Prevalence of Anti-glycoprotein V in patients with primary immune thrombocytopenia

Abstract

Immune thrombocytopenia (ITP) is an acquired form of thrombocytopenia that is primarily due to autoantibody-mediated destruction of platelets. The autoantibodies may also affect megakaryocytes and impair platelet production. ITP is a diagnosis of exclusion, characterized by isolated thrombo-cytopenia without a clinically apparent condition responsible for the low platelet count (Najaoui et al., 2018). The pathogenesis of ITP involves loss of tolerance to glycoproteins expressed on platelets and megakaryocytes. ITP is not a single disorder, but a syndrome in which thrombocytopenia may be primary or occur secondary to underlying infectious or immune processes (Takase et al., 2020). In approximately 60% of all ITP patients, autoantibodies are found, predominantly against platelet glycoprotein (GP) IIb/IIIa (~70%) and/or the GP Ib–IX–V complex (~25%). Antibodies against GPIa–IIa or GPVI are also detected in sporadic cases (~5%) (Rodeghiero and Carli, 2017). Glycoprotein V (GP V) is a major protein on the platelet membrane, with approximately 10,000 copies per platelet. Human platelet glycoprotein V (GP5) is a part of the Ib-V-IX system of surface glycoproteins that constitute the receptor for von Willebrand factor (VWF; MIM 613160). In vivo studies in mice have demonstrated that the absence of GP V increases both platelet adhesion and aggregation; but also decreases thrombus stabilization. GP V is cleaved by thrombin or, following platelet activation with collagen, by ADAM17/ TACE (Porcelijn et al., 2018).