Role Investigation of Interleukin- IL-21 rs763780 T/C Gene Polymorphism with Iraqi Rheumatoid Arthritis Patients

Abstract

Rheumatoid Arthritis (RA) is a chronic inflammatory condition characterized by autoantibodies development and an elevated spectrum of pro-inflammatory cytokines. This study aims to find a relationship between interleukin -21 rs682284 gene polymorphism and predisposition to rheumatoid arthritis development in a sample of Iraqi patients. In this study, there were 100 of subjects participated, about 50 of them rheumatoid arthritis (RA) so, represented patient group and the other 50 were apparently healthy who represented the control group. DNA was extracted, then the genotyping polymorphism (rs682284) of the gene Interleukin-21 was genotyped by TaqMan SNPs genotyping method. The genotyping and allele frequencies of IL-21 rs682284 for the two groups appeared that there were significant differences in genotype between patients and controls. The genotyping and allele frequencies of interleukin-21 rs6822844 G/T for the two groups appeared that there were found to be negative significant relation in genotype between patients and controls. Compared GT genotype between control and patients, heterozygous GT genotype was no associated with significant from controls (X²=0.782, OR=0.502); and the TT genotype was no associated significant risk for rheumatoid arthritis (X²=0.821, OR=0.569). In addition, allele frequency for T allele that were no significant differences of allele frequencies of IL-21 rs682284 G/T gene polymorphism with the risk of rheumatoid arthritis in a sample of Iraqi. Moreover, association between the serum IL-21 level and IL-21 rs682284 G/T genotype, patients with RA significantly increased (P<0.05) compared to controls. The serum Anti- Cyclic Citrullinated Peptide Antibodies (ACCPA) level and IL-21 rs682284 G/T genotype, patients with RA significantly increased (P<0.05) compared to controls.