Persistent and transient Helicobacter pylori infections in early childhood.

BACKGROUND: Helicobacter pylori, the main cause of peptic ulcer disease and gastric cancer in adult populations, is generally acquired during the first years of life. Infection can be persistent or transient and bacterial and host factors determining persistence are largely unknown and may prove relevant for future disease. METHODS: Two cohorts of healthy Chilean infants (313 total) were evaluated every 3 months for 18-57 months to determine pathogen- and host-factors associated with persistent and transient infection. RESULTS: One-third had at least one positive stool ELISA by age 3, with 20% overall persistence. Persistent infections were acquired at an earlier age, associated with more household members, decreased duration of breastfeeding, and nonsecretor status compared to transient infections. The cagA positive strains were more common in persistent stools, and nearly 60% of fully characterized persistent stool samples amplified cagA/vacAs1m1. Persistent children were more likely to elicit a serologic immune response, and both infection groups had differential gene expression profiles, including genes associated with cancer suppression when compared to healthy controls. CONCLUSIONS: These results indicate that persistent H. pylori infections acquired early in life are associated with specific host and/or strain profiles possibly associated with future disease occurrence.

Unidad de ACV en el Hospital de Clínicas: comportamiento clínico-epidemiológico de los pacientes con ACV (2007-2012) / Stroke Unit at the Hospital de Clínicas: clinical-epidemiological behavior in patients with stroke (2007-2012)

Introducción: El ataque cerebrovascular (ACV) es una importante causa de mortalidad, discapacidad y demencia en el mundo y en nuestro país. Provoca un gran impacto económico ya sea por gastos directos o indirectos. Objetivos: Describir aspectos clínicos, factores de riesgo e indicadores que permiten un adecuado manejo del ACV en su tratamiento agudo. Material y Métodos: Se realizó un estudio descriptivo y prospectivo de los ACV ingresados en el Hospital de Clínicas, entre 2007 y 2012 aplicando un protocolo con escalas clínicas, etiopatogénicas y funcionales, con test estadísticos adecuados. Resultados: Se protocolizaron 784 pacientes: 75% infartos, 16% hemorragias y 9% AIT. La HTA fue el factor de riesgo más frecuente. Un tercio llegó a puerta antes de las 4,5 h. En infartos y AIT se disminuyeron los días de internación y se mejoró la funcionalidad a 6 meses. Conclusiones: La formación de equipos entrenados en el diagnóstico y tratamiento del ACV disminuyeron el tiempo de internación y mejoraron la funcionalidad de estos pacientes.

Introduction: The cerebrospinal fluid (CSF) fistula is defined as the abnormal leak of fluid from the skull to outside the body through an osteomeningeal gap, which allows the passage of organisms to the intra-cranial space, with the risk of infection, potentially life-threatening. Divided as traumatic and non-traumatic, the condition is relatively common, and poses great challenges to neurosurgeons. Objective: to present the first case of post-traumatic CSF fistula in Uruguay, assessed with cistern MRI with diagnostic purposes. Case report: the case described is that of a patient that received treatment at the University Hospital (Hospital de Clínicas). The case is used to illustrate the condition and review the latest controversial issues involved in the algorithms for the diagnosis and therapy of the condition. Discussion: the main controversial issues found included the following: when to start prophylactic antibiotic (ATB) therapy following diagnosis; imaging tests requested for diagnosis, and type of therapy prescribed. Conclusions: The review of literature leads us to conclude that a correct diagnosis requires the routine use of CT and MRI; if doubts persist, cistern MRI, endoscopy, or cistern CT are indicated. With regards the therapeutic algorithm, we conclude that therapy should be conservative, applying medical therapy for two to four weeks; surgery will be prescribed if the fistula persists after that. Antibiotic therapy is an option and not a recommendation.

