Increased Factor VIII/von Willebrand Factor Antigen and von Willebrand Factor Activity in Scleroderma and in Raynaud's Phenomenon

Abstract

Von Willebrand factor activity and factor VIII/von Willebrand factor (fVIII/vWf) antigen concentrations were evaluated in 17 patients with scleroderma, nine patients with Raynaud's phenomenon, and eight control volunteers. Higher circulating levels of both activities were seen: von Willebrand factor, 374% ± 40% (percent of control values) in scleroderma patients, 502% ± 104% in patients with Raynaud's phenomenon and 102% ± 6% in control subjects (p < 0. 005, scleroderma versus control); fVIII/vWf antigen, 255% ± 24% in scleroderma patients; 271% ± 46% in patients with Raynaud's phenomenon, and 99% ± 4% in control subjects (p < 0.005, scleroderma versus control). Because endothelial cells synthesize and secrete both substances, the role of endothelial injury in vitro was investigated. Wound injury induced a 344% ± 33% increase in von Willebrand factor and a 115% ± 5% increases in fVIII/vWf antigen; cold injury induced 644% ± 66% and 150% ± 10% increases, and cytotoxic endothelial injury induced 1055% ± 83% and 185% ± 20% increases. In five patients with scleroderma, cold exposure led to a further increase in both activities. The observed increase of both activities in scleroderma and Raynaud's phenomenon may reflect in-vivo endothelial injury and regeneration in these related conditions.