What is the probability that a person will require a stem cell transplant over the course of a lifetime?
Answer:
Over the course of a lifetime up to age 70, the probability that a person will require a transplant of her own Stem Cells (”autologous” transplant) is 1 in 450 or 0.23%
Over the course of a lifetime up to age 70, and the probability of requiring any transplant, from yourself or another person [...]
Which poses less risk of passing an inherited disorder, transplants of adult bone marrow or infant cord blood?
Answer: This is a toss-up. More and more diseases are now recognized to have a genetic basis. We have always known that some diseases are passed by inheritence. Now we also recognize that some genetic mutations confer a greater predisposition to disease. For example, the “Philadelphia chromosome (translocation)” is associated with a predisposition [...]
How does long-term survival compare among recipients of bone marrow transplants versus cord blood transplants?
Answer: They are comparable. Among pediatric patients, the overall survival rates are comparable for the two transplant types, but the causes of death differ with each. Among Cord Blood transplants, the most common cause of death was complications during the long wait for engraftment. Among bone marrow transplants, more patients died of severe [...]
Until what age can a person receive a cord blood transplant?
Answer: Approximately age 70. A study at the University of Minnesota transplanted patients who were not eligible for high-dose chemotherapy, either due to age, co-existing medical problems, or previous treatment. The median age was 49 (range from 19 to 69). They received reduced conditioning chemo, also known as a “mini transplant”. Sustained engraftment [...]
What is the maximum degree of patient-donor incompatibility (mismatched HLA types) that can be tolerated in cord blood transplants?
Answer: Apparently quite large. Examples:
Several clinical trials presented at the 43rd annual meeting of the American Society of Hematology in Dec. 2001 were transplanting adults with multiple (from 2 to 6) mis-matched Cord Blood units. Surprisingly, although these patients initially show a mix of HLA types (”chimerism”) from the different units, over time [...]
Can the use of cord blood for adults be enhanced by expanding the number of stem cells in vitro?
Answer: Yes. Many biotech companies are developing techniques to rapidly grow Stem Cells in a laboratory environment. These methods are being used in clinical trials.
Example: Blood & Marrow Transplant Newsletter issue #51 reports on the first adult to survive a Cord Blood transplant with expanded Stem Cells. Published by Pecora et al. 2000 [...]
What is the minimum dose of stem cells from cord blood needed for engraftment of a new immune system?
Answer: This is the same as asking, “what is the maximum patient size that can be transplanted with a single Cord Blood collection?” The optimal dose is about 20 million nucleated cells per kilogram of body weight. “patients who received no more than 10 million nucleated cells per kilogram had a 75 percent [...]
Does cord blood carry a Graft-Versus-Leukemia effect?
Answer: Apparently very little, if any. Graft-versus-Tumor effect is known to be correlated with Graft-Versus-Host Disease (GVHD). Both are mediated by T-cells. While the T-cell content of umbilical Cord Blood is lower than bone marrow, it is not low enough to be the sole FACTor explaining the lower incidence of GVHD in cord [...]
How does Graft Versus Host Disease (GVHD) from cord blood compare to other sources of stem cells?
Answer: GVHD is less severe with Cord Blood than with bone marrow. In a study where all patients received an HLA-matched transplant from a sibling, and the results were controlled for age, the relative risk of Cord Blood versus bone marrow was 0.41 for acute GVHD and 0.35 for chronic GVHD.
The accepted explanation [...]
How long does it take cord blood to engraft in a transplant recipient?
Answer: At least a week longer than it takes bone marrow to engraft. Median engraftment times for bone marrow and Cord Blood are typically 18 and 26 days.
References:
Rocha, V., et al. (2000) NEJM 342:1846-54
Wadlow & Porter (2002) Biology of Blood & Marrow Transplantation vol.8(issue 12):637-647
New Answer: Research is underway to speed up engraftment. [...]
