Identification of the human eosinophil lineage-committed progenitor: revision of phenotypic definition of the human common myeloid progenitor

To establish effective therapeutic strategies for eosinophil-related disorders, it is critical to understand the developmental pathway of human eosinophils. In mouse hematopoiesis, eosinophils originate from the eosinophil lineage-committed progenitor (EoP) that has been purified downstream of the granulocyte/macrophage progenitor (GMP). We show that the EoP is also isolatable in human adult bone marrow. The previously defined human common myeloid progenitor (hCMP) population (Manz, M.G., T. Miyamoto, K. Akashi, and I.L. Weissman. 2002. Proc. Natl. Acad. Sci. USA. 99:11872–11877) was composed of the interleukin 5 receptor α chain+ (IL-5Rα+) and IL-5Rα− fractions, and the former was the hEoP. The IL-5Rα+CD34+CD38+IL-3Rα+CD45RA− hEoPs gave rise exclusively to pure eosinophil colonies but never differentiated into basophils or neutrophils. The IL-5Rα− hCMP generated the hEoP together with the hGMP or the human megakaryocyte/erythrocyte progenitor (hMEP), whereas hGMPs or hMEPs never differentiated into eosinophils. Importantly, the number of hEoPs increased up to 20% of the conventional hCMP population in the bone marrow of patients with eosinophilia, suggesting that the hEoP stage is involved in eosinophil differentiation and expansion in vivo. Accordingly, the phenotypic definition of hCMP should be revised to exclude the hEoP; an “IL-5Rα–negative” criterion should be added to define more homogenous hCMP. The newly identified hEoP is a powerful tool in studying pathogenesis of eosinophilia and could be a therapeutic target for a variety of eosinophil-related disorders

Hyperacute ischemic stroke treated with carotid-carotid artery bypass surgery “case report”

Thrombolytic therapy using heparin, urokinase, and tissue plasminogen activator (tPA) has been the standard treatment for hyperacute ischemic stroke (HIS) with worsening carotid artery stenosis. In recent years, endovascular treatments (thrombectomy and carotid artery stenting) have attracted attention, and neurosurgeons are increasingly participating in these treatments. A 70-year-old Japanese male presented to our hospital with aphasia and right hemiparesis. Emergency computed tomography ([CT] CT angiography and perfusion CT) revealed a small infarct core and a large hemiparesis due to occlusion near the left common carotid artery orifice. Because of hemorrhagic sequelae, tPA was not administered, and emergency endovascular treatment failed. Therefore, a bilateral common carotid artery bypass surgery was performed. Revascularization was performed within 51 min of the start of the surgery, and the time from onset to revascularization was 5 h. Aphasia and right hemiparesis resolved immediately after surgery. The only sequela observed was mild dyskinesia. Our report is the first to show that bilateral common carotid artery bypass is a novel and effective treatment for HIS

Development of functional human blood and immune systems in NOD/SCID/IL2 receptor γ chainnull mice

Here we report that a new nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse line harboring a complete null mutation of the common cytokine receptor γ chain (NOD/SCID/interleukin 2 receptor [IL2r] γnull) efficiently supports development of functional human hemato-lymphopoiesis. Purified human (h) CD34+ or hCD34+hCD38– cord blood (CB) cells were transplanted into NOD/SCID/IL2rγnull newborns via a facial vein. In all recipients injected with 105 hCD34+ or 2 × 104 hCD34+hCD38– CB cells, human hematopoietic cells were reconstituted at approximately 70% of chimerisms. A high percentage of the human hematopoietic cell chimerism persisted for more than 24 weeks after transplantation, and hCD34+ bone marrow grafts of primary recipients could reconstitute hematopoiesis in secondary NOD/SCID/IL2rγnull recipients, suggesting that this system can support self-renewal of human hematopoietic stem cells. hCD34+hCD38– CB cells differentiated into mature blood cells, including myelomonocytes, dendritic cells, erythrocytes, platelets, and lymphocytes. Differentiation into each lineage occurred via developmental intermediates such as common lymphoid progenitors and common myeloid progenitors, recapitulating the steady-state human hematopoiesis. B cells underwent normal class switching, and produced antigen-specific immunoglobulins (Igs). T cells displayed the human leukocyte antigen (HLA)–dependent cytotoxic function. Furthermore, human IgA-secreting B cells were found in the intestinal mucosa, suggesting reconstitution of human mucosal immunity. Thus, the NOD/SCID/IL2rγnull newborn system might be an important experimental model to study the human hemato-lymphoid system