Surface markers of platelet function in idiopathic nephrotic syndrome in children.

The objective of the study was to investigate platelet activation markers in whole blood in idiopathic nephrotic syndrome (INS) in children. The study group consisted of 34 children with 45 relapses of INS, 35 children in long-term remission of INS, and 26 healthy controls. Using flow cytometry we measured the percentage of platelet microparticles, platelet-platelet aggregates, and surface expression of CD62P (P-selectin) and CD42b (a component of von Willebrand factor receptor). We found an increased percentage of microparticles and platelet-platelet aggregates, decreased expression of CD42b in the first 2 weeks of INS relapse. CD62P expression was elevated only at the onset of INS relapse when compared with the long-term remission group and healthy subjects. Children in long-term INS remission did not differ from healthy controls. There was no significant correlation between platelet activation markers and selected biochemical factors of blood in children with INS. Activation of the coagulation cascade was confirmed by an elevated serum concentration of F1+2 prothrombin fragment during follow-up. These findings suggest that platelets may contribute independently to the prothrombotic state in the early stages of INS, but their role in triggering relapses remains to be investigated.