B-cell receptor specific for human platelet glycoprotein Ib alpha (Anti-GPIbα BCR)

The B-cell receptor (BCR) specific for human platelet glycoprotein Ib alpha (GPIbα) is a membrane-bound immunoglobulin found on the surface of autoreactive B cells in patients with immune thrombocytopenia (ITP) [PubMed: 21900605]. GPIbα (CD42b) is a critical component of the platelet GPIb-IX-V complex, which mediates platelet adhesion to the vascular subendothelium via von Willebrand factor [UniProt: P07359]. In ITP, B cells expressing this specific BCR differentiate into plasma cells that secrete anti-GPIbα autoantibodies, leading to the accelerated clearance of platelets by splenic macrophages and the inhibition of megakaryocyte maturation [PubMed: 21900605]. Unlike autoantibodies against GPIIb/IIIa, those targeting GPIbα are often associated with more severe bleeding and resistance to standard treatments like intravenous immunoglobulin (IVIG) [PubMed: 24106211]. Therapeutic strategies targeting this BCR aim to achieve precision immunosuppression by selectively eliminating the pathogenic B-cell clones while sparing the rest of the immune system. Experimental approaches include Chimeric Autoantibody Receptor (CAAR) T-cell therapy, which uses the GPIbα antigen to redirect T cells to kill only the B cells expressing the corresponding BCR [PubMed: 27365449].

Other names

Anti-GPIbα B-cell receptorGPIbα-specific B-cell receptorAnti-CD42b B-cell receptorITP-associated B-cell receptor

Selective depletion or inhibition of autoreactive B-cell clones expressing the GPIbα-specific receptor to prevent the production of anti-platelet autoantibodies and restore platelet counts.