ABSTRACT
Current thinking traces the development of allergic asthma from initial sensitization of naive T-helper (Th) cells (Th0) to environmental allergens through the expression and expansion of chronic allergen-mediated Th2-driven inflammation in the airway mucosa. Thus, T cells are at the epicenter of these responses, in large part because of their ability to synthesize and secrete an array of cytokines that are essential for acute and chronic allergic inflammation, be it in the airways, skin, nose, eyes, or intestine. CD4 T cells have been implicated as the principal cell type, and the Th2 cytokines they release include interleukin-4 (IL-4), IL-5, IL-6, IL-9, IL-10, IL-13, and granulocyte-macrophage colony stimulating factor (GM-CSF). There is increasing evidence that CD8 T cells (Tc2 cells), through release of IL-4 and IL-5, may also be involved in allergic diseases.
