Dec 8, 2023 · Antibodies against the chemokine platelet factor 4 (PF4) occur often, but only those that activate platelets induce severe prothrombotic disorders with associated thrombocytopenia.

Antibodies against platelet factor 4 (PF4), a protein released from alpha-granules of activated platelets, may cause a number of pathophysiological conditions. The most commonly known is heparin-induced thrombocytopenia (HIT), which develops in a small proportion of people treated with the anticoagulant drug heparin.

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.

Apr 1, 2022 · 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.

The anti-PF4 (ie, heparin-induced platelet antibody) test is an immunologic, enzyme-linked immunosorbent assay (ELISA) that detects IgG antibodies against the platelet factor 4 (PF4)/heparin complex. The assay uses heparin bound to protamine sulfate, and PF4 is supplemented through a platelet lysate.

Apr 3, 2025 · VITT is mediated by anti-platelet factor 4 (PF4) IgG-antibodies, activating platelets via Fc-gamma IIa receptors (FcgRIIa). We describe clinical and serological features of 18 patients with anti-PF4/heparin ELISA negative TTS in temporal relationship to …

Dec 28, 2023 · The new rapid anti-PF4 assay was designed to detect antibodies that only recognize anti-PF4 antibodies (as seen in VITT) with no or minimal cross-reactivity with anti-PF4/heparin antibodies. Serum (1:11) and citrated plasma (1:10) in …

Mar 1, 2024 · Platelet factor 4 (PF4) combines with heparin to form an antigen that could produce IgG antibodies and participate in heparin-induced thrombocytopenia (HIT). PF4 has attracted wide attention due to its role in novel coronavirus vaccine-19 (COVID-9)-induced immune thrombotic thrombocytopenia (VITT) and cognitive impairments.

Mar 12, 2025 · Anti-PF4 antibodies triggered by heparin treatment in heparin-induced thrombocytopenia (HIT) are known for more than 50 years. Interest in anti-PF4 disorders rekindled when first cases of vaccine-induced immune thrombocytopenia and thrombosis (VITT) occurred during the worldwide COVID-19 vaccination campaign.

Anti-platelet factor 4 immunothrombotic syndromes comprise a group of disorders that include heparin-induced thrombocytopenia and vaccine-induced immune thrombocytopenia and thrombosis. These are highly prothrombotic, immunological disorders characterised by specific clinical and pathological criter …