Allergen-specific immunotherapy - how does it work?

Allergen immunotherapy was introduced by Leonard Noon 100 years ago and is the only disease-modifying treatment for allergic individuals (Allergy, 2012). Allergen-specific immunotherapy is a desensitizing therapy for allergic diseases. It is potentially curative and specific method of treatment.

The mechanisms of action of allergen-specific immunotherapy include:

- early desensitization
- modulation of T-and B-cell responses and related antibody isotypes
- modulation of migration of eosinophils, basophils, and mast cells to tissues, and the release of their mediators


Mechanisms of allergen-specific immunotherapy (click to enlarge the image). The diagram is based on: Mechanisms of allergen-specific immunotherapy. Akdis CA, Akdis M. J Allergy Clin Immunol. 2011 Jan;127(1):18-27.

Regulatory T (Treg) cells are key regulators of peripheral tolerance to allergens. Skewing of allergen-specific effector T cells to a regulatory phenotype is a key in healthy immune response to allergens and successful outcome of allergen-specific immunotherapy.

Naturally occurring forkhead box protein 3-positive CD4(+)CD25(+) Treg cells and inducible T(R)1 cells contribute to the control of allergen-specific immune responses by:

- suppression of dendritic cells that support the generation of effector T cells
- suppression of effector T(H)1, T(H)2, and T(H)17 cells
- suppression of allergen-specific IgE and induction of IgG4
- suppression of mast cells, basophils, and eosinophils
- suppression of effector T-cell migration to tissues

New strategies for immune intervention will likely include targeting of effector and Treg cell subsets.



References:

Mechanisms of allergen-specific immunotherapy. Akdis CA, Akdis M. J Allergy Clin Immunol. 2011 Jan;127(1):18-27.

Subcutaneous Immunotherapy (SCIT)

Epicutaneous allergen-specific immunotherapy. Skin patches coated with allergens to treat hay fever - check the caveats too listed by WSJ and JACI, 2011.

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