Umbilical cord blood (UCB) derived stem cells

The growth of a fetus while in the uterus requires nutrients, oxygen and removal of waste substances. These essential substances pass from the mother's blood to the fetus blood through the placenta which grows in the wall of uterus and connects mother and developing fetus through the umbilical cord. The blood found within the umbilical cord is the baby's, not the mother's and it is a rich source of stem cells genetically unique to the baby. Routinely, after a baby is born, umbilical cord is discarded with the placenta. The UCB collection poses no health risk to either the mother or the baby, and it is a painless and non-invasive procedure that does not change the birth process.

Bone marrow is the primary graft source for transplantation in children, though the use of umbilical cord blood is increasing and the use of mobilized peripheral blood is decreasing. Historically the first cord blood transplant was performed in 1988 on a 6-years-old boy with the blood disorder Fanconi Anemia. During the period 2007 to 2011, peripheral blood accounted for 23% and cord blood accounted for 26% of allogeneic transplants in patients younger than twenty years. Use of umbilical cord grafts in patients >20 years, doubled during the decade analysed from 3 to 6%. Since first transplant, more than 20,000 cord blood transplants have been performed worldwide to treat blood and immune system disorders. There are an estimated 15,000 patients who need a stem cell transplant every year. Up to 40 percent of them cannot find tissue-matched donor with the same tissue type. Matching donors are even more difficult to identify for patients from ethnic minority and mixed racial backgrounds. UCB are less mature than cells from bone marrow and have greater proliferative and colony forming capacity, and are more responsive to some growth factors. Studies demonstrate that UCB contain sufficient amount of stem cells to reconstitute entire hematopoietic system of a child with myeloablative therapy and incidence of GVHD was 10-fold lower than with human leukocyte antigen-matched (HLA) bone marrow obtained from a sibling. Recent studies also demonstrate that UCB stem cells do not require to match the tissue as closely as bone marrow or peripheral blood for a successful transplant. Furthermore, UCB units are stored in a cord blood bank and could be used immediately. Relatively low numbers of stem cells in each cord blood donation

may cause delayed engraftment, but combination of two or more cord blood units with haplotype matched CD34 cells for a single patient provides high rates of sustained donor engraftment and decrease transplant related mortality in adults and large children.