The immune boundaries for stem cell based therapies: problems and prospective solutions

Introduction Classification and sources of stem cells Embryonic stem Adult stem cells Mesenchymal stem cells Bone marrow and cord blood stem cells Amniotic fluid stem cells Limitations of stem cells Alternatives to overcome the limitations of stem cells Histocompatibility and immune rejection Are ESCs immunogenic or immunoprivileged ? Overcoming the need for immune manipulation to avoid rejection Manipulating immune tolerance for stem cell-based therapies Conclusions Stem cells have fascinated the scientific and clinical communities for over a century. Despite the controversy that surrounds this field, it is clear that stem cells have the potential to revolutionize medicine. However, a number of significant hurdles still stand in the way of the realization of this potential. Chiefly among these are safety concerns, differentiation efficiency and overcoming immune rejection. Here we review current progress made in this field to optimize the safe use of stem cells with particular emphasis on prospective interventions to deal with challenges generated by immune rejection.