Transfusion and Apheresis Science 35 (2006) 119–123 intl.elsevierhealth.com/journals/tras 1473-0502/$ - see front matter  2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.transci.2006.05.012 EVect of the ABO blood group on the proliferative and clonogenic capacity of umbilical cord stem cells Isabel Galan b , Joaquin Santolaya-Forgas a,¤ , Juan De Leon b , Rebecca A. Uhlmann a , Daniel Montenegro a , Roderick Hume a , Giancarlo Mari a a Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Wayne State University, Hutzel Women’s Hospital, Box #4, 3990 John R., Detroit, MI 48201, United States b The Amarillo Women’s Health Research Institute, Texas Tech University Health Science Center at Amarillo, TX, United States Received 4 January 2006; received in revised form 2 May 2006; accepted 25 May 2006 Abstract Possible eVects of the ABO blood group on the proliferative and self-renewal capacity of umbilical cord CD34+ cells were evaluated. A, B and O (all Rh D+) CD34+ cells isolated from three placental blood samples were cultured in four plat- forms with hematopoietic growth factors on a 3-dimensional biocompatible matrix. Results from this study suggest that proliferation of CD34+ cells with the O phenotype may be greater than that of cells with the A or B phenotypes. Further ex vivo studies are required to conWrm this Wnding and to determine the eVect of the number and type of other genetically determined cell surface antigens on the capacity of hematopoietic stem cells to respond to cytokines. In addition, clinical studies aimed at determining if the CD34+ donor blood group aVects the time to functional hematological reconstitution are recommended.  2006 Elsevier Ltd. All rights reserved. 1. Introduction Hematopoietic progenitors can be identiWed as the subset of circulating mononuclear blood cells that express the cluster of diVerentiation marker 34 (CD34+) and can be used to correct or reconstitute the various hematological cell lines in patients with some malignant, degenerative or inherited disorders [1–3]. The two main prerequisites for this therapeu- tic approach are: (1) isolation of suYcient hemato- poietic progenitor cells from a donor; and (2) development of a mechanism for transfusing the adequate amount of these progenitor cells to pro- duce healthy, functional and stable peripheral blood cells. Because blood within the placenta is the same as that found in the fetus or in neonatal circulation and can be easily collected from the umbilical cord after delivery, it has become an alternative source of CD34+ cells [4–7]. In addition, it is hoped that this source of CD34+ cells will enhance the availability of progenitor cell blood banks and shorten the period needed to search for an unrelated donor when recipients have no sibling donor [8,9]. The main disadvantage to the use of placental blood is that the number of CD34+ cells isolated * Corresponding author. Tel.: +1 617 732 42 08; fax: +1 617 2646310. E-mail address: jsantolaya@partners.org (J. Santolaya- Forgas).