BOOSTED SYSTEMIC IMMUNE AND LOCAL RESPONSIVENESS AFTER INTESTINAL INFLAMMATION IN ORALLY SENSITIZED GUINEA-PIGS

Background & Aims: Intestinal inflammation resulting in disruption of the mucosal barrier function has been proposed as a cause of increased incidence of allergic diseases. This study was designed to evaluate w hether intestinal inflammation is able to change the immune responsive ness to sensitization and antigen challenge responses. Methods: Guinea pigs orally sensitized to cow's milk proteins were either treated or not treated with trinitrobenzenesulfonic acid (TNBS) to induce intesti nal inflammation and compared with control animals (not sensitized). S ystemic immune and local responsiveness to antigen challenge were asse ssed by measuring antibody serum titers, colonic fluid secretion, muco sal histamine level, and mucus depletion. Intestinal permeability was evaluated from Cr-51-ethylenediaminetetraacetic acid (EDTA) recovery a nd beta-lactoglobulin serum level. Results: Immunoglobulin E titers we re higher in TNBS treated animals than in non-TNBS-treated sensitized animals. Antigen challenge in TNBS treated animals induced a fourfold increase of colonic secretion and greater histamine and mucus depletio n than in non-TNBS-treated animals. Permeability to Cr-51-EDTA increas ed 5 days after TNBS treatment but was unchanged after antigen challen ge. In contrast to controls, beta-lactoglobulin was not detected in th e sera of challenged sensitized and TNBS-treated animals. Conclusions: Intestinal inflammation increasing gut permeability enhances the sens itization process. Therefore, local anaphylactic reactions are exacerb ated after antigen challenge.