title: Comparative quantitative analysis of cluster of differentiation 45 antigen expression on lymphocyte subsets.
abstract: BACKGROUND
  Since the recent introduction of radioimmunotherapy (RIT) using antibodies against cluster of differentiation (CD) 45 for the treatment of lymphoma, the clinical significance of the CD45 antigen has been increasing steadily. Here, we analyzed CD45 expression on lymphocyte subsets using flow cytometry in order to predict the susceptibility of normal lymphocytes to RIT.
  
  
  METHODS
  Peripheral blood specimens were collected from 14 healthy individuals aged 25-54 yr. The mean fluorescence intensity (MFI) of the cell surface antigens was measured using a FACSCanto II system (Becton Dickinson Bioscience, USA). MFI values were converted into antibody binding capacity values using a Quantum Simply Cellular microbead kit (Bangs Laboratories, Inc., USA).
  
  
  RESULTS
  Among the lymphocyte subsets, the expression of CD45 was the highest (725,368±42,763) on natural killer T (NKT) cells, 674,030±48,187 on cytotoxic/suppressor T cells, 588,750±48,090 on natural killer (NK) cells, 580,211±29,168 on helper T (Th) cells, and 499,436±21,737 on B cells. The Th cells and NK cells expressed a similar level of CD45 (P=0.502). Forward scatter was the highest in NKT cells (P<0.05), whereas side scatter differed significantly between each of the lymphocyte subsets (P<0.05). CD3 expression was highest in the Th and NKT cells.
  
  
  CONCLUSIONS
  NKT cells express the highest levels of CD45 antigen. Therefore, this lymphocyte subset would be most profoundly affected by RIT or pretargeted RIT. The monitoring of this lymphocyte subset during and after RIT should prove helpful.
authors.affiliation: Department of Laboratory Medicine, Graduate School, The Catholic University of Korea, College of Medicine, Seoul, Korea.
authors.forename: Mijeong
authors.initials: M
authors.lastname: Im
authors.forename: Hyojin
authors.initials: H
authors.lastname: Chae
authors.forename: Taehoon
authors.initials: T
authors.lastname: Kim
authors.forename: Hun-Hee
authors.initials: HH
authors.lastname: Park
authors.forename: Jihyang
authors.initials: J
authors.lastname: Lim
authors.forename: Eun-Jee
authors.initials: EJ
authors.lastname: Oh
authors.forename: Yonggoo
authors.initials: Y
authors.lastname: Kim
authors.forename: Yeon-Joon
authors.initials: YJ
authors.lastname: Park
authors.forename: Kyungja
authors.initials: K
authors.lastname: Han
mesh_terms: D000328:Adult; D000906:Antibodies / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000032:analysis* / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism*; D008223:Lymphoma / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D055611:Natural Killer T-Cells / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding; D016499:Radioimmunotherapy; D011933:Reagent Kits, Diagnostic; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology / Q000378:metabolism
chemical_list: D000906:Antibodies; D005456:Fluorescent Dyes; D011933:Reagent Kits, Diagnostic; D017493:Leukocyte Common Antigens; D016650:Fluorescein-5-isothiocyanate