Cord blood stem cells for hematopoietic stem cell transplantation in the UK: how big should the bank be?
BACKGROUND
A stored cord blood donation may be a valuable source of hemopoietic stem cells for allogeneic transplantation when a matched sibling donor is not available. We carried out a study to define the optimal size of a national cord blood bank for the UK.


METHODS
We calculated the actual numbers of possible donors and the chance of finding at least one donor for 2,000 unselected and for 722 non-North Western European patients for whom searches had been initiated as a function of three levels of HLA matching (4, 5 and 6 out of 6 alleles by HLA-A, -B low and -DRB1 high resolution HLA typing) according to various donor bank sizes.


RESULTS
With a bank size of 50,000, 80% of patients will have at least one donor unit available at the 5 out of 6 HLA allele match level (median 9 donors per patient), and 98% will have at least one donor at the 4 out of 6 allele match level (median 261). Doubling the size of the bank yields at least one donor for only an additional 6% of patients at the 5 of 6 allele match level. Moreover, for non-North Western European patients a 50,000 unit bank provides a donor for 50% at the 5 allele match level, and for 96% at the 4 allele match level.


CONCLUSIONS
A bank containing 50,000 units is optimal for the UK and larger banks would only marginally increase the chance of finding suitable units.
Querol
Sergio
S
Anthony Nolan Research Institute, Royal Free Hospital, Pond Street, London NW32QG, UK.
Mufti
Ghulam J
GJ
Marsh
Steven G E
SG
Pagliuca
Antonio
A
Little
Ann-Margaret
AM
Shaw
Bronwen E
BE
Jeffery
Robert
R
Garcia
Joan
J
Goldman
John M
JM
Madrigal
J Alejandro
JA
D001771:Blood Banks / Q000592:standards*; D036101:Cord Blood Stem Cell Transplantation; D005312:Fetal Blood / Q000166:cytology*; D006412:Hematopoietic Stem Cells; D006648:Histocompatibility; D006801:Humans; D014019:Tissue Donors / Q000600:supply & distribution; D006113:United Kingdom