Occurrence of terrestrial mammals in sugarcane plantations in the state of Goiás, Brazil / Ocorrência de mamíferos terrestres em canaviais no estado de Goiás, Brasil

The changes that are constantly occurring in the Cerrado biome have as main cause human action, which in most cases results in fragmented vegetation. Currently some areas of pasture, soy, maize and/or other crops are being replaced by sugar cane in the state of Goiás, Brazil. To verify the occurrence of mammals in the sugarcane monocultures area of influence in Caçu municipality, Goiás State, Brazil, were used low impact sampling techniques, where no medium or large size mammals were captured, only registered through direct data, traces and camera trap. The record of small mammals occurred with the support of Tomahawk traps. Four samplings were carried out lasting eight days with total identification of 36 species of mammals. The records showed the occupation of sugarcane by mammals. Since this is a space monoculture connector does not represent a barrier to the flow of some species present. (AU)

As constantes alterações no bioma Cerrado têm como causa principal a ação antrópica que, na maioria dos casos, deixa a vegetação fragmentada. Atualmente, algumas áreas de pastagem, soja, milho e outras culturas vêm sendo substituídas pela cultura da cana-de-açúcar no estado de Goiás, Brasil. Para verificar a ocorrência de mamíferos na área de influência da monocultura canavieira no município de Caçu, em Goiás, Brasil, foram utilizadas técnicas de amostragem de baixo impacto nas quais nenhum mamífero de médio e grande porte foi capturado, apenas registrado através de dados diretos, vestígios e câmera trap. O registro de mamíferos de pequeno porte ocorreu com auxílio de armadilhas do tipo Tomahawk. Foram realizadas quatro amostragens com duração de oito dias, com registro total de 36 espécies de mamíferos. Os registros mostraram a ocupação de canaviais por mamíferos, uma vez que essa monocultura é um conector espacial que não apresenta barreira para o fluxo de algumas espécies registradas. (AU)

Occurrence of terrestrial mammals in sugarcane plantations in the state of Goiás, Brazil / Ocorrência de mamíferos terrestres em canaviais no estado de Goiás, Brasil

The changes that are constantly occurring in the Cerrado biome have as main cause human action, which in most cases results in fragmented vegetation. Currently some areas of pasture, soy, maize and/or other crops are being replaced by sugar cane in the state of Goiás, Brazil. To verify the occurrence of mammals in the sugarcane monocultures area of influence in Caçu municipality, Goiás State, Brazil, were used low impact sampling techniques, where no medium or large size mammals were captured, only registered through direct data, traces and camera trap. The record of small mammals occurred with the support of Tomahawk traps. Four samplings were carried out lasting eight days with total identification of 36 species of mammals. The records showed the occupation of sugarcane by mammals. Since this is a space monoculture connector does not represent a barrier to the flow of some species present.

As constantes alterações no bioma Cerrado têm como causa principal a ação antrópica que, na maioria dos casos, deixa a vegetação fragmentada. Atualmente, algumas áreas de pastagem, soja, milho e outras culturas vêm sendo substituídas pela cultura da cana-de-açúcar no estado de Goiás, Brasil. Para verificar a ocorrência de mamíferos na área de influência da monocultura canavieira no município de Caçu, em Goiás, Brasil, foram utilizadas técnicas de amostragem de baixo impacto nas quais nenhum mamífero de médio e grande porte foi capturado, apenas registrado através de dados diretos, vestígios e câmera trap. O registro de mamíferos de pequeno porte ocorreu com auxílio de armadilhas do tipo Tomahawk. Foram realizadas quatro amostragens com duração de oito dias, com registro total de 36 espécies de mamíferos. Os registros mostraram a ocupação de canaviais por mamíferos, uma vez que essa monocultura é um conector espacial que não apresenta barreira para o fluxo de algumas espécies registradas.

Peptic ulcer disease in Helicobacter pylori-infected children: clinical findings and mucosal immune response.

