Allergenic molecules
A number of wheat allergens have been identified; some are involved in the development of respiratory allergies and others in the development of wheat food allergy (7).
In a study that investigated the IgE reactivity of different wheat recombinant allergens using serum from 22 patients that suffered from wheat respiratory allergy, the results showed that 91% of sera recognized wheat CAP. The six individual wheat recombinant allergens (thioredoxin H, serine proteinase inhibitor, glutathione transferase, profilin, dehydrin and 1-cis-peroxyredoxine) were recognized between 4.5 and 32% of serum samples (7). Profilin is a common cross-reactive allergen that is present in wheat seeds, wheat pollen and other grass pollens including timothy (7). The recombinant versions of the timothy grass allergens Phl p 1 and Phl p 5 were identified as marker allergens specific for grass pollen allergy (7).
This table, adapted from Allergome.org (8), shows allergens identified in wheat pollen.
Cross-reactivity
Cross-reactivity has been reported between wild grass and cereal pollen; cultivated maize, rice, wheat, rye, barley and oats, can induce symptoms in individuals sensitized to grass pollen (1). Cross-reactivity with common grass species (Anthoxanthum odoratum, Dactylis glomerata, Lolium perenne, Poapratensis and Phleum pratense) has been shown (9).
The Zea mays allergen 25 (Zea m 25) exhibits high IgE cross-reactivity with the T. aestivum allergen 25 (Tri a 25) (Weichel et al, 2006) while rice pollen shows weak cross-reactivity with wheat (1).
Profilin is recognized as a cross-reactive allergen in patients with baker’s asthma, food and pollen allergy (7).
