title: Estimation of systemic complement C3 activity in age-related macular degeneration.
abstract: OBJECTIVE
  To determine the role of systemic complement activation in the pathogenesis of age-related macular degeneration and to examine whether serum C3a des Arg reflects systemic complement activation, independent of individual complement component levels.
  
  
  METHODS
  Plasma complement C3a des Arg levels and a single nucleotide polymorphism at position 402 of the complement factor H gene (CFH) were determined in 3 groups of subjects: 42 subjects with early age-related maculopathy, 42 subjects with neovascular (wet) age-related macular degeneration, and a control group of 38 subjects with no clinical evidence of age-related changes at the macula.
  
  
  RESULTS
  The median (range) of plasma complement C3a des Arg levels in the age-related maculopathy and neovascular age-related macular degeneration groups were 52.6 (2.8-198.1) ng/mL and 60.9 (3.1-173.1) ng/mL, respectively. The levels were significantly raised compared with the control group (n = 38), which had a median (range) plasma complement C3a des Arg level of 40.3 (6.1-81.7) ng/mL (analysis of variance, P = .02). The concentration of plasma C3a des Arg did not differ significantly between those with different CFH genotypes (P = .07).
  
  
  CONCLUSIONS
  Systemic activation of the complement system may contribute to the pathogenesis of age-related macular degeneration independent of CFH polymorphism.
  
  
  CONCLUSIONS
  The results of this study may be relevant to aiming new treatment strategies toward reducing systemic low-grade inflammation.
authors.affiliation: Laser and Retinal Research Unit, King's College Hospital, King's College London, England. senswathi@aol.com
authors.forename: Sobha
authors.initials: S
authors.lastname: Sivaprasad
authors.forename: Temi
authors.initials: T
authors.lastname: Adewoyin
authors.forename: Tracey A
authors.initials: TA
authors.lastname: Bailey
authors.forename: Sam S
authors.initials: SS
authors.lastname: Dandekar
authors.forename: Sharon
authors.initials: S
authors.lastname: Jenkins
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Webster
authors.forename: Ngaihang Victor
authors.initials: NV
authors.lastname: Chong
mesh_terms: D020256:Choroidal Neovascularization / Q000097:blood* / Q000209:etiology / Q000235:genetics; D003167:Complement Activation / Q000502:physiology*; D015926:Complement C3a / Q000032:analysis*; D017242:Complement Factor H / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005838:Genotype; D006801:Humans; D008268:Macular Degeneration / Q000097:blood* / Q000209:etiology / Q000235:genetics; D020641:Polymorphism, Single Nucleotide
chemical_list: C493495:CFH protein, human; C044541:complement C3a, des-Arg-(77)-; D015926:Complement C3a; D017242:Complement Factor H