title: Interleukin-6 gene polymorphism (-174 G/C) is associated with toxoplasmic retinochoroiditis.
abstract: OBJECTIVE
  Experimental data have demonstrated a relevant role for IL-6 in the modulation of acute ocular toxoplasmosis. Therefore, we aim to investigate the possible association between the IL-6 gene polymorphism at position -174 and toxoplasmic retinochoroiditis (TR) in humans.
  
  
  METHODS
  Ninety-seven patients with diagnosed TR were recruited from the Uveitis Section, Federal University of Minas Gerais. For comparison, 83 healthy blood donors with positive serology for toxoplasmosis and without retinal signs of previous TR were included in the study. Genomic DNA was obtained from oral swabs of individuals and amplified using polymerase chain reaction (PCR) with specific primers flanking the locus -174 of IL-6 (-174G/C). PCR products were submitted to restriction endonuclease digestion and analysed by polyacrylamide gel electrophoresis to distinguish allele G and C of the IL-6 gene, allowing the detection of the polymorphism and determination of genotypes.
  
  
  RESULTS
  There was a significant difference in the genotype (χ(2) = 12.9, p = 0.001) and allele (χ(2) = 6.62, p = 0.01) distribution between TR patients and control subjects. In a subgroup analysis, there was no significant difference in genotypes and allele frequencies regarding TR recurrence.
  
  
  CONCLUSIONS
  This study suggests that the genotypes related with a lower production of IL-6 may be associated with the occurrence of TR.
authors: Internal Medicine Department, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil. cordeiro.cy@gmail.com
authors: Cynthia A
authors: CA
authors: Cordeiro
authors: Paula R
authors: PR
authors: Moreira
authors: Thais F
authors: TF
authors: Bessa
authors: Germano C
authors: GC
authors: Costa
authors: Walderez O
authors: WO
authors: Dutra
authors: Wesley R
authors: WR
authors: Campos
authors: Fernando
authors: F
authors: Oréfice
authors: Lucy H
authors: LH
authors: Young
authors: Antônio L
authors: AL
authors: Teixeira
mesh_terms: D000328:Adult; D000483:Alleles; D000818:Animals; D002825:Chorioretinitis / Q000235:genetics* / Q000378:metabolism / Q000469:parasitology; D004247:DNA / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005500:Follow-Up Studies; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics* / Q000378:metabolism; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D014126:Toxoplasmosis, Ocular / Q000235:genetics* / Q000378:metabolism / Q000469:parasitology
chemical_list: D015850:Interleukin-6; D004247:DNA