Scientific Study

Almond (Prunus dulcis) is widely used as a human food due to its flavor, nutrients, and health benefits, but it is also one of the most likely tree nuts to trigger allergies. Almond allergens, though, have not been studied as extensively as those of peanuts and other selected tree nuts. This work presents an update of the molecular properties of almond allergens to clarify some confusion about the identities of almond allergens and our perspective on characterizing putative almond allergens. Presently, the following almond allergens have been designated by the WHO/IUIS Allergen Nomenclature Sub-Committee: Pru du 3 (a non-specific lipid transfer protein 1, nsLTP1), Pru du 4 (a profilin), Pru du 5 (60S acidic ribosomal protein 2), Pru du 6 (an 11S legumin known as prunin), and Pru du 8 (an antimicrobial protein with cC3C repeats). Besides, almond vicilin and almond γ-conglutin have been identified as food allergens, although further characterization of these allergens is still of interest. In addition, almond 2S albumin was reported as a food allergen due to the misidentification of Pru du 8. Two more almond proteins have been called allergens based on their sequence homology with known food allergens and their 'membership' in relevant protein families that contain allergens in many species. These include the pathogenesis related-10 protein (referred to as Pru du 1) and the thaumatin-like protein (referred to as Pru du 2). Almonds thus have 5 known food allergens and five more likely ones that need to be investigated further.