After a patient receives a bone marrow transplant they are watched very closely for signs of graft-versus-host disease (GVHD).

When a patient receives a transplant of say a heart or liver, that patient is given drugs so that the body will not reject the organs. Your body does not recognize the organs as a part of you and the immune system will attack.

With GVHD it is the same concept but with a bone marrow transplant you are getting someone else's immune system. This foreign immune system does not recognize your organs and can then attack them. GVHD can affect different parts of the body such as the skin, eyes, stomach and intestines. GVHD can sometimes be easily treated and controlled or other times can be deadly.

GVHD can be acute or chronic. It is considered acute if it occurs within the first 100 days after the transplant and chronic if it persists or develops after day 100.

This study focuses on chronic GVHD and looks to determine the natural history of the disease and assess biological factors that may predict outcomes.