Infecção pelo Helicobacter pylori e perfil imunológico em pacientes com diferentes doenças gastroduodenais / Helicobacter pylori infection and immune profile of patients with different gastroduodenal diseases

ABSTRACT BACKGROUND: The association between infection with Helicobacter pylori and different gastroduodenal diseases is related to bacterial, host and environmental factors. Studies have demonstrated an association between the genetic diversity of H. pylori, especially in the vacA and cagA genes, and the development of digestive diseases such as peptic ulcer and gastric cancer. In addition, the nature of the host inflammatory response may explain these different manifestations of infection caused by this microorganism. In this respect, host factors that regulate the immune and inflammatory responses involving the functional interaction of H. pylori infection with different components of the immune system, particularly T cells, in gastroduodenal diseases still need further investigation. OBJECTIVE: To characterize the immune response, including immunity induced by infection with H. pylori, especially virulent strains (vacA alleles and cagA gene), by analyzing the cytokine profile and T-cell population present in gastroduodenal diseases in a Brazilian population. METHODS: In a prospective study, gastric biopsies were collected from 554 patients with different gastroduodenal diseases for histological analysis and for the determination of bacterial genotype and cytokine production (IL-4, IL-10, IFN-γ and IL-12) by ELISA. RESULTS: The predominant genotype of the H. pylori strains isolated from the patients studied was s1m1cagA+, which was more common among patients with gastric ulcer, duodenal ulcer and gastric cancer. A significant association was observed between the s1m1cagA+ genotype and a higher degree of inflammation, higher neutrophil activity and the development of intestinal metaplasia. The gastric concentrations of IFN-γ and IL-12 were significantly higher in patients infected with H. pylori than in uninfected individuals. Higher levels of these cytokines were detected in patients with gastric ulcer and cancer, while the levels of IL-4 and IL-10 in the gastric mucosa were lower in these patients. In addition, IFN-γ and IL-12 concentrations in gastric biopsies were higher in patients infected with the virulent s1m1cagA+ genotype. In contrast, IL-4 and IL-10 levels were higher in tissue infected with s2m2cagA in gastric biopsies. CONCLUSION: Our study shows that the interaction between the type of infectious strain and the Th1 immune response can influence and perpetuate gastric inflammation, and thus contributes to the development of the different clinical manifestations of H. pylori infection.

RESUMO CONTEXTO: A associação da infecção por Helicobacter pylori com diferentes doenças gastroduodenais pode estar associada a fatores bacterianos, do hospedeiro e do ambiente. Nesse contexto, estudos têm demonstrado que a diversidade genética do H. pylori, sobretudo nos genes vacA e cagA, está associada ao desenvolvimento de doenças gastroduodenais como a úlcera péptica e o câncer gástrico. Além disso, a natureza da resposta inflamatória do hospedeiro pode explicar essas diferentes manifestações da infecção por esse microrganismo. Portanto, fatores do hospedeiro que regulam as respostas imunológica e inflamatória, envolvendo a interação funcional da infecção por H. pylori com diferentes membros do compartimento imunológico, especialmente respostas imunes de células T nas doenças gastroduodenais, ainda precisam ser melhor estudados. OBJETIVO: Caracterizar a resposta imune, incluindo imunidade induzida por infecção pelo H. pylori, especialmente com cepas virulentas de H. pylori (alelos vacA e gene cagA), através da análise do perfil de citocinas e da caracterização da população de células T presentes em doenças gastroduodenais em nossa população. MÉTODOS: Em um estudo prospectivo, foram coletadas biópsias gástricas de 554 pacientes portadores das diferentes doenças gastroduodenais. Nas amostras biológicas destes pacientes foi realizada a determinação do genótipo bacteriano e a detecção das citocinas IL-4, IL-10, INF-γ e IL-12 através do método Elisa. Foram obtidas biópsias gástricas para avaliação histológica. RESULTADOS: Observamos que o genótipo predominante nas cepas de H. pylori isoladas dos pacientes estudados foi s1m1cagA positivo, sendo mais frequentes entre os pacientes com úlcera gástrica, úlcera duodenal e câncer gástrico. Houve associação significativa das cepas com o genótipo s1m1cagA positivo com maior grau de inflamação, atividade neutrofílica e desenvolvimento de metaplasia intestinal. As concentrações gástricas de INF-γ e IL-12 foram significativamente mais elevadas em pacientes infectados pelo H. pylori do que nos não infectados. Foram detectados níveis mais elevados dessas citocinas nos portadores de úlcera e câncer gástrico, sendo que nesses pacientes foram observados níveis mais baixos de IL-4 e IL-10 na mucosa gástrica. Além disso, as concentrações de INF-γ e IL-12 em biópsias gástricas, foram mais elevadas nos pacientes portadores das cepas bacterianas virulentas s1m1cagA+. Contrariamente, os níveis de IL-4 e IL-10 foram maiores em tecido infectado por cepas s2m2cagA. Pacientes com maior grau de inflamação, de atividade neutrofílica e presença de metaplasia intestinal, apresentaram níveis mais elevados de INF-γ e IL-12 e uma concentração mais baixa de IL-4 e IL-10 nas biópsias gástricas. CONCLUSÃO: Nosso estudo demonstra que a interação entre o tipo de cepa infectante e resposta imunológica com perfil Th1, podem influenciar e perpetuar a inflamação gástrica contribuindo para o desenvolvimento de diferentes manifestações clínicas na infecção pelo H. pylori.

