[Comparative study of von Willebrand factor in patients with temporal arteritis]

Giant cell arteritis, temporal arteritis (TA), is a vasculitis which affects large and medium-sized vessels. The von Willebrand factor (vWF) is synthesized by endothelial cells and megakaryocytes. Increased amounts of vWF are released into plasma in response to an endothelial damage. vWF levels were studied by Electro-Immunodiffusion in 16 patients with TA (8 of them with a positive biopsy) and their values were compared with 5 patients with Polymyalgia Rheumatica (PMR) and 32 controls. We found higher amount of vWF in global TA, biopsy-positive TA, biopsy-negative TA, and PMR than in controls. There were no relationship between vWF amounts in plasma and clinical findings nor the laboratory parameters. We feel that although in our study vWF might be of some help as an alternative to the biopsy in those patients with high suspicion of TA, the results of other authors raise doubt about the usefulness of the determination of vWF in TA.