Stem cell transplantation is often used in patients with
hematologic cancers who have had chemotherapy to help rebuild
their blood-forming and immune systems. But not every patient
has a stem cell donor who is a close enough genetic match. In
these cases, doctors may use umbilical cord blood, which is a
rich source of stem cells. Cord blood collections from two
newborns (a “double-unit” transplant) can be used to increase
the number of cord blood cells patients receive, further
enhancing their recovery. But even in this case, recovery can
take a long time. The purpose of this study is to see if
recovery during the first few weeks after transplantation can be
enhanced by using double-unit cord blood transplantation
followed by an infusion of blood stem cells from a close
relative in patients with hematological cancers that are
advanced or at high risk of relapse. To prevent a potential
complication of transplantation known as graft-versus-host
disease (where the white blood cells from the donor attack the
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