Abstract: The invention relates to predicting or determining risk of a hematopoietic cell transplant (HCT) from a donor to induce Graft vs. Host Disease (GVHD) in a HCT recipient; to classifying HCT from a candidate donor according to the risk of inducing GVHD in a HCT recipient; and to organizational constructs (e.g., databases) and methods of producing organizational constructs (e.g., databases) in which HCT of one or more candidate donors is classified or scored according to risk of inducing GVHD in a HCT recipient. The invention also relates to kits and arrays useful for predicting or determining risk of HCT from a candidate donor to induce GVHD in a HCT recipient, and for classifying or scoring such donors according to risk of inducing GVHD in a HCT recipient.