Heparin Increases HLA-G Levels in Primary Antiphospholipid Syndrome

Abstract EN

Objectives.

The aim of this study was to investigate the HLA-G serum levels in Primary Antiphospholipid Syndrome (PAPS) patients, its impact on clinical and laboratory findings, and heparin treatment.

Methods.

Forty-four PAPS patients were age and gender matched with 43 controls.

HLA-G serum levels were measured using an enzyme-linked immunosorbent assay (ELISA).

Results.

An increase in soluble HLA-G levels was found in patients compared to controls (3.35 (0–22.9) versus 1.1 (0–14), P=0.017).

There were no significant differences in HLA-G levels between patients with and without obstetric events, arterial thrombosis, venous thrombosis, or stroke.

Sixty-six percent of patients were being treated with heparin.

Interestingly, patients treated with heparin had higher HLA-G levels than ones who were not treated with this medication (5 (0–22.9) versus 1.8 (0–16) ng/mL, P=0.038).

Furthermore, patients on heparin who experienced obstetric events had a trend to increased HLA-G levels compared to patients who were not on heparin and did not have obstetric events (5.8 (0–22.9) versus 2 (0–15.2) ng/mL, P=0.05).

Conclusion.

This is the first study to demonstrate that serum HLA-G levels are increased in APS patients.

We also demonstrated that heparin increases HLA-G levels and may increase tolerance towards autoantigens.