THE WILLEBRANDS FACTOR ANTIGEN IN SYSTEMI C VASCULITIDES

ELISA was used to investigate concentrations of Willebrand's factor an tigen (WF III Ag) in 131 patients with various forms of systemic vascu litis (SV) and 93 patients with cardiovascular diseases. Compared to d onors, a mean WF III Ag level. proved significantly higher in all noso logical variants of SV except periarteritis nodosa. Skin livedo vascul itis did not produce noticeable deviations in WF III Ag levels versus those in donors, whereas atherosclerosis obliterans showed these level s to be significantly elevated. Essential hypertension patients had lo w values of WF III Ag. The highest mean level of the antigen was found in rheumatoid vasculitis and Wegener's granulomatosis in which the an tigen content rose to the highest for vascular affections levels (p<0. 05-0.01). High WF III Ag in Wegener's granulomatosis, periarteritis no dosa, leukocytoclustic vasculitis were indicative of renal involvement . Moreover, there was a tendency to an increase in the antigen quantit ies in Wegener's granulomatosis patients with intercurrent infections versus such without them. In other SV forms and atherosclerosis oblite rans. concentrations of the antigen were not related to clinical featu res of the disease.