[Ristocetin induced platelet aggregation in children with nephrotic syndrome]

In 22 children with steroid responsive nephrotic syndrome (SRNS), we examined platelets aggregability to ristocetin, and the data obtained wre compared with negative charge on platelet membrane based on the binding of cationic dye alcian blue 8GX (AB) or plasma levels of von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor (Rcof) activity. At the initial or relapse stage of SRNS, the enhanced platelet aggregation to ristocetin was observed, and correlated with the decreased alcian blue binding to platelets. Ristocetin-induced vWF:Ag binding to platelets by using 125I-vWF was significantly increased. In addition, ristocetin-induced platelets aggregation (RIPA) using washed nephrotic platelets still enhanced as found in the patient's platelets rich plasma (PRP), even when it was resuspended into normal plasma. These results suggest that the decrease of platelet surface negative charge play an important role of heighten RIPA found in children with SRNS.