title: Plasma levels of complement proteins from the alternative pathway in patients with age-related macular degeneration are independent of Complement Factor H Tyr⁴⁰²His polymorphism.
abstract: OBJECTIVE
  To investigate the influence of the Factor H (CFH) Tyr⁴⁰²His polymorphism on the plasma levels of the alternative pathway proteins CFH, C3, Factor B (FB), Factor D (FD), and Factor I (FI) and the inflammatory marker C-reactive protein (CRP) in 119 patients with age-related macular degeneration (AMD) and 152 unrelated control individuals.
  
  
  METHODS
  Patients with AMD and the control group were separated according to CFH polymorphism, age, and gender. Plasma complement proteins and CRP concentrations were determined with enzyme-linked immunosorbent assay, immunodiffusion, or nephelometry.
  
  
  RESULTS
  Significant differences in the concentrations of FD and FI were observed between the patients with AMD and the control individuals. We observed significantly reduced FD plasma levels in patients with AMD. We also identified a significant decrease in CFH plasma levels in female patients with AMD in relation to female controls. Plasma FI levels were significantly increased in patients with AMD compared to the control group. Regarding gender, a significant increase in FI plasma levels was observed in male patients. Finally, we found no significant correlation between the CFH Tyr(402)His polymorphism and the CFH, C3, FB, FD, FI, and CRP plasma levels.
  
  
  CONCLUSIONS
  Patients with AMD present altered levels of FD and FI in a manner independent of this CFH polymorphism, and gender apparently contributes to the plasma levels of these two proteins in patients with AMD and control individuals.
authors.affiliation: Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Aldacilene Souza
authors.initials: AS
authors.lastname: Silva
authors.forename: Anderson Gustavo
authors.initials: AG
authors.lastname: Teixeira
authors.forename: Lorena
authors.initials: L
authors.lastname: Bavia
authors.forename: Fabio
authors.initials: F
authors.lastname: Lin
authors.forename: Roberta
authors.initials: R
authors.lastname: Velletri
authors.forename: Rubens
authors.initials: R
authors.lastname: Belfort
authors.forename: Lourdes
authors.initials: L
authors.lastname: Isaac
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D003176:Complement C3 / Q000378:metabolism; D011415:Complement Factor B / Q000378:metabolism; D011416:Complement Factor D / Q000378:metabolism; D017242:Complement Factor H / Q000235:genetics* / Q000378:metabolism; D017244:Complement Factor I / Q000378:metabolism; D003170:Complement Pathway, Alternative / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005838:Genotype; D006801:Humans; D008268:Macular Degeneration / Q000097:blood / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D012737:Sex Factors
chemical_list: D003176:Complement C3; D017242:Complement Factor H; D002097:C-Reactive Protein; D017244:Complement Factor I; D011416:Complement Factor D; D011415:Complement Factor B