Hepatocyte antigen expression in subtypes of intestinal metaplasia of the stomach / Expresión del antígeno del hepatocito en los subtipos de metaplasia intestinal del estómago

OBJECTIVE: Recently, hepatocyte antigen (Hep) was introduced as a sensitive and reliable marker of intestinal metaplasia (IM). However, the distribution of Hep expression in subtypes of IM was not described. METHODS: We examined the expression of Hep in 58 cases of chronic gastritis associated with IM by immunohistochemical staining. Cases were classified as: 19 of IM Type I (complete) cases, 16 cases of IM Type II (incomplete) and 23 cases of IM Type III (incomplete). The distribution of Hep expression was classified into four groups according to the intensity of Hep expressing metaplastic cells: negative, low, moderate and high. We also compared expression of Hep with that of MUC-1, MUC-2 and MUC-5AC. RESULTS: Hep expression showed granular cytoplasmic staining and was specifically identified in columnar cells, but not in goblet cells. There was no significant difference between Hep expression and subtypes of IM (p > 0.005). However, the difference between the distribution of Hep expression among three subtypes of IM was significant (p < 0.001). No relationship was observed among the expression of Hep, MUC-1, MUC-2 and MUC-5AC. CONCLUSION: Results of the present study revealed that the distribution of Hep expression is high in the majority of the complete type (Type I) IM cases, moderate in the majority of the incomplete Type II IM cases and low in all of the incomplete Type III IM cases and suggest that besides its role as a sensitive marker in IM, the evaluation of the distribution of Hep expression might be useful in the classification of IM.

OBJETIVO: El antígeno del hepatocito (Hep) se introdujo recientemente como un marcador sensible y confiable de la metaplasia intestinal (MI). Sin embargo, no se describe la distribución de la expresión de Hep en los subtipos de MI. MÉTODOS: Se examinó la expresión de Hep en 58 casos de gastritis crónica asociados con MI mediante tinción inmunohistoquímica. Los casos fueron clasificados como: 19 casos de tipo MI (completo), 16 casos de tipo MI II (incompleto), y 23 casos de tipo MI III (incompleto). La distribución de la expresión del Hep se clasificó en cuatro grupos según la intensidad de Hep, que expresa las células metaplásticas: negativa, baja, moderada y alta. También se comparó la expresión de Hep con la de MUC-1, MUC-2 y MUC-5AC. RESULTADOS: La expresión de Hep mostró tinción citoplasmática granular, específicamente identificada en las células columnares, pero no en las células caliciformes. No hubo ninguna diferencia significativa entre la expresión de Hep y los subtipos de MI (p > 0.005). Sin embargo, la diferencia entre la distribución de la expresión del Hep entre tres subtipos de MI fue significativa (p < 0.001). No se observó relación alguna entre la expresión de Hep, MUC-1, MUC-2 y MUC-5AC. CONCLUSIÓN: Los resultados del presente estudio revelaron que la distribución de la expresión de Hep es alta en la mayoría de los casos MI de tipo completo (tipo I), moderada en la mayoría de los casos MI de tipo II, y baja en todos los casos MI de tipo III incompleto. Los resultados sugieren que además de su papel como marcador sensible en MI, la evaluación de la distribución de expresión del Hep podría ser útil en la clasificación de MI.

