Passive cutaneous anaphylaxis in guinea pigs elicited by gastric absorption of dextran induced by acetylsalicylic acid.

Passive cutaneous anaphylaxis (PCA) was elicited in guinea pigs sensitized with rabbit antidextran by the absorption of dextran macromolecules from the stomach induced by intragastric acetylsalicylic acid. The gastric contents had a pH sufficiently low to maintain the acid mainly in the unionized form since it is the latter which alters gastric permeability. The acid concentration required to induce PCA was below that which caused mucosal cell loss or bleeding. The maximal molecular weight of the absorbed dextran was approximately 25,000. Dextran was chosen as antigen because of its well-characterized physical and immunological properties. It is suggested that ingestion of acetylsalicylic acid may contribute to sensitization and allergic reactions to antigenic food materials by facilitating their absorption from the stomach.