ANTIBODIES TO ENDOTHELIAL CELLS AND TO β2-GLYCOPROTEIN I IN THE ANTIPHOSPHOLIPID SYNDROME: PREVALENCE AND ISOTYPE DISTRIBUTION

Structural Changes in β2-Glycoprotein I and the Antiphospholipid Syndrome

Oxidation of β2-glycoprotein I associates with IgG antibodies to domain I in patients with antiphospholipid syndrome

Domain I (DI) of beta-2-glycoprotein I (β2GPI) contains the immunodominant epitope for pathogenic antiphospholipid antibodies (aPL). DI is exposed in the linear form of the molecule but not in the circular form that comprises 90% of serum β2GPI. The majority of circulating β2GPI is biochemically reduced with two free thiols in Domain V. However, increased levels of oxidised β2GPI are found in p...

Antibodies to domain I of β-2-glycoprotein I and IgA antiphospholipid antibodies in patients with ‘seronegative’ antiphospholipid syndrome

The standard serological tests included in the classification criteria for antiphospholipid syndrome (APS) are those to detect immunoglobulin G (IgG) and IgM antibodies to cardiolipin (aCL) or β-2-glycoprotein I (anti-β2GPI) and the lupus anticoagulant. It is increasingly recognised, however, that some patients have typical thrombotic and non-thrombotic features of APS but test repeatedly negat...

A novel pathway for human endothelial cell activation by antiphospholipid/anti-β2 glycoprotein I antibodies.

Antiphospholipid Abs (APLAs) are associated with thrombosis and recurrent fetal loss. These Abs are primarily directed against phospholipid-binding proteins, particularly β(2)GPI, and activate endothelial cells (ECs) in a β(2)GPI-dependent manner after binding of β(2)GPI to EC annexin A2. Because annexin A2 is not a transmembrane protein, the mechanisms of APLA/anti-β(2)GPI Ab-mediated EC activ...

Isolated IgA Anti-β2 Glycoprotein I Antibodies in Patients with Clinical Criteria for Antiphospholipid Syndrome

Seronegative antiphospholipid syndrome (SNAPS) is an autoimmune disease present in patients with clinical manifestations highly suggestive of Antiphospholipid Syndrome (APS) but with persistently negative consensus antiphospholipid antibodies (a-PL). IgA anti-β 2 Glycoprotein I (aB2-GPI) antibodies are associated with APS. However, they are not currently considered to be laboratory criteria due...