Background: Rheumatoid arthritis (RA) is a common autoimmune inflammatory condition that particularly impacts joints. It is featured by an intensifying inflammation symmetrically regards the impacted joints causing destruction of cartilage and bone, disability and limitation of movement. The study aimed to determine gene expression of Forkhead box P3 (FoxP3) among rheumatoid arthritis patients. In addition, to assess DMARDs effect on FoxP3 expression.

Methods: This case-control study included 66 subjects allocated equally into: Group (1) included RA patients who were DMARDs naïve, Group (2) included 22 RA cases who were DMARDs treated, and Group (3) included 22 apparently healthy volunteers. All patients of the studied groups were conducted to history taking, complete physical and clinical assessment, Evaluation of disease activity by DAS-28, laboratory tests, and FoxP3 gene expression

Results: FoxP3 expression levels decreased among RA cases compared to controls. The lowest levels were detected among DMARD naïve group. There was statistically substantial negative association between FoxP3 expression values with TJC, SJC, GH, DAS-28 score, ESR, CRP, and RF titer among the studied RA patients. There was a remarkable negative relationship between FoxP3 expression levels with disease duration among the treated RA cases (P=0.04).

Conclusion: There are substantial differences of Forkhead box P3 (FoxP3) gene expressions between RA cases and normal controls. Moreover, the expression levels of these genes are affected by DMARDs treatment among RA cases and negatively associatated with the disease activity