RMC is typically seen in young individuals with the sickle cell trait. It is diagnosed when metastatic, is not responsive to systemic therapy and rapidly causes death. Because cure appears possible with early diagnosis, increased awareness of the disease could make an impact. The use of thalidomide or newer anti-angiogenesis agents should be considered for advanced disease. The role of ABL amplification with respect to etiology and as a therapeutic target should be investigated further.

Embryonic stem cell (ESC)-derived hematopoietic stem cells (HSC), unlike HSC harvested from the blood or marrow, are not contaminated by lymphocytes. We therefore evaluated whether ESC-derived HSC could produce islet cell tolerance, a phenomenon termed graft versus autoimmunity (GVA), without causing the usual allogeneic hematopoietic stem cell transplant complication, graft-versus-host disease (GVHD). Herein, we demonstrate that ESC-derived HSC may be used to prevent autoimmune diabetes mellitus in NOD mice without GVHD or other adverse side effects. ESC were cultured in vitro to induce differentiation toward HSC, selected for c-kit expression, and injected either i.v. or intrabone marrow (IBM) into sublethally irradiated NOD/LtJ mice. Nine of 10 mice from the IBM group and 5 of 8 from the i.v. group did not become hyperglycemic, in contrast to the control group, in which 8 of 9 mice developed end-stage diabetes. All mice with >5% donor chimerism remained free of diabetes and insulitis, which was confirmed by histology. Splenocytes from transplanted mice were unresponsive to glutamic acid decarboxylase isoform 65, a diabeticspecific autoantigen, but responded normally to third-party antigens. ESC-derived HSC can induce an islet cell tolerizing GVA effect without GVHD. This study represents the first instance, to our knowledge, of ESC-derived HSC cells treating disease in an animal model. STEM CELLS 2008;26: 381-386 Disclosure of potential conflicts of interest is found at the end of this article.

No abstract