**Acknowledgements**

We would like to thank Esther Heideveld, Joan Gallego Murillo, Department of Hematopoiesis and Laboratory for Cell Therapy (Sanquin, Amsterdam) for their experimental and scientific input.

We are grateful for the support by the Ministry of Health (PPOC: 11-035, 15-2089), the Landsteiner Foundation for Blood Transfusion Research (LSBR1141), the European Union (FA H2020-MSCA ITN-2015, RELEVANCE), and the Netherlands Organization for Scientific Research (NWO/ZonMw 40-41400-98-1327; 40-00812-98-12128).