OBJECTIVES: Peptic ulcer disease (PUD) is highly prevalent among adults but less common in children. Helicobacter pylori infection, the main cause of PUD, is, however, acquired extremely early in life. The aim of the study was to analyze clinical characteristics of children with PUD in a country with a high prevalence of the disease and to evaluate which host factors could determine this clinical outcome. METHODS: Children referred for upper gastrointestinal (GI) endoscopy with suspicion of peptic diseases were included prospectively during an 8-year period. Antral biopsies were performed to determine H pylori presence and mucosal cytokines profile. RESULTS: A total of 307 children between 3 and 18 years old were enrolled. Of the total, 237 children (46% boys) with complete data were included. H pylori infection was confirmed in 133 (56.1%) participants. Duodenal ulcer (DU) was diagnosed in 32 patients (13.5%); among them 29 were infected with H pylori (90.6%). Infected children had a nodular appearance of the gastric mucosa more often than noninfected children. Noninfected children had fewer lymphoid follicles and less inflammatory infiltrate than infected children. Only mucosal polymorphonuclear cell infiltration was more intense in DU-infected children as compared with non-DU-infected children. DU-infected children had higher levels of mucosal interferon-γ than noninfected and non-DU-infected patients. Non-DU-infected children had also higher levels of mucosal interleukin-10 than noninfected patients (P < 0.05). CONCLUSIONS: PUD in children, especially DU, is strongly associated with H pylori infection in developing countries. There is no distinctive clinical presentation of children with PUD. T-helper cytokine balance may influence clinical outcomes in children.

Dynamics of Helicobacter pylori detection in stools during the first 5 years of life in Chile, a rapidly developing country.

BACKGROUND: : Helicobacter pylori colonization/infection can be transitory or persistent, conditions that have not been thoroughly evaluated in young children. We aimed to characterize the dynamics of H. pylori stool detection and to determine host and environmental factors and symptoms associated with persistence. METHOD: : In a 5-year cohort study, we followed-up infants from birth with clinic visits every 3 months. Symptoms and environmental risk factor survey and a stool sample for H. pylori antigen detection were requested in every visit. Secretor/ABH histo-blood group phenotype was determined in saliva. RESULTS: : Overall, 218 of 1456 (15%) stool samples were positive for H. pylori and 39 of 96 (41%) children had at least 1 positive sample. Stool detection was transitory in 16 of 39 (41%), persistent in 19 (49%) and undetermined in 4 (10%) children. Persistence was acquired largely during the first 24 months (17/19 cases) and was associated with nonsecretor phenotype (32% versus 0% for transitory infection; P = 0.02) and daycare attendance (67% versus 26% for never infected; P = 0.019). Symptoms possibly associated with persistence were referred in only 1 child. CONCLUSIONS: : Nearly 20% of this Chilean cohort had persistent H. pylori stool sample detections during the first 5 years of life, acquired mostly during the first 24 months. Persistence was significantly associated with nonsecretor phenotype and daycare attendance, and possibly associated gastrointestinal symptoms were rare. This relatively common group of young children with persistent H. pylori colonization/infection will require further study.

Study on the population structure of the paradoxical frog, Pseudis bolbodactyla (Amphibia: Anura: Hylidae), using natural markings for individual identification

The goal of this study was to assess the population structure of Pseudis bolbodactyla Lutz, 1925 using natural markings to identify individuals. Recruitment, survival, and population size estimations were obtained using the Jolly-Seber stochastic method. A total of 166 individuals were captured, and the striped, spotted, and dotted patterns that make their recognition possible were recorded. Of the specimens captured, 27 were recaptured, including some at pre and post-metamorphic stages. The estimate maximum population size was 52. The indices of survival and recruitment varied among samplings. Sexual dimorphism in size and in the operational sex ratio were detected. Despite the limited scope of our characterization of the P. bolbodactyla population, our data might be useful in the interpretation and elaboration of new hypotheses about ecological processes acting on anuran populations.

