Two new routes to make blood: Hematopoietic specification from pluripotent cell lines vs. reprogramming of somatic cells.

Transplantation of hematopoietic stem cells (HSCs) to treat hematological disorders is routinely used in the clinic. However, HSC therapy is hindered by the requirement of finding HLA-matched donors, as well as attaining sufficient numbers of long-term HSCs in the graft. Therefore, ex vivo expansion of transplantable HSC remains one of the "holy grails" of hematology. Without the ability to maintain and expand human HSCs in vitro, two complementary approaches involving cellular reprogramming to generate transplantable HSCs have emerged. Reprogrammed HSCs represent a potentially inexhaustible supply of autologous tissue. On March 18(th) 2015, Dr. George Q Daley and Dr. Derrick J Rossi, two pioneers in the field, presented and discussed their most recent research on these topics in a webinar organized by the International Society for Experimental Hematology (ISEH). Here we summarize these seminars, and discuss the possibilities and challenges of the field of hematopoietic specification.