Women in childbearing age will be offered barrier methods of contraception to decrease the risk of pregnancy for a period of one year following the transplant. Subjects who become pregnant during year one of the study will be transferred to the inactive participant group. Pregnancy testing will be performed prior to research procedures and surgery. Subjects using oral contraceptive agents are included. Women without normal menstrual cycles will be offered hormone replacement therapy for a period of 3 cycles prior to treatment.