How does stem cells work?

Could anybody explain how stem cells work in transplantation? What's the significance of a fetus in stem cell research?

• Answer:

  A stem cell transplant is the infusion of healthy stem cells into your body. A stem cell transplant may be necessary if your bone marrow stops working and doesn't produce enough healthy stem cells. A stem cell transplant can help your body make enough healthy white blood cells, red blood cells or platelets, and reduce your risk of life-threatening infections, anemia and bleeding. Although the procedure to replenish your body's supply of healthy blood-forming cells is generally called a stem cell transplant, it's also known as a bone marrow transplant or an umbilical cord blood transplant, depending on the source of the stem cells. Stem cell transplants can use cells from your own body (autologous stem cell transplant), or they can use stem cells from donors (allogenic stem cell transplant). There are a large number of inherited genetic diseases (like sickle cell anemia) that can now be accurately diagnosed early in fetal life by examining fetal DNA obtained by chorionic villus sampling or amniocentesis. In most cases the testing is done because the disease has been identified to run in the family. Because stem cell defects result in such a wide of variety of diseases (hemoglobinopathies, immunodeficiencies, inborn errors of metabolism, etc.), the outcome for the fetus depends on that particular disease. The wide range of outcomes are anywhere from death or severe life-long impairment to survival and treatment after birth with minimal impairment. The most important consideration is the accuracy of the diagnosis through genetic counseling about the consequences of that particular inherited stem cell defect. If after full and complete counseling about the defect and its consequences, you choose to continue the pregnancy, you will start planning the proper time and place of delivery for optimal care after birth. For inherited stem cell defects that cause trouble at birth and require immediate treatment, the place of delivery will be the most important consideration.