Scientists may have found a way to predict who will develop graft versus host disease (GVHD) after a bone marrow transplant.
GVHD is a common but serious complication in patients who undergo this type of transplant, also known as a haemopoietic stem cell transplant. GVHD occurs when cells from the donated bone marrow attack the body of the person receiving them (the host or recipient), whose own immune system will have been repressed to allow the new bone marrow to flourish.
The skin, eyes, stomach and intestines are most often affected. While it can usually be treated with drugs that damp down the immune system (immunosuppressive drugs), it would be best to avoid GVHD altogether.
For BMT, the donor and the recipient must have tissue types that are as closely matched as possible. But GVHD can develop even after a very well matched BMT and it is unclear why. GVHD only develops if there are some mismatches between donor and host in certain cell markers (called histocompatibility antigens) between the donor and host, but does not inevitably develop.
Many scientists have investigated whether differences between the recipients determine whether the problem develops. In this study however, researchers from Canada have examined the donors, to see whether differences in their immune responses might make some more likely to cause GVHD.
T cells are specialised cells of the immune system present in blood and bone marrow. The researchers used a technique called microarray expression profiling to examine gene expression patterns of T cells of blood stem cell donors. From these patterns, they identified a number of genes whose expression levels discriminated between donors who caused GVHD and those that did not in matched recipients. Many of these genes are involved in TGF-b signalling (TGF-b is a protein that helps to control the immune system), cell growth, proliferation and inflammation.
These findings need to be confirmed in many more donors and need further investigation, but the concept of being able to identify a 'dangerous' donor may represent an important advance in transplantation medicine. It could help clinicians select low-risk donors for BMT and organ transfers and tailor patients' immunosuppressive drug treatments according to their donor-determined risk of GVHD.
The greater availability of cells for BMT through the increasing use of cord stem cells is also making it easier to find optimum donors. Expectant mothers interested in donating their baby's very valuable umbilical cord (which is usually just thrown away) need to check with their hospital in advance whether this facility is available.
IMPORTANT NOTE :
The information contained on this website is intended only as a guideline, not as a substitute for medical advice. Always consult your doctor if you or your child has any CGD symptoms or concerns.
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