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Umbilical Cord Stem Cells


Until recently, blood that remained in the umbilical cord and placenta after delivery was routinely discarded. Now that this blood is known to contain both hematopoietic stem cells and pluripotent mesenchymal cells, there has been a substantial increase in the clinical use and research investigation of umbilical cord blood in hematopoietic transplantation and regenerative medicine. Until now, standards for collection and processing were not well established. The debate continues regarding the private banking of autologous blood for "biologic insurance" versus public banking for access by the general population. Obstetricians should support the acquisition of cord units for public banking in their geographic location where cord blood banks have established collection procedures. Issues related to cost, quality control, and the need for ethnic diversity in public banks preclude the universal collection of units from all obstetric deliveries. Directed donation of cord blood should be considered when there is a specific diagnosis of a disease within a family known to be amenable to stem cell transplantation.


There are 3 types of cord blood banks: public banks, private banks, and directed-donation banks. Public banks involve allogeneic donation. At the time this article was written, there were a total of 22 public cord blood banks operating in the United States (Tables 2 and 3). In these situations, blood is collected from the general public in a manner analogous to whole blood donation. The stem cells are then stored in a central facility for public use. These units must meet rigorous standards for infectious disease testing identical to the blood donor pool for adult blood. Initial HLA testing, red cell blood type, and cell counts are performed. Units that do not meet certain criteria for cell count or volume are not included in the active inventory. Funding for the establishment of a public cord blood bank is problematic. Initial processing costs typically exceed $1,000 per unit stored. Most current public banks were initiated with research funding from the NIH or funding from local foundations. Recently the National Marrow Donor Program has subsidized cord blood banks in its member network. Public banks are allowed to recover some of their costs by charging insurance carriers for units used for transplant. Fees usually are on the order of $15,000 to $35,000 per unit (average $25,000). Sirchia et al studied an economic model for the initiation of a public cord blood bank. The establishment of an inventory of 10,000 units was proposed during the first 3 years. In years 4–7, only 3% of the inventory would be released for transplant, necessitating a charge per unit of approximately $12,000 to make the venture cost neutral.




Private banks were initially conceived for autologous use by a child that develops a disease later in its life. More recently private banks have promoted their use for allogeneic donation for siblings or parents. Some private banks offer directed donation at no charge to the patient if there is a sibling or parent with a known disease that can be treated with umbilical cord blood. Today there are more than 24 private banks established in the United States (Table 4). In general, units for private banks are collected on site by an obstetric provider and shipped to a central processing laboratory. Because these units are being collected primarily for autologous use, most banks limit their testing for maternal infectious diseases. Initial HLA typing is not undertaken. Families are charged an initial fee ($1,100–$1,750) followed by a yearly fee for continued storage ($115–$125).40 If a cord blood unit should later be needed, processing and shipment fees are billed to the health care insurance carrier.



The banking of umbilical cord blood for private use or public use is mired in emotion with very few facts. Private companies, particularly in the United States, have used direct patient advertising for recruitment, often using a promise of "biologic insurance" for the newborn. One company even offers a college savings plan as part of their package for storing cord stem cells. Important issues of future use, quality control, long-term availability, availability to those in need, and costs argue for public banking as a more practical approach to the use of umbilical cord blood.


In its committee opinion on this issue, the American College of Obstetricians and Gynecologists (ACOG) states "Parents should not be sold this service without a realistic assessment of their likelihood of return on their investment." Some private banks quote unrealistic odds for the future use of an umbilical cord blood unit stored in a private bank. One private bank cites a frequency of 1:27, with the future possibility of 50% of units ultimately being used. Autologous umbilical cord blood cannot be used to treat inborn errors of metabolism because the genetic mutation is already present in the stem cells. In addition, some subtypes of leukemia are associated with chromosomal translocations that have been found in fetal blood. For this reason, many pediatric hematologists will not use autologous stem cells to treat leukemia. In addition, the use of such cells would negate the beneficial graft-versus-leukemic effect (see above) that occurs with allogeneic stem cell transplants. This led Johnson to suggest the that the chance of an individual using an autologous unit of cord blood is approximately 1:2,700 (Fig. 3).




The definition of a "quality" umbilical cord blood unit is still being refined. Initial procedures developed in the NIH COBLT trial called for a minimum unit volume at the time of the collection of 60 mL or a total nucleated cell count of 6 x 108 or greater if the volume was between 40 and 60 mL; units with volumes of less than 40 mL were discarded. Public banks also have numerous other exclusion criteria that are meant to assure quality. Many banks now use a minimum of 1 x 109 total nucleated cell count to define an adequate unit; this results in as many as 65–70% of units being discarded after initial collection (Joanne Kurtzberg, MD, Director, Carolinas Cord Blood Bank at Duke, personal communication, July 1, 2005). The collection of units for private banking is subject to the pressure of "our only chance to collect cells." Therefore, suboptimal units are often sent to the collection facility. At the time of the processing, the private bank will usually contact the parents to have them decide whether to store or discard the unit. Many decide to proceed with storage with very little knowledge that the unit could not be realistically used at a later date.


Because umbilical cord blood banking is in its infancy, issues with long-term availability have not arisen. Studies have shown long-term survival of stem cells in cord units for up to 15 years after initial freezing. Viability of cells after this time has not been substantiated. This, therefore, calls into question the use of autologous stem cells harvested at birth for regenerative medicine many decades later. In addition, private banks must continue to recruit new donors to remain financially viable. What is to happen to privately donated units if a company becomes insolvent?


The final argument for public banking involves the use of a human resource for the greater good of mankind. Public banks collect units from patients with a wide ethnic diversity. Many actually seek out certain ethnic groups that are underrepresented in the national bone marrow registry. Private banking allows those of means to collect stem cells while the less fortunate have no access to this valuable resource. Because of the economics of maintaining a public bank based on current use, many public banks have found it necessary to curtail or even eliminate collection activity (this includes an initial effort by the Red Cross to establish a cord blood bank). The IOM report recommended federal funding for the acquisition of 100,000 new high quality units.7 Recently, the Senate Health, Education, Labor and Pensions Committee approved a bill (S.1317) to establish a national cord blood bank. The bill would authorize the use of 19 million dollars already set aside by Congress to support inventory growth in the years 2005 and 2006 and directs an additional 15 million dollars to be set aside each year between 2007 and 2010 to establish the national inventory suggested by the IOM report. The bill would also consolidate the current national bone marrow registry and the new cord blood registry under a newly created C. W. Bill Young Cell Transplantation Program. The bill is expected to pass the House without going to conference committee and will be sent to President Bush for signature.


All of these reasons have led many organizations and countries to take a stand against private banking. The American Academy of Pediatrics has suggested "...private storage of cord blood for biologic insurance is unwise." In Europe, the practice of private cord banking has been banned by law in Italy since 2002. The Royal College of Obstetricians and Gynaecologists states their position as "Routine directed commercial cord blood collection and stem cell storage cannot be recommended at the present time, because of the insufficient scientific base to support such practices...." The French National Consultative Ethics Committee's "...recommendation to decision makers is that they should encourage a considerable extension of cord public banks for essentially allogeneic purposes, rather than subscribing to the creation of private banks for strictly autologous purposes, the potential therapeutic usefulness of which is, as yet, in no way corroborated." Finally, in March of 2004, the European Group on Ethics in Science and New Technologies stated their position as follows: "The legitimacy of commercial cord blood banks for autologous use should be questioned as they sell a service which has presently no real use regarding therapeutic options. Thus, they promise more than they can deliver. The activities of such banks raise serious ethical criticisms."


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