Study on the population structure of the paradoxical frog, Pseudis bolbodactyla (Amphibia: Anura: Hylidae), using natural markings for individual identification

The goal of this study was to assess the population structure of Pseudis bolbodactyla Lutz, 1925 using natural markings to identify individuals. Recruitment, survival, and population size estimations were obtained using the Jolly-Seber stochastic method. A total of 166 individuals were captured, and the striped, spotted, and dotted patterns that make their recognition possible were recorded. Of the specimens captured, 27 were recaptured, including some at pre and post-metamorphic stages. The estimate maximum population size was 52. The indices of survival and recruitment varied among samplings. Sexual dimorphism in size and in the operational sex ratio were detected. Despite the limited scope of our characterization of the P. bolbodactyla population, our data might be useful in the interpretation and elaboration of new hypotheses about ecological processes acting on anuran populations.

Study on the population structure of the paradoxical frog, Pseudis bolbodactyla (Amphibia: Anura: Hylidae), using natural markings for individual identification

The goal of this study was to assess the population structure of Pseudis bolbodactyla Lutz, 1925 using natural markings to identify individuals. Recruitment, survival, and population size estimations were obtained using the Jolly-Seber stochastic method. A total of 166 individuals were captured, and the striped, spotted, and dotted patterns that make their recognition possible were recorded. Of the specimens captured, 27 were recaptured, including some at pre and post-metamorphic stages. The estimate maximum population size was 52. The indices of survival and recruitment varied among samplings. Sexual dimorphism in size and in the operational sex ratio were detected. Despite the limited scope of our characterization of the P. bolbodactyla population, our data might be useful in the interpretation and elaboration of new hypotheses about ecological processes acting on anuran populations.

Study on the population structure of the paradoxical frog, Pseudis bolbodactyla (Amphibia: Anura: Hylidae), using natural markings for individual identification

The goal of this study was to assess the population structure of Pseudis bolbodactyla Lutz, 1925 using natural markings to identify individuals. Recruitment, survival, and population size estimations were obtained using the Jolly-Seber stochastic method. A total of 166 individuals were captured, and the striped, spotted, and dotted patterns that make their recognition possible were recorded. Of the specimens captured, 27 were recaptured, including some at pre and post-metamorphic stages. The estimate maximum population size was 52. The indices of survival and recruitment varied among samplings. Sexual dimorphism in size and in the operational sex ratio were detected. Despite the limited scope of our characterization of the P. bolbodactyla population, our data might be useful in the interpretation and elaboration of new hypotheses about ecological processes acting on anuran populations.

Study on the population structure of the paradoxical frog, Pseudis bolbodactyla (Amphibia: Anura: Hylidae), using natural markings for individual identification

The goal of this study was to assess the population structure of Pseudis bolbodactyla Lutz, 1925 using natural markings to identify individuals. Recruitment, survival, and population size estimations were obtained using the Jolly-Seber stochastic method. A total of 166 individuals were captured, and the striped, spotted, and dotted patterns that make their recognition possible were recorded. Of the specimens captured, 27 were recaptured, including some at pre and post-metamorphic stages. The estimate maximum population size was 52. The indices of survival and recruitment varied among samplings. Sexual dimorphism in size and in the operational sex ratio were detected. Despite the limited scope of our characterization of the P. bolbodactyla population, our data might be useful in the interpretation and elaboration of new hypotheses about ecological processes acting on anuran populations.

[Rotavirus genotypes in children with gastroenteritis assisted in two public hospitals from Chile: viral strains circulating in a country without a universal vaccination against rotavirus]. / Genotipos de rotavirus aislados de niños chilenos con gastroenteritis atendidos en dos hospitales públicos: variantes virales circulantes en un país con uso limitado de vacunas anti-rotavirus.

