title: Programmed death-1 expression in cutaneous B-cell lymphoma.
abstract: BACKGROUND
  Numbers of programmed death-1 (PD-1) positive T cells have prognostic significance in some types of nodal B-cell lymphomas, but data on PD-1 expression in cutaneous B-cell lymphoma (CBCL) are few. In this study we determined the expression and distribution of PD-1 on neoplastic B cells and reactive T cells in skin sections from primary CBCLs.
  
  
  METHODS
  By means of immunohistochemical staining, PD-1 expression was investigated in skin biopsies from 10 patients with primary cutaneous marginal zone lymphoma (PCMZL), 18 patients with primary cutaneous follicle center lymphoma (PCFCL) and 12 patients with primary cutaneous diffuse large B-cell lymphoma-leg type (PCDLBCL-LT).
  
  
  RESULTS
  Neoplastic B cells were negative for PD-1 in all cases, except for two cases of PCDLBCL-LT. The frequency of PD-1(+) T cells was significantly higher in PCFCL than in PCMZL and PCDLBCL-LT, accounting for 20, 10 and 3% of the total number of infiltrating cells, and 60, 20 and 15% of the total number of CD3(+) T cells, respectively.
  
  
  CONCLUSIONS
  PD-1 is rarely expressed by the neoplastic B cells in CBCL. High percentages of PD-1(+) T cells, particularly if found outside germinal centers, support a diagnosis of PCFCL.
authors.affiliation: Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Fatma
authors.initials: F
authors.lastname: Çetinözman
authors.forename: Lianne
authors.initials: L
authors.lastname: Koens
authors.forename: Patty M
authors.initials: PM
authors.lastname: Jansen
authors.forename: Rein
authors.initials: R
authors.lastname: Willemze
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D016393:Lymphoma, B-Cell / Q000378:metabolism / Q000473:pathology*; D008224:Lymphoma, Follicular / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D061026:Programmed Cell Death 1 Receptor / Q000378:metabolism*; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology*; D013601:T-Lymphocytes / Q000378:metabolism* / Q000473:pathology; D055815:Young Adult
chemical_list: C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor
keywords: PD-1; cutaneous B-cell lymphoma; follicular helper T cell; non-Hodgkin lymphoma