Umbilical cord blood (UCB) has become a source of HSCs for pediatric patients. UCB has many progenitor cells and sufficient HSCs for transplantation in patients who weigh less than 40 kg (88 pounds). However, the limited number of cells available per unit collected makes UCB the least expected source of HSCs.
These HSCs are naïve in their immunologic function, resulting in a lower incidence of GVHD in transplanted patients. UCB can be collected before birth or, more commonly, after birth. Up to 150 mL of cord blood can be collected from the placenta and umbilical cord via the umbilical vein using a syringe, allowing the cord blood to drain by gravity. Samples are tested for infectious diseases, HLA type, and CD34 count, then cryopreserved with dimethyl sulfoxide (DMSO). A significant disadvantage of UCB as a transplant source is the donor cannot make a second donation.
