A cord blood transplant is a hematopoietic cell transplant that uses cord blood instead of bone marrow or peripheral blood as the source of blood-producing stem cells for the transplant. Cord blood cells are transplanted into a patient where they engraft and begin producing healthy blood cells. The procedure is typically preceded by a radiation or chemotherapy regimen that kills the malfunctioning or cancerous blood stem cells before replacing them with the healthy, transplanted cells.
Cord blood as a source of donor cells for transplant offers many benefits: It can be collected easily and stored for later use, it does not have to be matched to a patient’s tissue type for transplantation, and there is a lower risk of viral transmission or a serious complication known as graft-versus-host disease.
Importantly, outcomes for patients undergoing a cord blood transplant have improved dramatically over the last decade. Several studies have demonstrated equivalent outcomes for cord blood transplant patients and patients receiving bone marrow or peripheral blood transplants from unrelated donors. And a recent study including hundreds of patients treated at Seattle Cancer Care Alliance showed that for patients entering transplant with minimal residual disease (who are at high risk of relapse), those receiving cord blood transplant had better outcomes and a lower relapse rate than those who received stem cells from an adult unrelated donor. For patients without minimal residual disease, cord blood transplants and traditional transplants had very similar outcomes.
Despite its many advantages, cord blood has a significant hurdle that must be overcome: Each unit of cord blood contains a small number of stem cells. On average, cord blood carries only 10 percent of the number of stem cells found in donations of bone marrow and peripheral blood. This small number of cells significantly increases the time it takes for the new blood and immune system to take hold (engraft), especially the white blood cells, which puts patients at a much higher risk of developing life threatening infections early after the transplant. Fred Hutch researcher, Colleen Delaney has developed a breakthrough method that overcomes this hurdle.