Hello, I am reading RR Pathology and I am confused on this and was hoping that someone can clear it up. It says that Graft vs. Host disease is basically a problem of the donor T-cells recognizing the host tissue as foreign and it activates the hosts CD4 and 8 T-cells. So why is there a danger of GVH in a child with Digeorge syndrome who lacks a thymus and thus no T-cells. I ask becuase on pg. 54 of RR it says that there is a danger of GVH reaction. Thanks in advance.