WillyLover
2021-04-26 18:52:24
https://www.nejm.org/doi/full/10.1056/NEJMe2106315
PF4.
In almost every patient, high levels of antibodies to platelet factor 4 (PF4)–polyanion complexes were identified by enzyme-linked immunosorbent assay (ELISA), as well by assays based on platelet activation, which, when tested, was enhanced by addition of PF4. In contrast to heparin-induced thrombocytopenia, however, binding of antibody to PF4 occurred in the absence of heparin. This serologic pattern mirrors findings in patients with “atypical” or “autoimmune” heparin-induced thrombocytopenia, in whom thrombi develop in the absence of known previous exposure to heparin,6 but the distribution of thrombi in patients with that condition clearly differs from that in patients with VITT. On the basis of these reports, the diagnosis of VITT should be confirmed with an approved PF4 ELISA.