title: The response of gamma-H2AX in human lymphocytes and lymphocytes subsets measured in whole blood cultures.
abstract: OBJECTIVE
  To assess the use of phosphorylated histone H2AX protein (gamma-H2AX) in human blood leukocytes as a rapid screening tool for radiation biodosimetry using a method that examines the characteristics of gamma-H2AX phosphorylation in a variety of lymphocyte subsets following exposure to radiation.
  
  
  METHODS
  Human peripheral blood exposed to 0-10 Gy of (137)Cs irradiation and cultured for 0-48 h was analysed using a rapid whole blood flow cytometry assay to measure gamma-H2AX phosphorylation in different lymphocyte subpopulations.
  
  
  RESULTS
  Lymphocyte subsets displayed a similar linear dose response relationship, although cluster of differentiation 4(+) (CD4(+)) and CD8(+) lymphocytes were found to express H2AX phosphorylation on the order of 1.5 times higher than CD19(+) lymphocytes. Phosphorylation of all lymphocyte subsets reached a maximum at 1.5 h and had essentially returned to baseline levels 24 h post-exposure.
  
  
  CONCLUSIONS
  Differences in the expression level of gamma-H2AX between lymphocyte subsets were minimal. The usefulness of this assay for radiation biodosimetry is hampered by its relatively quick lifetime kinetics and large inter-individual variation. Therefore, it could only be useful if samples were obtained within 24 h of exposure. Even in this situation, the assay could only be used as an indicator of exposure and not a dosimeter.
authors.affiliation: Department of Physics, Carleton University, Ottawa, ON, Canada.
authors.forename: Andrei
authors.initials: A
authors.lastname: Andrievski
authors.forename: Ruth C
authors.initials: RC
authors.lastname: Wilkins
mesh_terms: D000328:Adult; D000818:Animals; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005434:Flow Cytometry; D006657:Histones / Q000097:blood* / Q000378:metabolism; D006801:Humans; D016131:Lymphocyte Subsets / Q000378:metabolism* / Q000528:radiation effects*; D008214:Lymphocytes / Q000378:metabolism* / Q000528:radiation effects*; D008297:Male; D054527:Mass Casualty Incidents; D008875:Middle Aged; D010766:Phosphorylation; D011874:Radiometry / Q000379:methods*; D013997:Time Factors
chemical_list: C468783:H2AX protein, human; D006657:Histones