Validation of short-term skin-sensitizing IgG antibodies to egg in atopic dermatitis by Prausnitz-Küstner (P-K) and oral P-K tests

抄録

We tried to evaluate the role of IgG antibodies in the wheal and flare reaction of infantile atopic dermatitis by in vivo skin-sensitizing methods. Sera from 49 patients under 6 years of age were heated at 56°C for 30min to inactivate IgE antibodies, according to previous reports. Two-fold serial dilutions of the heated serum were injected intracutaneously in both forearms of a non-allergic recipient. One hour later, the whole egg antigen (1:1000) was injected in the serum transfer sites of an arm and the reaction was read at 15min (IgG Prausnitz-Küstner (P-K) test). Immediately afterwards, a raw hen's egg was swallowed by the recipient and the serum transfer sites of the other arm were observed for 2h (oral IgG P-K test). Three patients under 1 year of age showed an immediate wheal and flare reaction in the IgG P-K test, but none of the patients showed a positive reaction in the oral IgG P-K test. The patients with a positive IgG P-K test had an IgE radioallergosorbent test (PAST) score >4 to egg white and a positive IgE P-K titer of >2⁸ to whole egg antigen. Two patients showed a positive reaction to the oral IgE P-K test to raw egg ingestion. Ovalbumin-specific IgG₁, IgG₃ and IgG₄ antibodies were assayed in 20 patients. IgG₁ and IgG₃ antibodies were significantly increased in two patients with a positive IgG P-K test, while levels of the IgG₄ antibody in positive patients were not significantly increased in comparison with levels in negative patients. In conclusion, these results suggest that the IgG antibody may play a role in the immediate type allergic reaction in infantile atopic dermatitis.