Low doses of chemo. Doctors want to capture the anti-tumor effect of the donor's immune cells and they do not need to totally kill all the patient's cancer cells at the time of transplant. These cells will do it over time. Therefore the transplant itself is not as dangerous as a full or standard transplant. However, the serious complications that occur from these same cells causing gvhd are still present.
Simply put.... A mini-allo transplant is one where a reduced intensity conditioning regimen is used to prepare for the infusion of stem cells and to facilitate engraftment. The term allo refers to the source of the stem cells themselves. An allo transplant involves cells from a donor other than the patient themselves. The donor could be related or not. Ask your transplant physicians for additional details.