Table II. Advantages and disadvantages of natural allergen extracts and recombinant/synthetic allergen molecules.

Natural allergen extracts

Advantages

• Preparation without extensive purification steps

• Contain several allergens of the allergen source

• Often reflect the allergen contents of the natural allergen sources

• Are already on the market with old authorizations

• Known to allergologists as traditional products

Disadvantages/limitations

• May contain nonallergenic components with different properties

• May be contaminated with allergens from other sources

• May present variable contents and ratios of allergens

• May present batch-to-batch variations due to manufacturing procedures and raw materials

• May be unstable and degrade

• Contents cannot be fully influenced by the manufacturer but are determined by the raw material

• Do not provide molecular information when used for diagnosis

• May cause allergic reactions on administration

• May not fulfill modern regulatory requirements for medicinal products

• May contain infectious materials

Recombinant/synthetic allergen molecules

Advantages

• Pure proteins/peptides of defined properties and quality

• Manufactured according to good manufacturing practice

• Can be produced in defined amounts and concentrations in reproducible manner

• Fulfill regulatory requirements for medicinal products, modern drugs, and vaccines

• Allergenic, immunogenic, and tolerogenic properties are predefined

• Allow specific targeting of immune mechanisms (eg, IgG induction, tolerance induction)

• Allow patient-tailored treatment

• Multiple advantages when used for diagnosis (ie, identification of culprit allergen molecules, revealing cross-reactivity, providing molecular profiles)

• Provide detailed diagnostic test information

• Production is independent of allergen raw materials

• Can be produced at costs comparable to natural allergen extracts

• Biologically safe due to GMP production

Possible disadvantages

• Require knowhow

• Require modern recombinant or synthetic production process

• Require new market authorization and clinical studies

• Need to produce different components

GMP, Good manufacturing practice.