Integrin beta-3 (HPA-1a isoform) (ITGB3 (HPA-1a))

Integrin beta-3 (ITGB3), also known as glycoprotein IIIa (GPIIIa) or CD61, is a cell surface receptor that forms a heterodimer with Integrin alpha-IIb to create the GPIIb/IIIa complex, which is essential for platelet aggregation and hemostasis (UniProt P05106). The HPA-1a isoform is a specific polymorphic variant of Integrin beta-3 defined by a leucine residue at position 33 of the mature protein, and it is the most common allele in Caucasian populations (NCBI Gene ID: 3690). This isoform is clinically significant as the primary target of maternal alloantibodies in Fetal and Neonatal Alloimmune Thrombocytopenia (FNAIT), a condition where maternal antibodies cross the placenta and destroy fetal platelets (PubMed: 31511315). In addition to its role in alloimmune disorders, the GPIIb/IIIa complex containing this isoform is the target of several antiplatelet drugs used to prevent coronary thrombosis, such as Abciximab and Eptifibatide (PubChem CID: 135398509). Emerging therapies, such as the monoclonal antibody RLYB212, specifically target the HPA-1a epitope to prevent maternal sensitization and protect the fetus from FNAIT-related complications (Rallybio, 2024).

Other names

CD61Platelet glycoprotein IIIaGPIIIaHuman Platelet Antigen 1aZw(a) antigenITGB3

Inhibition of the GPIIb/IIIa complex to prevent platelet aggregation; or specific binding to the HPA-1a epitope to prevent maternal alloimmunization or neutralize pathogenic antibodies.