Blocking von Willebrand factor for treatment of cutaneous inflammation

Von Willebrand factor (VWF), a key player in hemostasis, is increasingly recognized as a proinflammatory protein. Here, we found a massive accumulation of VWF in skin biopsies of patients suffering from immune complex (IC)-mediated vasculitis (ICV). To clarify the impact of VWF on cutaneous inflammation, we induced experimental ICV either in mice treated with VWF-blocking antibodies or in VWF(-/-) mice. Interference with VWF led to a significant inhibition of the cutaneous inflammatory response. We confirmed the major findings in irritative contact dermatitis, a second model of cutaneous inflammation. In vivo imaging of cutaneous inflammation in the dorsal skinfold chamber revealed unaffected leukocyte rolling on anti-VWF treatment. However, we identified that reduced leukocyte recruitment is accompanied by reduced vascular permeability. Although VWF-mediated neutrophil recruitment to the peritoneum was described to require the VWF receptor on platelets (glycoprotein Ibα (GPIbα)), the VWF/GPIbα axis was dispensable for cutaneous inflammation. As assessed in tail bleeding assays, we could exclude interference of VWF blockade with hemostasis. Of particular importance, anti-VWF treatment was effective both in prophylactic and therapeutic administration. Thus, VWF represents a promising target for the treatment of cutaneous inflammation, e.g., leukocytoclastic vasculitis.