Not only is the frequency of CD18 + CD8 + T cells reduced in L. chagasi patients, but also, the level of circulating memory T cells is significantly decreased during active VL (Hailu et al., 2005; Clarencio et al., 2009 ). This observation is in agreement with our findings in the experimental model of VL, where the majority of the CD8 + T cells displayed an effector phenotype during chronic infection (Joshi et al., 2009) .