[Potential usefulness of human iPS cells on the generation of platelets].

Repetitive transfusion of platelets expressing HLA not corresponded to recipient matched often induces anti-HLA antibody-based undesired events including unresponsiveness in platelet transfusion therapy. It is desirable to use platelets derived from HLA-matched iPS cells. In this context, we have recently established an in vitro culture system whereby human pluripotent stem cells can be differentiated into'unique sac-like structures' (ES-/iPS-sacs) containing hematopoietic progenitors generating platelets. Among various iPS clones, we also found critical role of c-MYC in human megakaryopoiesis, leading to efficient platelet production with an intact in vivo functionality of hemostasis and thrombosis within the vessel. We propose that use of HLA-matched hiPS cells may be one of useful strategies for the treatment of thrombocytopenia in patients requiring repeated transfusion.