2155
It begins when heparin exposure stimulates the formation of heparin - platelet factor 4 antibodies , which in turn triggers the release of procoagulant platelet particles .
 Chemical: heparin; Chemical: heparin
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: heparin; Chemical: heparin