Accurate diagnosis of food allergy depends on the identification of the causative allergenic molecule(s). The proposed study intends to investigate and compare the pattern of IgE antibody sensitisation in walnut allergic subjects from three different regions of Europe (south (SEU) and central/north (C/NEU), to evaluate the diagnostic utility of a panel of novel allergen reagents.

Accurate diagnosis of food allergy depends on the identification of the causative allergenic molecule(s). Thus, full characterization of the major allergens of walnut and their clinical importance is an important undertaking.

The proposed study intends to investigate and compare the pattern of IgE antibody sensitisation in walnut allergic subjects from three different regions of Europe (south (SEU) and central/north (C/NEU), to evaluate the diagnostic utility of a panel of novel allergen reagents.

With a view towards improved in vitro diagnostic methods, we intend to evaluate the diagnostic potential of recombinant walnut allergens in patients with walnut allergy confirmed by a positive provocation or supported by a convincing history of anaphylactic reaction(s) to walnut in the past, patients with pollinosis but no symptoms of walnut allergy and non-atopic control subjects.

Inclusion Criteria:

• Signed informed consent
• Group A: positive case history of allergic reaction(s) to walnut
• Group B: positive case history of allergy to birch, grass or olive pollen and no case history of allergic reaction(s) to walnut
• Group C: no case history of atopic disease

Exclusion Criteria:

• Known pregnancy
• Breast-feeding of infant
• Treatment with the following drugs (or shortest interval between last treatment and food challenge or SPT):
• corticosteroids (2 weeks): applied systemically, to the nose or locally on the skin test area.
• antihistamines (3 days) except hydroxyzine (10 days)
• betablocker agents (1 day)
• angiotensin converting enzyme inhibitors (2 days)
• Any major organic or infectious disease