Q:

8/1/2013
How clinically significant is corn allergy, and what cross-reactivities exist?

A:

Thank you for your inquiry.

Corn allergy is not common but clearly exists and can be significant in a given patient. There is extensive in vitro cross-reactivity between corn and other foods. The clinical significance of this cross-reactivity has not been clearly established, but in vitro cross-reactivity has been demonstrated to many cereal grains. In descending order of the degree of cross-reactivity, they are wheat, triticale, rye, barley, oat, rice, and maize. In addition, IgE-binding proteins to corn have shown cross-reactivity to rice, soybean, and peanut.

One of the major allergens in corn is a lipid transfer protein, and a high degree of cross-reactivity has been found between this protein and the lipid transfer proteins of peach, apple, walnut, hazelnut, peanut, rice, sunflower seed, French bean, and apricot.

However, it should be emphasized, as mentioned above, that this in vitro demonstration of cross-reactivity does not necessarily have clinical importance. Unfortunately, there are no definitive studies to establish the given importance of any of these cross-reactions in patients who have experienced anaphylactic reactions to corn. Therefore these studies give us very little practical guidance as to what foods a person who has corn allergy should avoid.

In sum, although extensive in vitro cross-reactivity exists between corn and other food allergens, the practical importance of this cross-reactivity has not been elucidated, and from a practical standpoint, we do not normally counsel avoidance of these foods in a corn-allergic patient, unless there is some clinical evidence to do so.

Thank you again for your inquiry and we hope this response is helpful to you.

References:
1 Lehrer SB, Reese G, Malo JL, Lahoud C, Leong-Kee S, Goldberg B, Carle T, Ebisawa M. Corn allergens: IgE antibody reactivity and cross-reactivity with rice, soy, and peanut. Int Arch Allergy Immunol 1999;118(2-4):298-9.
2. Block G, Tse KS, Kijek K, Chan H, Chan-Yeung M. Baker's asthma. Studies of the cross-antigenicity between different cereal grains. Clin Allergy 1984;14(2):177-85.
3. Asero R, Mistrello G, Roncarolo D, Amato S. Detection of some safe plant-derived foods for LTP-allergic patients. Int Arch Allergy Immunol 2007;144(1):57-63.

Sincerely,
Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology