Pregnant or lactating. Patients of childbearing potential must use an effective method of contraception from the time of study entry to at least one year post-transplant; effective methods include intrauterine device (IUD), hormonal (birth control pills, injections, or implants), tubal ligation/hysterectomy, partner s vasectomy, or barrier methods (condom, diaphragm, or cervical cap). Males on the protocol, and their partners of child-bearing potential, must also use an effective form of contraception at study entry and for one year post-transplant. The effects of the chemotherapy, the subsequent transplant, and the medications used after the transplant are highly likely to be harmful to a fetus. The effects upon breast milk are also unknown and may be harmful to the infant; therefore, women should not breastfeed during the interval from study entry to one year post-transplant.