Background: Rheumatoid arthritis (RA) is considered as one of the most important autoimmune diseases that cause different health problems. Objective: This study was conducted to estimate of DNA methylation correlated with patient treated with Methotrexate drugs. Materials and methods: Blood samples were collected from 75 patients with RA treated with MTX and 75 healthy individuals in Iraq. DNA was extracted from blood samples. ELISA method was used to detect DNA methylation in all samples. DNA denaturation was performed using High-temperature in thermocycle PCR. Results: ELISA results were as follows: a significant difference in DNA methylation was witnessed between the control and RA patients, where the DNA methylations decreased in patient at level 0.05. Statistically, a significant difference was witnessed in DNA methylation in patient groups and the duration of the disease. The results of DNA methylation were not significant in relation to the duration of MTX and RA disease. Significantly, the outcomes of DNA methylation among urban and rural individuals indicated that 85% of them were urban and 15% were rural. Family history in relation to DNA methylation revealed that there is not a statistically significant difference between the groups. Results of urban and rural DNA methylation in relation to residence were high in rural and non-significant. DNA methylation in RA patients related to the route of MTX treatment was non-significant. Conclusion: Low DNA methylation in patients with RA in comparison to healthy individuals suggests that DNA methylation plays a significant role in RA.
