Ernesto Guiraldes

Helicobacter pylori gastritis in children is associated with a regulatory T-cell response.

BACKGROUND & AIMS Helicobacter pylori infection in children infrequently causes gastroduodenal mucosal ulceration. Because H pylori induces T-cell dependent gastric inflammation in adults and T regulatory (Treg) cells suppress T-cell-dependent pathology, we evaluated gastric histopathology and Treg cell responses in H pylori-infected children and adults. METHODS Gastric tissue from 36 children and 79 adults with abdominal symptoms in Santiago, Chile, was evaluated prospectively for H pylori bacteria and histopathology using the Sydney classification and Treg responses using immunoassay, immunohistochemistry, and real-time polymerase chain reaction. RESULTS Eighteen (50%) of the children and 51 (65%) of the adults were infected with H pylori. Children and adults were colonized with similar levels of H pylori. However, the level of gastritis in the children was reduced substantially compared with that of the adults (P < .05). Coincident with reduced gastric inflammation, the number of Treg cells and levels of Treg cytokines (transforming growth factor [TGF]-beta1 and interleukin-10) were increased markedly in the gastric mucosa of H pylori-infected children compared with that of infected adults (P < .03 and < .05, respectively). Also, H pylori infection in the children was associated with markedly increased levels of gastric TGF-beta1 and interleukin-10 messenger RNA. Importantly, gastric TGF-beta1 in H pylori-infected children localized predominantly to mucosal CD25(+) and Foxp3(+) cells, indicating a Treg source for the TGF-beta1. CONCLUSIONS Gastric pathology is reduced and local Treg cell responses are increased in H pylori-infected children compared with infected adults, suggesting that gastric Treg cell responses down-regulate the inflammation and ulceration induced by H pylori in children.

CagA antibodies as a marker of virulence in chilean patients with Helicobacter pylori infection.

Background The bacterial and host factors that influence the clinical outcomes of the Helicobacter pylori infection have not been fully identified. Cytotoxin-associated gene product (CagA), one of the virulence factors, has been associated with a more aggressive form of infection. The authors studied the relationship between CagA status and clinical outcome in Chilean children and adults with H. pylori infection. Methods One hundred eighty consecutive patients undergoing upper gastrointestinal endoscopic analysis were enrolled after informed consent was obtained. Rapid urease test and histologic analysis were used to detect H. pylori infection. IgA and IgG antibodies to H. pylori whole cell antigen preparation and IgG antibodies to CagA were measured by enzyme-linked immunosorbent assay (ELISA). Results H. pylori infection was detected in 42% of the patients by biopsy or urease test and in 38% and 20% of patients by IgG and IgA antibodies, respectively. The prevalence of H. pylori either by the invasive or the serologic tests was directly related to patient age. Among patients with H. pylori, there was no significant association between age and prevalence of CagA. Nearly 70% of the patients with H. pylori and peptic ulcer disease had CagA-positive strains. In contrast, only 49% of the patients with chronic gastritis alone had CagA-positive strains (P < 0.05). Conclusions In Chile, patients infected with H. pylori have a proportion of CagA-positive strains similar to that reported in developed countries. CagA prevalence was not significantly different in adults and children infected with H. pylori, suggesting that variations in clinical outcome may be related to host immune or environmental factors.

Helicobacter pylori-associated gastroduodenal disease in symptomatic Chilean children: diagnostic value of serological assay.

Summary: A newly developed enzyme-linked immuno-sorbent assay (ELISA) IgG serological assay for the diagnosis of Helicobacter pylori infection was used recently in two epidemiological surveys in Chile. To evaluate the diagnostic efficacy of this assay in a local symptomatic pediatric population, we studied 70 school-age patients referred for upper gastrointestinal endoscopy because of complaints suggestive of gastroduodenal disease. Evidence for antral H. pylori infection was sought by three biopsy-related methods: culture, histology, and urease activity. IgG anti-H. pylori serum antibodies were determined by ELISA. Altogether, chronic antral gastritis was found in 55 patients and duodenal ulcers in nine; 11 subjects had normal histology. Sixty (86%) patients had H. pylori in the antrum. This group had significantly higher mean IgG optical density values when compared with the H. pylori-negative group (1.860 versus 0.669; p < 0.001). The sensitivity and specificity of the assay in detecting antral H. pylori were both 90% the positive predictive value was 98% and the negative, 60%. Accuracy of the assay was superior in predicting the presence or absence of gastroduodenal lesions with a sensitivity of 96%, a specificity of 92%, a positive predictive value of 98%, and a negative predictive value of 86%. We conclude that the diagnostic efficiency of this assay renders it appropriate both to screen for H. Pylori-associated gastroduodenal disease in individual patients and to be used in seroepi-demiological surveys.

Comparison of an oral rice-based electrolyte solution and a glucose-based electrolyte solution in hospitalized infants with diarrheal dehydration

Summary: This randomized trial compared the efficacy of a rice-based (50 g/L) oral rehydration solution with the standard glucose-based WHO/UNICEF solution in the treatment of 100 hospitalized infants, ages 3–18 months, with acute dehydrating diarrhea. The main outcomes examined were stool output and duration of diarrhea. Patients were placed on a “metabolic” bed so that intake and losses could be measured accurately throughout the study. Overall, 89% of patients were successfully rehydrated orally; the rehydration failure rate was similar in the two groups and it was significantly associated with infection by specific E. coli serotypes. Stool output in the first 24 h was 11% lower in the rice group (112 versus 126 ml/kg), but this difference was not significant. Neither stool output in the second 24 h nor total stool output were different between groups. The median duration of diarrhea was 3.8 days in the rice group and 3.9 days in the glucose group (p = NS). Other (secondary) outcomes, such as fluid intake, urine output, emesis losses, weight change, and electrolyte balance were also similar between the two groups. Some evidence of carbohydrate malabsorption was detected in 61% of the rice group versus 45% of the glucose group (p = NS) and was not associated with any particular treatment outcome. These results show that a rice-based oral rehydration solution is as efficacious as, but not better than the standard glucose-based solution in the treatment of infants with acute dehydrating diarrhea not associated with cholera.

Functional Diarrhea in Toddlers (Chronic Nonspecific Diarrhea)

Chronic nonspecific diarrhea (CNSD) is a leading cause of chronic diarrhea in otherwise well children, 1–3 years of age, and occurs, by definition, without underlying nutrient malabsorption. CNSD has been classified by the consensus committee Rome III within the functional digestive disorders of infancy and childhood, and its salient features and diagnostic criteria have been recently defined. Patients with CNSD typically look healthy, well nourished, and active and have a pattern of intermittent or nearly constant runny stools containing recognizable undigested vegetable. Often CNSD begins following a viral gastroenteritis. In most cases, the mechanism of diarrhea appears to be related to habitual excessive intake of hyperosmolar fluids such as soft drinks and fruit juices, as well as products that contain fructose or sorbitol. A pathogenic relationship exists, too, between CNSD and the ingestion of a diet low in fat. When the anomalous dietary patterns are corrected and the child’s diet is normalized, the typical result is a sustained return to normal stools.