Single nucleotide polymorphisms of interleukin-35 subunit genes predict host susceptibility to chronic hepatitis B virus infection among Iraqi patients

Abstract

Chronic hepatitis B virus (HBV) infection represents a complication of a major concern in public health. Interleukin-35 (IL-35) has been suggested to play a role in maintaining the viral persistence. It consists of two subunits (IL-12p35 and EBI3) that are coded by two genes located on different chromosomes; IL12A (3q25.33) and EBI3 (19p13.3), respectively. Single nucleotide polymorphisms (SNPs) of both genes have been associated with susceptibility to different diseases. Therefore, this study examined two intronic SNPs of IL12A (rs582054 and rs583911 in intron 2) and EBI3 (rs428253 and rs7254021 in intron 1) genes in 80 chronic HBV patients and 96 control with the aim to understand their susceptibility role in the disease. The method of SNP detection was allele-specific PCR using specific primers. Frequencies of rs582054 A allele and AT genotype were significantly increased in patients compared to control. C allele and CC genotype frequencies of rs428253 SNP were also significantly increased in patients. For rs583911 and rs7254021 SNPs, allele and genotype frequencies demonstrated no significant variation between patients and control. Haplotype analysis revealed that A-A haplotype of IL12A SNPs (rs582054 and rs583911) was associated with a significantly increased HBV risk. In contrary, G-C haplotype of EBI3 SNPs (rs428253 and rs7254021) was associated with a significant decreased risk. In conclusion, IL-35 subunit gene SNPs (IL12A rs582054 and EBI3 rs428253) are associated with susceptibility to develop chronic HBV infection among Iraqi patients.