title: Increased percentages of PD-1 on CD4+ T cells is associated with higher INF-γ production and altered IL-17 production in patients with systemic lupus erythematosus.
abstract: OBJECTIVE
  Programmed death (PD)-1 is a cell death receptor that, upon stimulation, leads to apoptosis. Previous studies have shown alteration of PD-1 expression on T cells and PD-1 genes in patients with systemic lupus erythematosus (SLE). The aim of this study was to assess the expression of this receptor on effector T cells in patients with SLE.
  
  
  METHODS
  In this study we enrolled 32 SLE patients and 31 healthy controls. T cells from peripheral blood were analysed by flow cytometry for the expression of PD-1. Interferon (IFN)-γ and interleukin (IL)-17-producing cells were investigated for the expression of this co-stimulatory marker.
  
  
  RESULTS
  Percentages of CD4(+) T cells expressing PD-1 were significantly increased in patients with SLE compared to healthy controls. The percentage of PD-1 expression was correlated with the production of INF-γ (r = 0.83, p < 0.0001). We also investigated the production of IL-17 by PD-1(+) CD3(+) T cells. Inactive patients (3.2 ± 1.2% vs. 5.9 ± 3.5%, p = 0.002) and patients without lupus nephritis (LN) (3.2 ± 1.5% vs. 5.9 ± 3.5%, p = 0.005) showed lower levels of IL-17 compared to healthy controls.
  
  
  CONCLUSIONS
  We have demonstrated increased expression of PD-1 on CD4(+) T cells in SLE patients and an association between PD-1 expression on CD4(+) T cells and IFN-γ expression on CD3(+) T cells. We have also shown that there is an altered subset of PD-1(+) T cells in inactive patients and patients without LN producing lower amounts of IL-17.
authors.affiliation: Department of Nephrology, University Hospital Essen, University Duisburg-Essen , Essen , Germany.
authors.forename: S
authors.initials: S
authors.lastname: Dolff
authors.forename: D
authors.initials: D
authors.lastname: Quandt
authors.forename: T
authors.initials: T
authors.lastname: Feldkamp
authors.forename: C
authors.initials: C
authors.lastname: Jun
authors.forename: A
authors.initials: A
authors.lastname: Mitchell
authors.forename: F
authors.initials: F
authors.lastname: Hua
authors.forename: C
authors.initials: C
authors.lastname: Specker
authors.forename: A
authors.initials: A
authors.lastname: Kribben
authors.forename: O
authors.initials: O
authors.lastname: Witzke
authors.forename: B
authors.initials: B
authors.lastname: Wilde
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D020381:Interleukin-17 / Q000378:metabolism*; D008180:Lupus Erythematosus, Systemic / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D061026:Programmed Cell Death 1 Receptor / Q000378:metabolism*
chemical_list: D020381:Interleukin-17; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor; D007371:Interferon-gamma