Platelet-activating anti-PF4 disorders: An overview

Platelet factor 4 (PF4) is a highly cationic tetrameric protein that can be targeted by platelet-activating anti-PF4 antibodies of immunoglobulin G (IgG) class. Certain features of PF4, including its multivalent nature (duplicate antigen sites per tetramer), the ability of many PF4 tetramers to undergo close approximation through charge neutralization, and the dimeric binding of IgG molecules, results in formation of IgG-containing immune …