Clinical performance of non-criteria antibodies to phospholipids in Chinese patients with antiphospholipid syndrome.

BACKGROUND

Increasing evidence suggests the role of non-criteria aPLs as important supplements to the current criteria aPLs in APS. In this study, we evaluated the clinical performance of a panel of non-criteria antibodies to phospholipid antigens, including, phosphatidylserine (aPS), phosphatidylinositol (aPI), sphingomyelin (aSM), phosphatidylcholine (aPC) and phosphatidylethanolamine (aPE) in a well-defined Chinese APS cohort.

METHODS

A total of 229 subjects were tested, including 86 patients with APS, 104 disease controls (DCs) and 39 healthy controls (HCs). Serum IgG/IgM aCL, IgG/IgM aβ2GP1, IgG/IgM aPS, IgG/IgM aPI, IgG/IgM aSM, IgG/IgM aPC, and IgG/IgM aPE were tested by ELISA.

RESULTS

The presence of aPE, aPS, aPI, aPC, and aSM in patients with APS and Disease Controls were 8.1% (7/86) and 1.0% (1/104), 37.2% (32/86) and 9.6% (10/104), 50.0% (43/86) and 8.7% (9/104), 23.3% (20/86) and 1.0% (1/104), and 18.6% (16/86) and 1.9% (2/104), respectively. In criteria aPLs, aCL IgG demonstrated the highest positive likelihood ratio (LR+) of 35.75, followed by LA (LR+ of 13.51) and aCL IgM (LR+ of 11.64). In non-criteria aPLs, aPC IgG demonstrated the highest LR+ of 24.94 followed by aSM IgM (LR+ of 14.97). Importantly, the non-criteria aPLs were detected in 18.8% (3/16) of seronegative APS patients. The criteria aPLs, including LA, IgG aCL and IgG aβ2GPI, were significantly correlated with both arterial thrombosis and venous thrombosis, while the non-criteria aPLs, including IgG aPS, IgM aPS, IgG aPI and IgG aPC were significantly associated with arterial thrombosis but not venous thrombosis.

CONCLUSIONS

In summary, our findings indicate that those non-criteria aPLs may be particularly helpful for patients in whom APS is highly suspected, but conventional aPLs are repeatedly negative as well as for predicting APS patients with arterial thrombosis.