Although infection with a cagA-positive Helicobacter pylori strain is considered a risk factor for the development of duodenal peptic ulcer in adults, this association has not been demonstrated in children. The presence of cagA was investigated by polymerase chain reaction in H. pylori strains isolated from 27 children with duodenal ulcer and 53 without duodenal ulcer. All patients (100%) with duodenal ulcer and 33 (62.3%) without ulcer were colonized by a cagA-positive strain (P=.00007). A cagA-positive status was also associated with a more marked macroscopic gastritis, with a greater inflammatory infiltrate of both mononuclear and polymorphonuclear cells in the antral and oxyntic gastric mucosae and degenerative and regenerative changes of the gastric mucosa. Increased cagA positivity was also associated with increased age, but no association between cagA-positive status and sex was observed.

The [13 C]urea breath test ( 13 C-UBT) and Helicobacter pylori stool antigen test (HpSA) for the diagnosis of H. pylori infection in children were validated. The sensitivity, specificity, and positive and negative predictive values were 93.8, 99.1, 97.8, and 98.0%, respectively, for the 13 C-UBT and 96.9, 100, 100, and 98.0%, respectively, for HpSA. Both tests are appropriate for diagnosing H. pylori infection in children. The [13 C]urea breath test ( 13 C-UBT) and a new developed immunoassay for the detection of Helicobacter pylori antigens in stool, the H. pylori stool antigen test (HpSA) (3), are noninvasive tests for H. pylori diagnosis.Although the 13 C-UBT has a good sensitivity for the diagnosis of the infection in all ages, low specificity for very young children has been found (6). With respect to the stool test, low sensitivity for this age group has been also reported (2, 10). Thus, we aimed to validate the 13 C-UBT and HpSA for the diagnosis of H. pylori infection in children.We studied prospectively 210 consecutive children aged 1 to 18 years who underwent esophagogastroduodenoscopy for investigation of gastric complaints. This project was approved by the Ethics Committee of our institution.At endoscopy, biopsy specimens were obtained from the antral and oxyntic gastric mucosa for culture, urease test, and histology. Children were considered to be H. pylori positive if at least two of the three tests were positive or if the culture alone was positive. They were considered negative if all tests were negative.The 13 C-UBT was performed on fasting children within 1 week after endoscopy. The children received 200 ml of orange juice containing 75 mg of [ 13 C]urea (or 100 ml containing 50 mg for those Ͻ30 kg). Breath samples at baseline and after 30 min were analyzed with a nondispersive infrared spectrometer (NDIRIS; Wagner Analysen Technik, Bremen, Germany). The results were considered positive when delta over baseline (DOB) was Ͼ4.0‰.Stool samples, collected on the occasion of the endoscopy, were maintained at Ϫ20°C for up 1 year before testing. HpSA (Premier Platinum HpSA; Meridian Diagnostic, Cincinnati, Ohio) was performed according to the manufacturer's recommendation, slightly modified: instead of a stick, a 10-l disposable loop was used to dilute stool samples, as proposed by Oderda et al. (9), and the plates were washed exhaustively to remove unbound material.Among the 210 children enrolled, 167 underwent the 13 C-UBT but 6 children were excluded (4 had only one positive test and 2 had equivocal results in the 13 C-UBT). The remaining 161 children (76 boys; mean age, 8.6 Ϯ 3.8 years; range, 1 to 18 years) were included in the final analysis (48 were H. pylori positive and 15 had peptic ulcer). The 13 C-UBT was positive for 45 of 48 infected children and for one of the 113 noninfected ones (Table 1). The three children with false-negative 13 C-UBT results were a 5-year-old boy (DOB ϭ 0.3), a 9-yearold girl (DOB ϭ 0.5), and a 14-year-old girl (DOB ϭ 0.2). The cultures for all of them were positiv...

Data concerning the geographic distribution of iceA alleles are scarce, and information on the association of the gene with the disease is rare and still controversial. Furthermore, no such study has been developed in Brazil, where duodenal ulcer and gastric adenocarcinoma are very common. We investigated, by PCR, the frequency of iceA alleles and cagA status in Helicobacter pylori strains isolated from 142 patients (62 children and 80 adults; 66 female; mean age, 30.0 years; age range, 3 to 78 years) with gastritis, duodenal ulcer, or gastric adenocarcinoma. iceA was identified in bacterium samples obtained from all patients. Eleven (7.7%) of them were infected with multiple strains. Among the patients with nonmixed infection, iceA2 allele was detected in 118 (90.1%). iceA2 allele was associated with ulcer (P ‫؍‬ 0.02) and with carcinoma (P ‫؍‬ 0.001). iceA2 amplicons of 229, 334, or 549 bp were detected, but none of them was associated with the patient's disorder. iceA2 strains were more frequent in patients older than 7 years (P ‫؍‬ 0.001). The gene was also more frequent in strains obtained from males (P ‫؍‬ 0.02). cagA was more common in strains obtained from carcinoma (P ‫؍‬ 0.0008) and ulcer patients (P < 0.006). cagA-positive strains were more frequent in children older than 7 years (P < 0.003). No association between cagA status and sex was found (P ‫؍‬ 0.28). In conclusion, we think iceA should not be used as a reliable marker for predicting the clinical outcome of H. pylori infection.

