Serum levels of fetuin-A as a novel biomarker for disease activity in patients with Takayasu arteritis and granulomatous polyangiitis

Objective The aim of the present study was to investigate serum fetuin-A (Fet-A) levels in patients with Takayasu arteritis (TA) and granulomatous polyangiitis (GPA) and to analyze the relationship between serum Fet-A levels and disease activity scores. Method Thirty-two TA and 28 GPA patients presented to the rheumatology clinic at Gazi University and met the criteria of American College of Rheumatology 1990 and 2012 International Chapell Hill meeting, respectively, and 20 healthy control subjects were included in the present study. We collected data on serum C-reactive protein (CRP), albumin, calcium, and phosphate levels as well as erythrocyte sedimentation rates. Calcification risk index (CRI) was calculated for each patient. The Birmingham Vasculitis Activity Score (BVAS) and Indian Takayasu Clinical Activity Score (ITAS), were used to assess disease activity in GPA and TA patients respectively. Results Serum Fet-A levels were significantly lower in the overall vasculitis group compared to control group ( p = 0.015). In subgroup analysis, Fet-A levels were significantly lower in those with active disease, compared to control group ( p = 0.001, for active TA ( n = 18) and GPA ( n = 17), respectively). However, there was no significant difference in serum Fet-A levels in inactive cases versus control subjects ( p = 0.061, for inactive TA ( n = 14) and GPA ( n = 11), respectively). Serum Fet-A levels negatively correlated with BVAS ( r = − 0.675) and ITAS scores ( r = − 0.385), as well as with CRP and CRI. Conclusion Our results suggest that serum Fet-A level could be a novel biomarker for assessment of activity status in patients with GPA or TA. Key Points • Serum Fetuin-A is negative acute phase protein and systemic calcification inhibitor synthesized in hepatocytes and secreted by various inflammation. • Serum Fetuin-A was negatively correlated with CRP, BVAS, and ITAS scores and significantly decreased in vasculitis patients with high disease activity. • Serum Fetuin-A could be a promising and useful biomarker for the assessment of disease activity for vasculitis, also that it might also be a predictor of long-term cardiovascular progression.