Challenges in Detecting Clinically Relevant Heparin-Induced Thrombocytopenia Antibodies.

Challenges in Detecting Clinically Relevant Heparin-Induced Thrombocytopenia Antibodies. Hamostaseologie. 2020 Nov;40(4):472-484 Authors: Warkentin TE Abstract Heparin-induced thrombocytopenia (HIT) is an antibody-mediated hypercoagulable state featuring high thrombosis risk and distinct pathogenesis involving immunoglobulin G-mediated platelet activation. The target of the immune response is a cationic "self" protein, platelet factor 4 (PF4), rendered antigenic by heparin. A key problem is that only a minority of anti-PF4/polyanion antibodies induced by heparin are pathogenic, i.e., capable of causing platelet activation and thereby clinical HIT. Since thrombocytopenia occurs frequently in hospitalized, heparin-treated patients, testing for "HIT antibodies" is common; thus, the problem of distinguishing between pathogenic and nonpathogenic antibodies is important. The central concept is that those antibodies that have platelet-activating properties demonstrable in vitro correlate well with pathogenicity, as shown by platelet activation tests such as the serotonin-release assay (SRA) and heparin-induced platelet activation assay. However, in most circumstances, immunoassays are used for first-line testing, and so it is important for clinicians to appreciate which immunoassay result profiles-in the appropriate clinical context-predict the presence of platelet-activating antibodies (Bayesian analysis). Clinicians with access to rapid, ...
Source: Hamostaseologie - Category: Hematology Authors: Tags: Hamostaseologie Source Type: research