Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Signal-regulatory proteins (SIRPs) comprise a novel transmembrane glycoprotein family involved in the negative regulation of receptor tyrosine kinase-coupled signaling pathways. To analyze the expression and function of SIRPs, we prepared soluble recombinant fusion proteins of the extracellular regions of SIRPalpha1 and SIRPalpha2, as well as a variety of monoclonal antibodies (MoAbs) against these domains. The antibodies reacted predominantly with monocytes, granulocytes, dendritic cells, and their precursors, as well as with bone marrow CD34(+), AC133(+), CD90(+) hematopoietic stem/progenitor cells. In contrast, SIRP expression was absent or significantly reduced on the majority of myeloid blasts from patients with acute myeloid leukemia (AML) or chronic myeloid leukemia (CML). Functional studies showed that the extracellular domains of SIRPalpha1 and SIRPalpha2 support adhesion of a number of primary hematopoietic cells and cell lines. This interaction could be blocked by 4 of 7 SIRPalpha1-reactive MoAbs. In addition, SIRPalpha1 and SIRPalpha2 competed for the same cell binding site, suggesting a common widely expressed SIRP ligand. In an approach to identify this molecule, MoAbs were generated against the SIRP-binding cell line CCRF-CEM, and MoAb CC2C6 was selected because of its capacity to inhibit cell binding to SIRPalpha1. Further analysis showed that this antibody recognized CD47, a ubiquitously expressed plasma membrane protein previously implicated in integrin function, host defense action, and neutrophil migration. In this study, we identify CD47 as the extracellular ligand for human SIRP and show that these two counterreceptors are involved in cellular adhesion.
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PMID:Human signal-regulatory protein is expressed on normal, but not on subsets of leukemic myeloid cells and mediates cellular adhesion involving its counterreceptor CD47. 1057 74

Unless they undergo transplantation, all patients with chronic myeloid leukemia (CML) will eventually develop a late phase of acute blast crisis (ABC). Although additional chromosomal abnormalities to the Philadelphia (Ph) chromosome may herald ABC in many CML cases, the mechanisms leading to this fatal event are obscure. Viral etiology, including the Epstein-Barr virus (EBV) has never been implicated in the pathogenesis of ABC in CML. Iloprost is an analogue of epoprostenol (prostacyclin; PGI2) commonly used for the treatment of peripheral vascular diseases and acts via inhibition of platelet activation, and by vasodilation. A case of ABC with blasts of undetermined lineage showing EBV infection in a male patient with Ph positive CML is described here. This unusual event developed during a course of treatment with the prostacyclin analogue, iloprost administered for vasculopathic leg ulcers. The proliferating blasts stained positively by immunohistochemistry only for the leukocyte common antigen (LCA/CD-45), and the EBV-latent membrane protein 1 (LMP-1). The only chromosomal abnormality detected by cytogenetic analysis was the conventional Ph-chromosome. It is suggested that ABC in this case of CML, was associated with EBV-activated blasts of undetermined lineage.
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PMID:Acute blast crisis with EBV-infected blasts, in a patient with chronic myeloid leukemia, and vasculitis. 1075 95

The erythrocyte skeleton plays an essential role in determining the shape and deformability of the red cell. Disruption of the interaction between components of the red cell membrane skeleton may cause loss of structural and functional integrity of the membrane. Several observations based on studies in vitro strongly suggest that phosphorylation may modify interactions between proteins, leading to a reduced affinity. In particular, increased phosphorylation of beta-spectrin decreases membrane mechanical stability. In order to investigate the presence of membrane protein defects we investigated the erythrocyte membrane protein composition and phosphorylation in 22 children with leukemia at diagnosis and during the remission phase. Sixteen children had acute lymphoblastic leukemia (ALL), three had chronic myeloid leukemia (CML) and three had acute myeloid leukemia (AML). Ten patients (eight ALL and two CML) displayed elliptocytosis and poikilocytosis, an increase of spectrin dimers (41.8 +/- 15.6) and an enhanced phosphorylation of beta-spectrin (108 +/- 15%) at diagnosis. These alterations disappeared during the remission phase. This is the first demonstration of a reversible erythrocyte membrane alteration in leukemia. Since the beta-spectrin phosphate sites are located near the C-terminal region and close to the head of the beta-chain that is involved in dimer-dimer interaction, we supposed that the beta-chain phosphorylation has an effect upon the interactions between spectrin dimers, ie the tetramerization process. The weakening of this process should be responsible for the presence of elliptocytes and poikilocytes as reported in hereditary elliptocytosis and pyropoikilocytosis.
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PMID:Reversible erythrocyte skeleton destabilization is modulated by beta-spectrin phosphorylation in childhood leukemia. 1123 68


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