[Delayed appearance of symptoms in immediate hypersensitivity: type I sensitization to galactose-α-1,3-galactose].

Delayed immediate-type allergy to innards and red meat can be mediated by IgE antibodies to galactose-α-1, 3-galactose (α-Gal). Apart from humans and Old World apes, α-Gal is ubiquitously expressed in glycoproteins and glycolipids. Thus, as α-Gal is immunogenic for humans, they can be easily sensitized even through a tick bite. Anti-α-Gal IgG represents approximately 1% of total IgG; IgE antibodies to α-Gal are comparably rare. However, in these patients, consuming red meat and especially innards can lead to the development of immediate type reactions such as urticaria. Cetuximab is a humanized IgG1 antibody containing murine α-Gal. Therefore, allergic reactions may occur with its first administration.