title: Expression of the CTL2 transcript variants in human peripheral blood cells and human tissues.
abstract: BACKGROUND
  The HNA-3a antigen is an important antibody target in the pathophysiology of transfusion-related acute lung injury (TRALI). It is encoded by the choline transporter-like protein 2 (CTL2) gene, which exists in the two transcript variants TV1 and TV2, differing in the upstream promoter and coding region. Only TV1 has been demonstrated to enable choline transport across the cell membrane.
  
  
  METHODS
  The aim of this study was to determine the CTL2 transcript pattern in human peripheral blood cells and tissues and its capacity to bind HNA-3a antibodies. RNA was isolated from human whole blood, isolated neutrophils, mononuclear blood cells, leukoreduced platelets, human lung, liver, and colon. After reverse transcription, the single-stranded cDNA was amplified using primer combinations specific for the respective transcript. Plasmids containing the entire CTL2 coding cDNA of the transcript variant TV1 or TV2 served as controls. HEK293T cells expressing both variants were used to determine the binding of HNA-3a antibodies.
  
  
  RESULTS
  The shorter TV2 transcript was demonstrated in each RNA sample derived from human peripheral blood tested so far, as well as in human lung and liver, whereas the longer TV1 transcript was only detected in human lung and colon. TV1 and TV2 had the same binding capacity to HNA-3a antibodies.
  
  
  CONCLUSIONS
  The expression of TV1 and TV2 is tissue and cell specific, with peripheral blood cells expressing only TV2. This does not affect binding of HNA-3a antibodies. Whether the unequal expression might be relevant in the pathogenesis of TRALI remains to be investigated.
authors.affiliation: German Red Cross Blood Service West, Bad Kreuznach and Hagen, Germany; Center for Innovation Competence: Humoral Immune Reactions in Cardiovascular Diseases (ZIK HIKE); Institute of Immunology and Transfusion Medicine, University Hospital Greifswald, Greifswald, Germany; Clinical and Experimental Pathology, Research Center Borstel, Airway Research Center North, Member of the German Center for Lung Research, Borstel, Germany.
authors.forename: Brigitte K
authors.initials: BK
authors.lastname: Flesch
authors.forename: Jan
authors.initials: J
authors.lastname: Wesche
authors.forename: Tom
authors.initials: T
authors.lastname: Berthold
authors.forename: Torsten
authors.initials: T
authors.lastname: Goldmann
authors.forename: Matthias
authors.initials: M
authors.lastname: Hundt
authors.forename: Andreas
authors.initials: A
authors.lastname: Greinacher
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bux
mesh_terms: D055371:Acute Lung Injury / Q000209:etiology; D001773:Blood Cells; D002460:Cell Line; D006801:Humans; D007519:Isoantigens / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics*; D026901:Membrane Transport Proteins / Q000235:genetics*
chemical_list: C518134:HNA-3a antigen, human; D007519:Isoantigens; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; C484524:SLC44A2 protein, human