No abstract

There are differences between children and adults in certain aspects of the Helicobacter pylori (HP) infection, among them the lower titre of IgG antibodies anti-HP in the former group. Thus, we investigated by means of flow cytometry

Duodenal ulcers in children are associated with Helicobacter pylori gastric infection with cagA-positive strains, but factors linked to the host are poorly known. The authors evaluated the role of proinflammatory interleukin-1 gene cluster polymorphisms in the pathogenesis of duodenal ulcer. They studied prospectively 437 children 1 to years old, 209 of whom were H. pylori positive and 228 of whom were H. pylori negative. IL1B-511-C/T, -31T/C, and IL1RN Variable number of tandem repeats were genotyped by polymerase chain reaction (PCR) restriction fragment length polymorphism, PCR with confronting two-pair primers, and PCR, respectively. cagA status was evaluated by PCR. The role of the proinflammatory cytokine genotypes in the genesis of duodenal ulcer was evaluated before and after stratification of H. pylori status on logistic regression models. In the group of children without duodenal ulcer, no association was observed between H. pylori status and proinflammatory polymorphisms. Furthermore, no association between IL1 cluster genotypes and cagA status was seen in the H. pylori-positive children. However, increasing age, male sex, and IL1RN*2 were independently associated with duodenal ulcer. After stratification, in the H. pylori-positive children, increasing age, male sex, the presence of ILRN*2 allele, and cagA-positive status were independently associated with duodenal ulcer. The risk for the development of duodenal ulcer increased when a combined association of the presence of IL1RN*2 allele and infection by a cagA-positive H. pylori strain was the variable. This study provides evidence supporting independent roles of IL1RN*2 allele and cagA-positive status in the genesis of duodenal ulcer in children. Helicobacter pylori infection is predominantly acquired in childhood and usually persists for life unless treated. In most persons, the natural history of infection is without complications, but peptic ulcer disease, distal gastric carcinoma, or mucosa-associated lymphoid tissue gastric lymphoma will occur in a small percentage of infected individuals (1-3).In children, DU, a severe complication of the infection is much less common than in adults. The pathobiology of the uncommon childhood-onset DU is uncharacterized, but this adverse outcome may be linked to a more marked gastric inflammatory response seen in children with DU than in infected children without DU (4 -6). Contributing factors include host genetics and bacterial virulence markers. In fact, the cagA-PAI and VacA, two of the major bacterial virulence factors involved in host cell modulation, are associated with the disease in childhood (6 -8). Several genes of the cag-PAI code proteins with similarities to components of type IV secretion systems induce an increased inflammation in the gastric mucosa through release of cytokines such as 10). In addition to the VacA properties linked to the gastric mucosa damage, the toxin may increase the inflammatory response of the gastric mucosa by different pathways, such as a recently demonstrated action i...

Several studies have demonstrated that enzyme-linked immunosorbent assay is not a sensitive and specific method to diagnoseHelicobacter pylori infection in children, especially in the younger ones. Since serum immune response can also be determined by immunoblotting and it permits the detection of antibodies to virulence factors such as CagA and VacA, we evaluated the accuracy of a commercial immunoblotting test to diagnose H. pyloriinfection and to assess the humoral immune response to differentH. pylori antigens in 122 children who underwent upper gastrointestinal endoscopy. The presence of H. pylori was determined in antral biopsy specimens by culture, preformed urease test, and histological analysis. H. pylori was identified by microbiological and histopathological methods in 66 children (including all of the 21 who had duodenal ulcer). Antibodies toH. pylori were detected in 63 infected children and in 8 noninfected ones. The sensitivity, specificity, and positive and negative predictive values of the immunoblotting test were 95.5, 85.7, 88.7, and 94.1%, respectively. The number of immunoreactive bands increased with age (P = 0.003), and the bands of 35 kDa (P = 0.013); 89 kDa, the VacA antigen (P = 0.001); and 116 kDa, the CagA antigen (P = 0.00004) were more frequently observed in older children. The frequency of the bands of 89 kDa (P = 0.001) and 116 kDa (P = 0.03) was higher in children with duodenal ulcer than in H. pylori-positive children without the disease. In conclusion, the immunoblotting test appears to be useful for the diagnosis of H. pylori infection in children, even in the younger ones.

Data concerning the association between vacA genotypes and disease in children in both developed and developing countries are scarce, especially because of the small number of children with a duodenal ulcer studied. The vacA genotypes ofHelicobacter pylori strains obtained from 65 children (24 with a duodenal ulcer and 41 without a duodenal ulcer; 33 girls; mean age, 10.2 years; age range, 1 to 17 years) were investigated as described by J. C. Atherton et al. (J. Clin. Microbiol. 37:2979–2982, 1999). Ten (15.4%) children were infected with more than one H. pylori strain. None of these patients were included in our analysis of the relationship between gastric disorders and specific vacA genotypes. The s1 allele was detected in all H. pylori strains isolated from patients with a duodenal ulcer and from 21 (58.3%) patients without a duodenal ulcer (P = 0.003). Strains with the s2 allele were found only in patients without ulcer (n = 15; 41.7%). Most s1 strains had the s1b allele (97.5%), a result similar to that reported for adults from the Iberian peninsula, which could reflect the Brazilian population origin. One untypeable s1 strain was isolated. The m1 allele was also more frequently found in strains obtained from duodenal ulcer patients (P= 0.028). The m2 allele was found in strains obtained from 20 (36.4%) children, 3 (15.8%) with an ulcer and 17 (47.2%) without an ulcer. Only one m hybrid strain (m1 and m2 hybrid) was detected. It was demonstrated for the first time that the frequencies of colonization with strains with the s1 allele (14.3% in children up to 8 years of age and 85.7% in older patients;P = 0.012) and of strains with the m1 allele (11.1% in patients up to the age 8 years and 88.9% in older children;P = 0.013) increase with age.