Graft-Versus-Host disease is a very common side effect of an allogenic bone marrow or cord blood transplant. This type of transplant is one that is given by a family member or unrelated donor and consists of blood forming cells. Graft-Versus-Host disease happens after a transplant as a response to a poor match between the donor and the recipient. While Graft-Versus-Host disease (GVHD) cannot be predicted, it is a common among people that have recently received a transplant.
GVHD occurs when the immune cells from the donated marrow or cord blood, also known as the host, attack the body of the transplant recipient, the host. GVHD can affect any part of the body yet the skin, the eyes, the stomach, and the intestines are the parts of the body most commonly affected. The severity of GVHD varies from person to person, in some people it’s very mild and in others it’s life threatening.
The reason that Graft-Versus-Host disease happens is that some of your donor’s immune cells literally attack your body. Your immune system uses markers called HLA antigens to identify which cells belong in your body and which do not. When your body finds cells, such as your donors, which do not belong in your body, it attacks the cells. With GVHD your donor’s immune cells do not recognize the HLA antigens on your cells, so they attack your cells.
Graft-Versus- Host disease is the reason that most doctors will do tests on your HLA antigens and any donors to find the best possible match for you. A closely matched donor or cord blood unit can drastically help reduce your risk of GVHD.
Doctors cannot predict when GVHD will occur, though they have found several ways to help reduce the risk. Using a closely match donor or cord blood is a very important step, and HLA matching should be done every time, with every host and donor. Using umbilical cord blood also seems to produce fewer cases of GVHD than when other sources are used. In addition, using drugs created to help prevent GVHD work well to reduce the risk in some patients. Drugs such as clycosporine and methotrexate are often used. Removing the T cells from the donated cells before transplant also seems to help since it’s the T cells that attack your cells and cause GVHD. New methods of removing the T cells are currently being developed to reduce the risk of GVHD.
GVHD can be a heart breaking disease when the patient has been looking forward to the transplant to improve his or her life to just become ill again with GVHD. Luckily, doctors are able to work with patients to help reduce the risk and catch the disease and treat it accordingly. HLA matching and new technology are helping to avoid GVHD and hopefully the success rates will only get better as we go along.