lewis-x-antigen and Peptic-Ulcer

Helicobacter pylori is a Gram-negative bacterium that infects over 50% of the world's population. This organism causes various gastric diseases such as chronic gastritis, peptic ulcer, and gastric cancer. H. pylori possesses lipopolysaccharides that share structural similarity to Lewis blood group antigens in gastric mucosa. Such antigenic mimicry could result in immune tolerance against antigens of this pathogen. On the other hand, H. pylori colonizes gastric mucosa by utilizing adhesins that bind Lewis blood group antigen-related carbohydrates expressed on gastric epithelial cells. After colonization, H. pylori induces acute inflammatory responses mainly by neutrophils. This acute phase is gradually replaced by a chronic inflammatory response. In chronic gastritis, lymphocytes infiltrate the lamina propria, and such infiltration is facilitated by the interaction between L-selectin on lymphocytes and peripheral lymph node addressin (PNAd), which contains 6-sulfo sialyl Lewis X-capped O-glycans, on high endothelial venule (HEV)-like vessels. H. pylori barely colonizes gland mucous cell-derived mucin where alpha1,4-GlcNAc-capped O-glycans exist. In vitro experiments show that alpha1,4-GlcNAc-capped O-glycans function as a natural antibiotic to inhibit H. pylori growth. These findings show that distinct sets of carbohydrates expressed in the stomach are closely associated with pathogenesis and prevention of H. pylori-related diseases, providing therapeutic potentialities based on specific carbohydrate modulation.

Topics: Adhesins, Bacterial; Animals; Chronic Disease; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; L-Selectin; Lewis X Antigen; Lipopolysaccharides; Molecular Mimicry; Mucin-2; Neutrophils; O Antigens; Oligosaccharides; Peptic Ulcer; Polysaccharides; Sialyl Lewis X Antigen; Stomach Neoplasms

Helicobacter pylori (H. pylori) infection is a pathogenic agent of gastric diseases, but their mechanisms are unclear. Effects of ammonia, tumor necrosis factor (TNF), and anti-Lewis autoantibodies induced after H. pylori infection on the development of gastric diseases were investigated. Ammonia disturbed the collagen metabolism in the ulcer base. Soluble TNF receptors regulate the action of TNF. The involvement of anti-Lewis autoantibodies in the development of peptic ulcer might be unlikely. Moreover, H. pylori-specific IgA in gastric juice and TNFalpha gene polymorphism in persons infected with H. pylori were studied. According to H. pylori-specific IgA titer in gastric juice, persons were divided into two histologically and endoscopically different states of disease. TNFA -857 single nucleotide polymorphism (SNP) may be associated with rugal hyperplastic gastritis and gastric carcinomas without severe atrophy. However, complete elucidation of pathogenic mechanisms of H. pylori-induced gastric diseases requires further research.

Topics: Ammonia; Animals; Antibodies; Helicobacter Infections; Helicobacter pylori; Humans; Immunoglobulin A; Lewis Blood Group Antigens; Lewis X Antigen; Peptic Ulcer; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Stomach Diseases; Tumor Necrosis Factor-alpha

In this study, we found Lewis X (Le(x)) determinants on 68% of Helicobacter pylori isolates from patients with chronic gastroduodenal diseases. Anti-Le(x) IgG were detected more frequently in the sera from dyspeptic children and adults (45 and 46%), with or without proved (culture) H. pylori infection, than in the sera from healthy individuals (14% and 25%). In contrast, the prevalence of anti-Le(x) IgM was higher in the groups of healthy individuals than in the groups of dyspeptic patients. Moreover, anti-Le(x) monoclonal antibody of IgM class enhanced the uptake of Le(x)(+) but not Le(x)(-) H. pylori isolates by phagocytes. In the sera from some dyspeptic patients, we detected Le(x)-anti-Le(x) IgG immune complexes (Le(x) ICs). There was a great difference between children and adults as regards the presence of Le(x) ICs. The immune complexes were found in the sera from nine out of 29 (27%) H. pylori-infected and three out of eight (37%) uninfected adult dyspeptic patients. In comparison, Le(x)-anti-Le(x) IgG ICs were detected only for two out of 18 (11%) H. pylori-infected children. Le(x) ICs were not found in the sera from healthy individuals. Our results suggest that anti-Le(x) IgM may play a protective role in H. pylori infections. In contrast, anti-Le(x) IgG and particularly Le(x)-anti-Le(x) IgG ICs might contribute to the pathogenesis of chronic H. pylori infections.

Topics: Adolescent; Adult; Aged; Antigens, Bacterial; Bacterial Proteins; Child; Dyspepsia; Helicobacter Infections; Helicobacter pylori; Humans; Immunoglobulin G; Lewis X Antigen; Middle Aged; Peptic Ulcer; Phagocytosis

We examined whether anti-Lewis x (Le(x)) and y (Le(y)) autoantibodies affect the pathogenesis of Helicobacter pylori-induced peptic ulcers. Of 11 patients with peptic ulcers, 10 patients had both anti-Le(x) and -Le(y) immunoglobulin G (IgG) antibodies, and 1 patient had only anti-Le(x) antibody. After successful eradication, we measured the serum titer of anti-Le(x) and -Le(y) antibodies. Six patients had a reduction of the titers of anti-Le(x) and/or -Le(y) antibodies, whereas no notable changes were detected in 5 patients in the follow-up. This result suggests that anti-Le(x) and -Le(y) autoantibodies had no critical role in the development of H. pylori-induced peptic ulcer.

Topics: Autoantibodies; Follow-Up Studies; Helicobacter Infections; Helicobacter pylori; Humans; Immunoglobulin G; Lewis Blood Group Antigens; Lewis X Antigen; Lipopolysaccharides; Peptic Ulcer; Recurrence