Allergenic extract

Allergenic extracts are complex mixtures of proteins, glycoproteins, and other organic molecules derived from natural sources such as pollens, dust mites, animal dander, fungi, or insect venoms (FDA, 2023). These mixtures are primarily used in allergen immunotherapy (AIT) to desensitize the immune system of individuals suffering from Type I hypersensitivities, such as allergic rhinitis and asthma (StatPearls, 2023). The biological function of these extracts in a clinical setting is to modulate the immune system toward a state of tolerance rather than hypersensitivity (J Allergy Clin Immunol, 2014). This therapeutic process involves shifting the immune response from a Th2-dominated profile to a Th1-dominated profile and inducing the production of regulatory T cells (Tregs) (PubMed, 2017). Additionally, the administration of these extracts stimulates the secretion of 'blocking' antibodies, specifically IgG4, which compete with IgE for allergen binding to prevent mast cell degranulation (WAO Journal, 2021). While highly effective, these complex mixtures present significant challenges in standardization and carry a risk of inducing severe systemic allergic reactions or life-threatening anaphylaxis (NIH, 2022).

Other names

Allergen mixtureComplex allergen mixtureEnvironmental allergenPollen extractStandardized allergenic extractVenom extract

Allergen immunotherapy (AIT) utilizes these extracts to induce peripheral T-cell tolerance, increase the population of regulatory T cells (Tregs), and promote a shift from a Th2-dominated to a Th1-dominated immune response, while also stimulating the production of allergen-specific IgG4 blocking antibodies (J Allergy Clin Immunol, 2014; PubMed, 2017).