For patients with blood diseases who need a stem cell transplant, doctors often turn to umbilical cord blood. But the small supply of blood in each cord is often inadequate to meet the needs of an adult patient (SN: 10/26/02, p. 261: Blood Booster: Growth signal shifts cord stem cells into high gear).
To up the stem cell dose in each transplant, researchers gave 32 adults with lethal blood cancers stem cell transplants from two cord-blood donors. Double cord-blood transplants have rarely been used because of fears that immune cells from two donors might attack each other and derail the treatment.
In all but three of the cases receiving double transplants, however, the stem cells successfully grafted into the patient’s bone marrow, says Juliet N. Barker of the University of Minnesota, Twin Cities.
In all the engrafted transplants, cells from one of the cords completely displaced the other within 100 days, Barker reported last month in Philadelphia at a meeting of the American Society of Hematology. The “winning” cord blood wasn’t necessarily the closest match with the patient’s blood and wasn’t always the larger of the two transplants, she notes.
Barker doesn’t know why one transplant wins out over the other, but the mere presence of the losing transplant seems to facilitate engraftment of the winner, she says.
Although all of the patients in the study were extremely ill, 12 are still alive.
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