Distribution of Inteleukin-6 Promoter Genetic Variants Among Toxoplasma gondii-Infected Pakistani Women

Abstract

Interleukin-6 (IL-6) is a multifunctional cytokine that plays a key role in infection control and pregnancy maintenance. IL-6 genetic variability affects the pregnancy outcome and susceptibility to Toxoplasma gondii (T. gondii) infection. This study aims to investigate the prevalence of IL-6 promoter polymorphisms in T. gondii-infected women. This study included 163 reproductive-age women, including 83 T. gondii-infected women and 80 control women. The blood and placental tissue samples were collected from participants. The DNA was extracted and amplified for T. gondii DNA and IL-6 gene promoter polymorphisms. The amplified IL-6 DNA was sequenced through Sanger's sequencing method. The -174 G/C, -373 AnTn Tract, -572 G/C, and -597 G/A polymorphisms were detected in the IL-6 gene promoter. The distribution of the CC genotype (0.49) in antibodies and DNA-positive women, the GG genotype in antibodies-positive and DNA-negative (0.47) and control women (0.56) at -174G/C SNP was significantly high (p=0.005). The GG genotype at -572G/C SNP was insignificantly (P=0.143) high in antibodies and DNA-positive (0.44), antibody-positive and DNA-negative (0.42), and control women (0.54). The frequency distributions of the AA genotype (0.42) in antibodies and DNA-positive, the GG genotype in antibodies-positive and DNA-negative (0.38), and control women (0.60) at -597G/A SNP were significantly high (P=0.0012). Frequencies of the A10T11/A10T11 (0.28) and the A9T11/A9T11 (0.27) genotypes in infected women, and the A8T12/A10T10 and the A10T10/A10T10 genotypes in control women (0.20 each) were significantly high (P<0.001). It is concluded that the frequency distributions of IL-6 genotypes at -174G/C, -597G/A, and -373 AnTn SNPs are significantly variable in T. gondii-infected women.