ABNORMALLY LARGE VON-WILLEBRAND-FACTOR MULTIMERS IN HENOCH-SCHONLEIN PURPURA

Allergic vasculitis phenomena seem to be involved in Henoch-Schonlein purpura (HSP), Elevated plasma levels of von Willebrand factor (vWf) a re a well recognized feature of vasculitis and have been taken as an i ndication of in vivo endothelial cell damage, Plasma factor VIII:C and vWf levels and vWf multimeric pattern were studied in 8 patients with HSP, during active disease and twice during the remission (3 and 9 mo nths later), Plasma vWf multimeric composition was evaluated using low resolution gels which better resolve large vWf multimers, During acti ve disease plasma factor VIII:C, vWf:Ag, and vWf:RCoF were normal in 5 % of patients and increased in three, but in each patient, platelets a ppeared to aggregate at doses of ristocetin lower than in normals, Fur thermore, all patients demonstrated the presence of abnormally large v Wf multimers usually found only in platelets and endothelial cells, Th ree and 9 months later, during remission, in spite of the normalizatio n of factor VIII:C and vWf levels, the abnormal multimers were still d etectable, as well as hyper-responsiveness to ristocetin, These findin gs confirm that damage and/or perturbation of endothelial cells is ass ociated with HSP. Moreover, the persistence of abnormality in the vWf multimeric pattern, when the disease is inactive, suggests that the me chanisms involved operate through the entire clinical course, (C) 1996 Wiley Liss, Inc.