Oxidised low-density lipoprotein and antibodies against oxidised low-density lipoprotein in patients with antiphospholipid syndrome.

Objectives: Recurrent thrombosis is one of the main clinical features of antiphospholipid syndrome (APS), and recent studies revealed that APS shares similar pathophysiological mechanisms with atherosclerosis. Oxidised low-density lipoprotein (OxLDL) and antibodies against OxLDL (anti-OxLDL) are involved in the development of atherosclerosis. This study aims to investigate the clinical significance of OxLDL and anti-OxLDL in APS patients.

Methods: One hundred and seventy APS patients and 39 healthy controls (HC) were enrolled. Clinical and laboratory data were collected from Clinical Data Center of Peking University People's Hospital. OxLDL and anti-OxLDL were detected using enzyme-linked immunosorbent assay.

Results: Among the 170 APS patients, 106 had isolated thrombotic APS. Compared with HC, APS patients exhibited higher titres of OxLDL [413.86 (220.11-853.67) ng/mL vs. 45.54 (0-105.98) ng/mL, p<0.001] and anti-OxLDL [107.62 (75.68-174.18) U/L vs. 44.13 (18.44-79.76) U/L, p<0.001]. Also, APS patients exhibited a higher positivity rate for OxLDL (88.2% vs. 5.1%, p<0.001) and anti-OxLDL (84.1% vs. 36.5%, p<0.001) compared to HC. APS patients with elevated levels of OxLDL had a higher rate of LAC positivity (68.0% vs. 45.0%, p=0.042). Furthermore, APS patients with positive anti-OxLDL demonstrated a higher occurrence of venous thrombosis (46.2% vs. 18.5%, p=0.008) and a lower rate of Coomb's test positivity (52.6% vs. 76.2%, p=0.049). Multivariate logistic regression revealed that anti-OxLDL positivity (OR 12.424, 95%CI 1.108-139.330, p=0.041) were risk factors for venous thrombotic APS.

Conclusions: This study indicates that the presence of anti-OxLDL may serve as potential markers for venous thrombosis in APS patients. OxLDL and anti-OxLDL may function as valuable biomarkers for monitoring APS.