KLF4 and sickle cell disease: In this study, we report that integration-free iPSC can be efficiently generated from human adult PB MNC of patients with sickle cell anemia, after brief suspension culture system, in 3-4 weeks by nucleofection of episomal vectors expressing the 5 factors OCT4, SOX2, C-MYC, KLF4, and LIN28 as a single polycistronic unit and expressing the SV40 large T antigen.