may appear to be a match but may be mismatched when typed at high resolution. More information about HLA and matching can be found in Appendix F.
Most cord blood banking involves the collection, storage, and distribution of cells for transplantation to unrelated individuals. These units are typed and stored anonymously so that any patient who might have a medical need may use them. This transplantation involving the transfer of cells from one individual to another genetically different individual is referred to as allogeneic transplantion, and the individual receiving the transplant may or may not be related to the donor.
HPC transplantation can also be done using autologous cells, in which an individual’s own cells are collected and stored and then reinfused, generally after high-dose anticancer therapy. Allogeneic and autologous transplantation each have benefits and disadvantages. The benefits of allogeneic transplantation include the ability to treat a wide range of conditions, both inherited and acquired, with HPCs from a healthy, unaffected donor. Allogeneic cells may also have immune effects that may aid in eradicating the recipient’s malignancy. Autologous transplantation carries the risk of the reinfusion of abnormal cells if the cells are collected after the onset of the disease and it lacks any immune-mediated anticancer effects. The major disadvantage of allogeneic transplantation is the use of non-native tissue for the graft, which necessitates the use of immunosuppressive therapy to avoid rejection and GVHD. Table 2-1 describes the details of conditions that may be treated by allogeneic or autologous HPC transplantation.
Engraftment of an HPC transplant is generally considered successful when neutrophil recovery is found. Neutrophils are the white blood cells that form the first line of defense against infection. Neutrophil recovery is an indication that the patient has begun to generate new blood cells and hematopoiesis1 is being restored. Neutrophil recovery, however, is not synonymous with the restoration of full immune function, which requires the production and maturation of various other types of white blood cells and