Skin tests with native, depigmented and glutaraldehyde polymerized allergen extracts

Area of Science:

• Allergen immunotherapy
• Clinical immunology
• Dermatology

Background:

• Standardized allergen extracts are crucial for accurate allergy diagnosis and monitoring treatment efficacy.
• Investigating modified allergen extracts can improve immunotherapy safety and effectiveness.

Purpose of the Study:

• To compare the in vivo and in vitro characteristics of three types of allergen extracts: native (N), depigmented (DP), and polymerized depigmented (DPP).
• To evaluate allergen extracts from Timothy grass (Phleum pratense), olive (Olea europaea), parietaria (Parietaria judaica), and dust mite (Dermatophagoides pteronyssinus).

Main Methods:

• Adult patients underwent duplicate skin prick testing with N, DP, and DPP extracts.
• Dose-response relationships were analyzed to determine the 10 histamine equivalent prick (HEP) dose for each extract type.
• In vitro analyses included major allergen quantification and specific IgE/IgG inhibition assays.

Main Results:

• Polymerized depigmented (DPP) extracts consistently required higher concentrations to elicit a wheal response compared to native (N) and depigmented (DP) extracts across all allergens.
• For example, D. pteronyssinus DPP required 2.11 mg, significantly more than N (0.20 mg) and DP (0.15 mg).

Conclusions:

• Polymerized depigmented allergen extracts exhibit significantly lower allergenicity in vivo.
• This reduced allergenicity suggests a potential for improved safety, enabling higher immunotherapy doses over shorter treatment durations.