Impact of Interleukin-21 Gene Polymorphism on IL-21 Serum Level in Iraqi Rheumatoid Arthritis Patients

Abstract

Interleukin-21 (IL-21) is a cytokine which plays a significant role in the pathogenesis and disease activity of rheumatoid arthritis (RA). Genetic polymorphisms IL-21 gene may alter the synthesis of IL-21cytokin. To investigate the polymorphisms of the IL-21 gene promoters with RA, one single nucleotide polymorphisms (SNPs) in the promoter of the IL-21 gene (rs2221903) in 60 Iraqi patients with RA and 20 controls were evaluated using polymerase chain reaction (PCR). Also, the serum level of IL-21 was measured. No significant differences were found in the genotype distribution, allele frequency and haplotype frequency for polymorphism of IL-21 gene between the RA and controls groups. Comparison to controls, patients with RA were more likely to have high level of IL-21. The present study concluded that there was no correlation between IL-21 polymorphism (rs2221903) and RA. The level of IL-21 was highly statistically significant in RA comparing to normal individual.