Platelet function and immune response

Altered platelet function may cause abnormal bleeding tendency or thrombosis. The goal of this article is to provide insights for understanding how platelet functions are related to immune response. Autoantibodies and drug-induced platelet antibodies have been demonstrated to downregulate or enhance platelet function. Drug-induced immune thrombocytopenia is an important adverse effect of glycoprotein IIb/IIIa antagonists. Platelets respond to binding of glycoprotein IIb/IIIa by partial platelet activation. This includes conformational changes of glycoprotein IIb/IIIa. Membrane changes may expose immunogenic neoantigens capable of abnormally altering immune responses. The presence of drug-dependent antibodies in an unexpectedly high frequency compared with the frequency of overt thrombocytopenia has opened a model for further studies. These may include monitoring of antiplatelet immune responses when new platelet antagonists are developed and comparisons of specific immune responses in other acute thrombocytopenias, such as those induced by quinidine or heparin and that associated with gold therapy or in acute profound thrombocytopenia, which may follow vaccination with live attenuated viruses.