Elevation of von Willebrand factor is independent of erythrocyte sedimentation rate and persists after glucocorticoid treatment in giant cell arteritis.

Von Willebrand factor (vWF) antigen levels were measured in 39 patients with biopsy-proven giant cell arteritis (GCA), 16 patients with polymyalgia rheumatica (PMR), 12 patients with Sjögren's syndrome, and 7 with choroiditis, as well as in 20 age- and sex-matched controls. Among GCA patients, 31 (group A) had clinically inactive disease and were taking low-dose glucocorticoids for at least 1 year; their vWF levels were high even in the presence of a normalized erythrocyte sedimentation rate (ESR). When the ESR and vWF were analyzed in another 8 GCA patients (group B) before and after treatment with glucocorticoids, vWF remained elevated even though the ESR returned to normal. Among the highest levels of vWF were those of 3 GCA patients who presented with ocular symptoms and positive temporal artery biopsies, but normal ESR. The presence of elevated vWF was not specific for GCA since elevated levels were also found in patients with PMR, Sjögren's syndrome, and choroiditis. The levels of vWF in GCA were significantly higher (P less than 0.01) than in these other conditions associated with myalgias and eye symptoms. Elevation of vWF levels may help in the differential diagnosis of GCA, particularly when the ESR is normal and ocular symptoms are present.