IL4 and leishmaniasis: One of the most discussed immunological aspects of both cutaneous (Castellano et al., 2009) and visceral (Heinzel et al., 1989; Wang et al., 1994) leishmaniasis is the dynamics between Th1 and Th2 responses, in which a dominant Th2 response, stimulated by the preponderant presence of cytokines such as interleukin-10 (IL-10) and interleukin-4 (IL-4), would suppress the effector profile of a Th1 response and clamp down the classical activation of macrophages (M1).