title: CD57+ T-cells are a subpopulation of T-follicular helper cells in nodular lymphocyte predominant Hodgkin lymphoma.
abstract: BACKGROUND
  Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is characterized by lymphocyte-predominant (LP) cells in a background of CD4+ CD57+ T-cells. These cells are normally present in the germinal center of lymphoid tissues. The cells rosetting LP cells are described to be PD-1 and BCL-6 positive, which are markers of T-follicular helper cells. This study was designed to address the question: are the CD57+ T cells in germinal centers of tonsil and NLPHL TFH cells?
  
  
  RESULTS
  Immunohistochemistry was performed on tonsil and NLPHL. For tonsil, cells per germinal center and for NLPHL, the area around LP cells was counted. Cells rosetting LP cells were also determined. In addition, flowcytometry was performed on cell suspensions. Cells directly rosetting LP cells are positive for CD57 and/or for two markers of T-follicular helper (TFH) cells, PD-1 and BCL-6. We show that in both tonsil and NLPHL more than 90 % of CD57+ T-cells are also positive for PD-1, whereas roughly half of the PD-1+ T-cells are CD57+. CD57+ cells co-express BCL-6 in tonsil and in the rosetting cells of NLPHL.
  
  
  CONCLUSIONS
  We conclude that CD57+ T-cells are TFH cells and form a subpopulation of TFH cells in tonsils and NLPHL.
authors.affiliation: Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Sattarzadeh
authors.affiliation: Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Arjan
authors.initials: A
authors.lastname: Diepstra
authors.affiliation: Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Bea
authors.initials: B
authors.lastname: Rutgers
authors.affiliation: Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Anke
authors.initials: A
authors.lastname: van den Berg
authors.affiliation: Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Lydia
authors.initials: L
authors.lastname: Visser
keywords: CD57+ T cells; Nodular predominant Hodgkin lymphoma; TFH cells