TSLP and infection: This canonical helminth-induced Th2 response comprises increased secretion of molecules, such as interleukin (IL)-4, IL-5 and IL-13 [3] as well as recently uncovered tissue-derived cytokines like IL-25 [4], IL-33 [5] and thymic stromal lymphopoietin (TSLP): [6] the latter three are produced early in infection, creating a local microenvironment in which T cells can fully polarize into Th2 cells.