In a recent phase I/II trial on CD133+ CB HSCs cultured in media containing TEPA, together with SCF, FLT-3 ligand, IL-6, and TPO, nine out of ten patients showed engraftment with an increase of CD34+ cell count, better median time to neutrophil, better platelet engraftment, and no cases of grades 3–4 acute GvHD. Here, IL6 is linked to graft versus host disease.