Investigators at St. Jude Children's Research Hospital have demonstrated in mice a way that might reduce the time it takes for a bone marrow transplant to rebuild a child's immune system, and so reduce the risk of potentially fatal virus infections that can occur during this time.
The St. Jude team showed that the current way of harvesting specific stem cells from donated bone marrow to capture many of the stem cells called CD34+ cells fails to capture many of the cells that might be more vigorous in reproducing and rebuilding the immune system. CD34+ cells give rise to a variety of blood cells including T lymphocytes, a critical part of the immune system that orchestrates the attack on invading microorganisms. The researchers showed in mice that most of the CD34+ stem cells left behind by the current harvesting method are especially vigorous in multiplying and producing T lymphocytes. In humans, the loss of many of these vigorous stem cells from the transplant might contribute to the delay in rebuilding the immune systema time lag that leaves children exposed to serious infections.
The St. Jude finding is important because children whose own bone marrow stem cells have been destroyed by chemotherapy or radiation treatments for cancer routinely undergo bone marrow transplantation. Therefore, reducing the time it takes for the immune system to regenerate T lymphocytes would be an important step in reducing infection risk in these children and improving their long-term outcomes.
A report on this work appears in the current online issue of the journal Stem Cell.
Stem cells that give rise to T lymphocyteswhether they are a person's own stem cells or donated cellsnormally gather in the thymus gland in the chest. There the stem cells receive their "marching orders" as new T lymphocyte warriors against invading bacteria, viruses and other potentially dangerous targets including cancer cells, and they develop a specialized homi
Contact: Bonnie Kourvelas
St. Jude Children's Research Hospital