Study the Association of IL-21 Gene Polymorphism and Some Immunological Markers with the Risk of Rheumatoid Arthritis Incidence in a Sample of Iraqi Patients

Abstract

Rheumatoid arthritis (RA) is a prevalent autoimmune disorder marked by chronic inflammatory synovial joints. Throughout the last decades several autoantibody systems have been discovered that are associated with RA, anti-CCP test (which measures antibodies directed to cyclic citrullinated peptides), anti-carp test (for determination of the levels of anti-CarP antibodies in patients with RA), IL-21 and IL-22 levels. The aim of the study the association of IL-21 gene polymorphism (rs2221903) with the risk of RA. The studied group include 60 RA cases (19 males and 41 females), who diagnosed was depend on the Revised diagnostic criteria established by the American College of Rheumatology (ACR), 2010. Enzyme-linked immunosorbent assay (ELISA) has been utilized in order to estimate the IL-22, IL-21, Anti-CARP and ACPA levels in serum of studied group and result of investigations were compared with 30 healthy apparently control individuals. IL-21 gene polymorphism assessed utilizing polymerase chain reaction (PCR) and result were compared with 20 controls. The present results revealed that a higher positivity of patients sera for ACPA, Anti-CARP, IL-21 and IL-22 (308.11 ± 27.13, 3896.89 ± 343.90, 118.69 ± 13.09 and 148.70 ± 6.07) respectively in comparison with control groups (3.75 ± 0.44, 39.37 ± 5.59, 27.89 ± 3.77 and 55.86 ± 4.73) correspondingly with highly significant differences (P < 0.001), but no significant variation were recorded in the distribution of genotype, frequency of allele and frequency of haplotype for polymorphism of IL-21 gene between the RA and controls groups. It was concluded that found frequency of haplotype for polymorphism of IL-21 gene between the RA and controls groups.