T-cell Subset Regulation in Atopy

Presentation of processed allergen by antigen-presenting cells to T-helper (Th) lymphocytes, which is influenced costimulatory signals, cytokines, chemokines, and regulatory T cells (Tregs), determines the development of different types of T-cell immunity. The discovery of Tregs revolutionized the primary concepts of immune regulation interpreted within the framework of a binary Th1/Th2 paradigm. Tregs play a central role in the maintenance of peripheral homeostasis, the establishment of controlled immune responses, and the inhibition of allergen-specific effector cells. Recently, some other T-cell subsets appeared, including Th17 and Th9 cells, which control local tissue inflammation through upregulation of proinflammatory cytokines and chemokines. This review aims to discuss our understanding of the T-cell subset reciprocal interaction in atopy.