We report a case of pure red cell aplasia (PRCA) subsequent to an allogeneic bone marrow transplantation with a major ABO mismatch, which was resistant to the standard treatment options such as plasma exchange, erythropoietin and changes in the immunosuppressive treatment. Accordingly, two cycles of Rituximab therapy were administered without success. The patient had a chronic graft-vs.-host disease of the liver, which meant that an additional donor leukocyte infusion could not be introduced. Instead, purified CD34(+) cells were administered after fludarabine and antithymocyte globulin therapy. As a result, the PRCA was resolved and the antidonor isohemagglutinin titer became undetectable.
Myogenic progenitors (MPs) generate myocytes that fuse to form myofibers during skeletal muscle development while maintaining the progenitor pool, which is crucial for generating sufficient muscle. Notch signaling has been known to reserve a population of embryonic MPs during primary myogenesis by promoting cell cycle exit and suppressing premature differentiation. However, the roles of individual Notch receptors (Notch1-4) during embryonic/fetal myogenesis are still elusive. In this study, we found that Notch1 and Notch2, which exhibit the highest structural similarity among Notch receptors, maintain the MP population by distinct mechanisms: Notch1 induces cell cycle exit and Notch2 suppresses premature differentiation. Moreover, genetic and cell culture studies showed that Notch1 and Notch2 signaling in MPs are distinctively activated by interacting with Notch ligand-expressing myofibers and MP-lineage cells, respectively. These results suggest that through different activation modes, Notch1 and Notch2 distinctively and cooperatively maintain MP population during fetal myogenesis for proper muscle development.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.