In vivo studies demonstrated that CD38 deficiency in mice conferred increased susceptibility to infection by several bacteria, namely Listeria monocytogenes (L. monocytogenes) [22], Mycobacterium avium (M. avium) [23] and Streptococcus pneumoniae (S. pneumoniae) [24,25], and the parasite Entamoeba histolytica (E. histolytica) [26]. This evidence concerns the gene CD38 and infection.