Specifically, for leishmaniasis, there are numerous benefits in the incorporation of adjuvants in vaccines, such as (1) enhancing immunogenicity and efficacy, (2) modulating T cell phenotypes toward Th1, (3) reducing the number of doses and (4) extending the induction of specific effector CD4+ and CD8+ T cells [11,22]. This evidence concerns the gene CD4 and leishmaniasis.