Associations between Polymorphisms within Interferon Gamma and Tumor Necrosis Factor Genes and Toxoplasma Retinochoroiditis in Ghanaian Patients

Ocul Immunol Inflamm. 2017 Oct;25(5):678-684. doi: 10.3109/09273948.2016.1159315. Epub 2016 Apr 15.

Abstract

Purpose: To evaluate associations between IFN-γ +874T/A and TNF-α-308G/A polymorphism with the development of Toxoplasma retinochoroiditis.

Methods: By ARMS-PCR, a cross-sectional genetic study involving 30 patients with Toxoplasma retinochoroiditis and 87 controls was carried out.

Results: IFN-γ +874: by comparing with the AA genotype, individuals with the TT genotype had a 3.4 odds ratio (OR); AT had a 1.6 OR; and the T allele had a higher OR (1.6), indicating a likely susceptibility of IFN-γ +874T to the infection, though the overall distribution was not significant (p = 0.259). For TNF-α-308G/A, individuals with both GA and AA genotypes had lower ORs when compared with the GG genotype, implying the A allele could confer protection against Toxoplasma ocular lesions.

Conclusions: IFN-γ +874T allele may increase the risk of ocular lesions in Toxoplasma infection. The principle of natural selection seems to also play a role. The less common TNF-308A allelic form could be protective against the development of Toxoplasma ocular infection.

Keywords: Genes; Ghana; Toxoplasma; interferon gamma; retinochoroiditis; tumor necrosis factor.

MeSH terms

  • Adult
  • Chorioretinitis / diagnosis
  • Chorioretinitis / epidemiology
  • Chorioretinitis / genetics*
  • Cross-Sectional Studies
  • Female
  • Gene Amplification
  • Gene Frequency
  • Genotype
  • Ghana / epidemiology
  • Humans
  • Interferon-gamma / genetics*
  • Male
  • Middle Aged
  • Odds Ratio
  • Polymerase Chain Reaction
  • Polymorphism, Single Nucleotide*
  • Toxoplasmosis, Ocular / diagnosis
  • Toxoplasmosis, Ocular / epidemiology
  • Toxoplasmosis, Ocular / genetics*
  • Tumor Necrosis Factor-alpha / genetics*

Substances

  • Tumor Necrosis Factor-alpha
  • Interferon-gamma