Immunotherapy with allergens
R. W. Weber
Allergen immunotherapy has been shown to be efficacious in numerous studies
for the clinical indications of allergic asthma and rhinitis, as well as
hymenoptera venom hypersensitivity. How allergen immunotherapy improves
clinical symptoms is still not entirely clear. Decreases in specific IgE
follow a complex cascade of effects: a shifting of the cytokine milieu from
T(H)2 to T(H)1 predominance, with resultant decrease in interleukin 4,
decreased recruitment and activation of eosinophils, and decreased
proliferation of mast cells. Allergen exposure has a lessened ability to
stimulate an inflammatory cell response, with decreased target organ
hyperreactivity. Since allergen immunotherapy is not without risk, the
decision needs to be made whether injection therapy is safe and provides
benefit not achievable by medical management. The continued clarification
of optimal allergen concentrations through careful studies of standardized
extracts will allow better control of adverse events by limiting
unnecessarily potent mixtures.