VON-WILLEBRAND-FACTOR IN JUVENILE DERMATOMYOSITIS

Objective. To evaluate whether plasma von Willebrand factor (VWF) leve ls are a useful indicator of disease activity in juvenile dermatomyosi tis (DM). Methods. Serum vWF levels were prospectively measured in 15 patients with juvenile DM and were compared to serum muscle enzyme lev els, muscle strength, and presence of extramuscular manifestations. Re sults. 6/15 active disease periods were accompanied by an increase in vWF; 9 were not. Elevated VWF levels did not relate to the presence of active skin disease or calcinosis. vWF was not consistently related t o muscle strength, CPK, or aldolase in the study group. Two patients h ad elevations of VWF in association with viral infections while their DM was quiescent. Conclusion. An elevated vWF level is often indicativ e of a disease exacerbation in DM, and thus may be helpful in managing difficult cases. However, it is not consistently elevated in, nor spe cific for active disease in DM. It therefore cannot be recommended as a routine test in patients with DM. When used, results should be inter preted with caution.