The only available cure to date for CGD is Bone Marrow Transplantation (BMT), where the blood-making cells from a specially matched brother or sister donor (allogeneic) or a similarly matched unrelated donor are given to the patient after the patient has undergone some kind of chemotherapy or radiation in preparation for receiving the cells. If the cells from the donor engraft (or survive in the marrow), the patient can be cured; however, there is a risk that the cells may not engraft or that they may later get rejected from the body. Also, the cells from the donor can react against the patient, causing a serious disorder called Graft Versus Host Disease (GVHD). Although there are a number of methods used to try to reduce and/or prevent graft rejection and/or GVHD, these complications can still occur even with the newer methods now being developed. The risks of such complications are lower when a brother or sister is used as the donor; however, not all patients (even those with siblings) will have an ideally matched donor. Hence, transplantation, especially when using an unrelated donor, is not always a perfect cure.