Antacid medication inhibits digestion of dietary proteins and causes food allergy: a fish allergy model in BALB/c mice.
BACKGROUND
Digestible proteins were supposed to be irrelevant for oral sensitization and induction of food allergy. Approximately 10% of the adult population uses antacids for the treatment of dyspeptic disorders, drugs that hinder peptic digestion. In these patients, proteins that are normally degradable might act as food allergens.


OBJECTIVE
We aimed to study the influence of antacid intake on the allergenicity of dietary proteins, taking sturgeon caviar and parvalbumin, the major fish allergen, as examples.


METHODS
Caviar proteins and recombinant parvalbumin from carp, rCyp c 1, were applied for intragastric feedings with or without the antacids sucralfate, ranitidine or omeprazole, using a Balb/c mouse model.


RESULTS
Both caviar proteins and parvalbumin were rapidly degraded in an in vitro digestion assay at pH 2.0, but not at pH 5.0, imitating the effect of antacids. The groups fed with caviar in combination with ranitidine hydrochloride intramuscularly or sucralfate orally had significant levels of caviar-specific IgE antibodies (P <.01), T-cell reactivity, and elevated counts of gastrointestinal eosinophils and mast cells. Food allergy in these groups was further evidenced by oral provocation tests and positive immediate-type skin reactivity. In contrast, feedings with caviar alone led to antigen-specific T-cell tolerance. None of the groups showed immune reactivity against the daily mouse diet. As a proof of the principle, feeding mice with parvalbumin in combination with ranitidine or omeprazole intramuscularly induced allergen-specific IgE antibodies (P <.05).


CONCLUSIONS
When antacid medication impairs the gastric digestion, IgE synthesis toward novel dietary proteins is promoted, leading to food allergy.
D000284:Administration, Oral; D000328:Adult; D000485:Allergens / Q000008:administration & dosage / Q000276:immunology; D000818:Animals; D000863:Antacids / Q000009:adverse effects*; D052179:Antigens, Plant; D002135:Calcium-Binding Proteins / Q000008:administration & dosage / Q000276:immunology; D004044:Dietary Proteins / Q000276:immunology / Q000378:metabolism*; D004063:Digestion / Q000187:drug effects*; D004195:Disease Models, Animal; D004804:Eosinophils / Q000276:immunology; D005260:Female; D029941:Fish Proteins; D005399:Fishes / Q000276:immunology; D005512:Food Hypersensitivity / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D005753:Gastric Mucosa / Q000276:immunology / Q000648:ultrastructure; D006801:Humans; D007073:Immunoglobulin E / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008407:Mast Cells / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008854:Microscopy, Electron; D010320:Parvalbumins / Q000008:administration & dosage / Q000276:immunology; D012882:Skin Tests; D013601:T-Lymphocytes / Q000276:immunology
D000485:Allergens; D000863:Antacids; D052179:Antigens, Plant; D002135:Calcium-Binding Proteins; C454159:Cyp c 1.01 protein, carp; D004044:Dietary Proteins; D029941:Fish Proteins; D010320:Parvalbumins; D007073:Immunoglobulin E