CD8A and heart disorder: Upregulation of CTLA-4 expression by peripheral CD4+ and CD8+T cells from subjects in the indeterminate but not in the cardiac forms of the disease, upon exposure to autologus T. cruzi-infected monocytes was reported [48] ; whereas in another study increased percentages of T. cruzi antigen-responsive CD4+CD25hiCTLA-4+T cells were only observed in patients with cardiac disease [49].