[Cord blood banks].

Cord blood is an excellent source of stem cells which are universal for all other cells of the whole body. They have the ability to develop in any of the body cells, depending on stimulation by different growth factors. The ease of sampling, cryopreservation, and above all successful engraftment make placental blood a possible alternative for bone marrow donation. The advantages of cord blood cells over bone marrow stem cells in allogeneic transplants include their young age and immature status, which reduce the severity of graft versus host reaction. However, the number of cells is much more limited than with bone marrow (about ten time less); therefore, for the time being, the procedure is not equivalent to marrow donation. Cord blood banks would increase HLA diversity, and they are therefore expected to solve two sets of immunogenetic problems: (1) since less stringent compatibility is needed, children with a rare HLA group could benefit from a graft when the donor is not perfectly matched; and (2) HLA types infrequently represented in registries may be represented more readily in placental blood banks; although they occur repeatedly in certain ethnic groups or populations, they are only rarely donated to volunteer registries, while these populations are also concerned in transplantation. Many countries in the world have recognized the significance of collecting and preserving cord blood stem cells and their ability to heal or at least improve life.