BACKGROUND: Rotavirus is the main cause of severe gastroenteritis (GE) in children. Two vaccines currently available have proven efficacy against the predominant genotypes. Rotavirus genotypes vary both geographically and/or temporally. Genotype surveillance is important to monitor trends associated or not with vaccine use. AIM: To update information on rotavirus genotypes circulating in two main cities of Chile. METHODOLOGY: Between May 2009-March 2010, children < 5y of age receiving medical care for GE in two large hospitals were recruited; none of these children had received rotavirus vaccine previously. Epidemiological information was recorded in an ad-hoc form and stool samples were collected for rotavirus detection by a commercial ELISA. Genotyping was performed by semi-nested RT-PCR. RESULTS: A total of 296/967 samples (31%) were positive for rotavirus, with a peak in November/ December mostly in children 7-24 months old (67%). G9P[8] was the predominant genotype (76%), followed for G1P[8] (6%) and G2P[4] (6%) in both cities. CONCLUSIONS: Rotavirus caused one third of GE requiring emergency room care and/or hospitalization, mostly in children within an age range susceptible to benefit from rotavirus vaccines. G9P[8], a genotype against which rotavirus vaccines have demonstrated high efficacy, was by far the most frequent rotavirus variant. Continued surveillance in Chile is crucial for providing background information on disease burden and strain diversity before the introduction of rotavirus vaccines.

Genotipos de rotavirus aislados de niños chilenos con gastroenteritis atendidos en dos hospitales públicos: variantes virales circulantes en un país con uso limitado de vacunas anti-rotavirus / Rotavirus genotypes in children with gastroenteritis assisted in two public hospitals from Chile: viral strains circulating in a country without a universal vaccination against rotavirus

Background: Rotavirus is the main cause of severe gastroenteritis (GE) in children. Two vaccines currently available have proven efficacy against the predominant genotypes. Rotavirus genotypes vary both geographically and/or temporally. Genotype surveillance is important to monitor trends associated or not with vaccine use. Aim: To update information on rotavirus genotypes circulating in two main cities of Chile. Methodology: Between May 2009-March 2010, children < 5y of age receiving medical care for GE in two large hospitals were recruited; none of these children had received rotavirus vaccine previously. Epidemiological information was recorded in an ad-hoc form and stool samples were collected for rotavirus detection by a commercial ELISA. Genotyping was performed by semi-nested RT-PCR. Results: A total of 296/967 samples (31%) were positive for rotavirus, with a peak in November/ December mostly in children 7-24 months old (67%). G9P[8] was the predominant genotype (76%), followed for G1P[8] (6%) and G2P[4] (6%) in both cities. Conclusions: Rotavirus caused one third of GE requiring emergency room care and/or hospitalization, mostly in children within an age range susceptible to benefit from rotavirus vaccines. G9P[8], a genotype against which rotavirus vaccines have demonstrated high efficacy, was by far the most frequent rotavirus variant. Continued surveillance in Chile is crucial for providing background information on disease burden and strain diversity before the introduction of rotavirus vaccines.

Antecedentes: Rotavirus es la principal causa de gastroenteritis (GE) grave en niños. Actualmente se dispone de dos vacunas con eficacia demostrada contra los genotipos predominantes en el mundo. Los genotipos de rotavirus varían en el tiempo y de una región a otra. Es importante mantener la vigilancia de los genotipos circulantes para monitorizar las tendencias asociadas o no al uso de vacunas. Objetivo: Actualizar la información sobre genotipos de rotavirus circulantes en dos ciudades importantes de Chile (Santiago y Valparaíso). Metodología: Entre mayo 2009 y marzo 2010 se reclutaron niños bajo 5 años de edad con GE atendidos en dos hospitales; ninguno de ellos con historia previa de vacunación anti-rotavirus. Se registró información epidemiológica y se tomó muestra de deposición para detección de rotavirus mediante ELISA comercial. Se realizó genotipificación mediante RPC-TR semi-anidada. Resultados: Se detectó rotavirus en 296/967 muestras analizadas (31%), con un pico de frecuencia en noviembre/diciembre y afectando predominantemente al grupo de 7-24 meses de edad (67%). G9P[8] fue el genotipo predominante (76%), seguido por G1P[8] (6%) y G2P[4] (6%) en ambas ciudades. Conclusiones: Rotavirus causó un tercio de las GE en este grupo, afectando especialmente al grupo de edad que podría beneficiarse con la vacunación anti-rotavirus. G9P[8], una de las variantes contra las cuales las vacunas antirotavirus han demostrado alta eficacia, fue por lejos el genotipo más frecuente. Es necesario continuar la vigilancia en Chile de modo de conocer el impacto de la enfermedad y diversidad de variantes antes de la incorporación de una vacuna anti-rotavirus.

