چکیده (انگلیسی):

Successful allergen-specific immunotherapy (AIT) is associated with a marked decrease in symptoms on allergen
exposure, a reduced requirement for ‘rescue’ anti-allergic drugs and improvement in patients’ quality of life.
These benefits persist for at least several years following discontinuation of immunotherapy - the hallmark of
clinical and immunological tolerance. AIT has been shown to modulate both innate and adaptive immunological
responses. Early suppression of innate effector cells of allergic inflammation (mast cells, basophils), regulation
of pro-allergic T helper 2 type (Th 2) responses and IgE+ B cell responses have been shown to occur both in
the tissue and in the peripheral blood during AIT. The allergen-tolerant state is associated with local and systemic
induction of distinct populations of allergen-specific T regulatory cells including IL-10+ Tregs (Tr1 cells),
TGF-β+ Tregs and FoxP3+ memory T regs. B cells are switched in favour of producing IgG (particularly IgG4)
antibodies and associated blocking activity for IgE-dependent events, including basophil activation and IgEfacilitated
allergen binding to B cells. An induction of IL-10+ B regulatory cells and alterations in dendritic cell
subsets have also recently been described. These events are followed by the induction of T regulatory cells,
suppression of allergen-specific T cell proliferation and immune deviation from Th2 in favour of Th1 responses.
Alternative mechanisms of tolerance include apoptosisdeletion of antigen-specific memory Th2 cells andor a
failure of co-stimulation leading to T cell anergy.