Associations between cytokine gene polymorphisms and rheumatoid arthritis in Turkish population

R heumatoid Arthritis (RA [MIM 180300]) is a chron- ic, painful, systemic, inflammatory, autoimmune disease with unknown etiology and it is characterized by the proliferation of synovial cells, dysfunction of joints [1].The prevalence of the disease is almost 1% worldwide and the Female/Male ratio is 2-3/1 [2].Pain, joint deformity, physical dysfunction decrease the life quality of patients and the rheumatoid factor is found positive in 75-80% of the patients [3].According to the common view accepted today, the disease of RA begins with the antigenic stimulation of the environmental factors that we do not yet know exactly in genetically predisposed individuals and is ABSTRACT OBJECTIVE: Various cytokine polymorphisms have been associated with genetic risk factors predisposing to Rheumatoid Arthritis (RA) in different populations.To predict the clinical outcome as well as response to therapy in RA, studies aimed to describe genetic markers.The present study aims to search for polymorphisms of 13 cytokine coding genes in the Eastern Black Sea Region of Turkey.METHODS: DNAs of 49 patients and 96 healthy bone marrow and kidney donors were isolated from peripheral blood samples.Genotyping was performed using the Heidelberg Cytokine Typing Tray kit.PCR products were visualized on an agarose gel, and results were analyzed using the interpretation scheme provided with the kit.Arlequin 3.5 software was used for statistical analysis. RESULTS:No positive association was found between allele frequencies and the disease.However, a negative association was found for the IL-A -889 C allele (p=0.02,OR=0.533,Wald's 95% CI=0.318-0.893).IL-12 -1188 CC (p=0.01,OR=3.667,Wald's 95% CI=1.246-10.786),IL-4 -1098 GT (p=0.02,OR=2.405,Wald's 95% CI=1.129-5.125)genotypes were found positively associated with the RA, while IL-4 -590 CT (p=0.02,OR=0.422,Wald's 95% CI=0.201-0.886)was found negatively associated with the disease.In addition, IL-6 GG haplotype was found positively associated with the RA (p=0.02,OR=1.880,Wald's 95% CI=1.086-3.254). CONCLUSION:Our findings suggest that some polymorphisms of the IL-1A, IL-2, IL-4, IL-6 and IL-12 could be responsible for the susceptibility or protective to RA in our study population.Multi-centered and large numbers of subjects containing studies that search for cytokine polymorphisms will gather more information regarding the susceptibility to RA of Turkish patients.