Inverse correlation between allergy markers and Helicobacter pylori infection in children is associated with elevated levels of TGF-ß.

OBJECTIVES: We evaluated allergy/hypersensitivity clinical markers and their correlation with Helicobactor pylori infection in children and adults to analyze how early acquisition of H. pylori could modulate allergic disorder expression. PATIENTS AND METHODS: H. pylori presence was assessed by the rapid urease test and histology of antrum biopsies in 165 patients. Skin tests, serum IgE, and two clinical allergy questionnaires were performed. Allergy severity was operationally defined using a combined score. Findings were correlated with H. pylori status and cytotoxin-associated gene A presence in pediatric and adult patients. Transforming growth factor ß (TGF-ß) levels were measured by an enzyme-linked immunosorbent assay in serum and gastric biopsies of H. pylori (+) patients. RESULTS: H. pylori (-) children had more positive skin tests to a higher number of antigens than H. pylori (+) children (P<0.05). Operationally defined allergy inversely correlates with H. pylori infection in children, but not in adults. The percentage of H. pylori infection was lower in children with severe allergy (32.3%) compared with children with mild allergy (43.4%) or no allergy (64.3%) (P<0.05). Colonization with virulent strains (cytotoxin-associated gene A+) showed a nonsignificant inverse correlation with severity of allergies in pediatric patients. H. pylori-infected children, but not adults, without allergy markers showed increased levels of TGF-ß compared with allergic children both in serum and gastric mucosa (P<0.05). CONCLUSION: There was a strong inverse correlation between allergy markers and H. pylori infection in pediatric patients associated with elevated levels of TGF-ß locally and systemically. H. pylori-associated chronic gastritis might downregulate clinical allergy expression.

Prospective characterization of norovirus compared with rotavirus acute diarrhea episodes in chilean children.

BACKGROUND: Rotavirus and more recently noroviruses are recognized as main causes of moderate to severe acute diarrhea episodes (ADE) in children < or =5 years of age. Comparing epidemiologic and clinical features of norovirus to rotavirus ADE will aid in the decision-making process required to develop norovirus vaccines. METHODS: Surveillance for ADE occurring in children < or =5 years of age was implemented in the emergency department (ED) and ward of a large hospital in Santiago and Valparaiso, and in 4 outpatient clinics in Santiago. A stool sample was obtained within 48 hours of consultation for rotavirus detection by enzyme-linked immunosorbent assay and noroviruses by enzyme-linked immunosorbent assay or reverse transcription polymerase chain reaction. For ED and hospital rotavirus and norovirus ADE parents were instructed to monitor clinical findings associated with severity until the end of the episode. The 20-point Vesikari score was used to determine disease severity. RESULTS: Between July 2006 and October 2008 rotavirus and noroviruses were detected in 331 (26%) and 224 (18%) of 1913 ADE evaluated. The proportion of rotavirus-positive samples in hospital ward, ED, and outpatient clinic was 40%, 26% to 30%, and 13% compared with 18%, 17% to 19%, and 14% for noroviruses. Mean age and 25%-75% interquartile interval of children with rotavirus and norovirus ADE were remarkably similar, 15.6 months (9-20), and 15.5 months (9-19), respectively. Rotavirus cases displayed an autumn-winter peak followed 2 to 3 months later by the norovirus peak. The mean (interquartile) for the Vesikari score was 12.9 (11-15) and 11.9 (9-14.5) for rotavirus (N = 331) and norovirus (N = 224) ADE, respectively, P = 0.003. Compared with norovirus, rotavirus ADE were more common in the 11 to 16 severity score interval (P = 0.006), had a higher maximum stool output in a given day (P = 0.01) and more frequent fever (P < 0.0001). Duration of diarrhea, presence, duration and intensity of vomiting, and intensity of fever did not differ between viruses. Mixed rotavirus and norovirus infections were uncommon (<1%) and not clinically more severe. Clinical severity of ADE in young infants was similar for rotavirus and lower (P = 0.03) for noroviruses compared with older children. CONCLUSION: Noroviruses are a significant cause of moderate to severe endemic ADE in Chilean children. Although significantly less severe than rotavirus as a group, most norovirus episodes were moderate to severe clinically. An effective norovirus vaccine would be of significant additional benefit to the current rotavirus vaccine in decreasing disease burden associated with ADE.

