PTGDR2 and rheumatoid arthritis: The aim of this study was to investigate the expression pattern of CD183 (CXCR3) chemokine receptors on peripheral lymphocytes and other relevant biomarkers in RA patients including a prostaglandin D2 receptor (CD4+ CD294+), an interleukin‐7 receptor‐α (CD4+ CD127+), and a transcription factor (CD4+ FOXP3+) as diagnostics biomarkers for detecting RA, and determine their relationship with disease activity.