Endothelial Cell-Activating Antibodies in COVID-19

Area of Science:

• Immunology
• Vascular Biology
• Infectious Diseases

Background:

• Endothelial dysfunction is a key feature of severe COVID-19, leading to thromboinflammatory complications.
• The specific factors causing COVID-19-related endotheliopathy are largely unknown.

Purpose of the Study:

• To identify circulating factors in COVID-19 that activate and cause dysfunction in endothelial cells.
• To investigate the role of antibodies in COVID-19-induced endotheliopathy.

Main Methods:

• Endothelial cells were exposed to serum/plasma from COVID-19 and sepsis patients.
• Expression of cell adhesion molecules (E-selectin, VCAM-1, ICAM-1) was measured.
• The impact of antiphospholipid antibodies and IgG was assessed.

Main Results:

• COVID-19 serum/plasma significantly increased cell adhesion molecule expression.
• Elevated soluble ICAM-1 and E-selectin correlated with disease severity.
• Antiphospholipid antibodies in COVID-19 serum were potent drivers of endothelial activation; IgG depletion reduced this effect.

Conclusions:

• Specific antibodies in some COVID-19 patients can drive endotheliopathy.
• These findings highlight the role of autoantibodies in severe COVID-19 thromboinflammation.