Abstract
Purpose: :
Considering the importance of TNF-α in pathogenesis of toxoplasmic retinochoroiditis (TR) and that the presence of this functional polymorphism affect the levels of cytokines produced, we aim to investigate the possible association between TNF-α (-308G/A) polymorphism and TR in humans.
Methods: :
Cross-sectional study which included one hundred Brazilian patients meeting well-defined criteria for the diagnosis of TR and fifty age and gender matched control subjects with no signs of ocular toxoplasmosis in whom anti-toxoplasma antibody analysis revealed positive immunoglobulin G titers. Genomic DNA was obtained from oral swabs of all subjects and amplified using the polymerase chain reaction (PCR) with specific primers flanking the locus -308 of TNF-α. PCR products were submitted to restriction endonuclease digestion and analyzed by polyacrylamide gel electrophoresis, to distinguish alleles G and A of the TNF-α gene, allowing for the determination of the genotypes and detection of the polymorphism.
Results: :
There was no significant difference in the genotype (x² = 0.79, P = 0.67), allele (x² = 0.095, P = 0.75), and allele carriage (x² = 0.70, P = 0.40) distribuitions in patients with TR compared with control subjects. Prevalences of the genotype (x² = 0.2.05, P = 0.35) and allele (x² = 0.13, P = 0.71) distribuitions did not significantly differ between with and without recurrence episode groups.
Conclusions: :
This study is the first to study the association between the TNF-α polymorphism and occurrence of TR in humans. We demonstrated that the TNF-α (-308G/A) is not associated with occurrence or recurrence of TR.
Keywords: retinochoroiditis • immunomodulation/immunoregulation • inflammation