Elevated circulating endothelial membrane microparticles in paroxysmal nocturnal haemoglobinuria

Area of Science:

• Hematology
• Vascular Biology
• Immunology

Background:

• Endothelial cell membrane microparticles (ECMP) are biomarkers of endothelial activation and injury.
• Paroxysmal nocturnal haemoglobinuria (PNH), aplastic anaemia (AA), and sickle cell disease (SCD) are hematologic disorders with potential vascular complications.

Purpose of the Study:

• To investigate the levels of circulating ECMP in patients with PNH, AA, and SCD compared to healthy donors (HD).
• To assess the potential of ECMP as indicators of endothelial cell status in these hematologic conditions.

Main Methods:

• Peripheral blood samples were collected from patients with PNH (n=9), AA (n=10), SCD (n=8), and HD (n=11).
• Three-color flow cytometry was used to analyze ECMP, specifically CD105+ and CD144+ microparticles, with annexin V-binding (AVB) assay for phosphatidylserine exposure.
• Antibodies to endothelial antigens CD105, CD144, and inflammatory marker CD54 were employed.

Main Results:

• Elevated levels of CD105+AVB+ ECMP were observed in SCD and PNH patients compared to AA and HD groups (P < 0.05).
• ECMP expressing CD54 (inflammatory marker) and CD144 (endothelial marker) were significantly increased in SCD and PNH patients.
• AA patients showed no significant elevation in these ECMP populations compared to healthy donors.

Conclusions:

• Circulating ECMP levels, particularly CD54+ and CD144+ populations, are elevated in SCD and PNH, reflecting endothelial inflammation and injury.
• Analysis of ECMP shows promise for monitoring the vascular endothelium status in PNH and SCD patients.