title: Common expression of an unusual CD45 isoform on T cells from patients with large granular lymphocyte leukaemia and autoimmune lymphoproliferative syndrome.
abstract: Patients with T-cell large granular lymphocyte (T-LGL) leukaemia and autoimmune lymphoproliferative syndrome (ALPS) share many features, including autoimmunity and an expansion of (cytotoxic) T cells, which in ALPS patients express an unusual (B220) isoform of CD45, corresponding to an altered O-glycosylation profile. Here we showed that T-LGL leukaemia cells also expressed this B220 isoform. We hypothesize that B220+ T cells constitute proliferating T cells that have become competent to undergo apoptosis, but that constitutive (ALPS) or functional (T-LGL) defects prevent this process. Altered O-glycosylation of the extracellular domains of CD45 may have consequences for this tyrosine phosphatase as a regulator of cell proliferation and survival.
authors.affiliation: The Immunology Service, Department of Laboratory Medicine, Clinical Center and Metabolism Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. BlessingJacobH@uams.edu
authors.forename: Jack J H
authors.initials: JJ
authors.lastname: Bleesing
authors.forename: John E
authors.initials: JE
authors.lastname: Janik
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Fleisher
mesh_terms: D017209:Apoptosis; D001327:Autoimmune Diseases / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002455:Cell Division; D005434:Flow Cytometry; D006031:Glycosylation; D006801:Humans; D015458:Leukemia, T-Cell / Q000276:immunology*; D017493:Leukocyte Common Antigens / Q000032:analysis*; D008232:Lymphoproliferative Disorders / Q000276:immunology*; D020033:Protein Isoforms / Q000032:analysis*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D020033:Protein Isoforms; D017493:Leukocyte Common Antigens