Immunodetection of Helicobacter sp. and the associated expression of ABO blood group antigens in the gastric mucosa of captive and free-living New World primates in the Amazon region

The histo-blood group ABH antigens were first described in humans. These antigens are only present on erythrocytes from great apes and humans, while in more primitive animals they are found in tissues and body fluids. The ABH antigens are mainly distributed in tissues exposed to the external environment and potentially serve as ligands for pathogens or inhibitors of tissue connections. The objective of this paper was two-fold: (i) to determine the presence of Helicobacter sp. in the gastric mucosa of 16 captive and 24 free-living New World monkeys and (ii) to evaluate the presence of histopathological alterations related to bacterial infection and the associated expression of ABH antigens in the tissue. Stomach tissues from 13 species of monkey were assessed using haematoxylin-eosin and modified Gram staining (Hucker) methods. An immunohistochemical analysis of the tissue revealed the presence of infectious bacteria that were characteristic of the genus Helicobacter sp. The results demonstrate that various species of monkey might be naturally infected with the Helicobacter sp. and that there is an increased susceptibility to infection. This study serves as a comparative analysis of infection between human and non-human primates and indicates the presence of a new species of Helicobacter.

IL-10, TNF-alpha and IFN-gamma levels in serum and stomach mucosa of helicobacter pylori-infected patients

H. pylori is a human pathogen that colonizes the epithelium of the stomach. The host immune response may influence the disease process, where cytokines play important roles in the development of disease. In this study, the concentrations of selected cytokines in the gastric antrum and stomach body mucosa and also in the serum were evaluated. Eighty patients according to their rapid urease test were divided into two groups: H. pylori positive [n=39] and H.pylori-negative [n=41]. The concentrations of cytokines in biopsies and serum were determined by ELISA method. The mean TNF-alpha and IFN-gamma levels in the infected group were significantly higher than that of uninfected patients. In contrast, IL-10 level in most patients was undetectable. The mean antral of stomach TNF-alpha and IFN-gamma levels were significantly higher than that of the stomach body. IFN-gamma serum level showed positive correlation with antrum and stomach body levels, whereas no correlation was found in TNF-alpha in different samples. Higher levels of TNF-alpha and IFN-gamma in antral indicate that the colonization of bacteria in the antrum may be higher than stomach body [culture results from two sites support this statement]. Increased serum level of IFN-gamma indicates the activation of circulating-T cells against infection. Induced H. pylori-related TNF-alpha is concentrated is gastric mucosa and this pathogen does not cause any significant change in the serum level of this cytokine. Therefore H. pylori by inducing certain inflammatory cytokines but not IL-10 may contribute the process of disease development

Inmunidad y Helicobacter pylori / Immunity and Helicobacter pylori

Helicobacter pylori, es una bacteria Gram negativa que coloniza la mucosa gástrica y contribuye al desarrollo de patologías como la gastritis crónica, úlceras duodenales y en menor medida cáncer gástrico. Si bien la infección por H. pylori por sí sola es capaz de producir daño al epitelio gástrico a través de la expresión de numerosos factores de virulencia, es la respuesta inmune local la mayor responsable de la patogenia de las enfermedades asociadas a dicha infección. La clásica dicotomía en la respuesta T helper tipo 1 vs tipo 2 para explicar el daño asociado a la bacteria, ha dado paso a un escenario más complejo con la reciente descripción de las células T regulatorias y la existencia de nuevos perfiles de respuesta T helper como Th 17. El delicado equilibrio entre virulencia y respuesta infl amatoria inmune es principalmente regulado por la intensidad de la respuesta T regulatoria, cuya supresión permite la expresión de una respuesta efectora potencialmente responsable del daño final.

Helicobacter pylori a Gram negative bacterium that colonizes gastric mucosa and that has been associated to different disease such as chronic gastritis, duodenal ulcers and gastric cancer. Although the infection by itself is able to produce damage to the gastric mucosa through the expression and interaction of well-known virulence factors, the immune local response is strongly involved in the pathogenesis of H. pylori-associated diseases. The classic dichotomy T helper type 1 vs type 2 response to explain the damage associated to the bacterium, has been reevaluated in a more complex scenario with the recent description of the T regulatory response and the new patterns of T helper response such as Th17. The extremely well balanced equilibrium between virulence and immune inflammatory response is mainly regulated by the intensity of the T regulatory response; its suppression would allow the expression of different T helper responses that account for the final damage and clinical outcomes.

