Antiphosphatidylserine antibodies are elevated in normal tension glaucoma

Area of Science:

• Ophthalmology
• Immunology
• Pathophysiology

Background:

• Open-angle glaucoma encompasses primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG).
• Both POAG and NTG may be linked to autoimmune mechanisms.
• Phospholipid antibodies (APL) are implicated in various autoimmune conditions.

Purpose of the Study:

• To investigate the association between antibodies to phospholipids (APL) and their subspecies (cardiolipin, phosphatidylserine, beta2-glycoprotein) and normal tension glaucoma (NTG) versus primary open-angle glaucoma (POAG).
• To compare APL levels in NTG patients, POAG patients, and healthy controls.

Main Methods:

• A prospective study was conducted involving 43 NTG patients, 40 POAG patients, and 40 healthy controls.
• Levels of IgG and IgM antibodies to phospholipids (APL), cardiolipin (ACL), phosphatidylserine (APS), and beta2-glycoprotein (beta2GP) were determined.
• Statistical analysis was performed to compare antibody concentrations between groups.

Main Results:

• Antibodies to phosphatidylserine (APS) were significantly elevated in NTG patients (IgG: 20.6 +/- 2.7 U/ml, IgM: 24.4 +/- 3.4 U/ml) compared to POAG patients (IgG: 8.8 +/- 1.2 U/ml, IgM: 11.0 +/- 1.7 U/ml) and healthy controls (IgG: 7.7 +/- 1.3 U/ml, IgM: 12.8 +/- 1.5 U/ml).
• No significant differences were noted for other APL subspecies between the groups (data not shown).
• The findings suggest a specific association between APS and NTG.

Conclusions:

• Elevated APS concentrations in NTG patients indicate a potential autoimmune component in this glaucoma subtype.
• The binding specificity of APS to phosphatidylserine, which is exposed during apoptosis, may contribute to local thrombosis in NTG.
• Further research is warranted to elucidate the precise role of APS in NTG pathogenesis and its implications for treatment.