Lack of diagnostic utility of specific immunoglobulin M in Helicobacter pylori infection in children.

BACKGROUND: Helicobacter pylori infection results in a systemic immune response characterized by the initial rise of immunoglobulin (Ig) M followed by the elevation of IgG- and IgA-specific antibody levels in serum. Age and regional considerations may modify the accuracy of serological tests. OBJECTIVES: To determine the accuracy of specific IgG, IgA, and IgM in H pylori infection determination in different age groups. PATIENTS AND METHODS: We enrolled 179 patients referred for endoscopy. Patients were considered infected if they had positive histological or urease test results for H pylori. Titers of IgG, IgA, and IgM were determined in serum by enzyme-linked immunosorbent assay. Through receiver operator characteristic curves, cutoff, sensitivity, and specificity values were obtained. Agreement and correlation between immunoglobulin titers and inflammation markers were explored. RESULTS: Infection with H pylori was present in 58% of adults, 62% of adolescents, and 25% of children. Sensitivity and specificity were higher in children younger than 12 years old for IgG and IgA. All diagnostic performance values were lower for IgM. Agreement measures were approximately 0.5 in adults and reached values of approximately 0.7 for adolescents and children. IgM had negative agreement with other methods. There was a correlation between inflammation markers, H pylori load, and immunoglobulin titers for IgG and IgA. These associations decreased with age and were not observed for IgM. CONCLUSIONS: IgG and IgA serological tests reached high performance values, particularly in children younger than 12 years old, indicating that they are reasonable screening methods once cutoff values are adjusted to local population and age. IgM does not present an additional contribution.

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.

Relationship between Helicobacter pylori virulence factors and regulatory cytokines as predictors of clinical outcome.

Helicobacter pylori infection is highly prevalent in Chile (73%). Usually a minority of infected patients develops complications such as ulcers and gastric cancer that have been associated with the presence of virulence factors (cagA, vacA) and host T helper response (Th1/Th2). Our aim was to evaluate the relationship between strain virulence and host immune response, using a multiple regression approach for the development of a model based on data collected from H. pylori infected patients in Chile. We analyzed levels of selected cytokines determined by ELISA (interleukin (IL)-12, IL-10, interferon (IFN)-gamma and IL-4) and the presence of cagA and vacA alleles polymorphisms determined by PCR in antral biopsies of 41 patients referred to endoscopy. By multiple regression analysis we established a correlation between bacterial and host factors using clinical outcome (gastritis and duodenal ulcer) as dependent variables. The selected model was described by: clinical outcome=0.867491 (cagA)+0.0131847 (IL-12/IL-10)+0.0103503 (IFN-gamma/IL-4) and it was able to explain over 90% of clinical outcomes observations (R(2)=96.4). This model considers that clinical outcomes are better explained by the interaction of host immune factors and strain virulence as a complex and interdependent mechanism.

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.