Background: Impairment of gastric digestion due to pH elevation increases the risk for food allergy induction. As patients after Roux-en-Y gastric bypass (RYGB) surgery have lower gastric acidity and less gastric gland secretion, we aimed to analyse in a prospective study the effect of limiting gastric digestion capacity by surgical intervention on the immune response towards allergens.
Methods: Nine patients undergoing RYGB surgery for morbid obesity and one control patient having undergone surgery for treatment of an incisional hernia were enrolled in the study. Before and 1, 3, 6, 9 and 12 months after surgery, blood was collected for analysis of specific IgE antibodies, and patients were subjected to skin prick testing with 16 food and 18 aeroallergens.
Results: Skin prick test results revealed an increase of positive reactions indicating sensitisations towards the tested food and aeroallergens in 77.8 and 88.9 % of the patients, respectively, after surgical elimination of gastric digestion. These results were in line with elevated titers of food- and aeroallergen-specific IgE antibodies in 7 out of 9 (7/9) and 5/9 patients, respectively, after RYGB surgery. Serum cytokine levels revealed a mixed response for IFN-γ and were mostly beneath detection limit for IL-4.
Conclusion: A change of IgE reactivity pattern occurred after impairment of gastric digestion due to surgical elimination underlining the important gastric gatekeeping function during oral sensitisation. Even though this study indicates an increased allergy risk for gastric bypass patients, further studies are needed to investigate in-depth the immunological changes associated with RYGB surgery.
Keywords: Bariatric surgery; Food specific IgE; Laparoscopic gastric bypass; Sensitisation; Skin prick test.