Minor histocompatibility antigens, also called mHAgs, are HLA-bound peptides that can differ between hematopoietic stem cell transplantation recipients and their donors as a result of genetic polymorphisms. While some mHAgs can be used as T-cell targets, some mHAgs can also increase the risk of graft-vs-host disease (GvHD), which is a limiting factor of the curative effects of allogeneic hematopoietic stem cell transplantation. In sex-mismatched stem cell transplant for male patients with female donors, it is believed that the chromosome Y-encoded antigens presented on the cell surface provide a target for donor T-cells. My work will focus on identifying the chromosome Y-encoded antigens that are associated with GvHD.