Marcadores de alergia alimentaria en enfermedad péptica / Food allergy markers in peptic disease

Background: The double-blind food challenge is the gold standard for diagnosis of food allergy, even though it is difficult to standardize and execute. An increase in allergy prevalence worldwide accentuates the importance of evaluating food allergy markers, in order to help the diagnosis. Objective: Elaboration of an operational definition for food hypersensitivity (FH) and evaluate the role of allergy markers, endoscopic and histological findings, gastric mucosa cytokines and personal/family history of allergy in children. Method: Enrollment of children with suspected peptic disease referred for endoscopy. We obtained antral biopsies for histological evaluation (eosinophil and mast cell count) and measurement of mucosal cytokines through an ELISA test. Patients were evaluated with Prick test, total serum IgE and clinical questionnaires for allergies. They were divided into two groups; children with and without food hypersensitivity. Results: 97 children were enrolled (mean: 11.7 +/- 3, range 3-18). 4 percent of children had FH. The endoscopic findings did not correlate with the presence of FH. 74.1 percent of patients without FH had eosinophils in the gastric mucosa compared to groups with FH which had 100 percent) (p < 0.05). Only IL-2 among the evaluated cytokines was found in a greater concentration in patients without FH. 33 percent> of patients considered themselves having history of personal allergies versus 11.8 percent of people without FH (p < 0.05). Conclusions: 12,4 percent of children with digestive symptoms referred to endoscopy have FH. There are no clinical, endoscopic or histological differences between patients with or without FH.

Introducción: El diagnóstico de alergia a alimentos se fundamenta en la prueba de provocación oral doble ciego, de difícil estandarización y ejecución. El aumento de la prevalencia de alergia hace necesario la evaluación de marcadores de alergia a alimentos para facilitar el diagnóstico. Objetivo: Evaluar en niños, a partir de una definición operacional de hipersensibilidad a alimentos (HA), el rol de algunos marcadores de hipersensibilidad, hallazgos endoscópicos e histológicos, citoquinas de mucosa gástrica, y antecedentes personales y familiares de alergia. Métodos: Se enrolaron niños referidos a endoscopia por sospecha de enfermedad péptica. Se obtuvieron biopsias antrales para evaluación histológica (incluyendo eosinófilos y mastocitos) y citoquinas mediante ELISA. Se les realizó test cutáneo (TC), IgE total sérica y cuestionarios clínicos de alergia. Se dividió en 2 grupos, niños con y sin HA según criterio establecido. Resultados: Se reclutaron 97 niños (promedio: 11,7 +/- 3 años, rango 3 a 18). Un 12,4 por ciento de los niños presentó HA. Los hallazgos endoscópicos no se relacionaron con la presencia de HA. Un 74,1 por ciento de los pacientes sin HA presentó eosinófilos en la mucosa gástrica comparado con un 100 por ciento en el grupo con HA (p < 0,05). Sólo IL-2 se encontró en mayor concentración en pacientes sin HA. Un 33,3 por ciento de la población con HA consideró tener antecedentes personales de AA versus un 11,8 por ciento de los sin HA (p < 0,05). Conclusiones: La HA en niños referidos a endoscopia por síntomas digestivos está presente en un 12,4 por ciento, sin elementos clínicos, endoscópicos o histológicos que los diferencien de niños sin HA.

Gastrointestinal manifestations of cow's milk protein allergy during the first year of life.

BACKGROUND: Cow's milk protein sensitive enteropathy (CMPSE) is a common condition in the first year of life. Clinically CMPSE usually presents with symptoms like vomiting, chronic diarrhea, mucous bloody diarrhea and hematemesis. More unusual symptoms associated with CMPSE are infantile colic, gastroesophageal reflux and chronic constipation. The objective of this study was to assess the gastrointestinal manifestations and allergic march in CMPSE patients. METHOD: The authors reviewed the records of 10 CMPSE patients observed by the Gastrointestinal Unit at King Chulalongkorn Memorial Hospital from 1997-2001 including patient characteristics, laboratory investigations, endoscopy and follow-up outcome. RESULTS: Of 10 CMPSE patients, the median age of CMPSE onset was 3.5 months. The gastrointestinal manifestations were hematemesis (n = 6), mucous bloody diarrhea (n = 3) and chronic watery diarrhea (n = 2). Exclusively breast-fed infants seemed to have more delayed onset of symptoms than those who were not. Anemia (n = 3), high serum IgE (n = 4) and positive skin prick test for cow's milk (n = 5) were found. Neither peripheral eosinophilia nor hypoalbuminemia was found. Endoscopy revealed acute and chronic gastritis. Treatment was successful by changing to soy or extensive hydrolysate formula with mean duration of cow's milk intolerance of 24 months. In 2-year follow-up, three of ten patients who had high serum IgE level developed allergic rhinitis and eczema. CONCLUSION: CMPSE can be manifested in various symptoms. Exclusive breast feeding for more than 4 months can postpone the onset of CMPSE. Serum IgE or specific IgE level to cow's milk protein may identify the atopic career of CMPSE individuals.

