CXCL9 and NT-proBNP, a notable link between inflammatory mediator and cardiovascular disease biomarker in rheumatoid arthritis.

INTRODUCTION: Cardiovascular disease (CVD) is the most critical extra-articular manifestation of rheumatoid arthritis, and inflammatory molecules contribute to its pathogenesis. Recently, CXCL9 has been considered an inflammatory chemokine associated with the pathogenesis of CVD. Here, we evaluated the association of plasma CXCL9 with well-established cardiac biomarkers, including HS-CRP (High sensitivity C-reactive protein) and NT-ProBNP (N-terminal pro-B-type natriuretic peptide), in newly diagnosed and under-treatment RA patients. METHODS: Thirty newly diagnosed patients, 30 under-treatment RA patients, and 30 healthy subjects were recruited. The plasma concentration of CXCL9 and NT-ProBNP was measured using the ELISA method. The HS-CRP levels was measured in plasma samples using latex-enhanced immunoturbidimetric test. RESULTS: We found increased plasma levels of CXCL9, HS-CRP, and NT-proBNP in RA patients compared to healthy subjects, besides that the concentration of CXCL9, HS-CRP, and NT-ProBNP showed elevated levels in newly diagnosed RA patients compared to under-treatment group. The mean plasma concentration of CXCL9, NT-proBNP, and HS-CRP were statistically different among healthy subjects, newly diagnosed, and under-treatment RA patients (p < 0.001, p = 0.016, and p < 0.001, respectively). We also found a significant positive correlation between CXCL9 and DAS-28 (p = 0.0005, r = 0.436) in the patients' group (new-case + under-treatment). There was a significantly positive correlation between CXCL9 and NT-proBNP in newly diagnosed and under-treatment patients (p = 0.020, r = 0.424; p < 0.0001, r = 0.853, respectively). In the patient's group (new-case + under-treatment), there was a significantly positive correlation between CXCL9 with NT-proBNP (p < 0.001, r = 0.703) and CXCL9 with HS-CRP (p = 0.015, r = 0.313). CONCLUSION: CXCL9 correlates significantly with well-established cardiovascular biomarkers, including HS-CRP and NT-ProBNP in RA patients. Key Points • CXCL9 is an inflammatory marker in RA. • CXCL9 has correlated with DAS-28. • There is a strong correlation between CXCL9 with NT-proBNP and HS-CRP.