Immediate hypersensitive reactions to the ingestion of egg white and IgE binding to the egg white components

IgE is considered to be involved in immediate hypersensitive reactions (IHR) following egg ingestion. IgE antibody levels to egg-white (EW) antigens in the IHR-positive group (n = 19, mean age +/- SD = 5.2 +/- 4.5 yr) were higher than those in the IHR-negative group (n = 13, mean of age +/- SD = 3.6 +/- 2.2 yr). However, even in the IHR-negative group, some patients showed high IgE to EW. RAST inhibition tests with heat-treated (100 degrees C, 5, 10, and 30 min) egg-white antigens were performed on 13 serum samples from subjects with IHR and 9 serum samples from subjects without IHR. Heat treatment decreased the IgE-binding activity of egg white and it was speculated that IgE from IHR-negative subjects bound to relatively heat-unstable sites of egg-white antigens. Furthermore, we selected IHR-negative subjects (n = 8, mean of age +/- SD = 3.0 +/- 1.7 yr) with higher IgE antibody levels than the lowest limit of IgE to EW of the IHR-positive group and compared IgE to ovomucoid (OM), ovalbumin (OA), conalbumin (CA), and lysozyme (Ly) between these IHR-negative and positive groups. IgE-binding activities to egg-white components, including OA, CA, and Ly but not OM, were significantly decreased with heat treatment. The IHR-negative group showed significantly lower IgE to OM (untreated, 5, 10, 30 min treatment) and 5 min treated OA alone than the IHR-positive group, while no difference was found in IgE to other components between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)