PT with heat-processed apple peel extract to detect LTP hypersensitivity

Area of Science:

• Food allergy diagnostics
• Immunology
• Allergen characterization

Background:

• Accurate allergen-resolved diagnosis is essential for food allergies, particularly those involving both labile and stable allergens.
• Current diagnostic methods lack specificity for differentiating sensitivities to various food allergens.
• Lipid transfer protein (LTP) is a stable, potentially hazardous allergen found in apples.

Purpose of the Study:

• To evaluate the clinical utility of skin prick testing (SPT) using a heat-processed apple peel extract.
• To determine if this extract can reliably detect hypersensitivity to lipid transfer protein (LTP) in apple-allergic patients.
• To establish an accessible method for identifying sensitization to stable apple allergens.

Main Methods:

• Skin prick testing (SPT) was performed on 23 apple-allergic patients using raw and heat-processed apple peel extracts.
• Patients were categorized based on IgE reactivity to birch pollen, indicating probable sensitization to labile (Mal d 1, Mal d 4) or stable (Mal d 3, LTP) allergens.
• IgE reactivity to the heat-processed extract was confirmed via immunoblot analysis.

Main Results:

• SPT with raw apple extract yielded positive results in 87% of patients.
• The heat-processed apple extract specifically induced positive SPT reactions in 100% of patients presumed to be sensitized to LTP.
• Immunoblotting confirmed IgE reactivity to a 10 kDa protein, identified as LTP, in the heat-processed extract.

Conclusions:

• The heat stability of LTP allows for the development of specific diagnostic extracts.
• Heat-processed apple peel extract is a clinically useful tool for in-vivo allergen-resolved diagnosis of LTP hypersensitivity.
• This method offers a practical approach to identifying patients at risk from stable apple allergens.