Peanuts and tree nuts are two of the most common elicitors of
immunoglobulin E (
IgE)-mediated
food allergy.
Nut allergy is frequently associated with systemic reactions and can lead to potentially life-threatening respiratory and circulatory symptoms. Furthermore,
nut allergy usually persists throughout life. Whether sensitized patients exhibit severe and life-threatening reactions (e.g.,
anaphylaxis), mild and/or local reactions (e.g., pollen-
food allergy syndrome) or no relevant symptoms depends much on
IgE recognition of digestion-resistant class I food
allergens,
IgE cross-reactivity of class II food
allergens with respiratory
allergens and clinically not relevant plant-derived
carbohydrate epitopes, respectively. Accordingly, molecular
allergy diagnosis based on the measurement of
allergen-specific
IgE levels to
allergen molecules provides important information in addition to provocation testing in the diagnosis of
food allergy. Molecular
allergy diagnosis helps identifying the genuinely sensitizing nuts, it determines
IgE sensitization to class I and II food
allergen molecules and hence provides a basis for personalized forms of treatment such as precise prescription of diet and
allergen-specific
immunotherapy (AIT). Currently available forms of nut-specific AIT are based only on
allergen extracts, have been mainly developed for peanut but not for other nuts and, unlike AIT for respiratory
allergies which utilize often subcutaneous administration, are given preferentially by the oral route. Here we review prevalence of
allergy to peanut and tree nuts in different populations of the world, summarize knowledge regarding the involved nut
allergen molecules and current AIT approaches for
nut allergy. We argue that nut-specific AIT may benefit from molecular subcutaneous AIT (SCIT) approaches but identify also possible hurdles for such an approach and explain why molecular SCIT may be a hard nut to crack.