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

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
• interferon gamma
• retinochoroiditis
• Toxoplasma
• tumor necrosis factor

ACKNOWLEDGMENTS

The authors are grateful to the staff of the Departments of Optometry and Biomedical and Forensic Sciences for their contribution towards this work.

DECLARATION OF INTEREST

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.