title: Expression of Programmed Death 1 Ligand in Different Compartments of Chronic Lymphocytic Leukemia.
abstract: BACKGROUND
  The programmed death 1 (PD-1) receptor pathway is responsible for the negative regulation of both T and B lymphocytes upon activation of these cells. There is growing evidence that chronic lymphocytic leukemia (CLL) cells exploit the PD-1 ligand (PD-L1) to resist antitumor immune reactions and maintain their survival by shaping their own microenvironment.
  
  
  METHODS
  We used a quantitative RT-PCR method to analyze PD-L1 gene expression in bone marrow and peripheral blood mononuclear cells, representing the proliferation and accumulation compartments of CLL.
  
  
  RESULTS
  PD-L1 expression was found to be significantly higher in 112 CLL patients than in controls. Levels of PD-L1 expression in bone marrow and peripheral blood were comparable and showed a positive correlation. Furthermore, expression of PDL1 strongly correlated with expression of PD-1 receptor in mononuclear cells from the same compartment, and was not affected by incubation with immunomodulatory drug thalidomide.
  
  
  CONCLUSIONS
  PD-L1 expression is shared between CLL cells localized in distinct disease compartments, demonstrating that PD-1/PD-L1 a universal target for therapy.
authors.forename: Maciej
authors.initials: M
authors.lastname: Grzywnowicz
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Karczmarczyk
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Skorka
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Zajac
authors.forename: Joanna
authors.initials: J
authors.lastname: Zaleska
authors.forename: Sylwia
authors.initials: S
authors.lastname: Chocholska
authors.forename: Waldemar
authors.initials: W
authors.lastname: Tomczak
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Giannopoulos
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D060890:B7-H1 Antigen / Q000096:biosynthesis*; D001854:Bone Marrow Cells / Q000378:metabolism* / Q000473:pathology; D005260:Female; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood* / Q000473:pathology / Q000628:therapy; D007963:Leukocytes, Mononuclear / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D061026:Programmed Cell Death 1 Receptor / Q000096:biosynthesis
chemical_list: D060890:B7-H1 Antigen; C423236:CD274 protein, human; D009363:Neoplasm Proteins; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor