Cutting edge: dysfunctional CD8+ T cells reside in nonlymphoid tissues during chronic Trypanosoma cruzi infection.

Chagas disease is caused by persistent Trypanosoma cruzi infection in muscle tissue that ultimately results in chronic inflammation and tissue destruction. It is unclear why T. cruzi is cleared from some tissues but persists in others, despite an active inflammatory response. In this study, we show that the majority of CD8(+) T cells present in muscle tissue express memory and effector cell surface markers but have sharply attenuated effector function compared with their splenic counterparts. The dysfunction of CD8(+) T cells in the muscle tissue suggests a mechanism by which T. cruzi can persist in that location and cause inflammatory damage.