To be immunogenic, or not to be: that's the iPSC question.

The unexpected finding that autologous induced pluripotent stem cell (iPSC)-derived teratomas are immunogenic in syngeneic hosts sparked pessimism over their therapeutic potential; however, two recent reports (Guha et al., 2013 and Araki et al., 2013; the latter in this issue of Cell stem cell) contradict previous findings, showing no immunogenicity of in vitro differentiated syngeneic iPS-derived cells and supporting their safety.