Signal-joint TRECs May Predict Stem Cell Transplant Success
Related News: Stem Cell ResearchMeasuring the quantity of a particular type of immune cell DNA in the blood could help physicians predict whether a bone marrow stem cell transplant will restore a population of T lymphocytes (T Cells) in a child.
This finding could help physicians predict if children receiving such a transplant will experience either failure or a delay in the reconstitution of the T cell population. Furthermore, if the transplant is successful, T cells arising from donated stem cells will be available to launch attacks on the patient’s cancer cells—the so-called “graft-versus-tumor” response.
This will further improve the patient’s outcome following initial therapy (chemotherapy, irradiation and surgery).
The St. Jude team showed that the more copies of tiny rings of DNA called signal-joint TRECs (sjTRECs) there are in a child’s blood, the more likely it is that the patient’s thymus gland can act as an efficient factory where stem cells become T cells. The thymus is an immune system organ behind the breastbone that processes immature “precursor” immune cells into specialized T cells.
The target that a T cell recognizes and attacks depends on the makeup of its receptor, which is constructed of protein building blocks. Each protein building block is coded by a specific gene. sjTRECs form during a “mix-and-match” rearrangement of these genes into any one of countless combinations. The rings represent sections of DNA cut out of chromosomes during the mixing and matching of genes that are chosen to build a particular receptor. Each T cell uses the resulting combination of genes to make a receptor that lets the cell recognize a specific target. When stimulated to multiply, each of those cells produce an army of immune cells against their designated target.
Posted on February 25, 2005 09:15 PM