IL4 and infection: Interleukin-4 (IL-4), a multifunctional pleiotropic cytokine mainly produced by activated T helper 2 (Th2) cells, plays important roles as a mediator and modulator of immune and inflammatory responses [9]; it is not only involved in humoral and cell-mediated immunity, but also an essential regulator in the immune response of B cells, T cells, and macrophages to fight against infections and malignant cells [10]; Th2 diseases are, in their majority, driven by IL-4 [11].