title: Increased apoptotic peripheral blood neutrophils in systemic lupus erythematosus: relations with disease activity, antibodies to double stranded DNA, and neutropenia.
abstract: OBJECTIVE
  To quantify the percentage of apoptotic peripheral blood neutrophils in systemic lupus erythematosus (SLE) and to determine the relations with disease activity and neutropenia.
  
  
  METHODS
  Neutrophil apoptosis in SLE patients (n =50) was assessed by flow cytometry using annexin V binding and fluorescent labelled anti-fas. Rheumatoid arthritis (RA, n =20) and inflammatory bowel disease patients (IBD, n =20) were studied as disease controls.
  
  
  RESULTS
  The percentage of apoptotic neutrophils, determined by annexin V binding, was increased in peripheral blood of SLE patients (median = 3.25%) compared with normal healthy donors (n =20, median = 1.20%) and disease controls (RA: median = 1.15%) (IBD: median = 1.15%). SLE neutrophil apoptosis correlated positively with lupus disease activity measured by SLAM score. SLE patients with increased antibodies to dsDNA (>10 mg/ml) had increased apoptotic neutrophils. Eight of 14 neutropenic SLE patients had increased apoptotic neutrophils. Increased neutrophil fas expression compared with normal controls was observed in SLE, RA, and IBD.
  
  
  CONCLUSIONS
  Neutrophil fas expression is increased non-specifically in inflammatory disease. Increased circulating apoptotic neutrophils in SLE correlate positively with disease activity (SLAM) and may contribute to autoantigen excess including dsDNA.
authors.affiliation: Department of Rheumatology, Musgrave Park Hospital, Stockman's Lane, Belfast BT9 7JB.
authors.forename: P A
authors.initials: PA
authors.lastname: Courtney
authors.forename: A D
authors.initials: AD
authors.lastname: Crockard
authors.forename: K
authors.initials: K
authors.lastname: Williamson
authors.forename: A E
authors.initials: AE
authors.lastname: Irvine
authors.forename: R J
authors.initials: RJ
authors.lastname: Kennedy
authors.forename: A L
authors.initials: AL
authors.lastname: Bell
mesh_terms: D000974:Antibodies, Antinuclear / Q000032:analysis*; D017209:Apoptosis; D016022:Case-Control Studies; D016179:Granulocyte Colony-Stimulating Factor / Q000097:blood; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000097:blood; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D009503:Neutropenia / Q000276:immunology*; D009504:Neutrophils / Q000502:physiology*; D018709:Statistics, Nonparametric
chemical_list: D000974:Antibodies, Antinuclear; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor