Another study investigating CD8 + T cell responses in patients infected with L. chagasi has revealed that the frequency of CD18 + CD45RO + CD8 + T cells is significantly decreased in the spleen of patients with active VL (Clarencio et al., 2009 ). In contrast, CD18 + CD8 + T cells seem to be retained in the bone marrow of VL patients. CD18, or integrin β-2, is the β subunit of LFA-1 (CD11a), CD11b, CD11c, and CD11d. In humans, lack of CD18 www.frontiersin.org causes leukocyte adhesion deficiency, a disorder characterized by lack of leukocyte extravasation from blood into the tissue (Bunting et al., 2002) . With exception of the fact that CD18 + cells appear in the granulomas of dogs with asymptomatic VL (Sanchez et al., 2004) , very little is known about the function of CD18 + CD8 + T cells during VL and whether cells lacking CD18 expression have similar migratory capacity and effector functions to their CD18 + counterparts.