[Red blood cell production for transfusion purposes. A stem cell ex vivo fate]

In vitro generation of red blood cells (RBC) makes sense in a context of recurrent shortage. It could be an interesting complementary source for "classic" transfusion products by combining the sufficiency of supply, homemade production of a particular phenotype of interest and reduced risk of infection. The question that arises is how to produce in vitro RBC? Here we retrace the steps that led to the production of functional RBC, from basic knowledge of in vivo erythropoiesis to in vitro generation of RBC from different sources of stem cells. Regarding the adults HSC, the major finding lies in the recent establishment of proof of concept of their transfusion in humans. Because the induced pluripotent stem cells (IPS) can proliferate indefinitely and be selected for a phenotype of interest, they are obviously the best source of stem cells. Proof of concept of generation of RBC from IPS has been made, but still has to be optimized. We also discuss the key points that need to be solved to achieve clinical transfusion application.