Deteccion de anticuerpos contra la mucosa gastrica en pacientes con gastritis superficial, gastritis cronica atrofica y ulcera duodenal infectados con Helicobacter pylori / Detection antigastric autoantibodies in patients with gastroduodenal disease and infected with helicobacter pylori

Se detectó la presencia de autoanticuerpos contra la mucosa gástrica en pacientes con enfermedad gastroduodenal e infectados con Helicobacter pylori. Métodos: se estudiaron 39 pacientes, se tomaron biopsias gástricas y suero. Los anticuerpos IgG anti H. pylori se detectaron por la técnica de ELISA. Para la detección de anticuerpos antigástricos se utilizaron técnicas de inmunohistoquímica. Resultados: se detectó la bacteria en el 97,5 por ciento de los casos. Los anticuerpos contra la mucosa gástrica se encontraron en el 12,8 por ciento de los pacientes. Se hallaron dos patrones: a) autoanticuerpos contras las células parietales, b) autoanticuerpos contra la membrana apical del epitelio glandular. Conclusión: se evidenció la presencia de autoanticuerpos contra la mucosa gástrica en pacientes con enfermedad gastroduodenal, infectados con Helicobacter pylori. La presencia de autoanticuerpos puede estar involucrada en el desarrollo de la in.amación y posterior atro.a de la mucosa

Helicobacter pylori and associated histopathological changes in gastric biopsies of patients with leprosy.

Two antral biopsies each from 104 patients of leprosy and 100 controls were studied to find out the prevalence of H. pylori and associated histopathological changes. Sections were stained with hematoxylene and eosin, AB/PAS (Ph 2.5) and Loeffler's methylene blue stains. Infection by H. pylori, inflammation and atrophy were found to be significantly more in leprosy patients as compared to controls (p < 0.01, < 0.005 and < 0.02 respectively). On comparing the histopathological changes in various subgroups of leprosy, H. pylori, inflammation and activity showed a statistically decreasing trend from tuberculoid to lepromatous subgroups (p < 0.05, < 0.001, < 0.01 respectively). Atrophy showed a significant increasing trend from tuberculoid to lepromatous group (< 0.001), it is concluded that despite a low prevalence of H. pylori and associated gastritis in patients with lepromatous leprosy, gastric epithelial damage is more marked due to altered immune response.

Expression of Mucosal Cyto-Chemokine mRNAs in Patients with Helicobacter pylori Infection

BACKGROUND: Helicobacter pylori-induced destruction of the gastroduodenal mucosal barrier is initiated with mucosal infiltration of inflammatory cells. Cytokines and chemokines have been suggested to play important roles in the migration and activation of these inflammatory cells into the mucosa. The present study aimed to investigate expression rates of cyto-chemokine mRNAs using gastric mucosal biopsy specimens. METHODS: In 98 patients infected with Helicobacter pylori, mucosal mRNA expression rates of cytokines (IL-1beta, IL-6, and IL-10), C-C chemokines (macrophage inflammatory protein 1alpha [MIP-1alpha], and macrophage inflammatory protein 1beta [MIP-1beta], monocyte chemotactic and activating factor [MCAF], regulated on activation, normal T cell expressed and presumably secreted [RANTES]) and C-X-C chemokines (IL-8 and growth regulated alpha [GRO-alpha]) were examined using reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The expression rates of mRNA for IL-8, GRO-alpha, MIP-1alpha and RANTES were significantly more increased in H. pylori-positive patients than in H. pylori- negative patients. However, the expressions of IL-1beta, IL-6 and IL-10 mRNA were statistically not different between two groups. After eradication of H. pylori, expressions of mRNA for three cytokines (IL-1beta, IL-6 and IL-10), four C-C chemokines (MIP-1alpha, MIP-1beta, MCAF and RANTES) and two C-X-C chemokines (IL-8 and GRO-alpha) were significantly decreased. CONCLUSION: These results suggest that C-X-C chemokines and some C-C chemokines play important roles in H. pylori-associated peptic ulcer diseases.

