title: Impaired phagocytosis of apoptotic cell material by monocyte-derived macrophages from patients with systemic lupus erythematosus.
abstract: OBJECTIVE
  To investigate whether the established impaired phagocyte function in systemic lupus erythematosus (SLE) patients also affects apoptotic cell clearance. Accumulation of apoptotic waste as a source for autoantigens that induce and maintain autoimmune responses is discussed.
  
  
  METHODS
  Apoptosis was detected by morphology and propidium iodide staining. In vitro phagocytosis of autologous apoptotic cells in cultured peripheral blood mononuclear cells was evaluated microscopically. Cross-feeding experiments were performed to investigate phagocytosis of heterologous apoptotic cells by in vitro-differentiated macrophages. Furthermore, the effect of annexin V on the phagocytosis of apoptotic cells was investigated.
  
  
  RESULTS
  Reduced clearance of apoptotic cells in SLE patients was observed. The defective clearance appeared to reflect phagocyte dysfunction and not an abnormal execution of apoptosis. A similar picture was seen when in vitro-differentiated macrophages from control populations were treated with annexin V.
  
  
  CONCLUSIONS
  Noninflammatory engulfment phagocytosis of apoptotic cells is decreased in SLE patients. Persistently circulating apoptotic waste may encounter inflammatory removal pathways and serve as immunogen for the induction of autoreactive lymphocytes and as antigen for immune complex formation.
authors.affiliation: Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Herrmann
authors.forename: R E
authors.initials: RE
authors.lastname: Voll
authors.forename: O M
authors.initials: OM
authors.lastname: Zoller
authors.forename: M
authors.initials: M
authors.lastname: Hagenhofer
authors.forename: B B
authors.initials: BB
authors.lastname: Ponner
authors.forename: J R
authors.initials: JR
authors.lastname: Kalden
mesh_terms: D017304:Annexin A5 / Q000494:pharmacology; D017209:Apoptosis; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000473:pathology*; D008264:Macrophages / Q000187:drug effects / Q000473:pathology*; D010587:Phagocytosis / Q000187:drug effects
chemical_list: D017304:Annexin A5