- A condition that occurs when donated stem cells or bone marrow (the graft) see the healthy tissues in the patient’s body (the host) as foreign and attack them. It can also occur after an organ transplant. Graft-versus-host disease can cause damage to the host’s tissues and organs, especially the skin, liver, intestines, eyes, mouth, hair, nails, joints, muscles, lungs, kidneys, and genitals. The signs and symptoms may be severe and life threatening. Graft-versus-host disease can occur within the first few months after transplant (acute) or much later (chronic). Also called GVHD.