INTERLEUKIN-10 GENE POLYMORPHISM (–1082G/A) IS ASSOCIATED WITH CONGENITAL TOXOPLASMOSIS
Moshira M. F. Helmy*, Ahmed Abdel-Aziz El-Barbary** and Laila Rashed***
Departments of Parasitology* & Obstetrics and Gynecology**, Faculty of Medicine, Misr University for Science and Technology, Egypt.Department of Biochemistry***, Faculty of Medicine, Cairo University, Egypt.
The present study was carried out on pregnant women infected with T. gondii, to investigate the possible association between an IL10 gene polymorphism at position –1082 and transplacental congenital toxoplasmosis during pregnancy. A total of 41 pregnant women of different stages of gestation [GI: 26.8 % (11/ 41 women in the 1st trimester of pregnancy), GII: 31.7 % (13/41 women in the 2nd trimester of pregnancy), and GIII: 41.5 % (17 /41 women in the 3rd trimester of pregnancy)], sero-positive for Toxoplasma (high Toxoplasma-specific IgM antibody titer) were selected. Congenital transplacental infection was detected in 10/41 fetuses by the ultrasound [34.8% (8/23 pts.) of untreated pregnant women, and 11.1% (2/18 pts.) of treated pregnant women]. Severe (CNS) fetal infection was recorded in 9% (4/41 pts.), enlarged liver in 2.4 % (1/41 pts.), whereas, chorioretinitis was recorded in 9.8 % (4/41 pts.) and ventricular dilatation in 2.4% (1/41 pts.). Genomic DNA was obtained from serum of patients 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. There was a significant difference in the genotype distribution between pregnant women with transplacental congenital toxoplasmosis and control subjects (P < 0.04). Carriers of the IL10 –1082 A allele (AA+AG genotypes) were more often among patients with transplacental congenital toxoplasmosis fetal infections than control subjects (P < 0.01). In a subgroup analysis, there was no significant difference in genotypes and allele carriage regarding toxoplasmosis in the pregnant women and recurrence of miscarriage or stillbirth. In conclusion, this study suggests that the genotypes are related with a low production of IL-10 and association of the IL10 gene polymorphism –1082G/A with occurrence and severity of the disease.