The role of these cell populations in chronic tissue damage needs further investigation, however it is known that CD38+/HLA-DR+, CD8+/CD69+ and DP T cells can produce perforin and IFN-γ in chagasic patients [2], [12], [54]; and previous studies have indirectly implicated DP T cells in tissue damage in Chagas disease [12] and other infectious models [55]. This evidence concerns the gene PRF1 and Chagas disease.