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Blood, 15 April 2006, Vol. 107, No. 8, pp. 3138-3144. Prepublished online as a Blood First Edition Paper on December 22, 2005; DOI 10.1182/blood-2005-07-2804. This Article Full Text Full Text (PDF) All Versions of this Article: 2005-07-2804v1 107/8/3138    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Kotsianidis, I. Articles by Karadimitris, A. Search for Related Content PubMed PubMed Citation Articles by Kotsianidis, I. Articles by Karadimitris, A. Related Collections Hematopoiesis and Stem Cells Immunobiology Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  HEMATOPOIESIS Regulation of hematopoiesis in vitro and in vivo by invariant NKT cells Ioannis Kotsianidis, Jonathan D. Silk, Emmanouil Spanoudakis, Scott Patterson, Antonio Almeida, Richard R. Schmidt, Costas Tsatalas, George Bourikas, Vincenzo Cerundolo, Irene A. G. Roberts, and Anastasios Karadimitris From the Department of Haematology, Hammersmith Hospital, Imperial College London, United Kingdom; the Department of Haematology, Democritus University of Thrace Medical School, Alexandroupolis, Greece; the Tumour Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford, United Kingdom; and the Department of Chemistry, University of Konstanz, Germany. Invariant natural killer T cells (iNKT cells) are a small subset of immunoregulatory T cells highly conserved in humans and mice. On activation by glycolipids presented by the MHC-like molecule CD1d, iNKT cells promptly secrete T helper 1 and 2 (Th1/2) cytokines but also cytokines with hematopoietic potential such as GM-CSF. Here, we show that the myeloid clonogenic potential of human hematopoietic progenitors is increased in the presence of glycolipid-activated, GM-CSF–secreting NKT cells; conversely, short- and long-term progenitor activity is decreased in the absence of NKT cells, implying regulation of hematopoiesis in both the presence and the absence of immune activation. In accordance with these findings, iNKT-cell–deficient mice display impaired hematopoiesis characterized by peripheral-blood cytopenias, reduced marrow cellularity, lower frequency of hematopoietic stem cells (HSCs), and reduced early and late hematopoietic progenitors. We also show that CD1d is expressed on human HSCs. CD1d-expressing HSCs display short- and long-term clonogenic potential and can present the glycolipid -galactosylceramide to iNKT cells. Thus, iNKT cells emerge as the first subset of regulatory T cells that are required for effective hematopoiesis in both steady-state conditions and under conditions of immune activation. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: L. Gargiulo, S. Lastraioli, G. Cerruti, M. Serra, F. Loiacono, S. Zupo, L. Luzzatto, and R. Notaro Highly homologous T-cell receptor beta sequences support a common target for autoreactive T cells in most patients with paroxysmal nocturnal hemoglobinuria Blood, June 1, 2007; 109(11): 5036 - 5042. [Abstract] [Full Text] [PDF] D. H. Chang, N. Liu, V. Klimek, H. Hassoun, A. Mazumder, S. D. Nimer, S. Jagannath, and M. V. Dhodapkar Enhancement of ligand-dependent activation of human natural killer T cells by lenalidomide: therapeutic implications Blood, July 15, 2006; 108(2): 618 - 621. [Abstract] [Full Text] [PDF]

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