Purpose: Experimental data have demonstrated a relevant role for IL-10, an anti-inflammatory cytokine, in the modulation of acute ocular toxoplasmosis. Therefore, this study was conducted to investigate the possible association between an IL10 gene polymorphism at position -1082 and toxoplasmic retinochoroiditis (TR) in humans.
Methods: One hundred patients with diagnosed TR were recruited from the Uveitis Section, Federal University of Minas Gerais. For comparison, one hundred 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 -1082 of IL10 (-1082G/A). PCR products were subjected to restriction endonuclease digestion and analyzed by polyacrylamide gel electrophoresis, to distinguish allele G and A of the IL-10 gene, allowing the detection of the polymorphism and determination of genotypes.
Results: There was a significant difference in the genotype distribution between TR patients and control subjects (chi(2) = 6.33, P = 0.04). Carriers of the IL10 -1082 A allele (AA+AG genotypes) were more often patients with TR than control subjects (chi(2) = 5.97, P = 0.01, OR, 2.55; 95% CI, 1.11 < OR < 5.55). In a subgroup analysis, there was no significant difference in genotypes and allele carriage regarding visual acuity, involvement of both eyes and TR recurrence.
Conclusions: This study suggests that the genotypes related with a low production of IL-10 may be associated with the occurrence of TR.