- Subjects with a history of allogeneic stem cell transplant are eligible for study participation provided the following eligibility criteria are met: transplant was greater than 100 days prior to study enrolment, subject has not taken immunosuppressive medications (per protocol) for at least 1 month, no signs or symptoms of graft versus host disease other than Grade 1 skin involvement, no active infection, subject meets the remainder of the eligibility criteria outlined in this protocol.