Abstract
Atopic dermatitis (AD) is associated with the effects of T helper type 2 (Th2) and Th22 cytokines. Recent studies, however, have also implicated Th17 in acute AD. Functional studies of Th2 and Th22 cytokines revealed their roles in generating molecular changes during AD; IL-17A's role, however, has yet to be defined. The report by Nakajima et al. (this issue) begins to define that role by demonstrating IL-17A's ability to induce Th2 inflammation in acute disease.