[Assessment of allergenic activity of heated and ovomucoid-depleted egg white]

We investigated allergenic activity of heated and ovomucoid (OM)-depleted egg white by RAST inhibition tests, skin tests and and oral challenge tests. Freeze-dried egg white, OM and ovalbumin (OA) were coupled with CNBr-activated paper discs. Freeze-dried, heated, and heated and OM-depleted egg white antigens were used as inhibitors in RAST inhibition tests. Freeze-dried egg white significantly inhibited the IgE-binding to freeze-dried egg-white-, OM- and OA-discs. Heated egg white showed a significant inhibition against only OM-disc, but heated and OM-depleted egg white didn't effectively suppress IgE-binding to all discs. Fifty-six patients were subjected for skin tests and 27 patients for oral challenge tests with freeze-dried egg white, heated egg white and heated and OM-depleted egg white. Eighteen of 25 subjects with positive prick tests results to freeze-dried egg white showed negative results to heated egg white. Four of 7 cases with positive prick test results to heated egg white gave negative results to heated and OM-depleted egg white. 20-minutes patch tests showed almost similar results to prick tests. Four of 8 subjects showing positive oral challenge tests with freeze-dried egg white were negative to heated egg white. All of 4 with positive oral challenge tests by heated egg white were negative results to heated and OM-depleted egg white. These evidence indicated that heated and OM-depleted egg white was more hypoallergenic than heated egg white.