Potential mechanism of chronic graft-versus-host disease (GVHD) induction.

Autoreactive T cells are generated by prior damage to the immune system from acute GVHD, host immune system factors such as age, and/or T helper cell population administered with the transplant. Effector cells help generate a graft versus tumor effect as well as chronic GVHD. (Figure from Dr. A. Hess, Johns Hopkins Oncology).