Consistent with previous findings that chronic Echinococcus infection modulates host immunity by inducing the proliferation of Treg cell proliferation [44,45], we found a significant expansion of CD4+ FoxP3+ Treg cells in the E. multilocularis infection model (Figure 2a); this indicates that immune suppression was induced by the helminth infection. This evidence concerns the gene FOXP3 and helminthiasis.