title: Polymorphisms of CD16A and CD32 Fcγ receptors and circulating immune complexes in Ménière's disease: a case-control study.
abstract: BACKGROUND
  Autoimmune diseases with elevated circulating autoantibodies drive tissue damage and the onset of disease. The Fcγ receptors bind IgG subtypes modulating the clearance of circulating immune complexes (CIC). The inner ear damage in Ménière's disease (MD) could be mediated by an immune response driven by CIC. We examined single-nucleotide polymorphism (SNPs) in the CD16A and CD32 genes in patients with MD which may determine a Fcγ receptor with lower binding to CIC.
  
  
  METHODS
  The functional CD16A (FcγRIIIa*559A > C, rs396991) and CD32A (FcγRIIa*519A > G, rs1801274) SNPs were analyzed using PCR-based TaqMan Genotyping Assay in two cohorts of 156 mediterranean and 112 Galicia patients in a case-control study. Data were analyzed by χ2 with Fisher's exact test and Cochran-Armitage trend test (CATT). CIC were measured by ELISA for C1q-binding CIC.
  
  
  RESULTS
  Elevated CIC were found in 7% of patients with MD during the intercrisis period. No differences were found in the allelic frequency for rs396991 or rs1801274 in controls subjects when they were compared with patients with MD from the same geographic area. However, the frequency of AA and AC genotypes of CD16A (rs396991) differed among mediterranean and Galicia controls (Fisher's test, corrected p = 6.9 × 10-4 for AA; corrected p = 0.02 for AC). Although genotype AC of the CD16A receptor was significantly more frequent in mediterranean controls than in patients, [Fisher's test corrected p = 0.02; OR = 0.63 (0.44-0.91)], a genetic additive effect for the allele C was not observed (CATT, p = 0.23). Moreover, no differences were found in genotype frequencies for rs396991 between patients with MD and controls from Galicia (CATT, p = 0.14). The allelic frequency of CD32 (rs1801274) was not different between patients and controls either in mediterranean (p = 0.51) or Galicia population (p = 0.11).
  
  
  CONCLUSIONS
  Elevated CIC are not found in most of patients with MD. Functional polymorphisms of CD16A and CD32 genes are not associated with onset of MD.
authors.affiliation: Otology & Neurotology Group CTS495, Department of Otolaryngology, Hospital de Poniente, El Ejido, Almería, Spain. antonio.lopezescamez@ephpo.es
authors.forename: José A
authors.initials: JA
authors.lastname: Lopez-Escamez
authors.forename: Pablo
authors.initials: P
authors.lastname: Saenz-Lopez
authors.forename: Irene
authors.initials: I
authors.lastname: Gazquez
authors.forename: Antonia
authors.initials: A
authors.lastname: Moreno
authors.forename: Carlos
authors.initials: C
authors.lastname: Gonzalez-Oller
authors.forename: Andrés
authors.initials: A
authors.lastname: Soto-Varela
authors.forename: Sofía
authors.initials: S
authors.lastname: Santos
authors.forename: Ismael
authors.initials: I
authors.lastname: Aran
authors.forename: Herminio
authors.initials: H
authors.lastname: Perez-Garrigues
authors.forename: Agueda
authors.initials: A
authors.lastname: Ibañez
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Lopez-Nevot
mesh_terms: D000328:Adult; D000368:Aged; D000936:Antigen-Antibody Complex / Q000097:blood*; D001327:Autoimmune Diseases / Q000097:blood / Q000235:genetics; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008575:Meniere Disease / Q000097:blood / Q000235:genetics*; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011446:Prospective Studies; D017452:Receptors, IgG / Q000235:genetics*
chemical_list: D000936:Antigen-Antibody Complex; C445323:FCGR2A protein, human; C496124:FCGR3A protein, human; D017452:Receptors, IgG