Conditional <i>Scl</i> knockout (KO) mice crossed with transgenic mice expressing Cre recombinase under the control of the mouse platelet factor 4 (<i>Pf4</i>) promoter generated megakaryocytes with markedly reduced but not absent <i>Scl</i> These <i>Pf4Sclc</i>-KO mice had mild thrombocytopenia and subtle defects in platelet aggregation.
Heparin-induced thrombocytopaenia was second diagnosed because of persistent severe thrombocytopaenia after 2 weeks of treatment associated with positive conversion of antibodies against platelet factor 4, and a positive functional assay.
Finally, IdeS prevented thrombocytopenia and hypercoagulability induced by 5B9 with heparin in transgenic mice expressing human PF4 and FcγRIIA receptors.
This glycopolymer was further examined for cross-bioactivity using a solution-based competitive biolayer interferometry assay with other HS-binding proteins (growth factors, P-selectin, and platelet factor 4), which are responsible for mediating angiogenic activity, cell metastasis, and antibody-induced thrombocytopenia.
The purpose of this study was to investigate the prevalence of posttransplant thrombocytopenia and its association with other clinical conditions and genetic polymorphisms of SDF1 and PF4 genes a long time after transplantation.
Even though the degree of thrombocytopenia and platelet activation were similar between dengue-infected and HIV plus dengue-coinfected patients, plasma levels of the platelet-derived chemokines RANTES/CCL5 and PF4/CXCL4 were lower in coinfection.
Here we show that the expression of PF4 on platelets and development of thrombocytopenia are modulated by the (re)distribution of PF4 among hematopoietic and endothelial cell surfaces.
Immediately postoperatively, while treated with unfractionated heparin, the patient developed thrombocytopaenia with positive platelet factor 4 antibodies and an abnormal serotonin functional platelet assay, consistent with heparin-induced thrombocytopaenia.
HIT diagnosis is established by recognizing thrombocytopenia and/or thrombosis in an affected patient and from the results of serological tests such as the platelet factor 4 (PF4)/heparin immunoassay (PF4 ELISA) and serotonin release assay (SRA).
However, the effect of platelet factor 4-cre on plasma FXIII-A was exerted outside of the megakaryocyte lineage because plasma FXIII-A was not reduced in the Mpl<sup>-/-</sup> mouse, despite marked thrombocytopenia.
HIT is characterized by an acute, transient prothrombotic state combined with thrombocytopenia and is caused by platelet-activating IgG antibodies that bind to complexes of heparin and platelet factor 4.
With immunohistochemistry, we examined in vivo free PF4 in murine bone marrow before and after radiation injury and in the setting of megakaryocytopenia and thrombocytopenia.
Delayed-onset heparin-induced thrombocytopenia is caused by immunoglobulin G antibodies that are reactive against the heparin-platelet factor 4 complex in the absence of circulating heparin.
Pathogenicity of human anti-platelet factor 4 (PF4)/heparin in vivo: generation of mouse anti-PF4/heparin and induction of thrombocytopenia by heparin.
These findings indicate that antibodies associated with HITP react with PF4 complexed with heparin in solution or with glycosaminoglycan molecules on the surface of endothelial cells and provide the basis for a new hypothesis to explain the development of thrombocytopenia with thrombosis or disseminated intravascular coagulation in patients sensitive to heparin.