title: Fc gamma receptor IIIb polymorphism and systemic lupus erythematosus: association with disease susceptibility and identification of a novel FCGR3B*01 variant.
abstract: OBJECTIVE
  The objective of this study was to evaluate the association between Fc gamma receptor IIIb polymorphism and susceptibility to systemic lupus erythematosus and clinical traits of the disease.
  
  
  METHODS
  Genomic DNA was obtained from 303 consecutive systemic lupus erythematosus patients and 300 healthy blood donors from the southeastern region of Brazil. The polymorphic region of the FCGR3B gene was sequenced and the alleles FCGR3B*01, FCGR3B*02 and FCGR3B*03 were analyzed.
  
  
  RESULTS
  The FCGR3B*01 allele was more frequent in systemic lupus erythematosus patients (43.1%) while the FCGR3B*02 allele prevailed among controls (63.7%) (P = 0.001). The FCGR3B*03 allele was found equally in both groups. The FCGR3B*01/*01 (20.7%) and FCGR3B*01/*02 (41.1%) genotypes were more frequent among systemic lupus erythematosus patients (P = 0.028 and P = 0.012, respectively) while the FCGR3B*02/*02 genotype was more frequent in controls (45.5%) (P < 0.001). One variant of the FCGR3B*01 allele previously described in Germany was found in only one control. A new variant of the FCGR3B*01 allele with two substitutions (A227G/G277A) was found in one control. Three variants of the FCGR3B*02 allele previously described in African-Americans, Brazilians, Chinese and Japanese were found in ten 10 patients and two controls. In addition, several single nucleotide polymorphisms at non-polymorphic positions were identified in both patients and controls.
  
  
  CONCLUSIONS
  Susceptibility to systemic lupus erythematosus was associated with the FCGR3B*01 allele, as well as with the FCGR3B*01/*01 and FCGR3B*01/*02 genotypes. No association was found between FCGR3B genotypes and clinical manifestations, disease severity or the presence of autoantibodies.
authors.affiliation: Disciplina de Reumatologia, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: V C
authors.initials: VC
authors.lastname: Santos
authors.affiliation: Disciplina de Reumatologia, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: Grecco
authors.affiliation: Disciplina de Reumatologia, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: K M C
authors.initials: KM
authors.lastname: Pereira
authors.affiliation: Disciplina de Hematologia, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: C C N
authors.initials: CC
authors.lastname: Terzian
authors.affiliation: Disciplina de Reumatologia, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: L E C
authors.initials: LE
authors.lastname: Andrade
authors.affiliation: Disciplina de Reumatologia, Universidade Federal de São Paulo, São Paulo, Brazil n_psilva@hotmail.com.
authors.forename: N P
authors.initials: NP
authors.lastname: Silva
mesh_terms: D004198:Disease Susceptibility; D005260:Female; D058851:GPI-Linked Proteins / Q000235:genetics; D005787:Gene Frequency; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000208:ethnology / Q000235:genetics*; D008297:Male; D020641:Polymorphism, Single Nucleotide; D017452:Receptors, IgG / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: C428200:FCGR3B protein, human; D058851:GPI-Linked Proteins; D017452:Receptors, IgG
keywords: FCGR3B; gene polymorphism; immune complex; systemic lupus erythematosus