von Willebrand factor in the plasma of patients with rheumatic diseases.

von Willebrand factor (vWf), an endothelial cell product, was evaluated in 39 patients with rheumatoid arthritis, 19 patients with connective tissue diseases and vasculitis, 21 patients with nonrheumatoid inflammatory arthritides, 14 patients with osteoarthritis and 19 controls. High plasma vWf levels were found in rheumatoid arthritis patients: 196.35 +/- 85.8 (p less than 0.001 versus control) connective tissue diseases and vasculitides: 306.50 +/- 43.4 (p less than 0.001 versus control) and inflammatory nonrheumatoid arthritides: 193.35 +/- 90.6 (p less than 0.01 versus control). Highly increased vWf concentrations of more than 300%, were found in one patient presenting Wegener granulomatosis, 6 patients with vasculitis associated to connective tissue diseases, 7 patients with rheumatoid arthritis and 2 patients with active forms of inflammatory arthritides. vWf was correlated with fibrinogen in the subgroup of systemic lupus erythematosus patients. Elevated vWf levels may reflect vascular damage as well as the acute phase reaction. Highly elevated levels of vWf appear to indicate a poor prognosis.