Gastrite associada ao Heliocobacter pylori em adultos e crianças: estudo comparativo / Helicobacter pylori associated gastritis in adults and children: a comparative study

A reaçäo inflamatória da gastrite por H. pylori é pouco estudada em crianças. Objetivos: Analisar a reaçäo inflamatória e imune da gastrite por H. pylori em adultos e crianças, 15 com ulcera duodenal (UD) e 47 adultos, 21 com UD. A análise histológica foi feita, segundo o Sistema Sydney; o exsudato imune foi semi-quantificado; o microrganismo foi pesquisado por cultura, urease e histologia. Os genes ureA e cagA foram pesquisados por Elisa. Resultados: Em crianças, a reaçäo inflamatória predominou nos casos com UD em relaçäo àqueles sem UD (p<0,01). Nos dois grupos, a inflamaçäo predominou no antro (p<0,01), mas a atividade foi semelhante no antro e corpo. A resposta imune foi idêntica no antro e no corpo dos casos com UD. Nos adultos com UD, a inflamaçäo e a atividade foram mais intensas no antro do que no corpo (P<0,0007). A reaçäo imune predominou no antro (p<0,032) em ambos os grupos. Näo houve correlaçäo entre a colonizaçäo bacteriana e a reaçäo inflamatória e imune. Nos casos com UD, isolaram-se predominantemente cepas cagA+, em crianças (93 por cento) e adultos (83 por cento). A infecçäo por cepas cagA+ correlacionou-se com o exsudato plasmocitário (p<0,03) e com a inflamaçäo e a atividade (p<0,04) em crianças. Conclusäo: A resposta inflamatória na gastrite associada ao H. pylori é diferente em adultos e crianças. Conclusäo A resposta inflamatória na gastrite associada ao H. pylori é diferente em adultos e crianças. Conclusäo, o que pode estar relacionado com diferenças na secreçäo ácida e com aspectos evolutivos da infecçäo

The mucosal adjuvanticity of two nontoxic mutants of Escherichia coli heat-labile enterotoxin varies with immunization routes

Escherichia coli heat-labile enterotoxin (LT), which causes a characteristic diarrhea in humans and animals, is a strong mucosal immunogen and has powerful mucosal adjuvant activity towards coadministered unrelated antigens. Here we report the different mucosal adjuvanticity of nontoxic LT derivatives, LTS63Y and LTdelta110/112, generated by immunizing through two different mucosal routes. Intragastric (IG) immunization with Helicobacter pylori urease alone resulted in poor systemic IgG and IgA responses and no detectable local secretory IgA, but IG co-immunization with urease and LTdelta110/112 induced high titers of urease-specific local secretory IgA and systemic IgG and IgA, comparable to those induced by wild-type LT. LTS63Y showed far lower adjuvant activity towards urease than LTdelta110/112 in IG immunization, but was more active than LTdelta110/112 in inducing immune responses to urease by intranasal (IN) immunization. LTdelta110/112 predominantly enhanced the induction of urease-specific IgG1 levels following IG immunization, whereas LTS63Y induced high levels of IgG1, IgG2a and IgG2b following IN immunization. In addition, quantitative H. pylori culture of stomach tissue following challenge with H. pylori demonstrated a 90-95% reduction (p < 0.0002) in bacterial burden in mice immunized intranasally with urease using either mutant LT as an adjuvant. These results indicate that the mechanism(s) underlying the adjuvant activities of mutant LTs towards coadmnistered H. pylori urease may differ between the IN and IG mucosal immunization routes.

Gastrointestinal immune responses in HIV infected subjects

The gut associated lymphoid tissue is responsible for specific responses to intestinal antigens. During HIV infection, mucosal immune deficiency may account for the gastrointestinal infections. In this review we describe the humoral and cellular mucosal immune responses in normal and HIV-infected subjects.

A circulaçäo sanguínea como mecanismo de defesa da mucosa gástrica / The blood circulation as defense mechanism of gastric mucosa

O autor analisa o papel da circulaçäo sangüinea como um mecanismo de defesa da mucosa gástrica