Abstract

The role of the innate immune system in asthma initiation is being increasingly recognised, and several innate epithelial cytokines, such as interleukin 33 (IL-33), IL-25 and thymic stromal lymphopoietin, have been described as important in asthma pathogenesis. However, until now, the mechanism by which these cytokines initiate Th2 responses and form a link with the adaptive immune system was undetermined. The recent discovery of a new group of non-T, non-B innate helper cells, which are induced by epithelial innate cytokines and secrete the Th2 cytokines IL-4 and IL-13, may provide a mechanism by which the innate and adaptive immune systems become activated in asthma.