Pathophysiology of thrombotic APS: where do we stand?

Area of Science:

• Immunology
• Hematology
• Pathology

Background:

• Antiphospholipid syndrome (APS) diagnosis relies on thrombotic events or fetal loss alongside antiphospholipid antibodies.
• The term APS is misleading as pathogenic auto-antibodies target β(2)-glycoprotein I, not phospholipids.
• The pro-thrombotic role of anti-β(2)-glycoprotein I auto-antibodies was previously unclear due to a lack of clear phenotype in β(2)-glycoprotein I-deficient individuals.

Purpose of the Study:

• To elucidate the role of β(2)-glycoprotein I in the thrombotic mechanisms of Antiphospholipid Syndrome (APS).
• To investigate the pathogenic contribution of auto-antibodies targeting β(2)-glycoprotein I in APS.
• To understand why auto-antibodies against β(2)-glycoprotein I are pro-thrombotic.

Main Methods:

• Passive transfer of patient-derived antiphospholipid antibodies into animal models (mice).
• Assessment of thrombotic complications in recipient animals.
• Analysis of the role of β(2)-glycoprotein I in mediating antibody-induced thrombosis.

Main Results:

• Passive transfer of patient antibodies into mice induced an increased thrombotic response.
• This model provided novel insights into the pathogenic role of β(2)-glycoprotein I in APS.
• Confirmed the pro-thrombotic nature of auto-antibodies targeting β(2)-glycoprotein I.

Conclusions:

• β(2)-glycoprotein I is crucial in the pathology of Antiphospholipid Syndrome.
• Animal models are valuable for understanding APS pathogenesis.
• Auto-antibodies against β(2)-glycoprotein I are key drivers of thrombosis in APS.