The dual role of interleukin-25 in the control of immune-mediated pathologies.

Interleukin-25 (IL-25) plays a key role in the initiation and expansion of T helper (Th) 2 cell-mediated immune responses, thereby contributing to allergic diseases and host defense against helminthic parasites. More recent studies have however shown that IL-25 can also control the function of non-T cells, such as antigen presenting cells and endothelial cells, and reduces Th1/Th17-mediated pathologies. These new and exciting observations reveal a broader role for IL-25 than previously anticipated, and delineate various scenarios where therapeutic interventions around IL-25 activity can be imagined.