Final answer:
Activated CTLs contribute to tissue damage in aplastic anemia through cytokine secretion and inducing apoptosis in target cells via granzymes and perforin.
Step-by-step explanation:
Activated cytotoxic T lymphocytes (CTLs) play a major role in tissue damage in aplastic anemia partially because of the secretion of cytokines and their ability to induce apoptosis in target cells. CTLs, once activated, use the release of granzymes and perforin to mediate the destruction of cells presenting the same antigen in conjunction with Major Histocompatibility Complex class I (MHC I). In aplastic anemia and other cytotoxic T cell-mediated conditions, these CTLs contribute to tissue damage by targeting and destroying host cells that they mistakenly identify as foreign or infected.