Mice infected with Hymenolepis diminuta [46] and treated with the adult worm extract [47] or treated with IL-4/IL-13–differentiated M2 macrophages [44] have significantly reduced pathology in experimentally induced colitis; this protective effect is abrogated when IL-10 [46] or macrophages [44] are depleted. The gene discussed is IL4; the disease is colitis.