Inhibition of the allergic response by regulatory T cells.

PURPOSE OF REVIEW: Allergic diseases are caused by the overdevelopment of T-helper type 2 biased immune responses in susceptible individuals. A number of recent studies indicate that regulatory T cells play an important role in controlling such T-helper type 2 biased responses not only in animal models, but in humans as well, and these will be reviewed in this article.

RECENT FINDINGS: A family of regulatory cells appears to be involved in regulating allergies. Both naturally occurring CD4CD25 regulatory T cells and inducible forms of antigen-specific regulatory T cells, both expressing the transcription factor foxp3, have been shown to inhibit the inappropriate immune responses involved in allergic diseases. Impaired expansion of natural or adaptive regulatory T cells is hypothesized to lead to the development of allergy, and treatment to induce allergen-specific regulatory T cells could provide curative therapies for allergy and asthma.

SUMMARY: Allergen-specific regulatory T cells play an important role in controlling the development of allergy and asthma.