My uncle donated 8.7 million stem cells. They said the minimum that they needed was 3 million. They need at least 3 million to increase chances of the cells grafting, which means that the body accepts the cells and the cells start producing blood for the body - white blood cells, red blood cells and platelets. They have a cap at 8 million because beyond that, there are increased changes for Graft vs. Host disease, which is a condition where the body attacks the cells because they are foreign. Since I mom got over 8.0 million cells, I naturally had questions. The best response I got was (paraphrased): Well, studies show that 8 million is max, but 8.7 million isn't that much more (that's almost 10% more!) and we think it will be ok. We want to increase her chances.So here's to the cells grafting, the body accepting all that is done to it, the bone marrow making new cancer free blood cells, and my mom never suffering Graft vs. Host Disease!