).

CONCLUSIONS

The prevalence of H. pylori infection is as low as 3% among junior high school students aged 12-15 years in Japan. The disappearance of H. pylori is accelerating in Japanese children.

Usefulness of a serological panel test in the assessment of gastritis in symptomatic children

BACKGROUND

Non-invasive methods are advisable for the detection of Helicobacter pylori-related chronic gastritis in pediatric patients. Serum pepsinogens I and II (sPGII and sPGII), gastrin-17 (G-17) and anti-H. pylori antibodies (IgG-Hp) have been proposed as a 'serological gastric biopsy'.

AIM

To assess H. pylori infection and to evaluate gastric mucosa status in a pediatric population by means of serological parameters such as sPGI, sPGII, G-17 and IgG-Hp.

METHODS

45 consecutively children evaluated for upper gastrointestinal symptoms were analyzed. All children were submitted to upper gastrointestinal endoscopy with biopsies. Serum samples were analyzed for IgG-Hp, sPGII, sPGI and G-17 (Biohit, Helsinki, Finland).

RESULTS

18 children had H. pylori-related mild or moderate non-atrophic chronic gastritis. They presented significantly higher mean levels of sPGII and of IgG-Hp than negative ones, either under or up to 10 years. sPGI showed significantly increased levels in H. pylori-positive patients only over 10 years. G-17 levels were not different between H. pylori-positive and -negative ones. The best cut-offs of IgG-Hp, sPGII and of product IgG-Hp x sPGII, to identify H. pylori infection, were 30 IU/l, 9 microg/l, and 241 IU/l x microg/l, respectively. The product IgG-Hp x sPGII identified H. pylori infection with a 100% sensitivity, 92% specificity, 90% positive predictive value and 100% negative predictive value. IgG-Hp and IgG-Hp showed a correlation (r = 0.94; p < 0.001).

CONCLUSIONS

Combined analysis of sPGII and IgG-Hp antibody levels could be recommended as a non-invasive panel for the assessment of H. pylori-related histological alterations of gastric mucosa in childhood.

Problem of distinguishing false-positive tests from acute or transient Helicobacter pylori infections

BACKGROUND

Reliable detection of acute Helicobacter pylori infections remains problematic. The high prevalence of false-positive non-invasive tests in low H. pylori prevalence populations makes identification of acute and transient infections difficult.

METHODS

We explored the use of serum pepsinogens (PG) for diagnosis of acute infection in patients following H. pylori challenge such that the onset of the infection was known. We then compared those findings to a group of children with presumed acute infections defined as a positive urea breath test (UBT) and negative IgG serology.

RESULTS

We examined the pattern and calculated cut-off values of PG levels in 18 adult volunteers with known acute H. pylori infection. We then compared the results with sera from nine symptomatic children with presumed acute H. pylori infection and a matched control group of nine children who did not meet criteria for acute H. pylori infection. In acute infection, both PGI and II levels increased following H. pylori infection reaching a peak by 2 weeks post-infection. The frequency of a positive test defined as a value > mean +2 SD was 17, 71, and 94% at week 1, 2, and 4 post-infection, respectively. Only one child with presumed acute H. pylori infection had an elevated serum PGI and one had an elevated PGII. Five of the children had follow-up UBTs and four were negative consistent with the diagnosis of false-positive UBT. H. pylori infection was confirmed in the child with an elevated PGI level.

CONCLUSIONS

These data suggest that a single positive noninvasive test in populations of low prevalence is most likely a false-positive result. This suggests that a single positive test requires confirmation preferably using a test that measures a different parameter (e.g., UBT confirmed by stool antigen test). It appears that most "transient"H. pylori infections are diagnosed on the basis of false-positive tests. PG levels are possible candidates as the confirmatory test.

Impact of CagA status on serum gastrin and pepsinogen I and II concentrations in Japanese children with Helicobacter pylori infection

The study aimed to determine the association between cytotoxin-associated gene product (CagA), serum gastrin and pepsinogen levels in Japanese children infected with Helicobacter pylori. Three hundred children were enrolled in the study. H. pylori infection was assessed using an enzyme-linked immunosorbent assay, and CagA status was assessed using immunoblotting. Serum gastrin and pepsinogen concentrations were measured by radioimmunoassay. H. pylori seroprevalence was 12.3% (37/300) and CagA status was identified in 28/37 H. pylori-seropositive children (75.7%). Serum pepsinogen I and II levels were significantly higher in CagA-seropositive than CagA-seronegative children with H. pylori infection. There was no significant relationship between CagA seropositivity and serum gastrin levels. In conclusion, CagA status has a significant impact on serum pepsinogen levels, possibly through enhanced gastric mucosal inflammation.

