Chronic GVHD is a medical condition that may occur after the participant has received bone marrow, stem cell or cord blood transplant. The donor's immune system may recognize the participant's body (the host) as foreign and attempt to 'reject' it. This process is known as graft-versus-host-disease. Traditional standard therapy to treat cGVHD is prednisone (steroids). Interleukin-2 (IL-2) is a natural protein involved with regulation of white blood cells (WBCs). WBCs are part of the immune system.The investigators looking to see whether IL-2 helps control chronic GVHD by stopping the donor's immune system from 'rejecting' the participant's body.