Von Willebrand factor: a possible biomarker for disease activity in vasculitis.

Objective: Inflammation markers, e.g. C- reactive protein (CRP) and sedimentation rate, can be normal despite active vasculitis. Von Willebrand factor (vWF) is secreted from endothelial cells in response to vascular damage. Some reports suggest increased vWF levels in vasculitis. This study aimed to evaluate vWF serum concentration in vasculitis patients as a possible biomarker of disease activity and to review the current literature.

Method: Adult patients with systemic vasculitis were prospectively enrolled. Disease activity was recorded using the Birmingham Vasculitis Activity Score (BVAS) version 3. Blood group-adjusted vWF antigen serum level was evaluated at diagnosis and, when available, after treatment.

Results: Twenty-five vasculitis patients were compared to 15 healthy controls. The mean age of patients was 56 ± 17 years and 56% were women. Forty percent had anti-neutrophil cytoplasmic autoantibody-associated vasculitis, 20% giant cell arteritis, 16% polyarteritis nodosa, 8% Takayasu arteritis, and the rest had other vasculitides. The mean disease duration was 3.4 ± 4.8 years. Mean vWF was higher in patients with active vasculitis than in healthy controls (212 ± 81% vs 106 ± 26%, p < 0.001). vWF levels directly correlated with BVAS. In 13 patients with active vasculitis who reached remission or low disease activity after treatment, vWF level at follow-up decreased significantly. In three out of five patients who were treated with interleukin-6 inhibitors, vWF was elevated despite normal CRP levels, while vasculitis was clinically active.

Conclusion: vWF antigen serum level is increased in active vasculitis and could potentially serve as a biomarker for active disease.