After a donor stem-cell transplant, there is a possibility that the donor cells will react against your own. This is called graft-versus-host disease (GVHD). Having GVHD does not mean the transplant has failed. Indeed, it can even have its benefits, as the donor cells can attack any cancer or leukemia cells that have survived.

The effects of GVHD are usually mild, although in some people they can be severe. You will be given medication to prevent GVHD or to make it less severe if it happens. These are called immunosuppressive drugs and they work by weakening the immune system.

Acute GVHD generally occurs in the first three months after a transplant. In some cases, it develops later. You are more likely to be affected by acute GVHD if you have had total body irradiation, if your donor is not an exact match, or if you have not taken your immunosuppressant drugs. Chronic GVHD may happen more than 100 days after the transplant.

The symptoms of GVHD will depend on the affected body parts. You will be given treatment and support to manage any symptoms of GVHD.