Limitations of Cord Blood Transplantation
Despite its potential benefits, cord blood transplantation also has a number of potential limitations. The quantity and quality of cord blood included in a single unit may not be sufficient to obtain an appropriate transplant in tallish children and adults. The optimal output required for a safe and successful cord blood transplant remains unknown, and that is an important factor of limitation which hinders the widespread use of umbilical cord blood, particularly among adults. The limited amount of hematopoietic cells from individual donations of umbilical cord blood, has been proved to be the most important disadvantage of umbilical blood, as a source of hematopoietic stem cells for clinical transplantation. It is also possible to attend a transfer of abnormal cells on the genetic level. In addition, some clinical results indicate that the frequency and rate of myeloid and thrombocytary engraftments are lower than what is found in the case of comparably matched bone marrow, leading thus to apossible increase in mortality associated with transplantation and failure of the engraftment.
Unlike bone marrow donors or those donating peripheral blood progenitor cells, from which it is almost always possible to solicit donations as needed, unrelated cord blood donors are not able to provide a second donation in the presence of bone marrow failure or a recurrence of the disease. Finally, the collection, storage and transplantation of cord blood raises many financial, ethical and regulatory issues among health care providers and within society.