6910
The secretion levels of interleukin-6 ( IL-6 ) and von Willebrand factor ( vWF ) were determined, to serve as markers for EC activation .
 ( protein: interleukin-6, None) , ( protein: IL-6, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: interleukin-6, None) , ( protein: IL-6, None) 