Transient and persistent Helicobacter pylori colonization in Native American children

Helicobacter pylori is chiefly acquired in childhood, but the exact timing of acquisition is not well understood. The main goal of this study was to assess H. pylori acquisition in a pediatric population. We studied two cohorts of Native American children: a birth cohort of 50 children and 58 older children (mean age, 53 months). We measured serum immunoglobulin G (IgG), IgM, and IgA antibodies to H. pylori whole-cell antigen and IgG antibodies to CagA. Among 44 birth cohort children monitored for more than 12 months, 24 (54.5%) had seroconversions, 7 (15.9%) were transient, and 17 (38.6%) were persistent. Among the older children, 49 (84.5%) of the 58 children were monitored for 1 year; 34 (69.4%) had H. pylori antibodies at study entry. During the next year, 7 (20.6%) children seroreverted, and of 15 initially negative children, 5 (33.3%) seroconverted. In both groups, evaluation of CagA antibodies increased the sensitivity of H. pylori detection. Serum pepsinogen I (PGI) levels in H. pylori-negative children rose significantly until age 6 months and remained constant for the next 19 months. At the time of H. pylori seroconversion, PGI peaked to levels significantly higher than in the never-seroconverted (P = 0.02) and the pre-seroconverted (P = 0.03) children, but then declined to levels paralleling those of H. pylori-negative children. Thus, H. pylori acquisition, accompanied by a transient PGI increase, was frequent in this population, especially in the second and third years of life, but often was brief.

A comprehensive review of the natural history of Helicobacter pylori infection in children

Across populations of children, Helicobacter pylori prevalence ranges from under 10% to over 80%. Low prevalence occurs in the U.S., Canada, and northern and western Europe; high prevalence occurs in India, Africa, Latin America, and eastern Europe. Risk factors include socioeconomic status, household crowding, ethnicity, migration from high prevalence regions, and infection status of family members. H. pylori infection is not associated with specific symptoms in children; however, it is consistently associated with antral gastritis, although its clinical significance is unclear. Duodenal ulcers associated with H. pylori are seldom seen in children under 10 years of age. H. pylori-infected children demonstrate a chronic, macrophagic, and monocytic inflammatory cell infiltrate and a lack of neutrophils, as compared with the response observed in adults. The effect of H. pylori infection on acid secretion in children remains poorly defined. The events that occur during H. pylori colonization in children should be studied more thoroughly and should include urease activity, motility, chemotaxis, adherence, and downregulation of the host response. The importance of virulence determinants described as relevant for disease during H. pylori infection has not been extensively studied in children. Highly sensitive and specific methods for the detection of H. pylori in children are needed, especially in younger pediatric populations in which colonization is in its early phases. Criteria for the use of eradication treatment in H. pylori-infected children need to be established. Multicenter pediatric studies should focus on the identification of risk factors, which can be used as prognostic indicators for the development of gastroduodenal disease later in life.

Positive association between Helicobacter pylori infection and food allergy in children

BACKGROUND

In children Helicobacter pylori has been involved as a pathogenetic factor in gastritis and duodenal ulcer and as a cofactor in protein-losing enteropathy, chronic diarrhoea, short stature, and gastritis lymphoproliferative disease. A subset of an H. pylori strain possesses an antigen, CagA, as a virulence factor. In the present study we determined anti-H. pylori IgG and anti-CagA IgG titres in children with food allergy.

METHODS

Ninety paediatric patients were studied: 30 with food allergy, 30 with atopic asthma, and 30 with inflammatory bowel disease. Anti-H. pylori IgG and anti-CagA IgG were determined in all children by means of a commercial enzyme immunoassay (ELISA).

RESULTS

The anti-H. pylori IgG titre was significantly higher in allergic patients than in the other two groups. The anti-CagA IgG titre did not differ significantly between the patients.

CONCLUSIONS

These findings show a positive association between H. pylori infection and food allergy in children. We hypothesize that virulence factors other than CagA may be involved in the pathogenesis of H. pylori infection in paediatric patients with food allergy.