To evaluate the clinical significance of 24 antiphospholipid antibodies in pregnant women with antiphospholipid syndrome(APS).

Case-control study was carried out: 28 APS pregnant women, 34 non-APS pregnant women and 39 health controls were enrolled. Anti-cardiolipin (aCL), anti-β2-glycoprotein 1(aβ2GP1), anti-annexin-A5 anti-prothrombin antibodies (aPT), anti- phosphatidylserine antibodies aPS, anti-phosphatidyl ethanolamine antibodies (aPE), anti-phosphatidyl inositol antibodies (aPI), anti-phosphatidyl choline antibodies (aPC), anti-sphingomyelin antibodies (aSPH), antibodies (aAXN5), and anti-phosphatidylserine-prothrombin complex antibodies (aPT/PS) were detected by enzyme-linked immununosorbent assay(ELISA). Lupus anticoagulant (LA) was tested by Dilute Russell′s viper venom time (dRVVT). The prevalence of antiphospholipid antibodies in the three groups were compared (Chi-Square test or Fisher′s exact test). The antibody levels in different groups were compared using nonparametric Mann–Whitney U tests. The diagnostic efficacy of antiphospholipid antibodies was analyzed by cross table using clinical diagnosis of APS as gold standard.

The prevalence of aCL-IgM, aβ2GP1-IgG, aβ2GP1-IgA, aPT/PS-IgG, aPT/PS-IgM, aPS-IgG, aPI-IgG,and LA were higher in APS pregnant women than those in non-APS pregnant women (P < 0.0001, P < 0.015, P< 0.037, P< 0.0001, P< 0.030, P< 0.018, P< 0.0001, and P<0.001, respectively). For differentiating APS pregnant woman from non-APS pregnant woman, LA displayed the highest sensitivity (75%), followed by IgG aPT/PS (57.1%) and IgM aCL (50%). All the aPLs, except aPT/PS-IgM demonstrated a high specificity (> 97.1%) in differentiating APS pregnant women from non-APS in pregnant women. Although there was no significantly differenct prevalence of aPLs between patients with thrombosis and without thrombosis, the median levels of aCL-IgM [19.3(43.2) MPL/ml vs 8.3(17.7) MPL/ml], aPT/PS-IgG [71.4(78.2) U/ml vs 16.7(31.5) U/ml], aPT/PS-IgM [95.0(127.7) U/ml vs 15.3(15.1) U/ml], aPT-IgG [9.1(18.1) U/ml vs 5.0(4.1) U/ml] and LA [1.70(0.29) vs 1.21(0.41)] were significantly higher in patients with thrombosis (P=0.006, P=0.041, P=0.019, P=0.041, and P=0.006, respectively). Furthermore, the prevalence of multiple aPLs was significantly higher in APS pregnant women with thrombosis than those without thrombosis (86.67% vs. 38.46%, P=0.016).

LA, aCL-IgM and aPI-IgG play important roles in diagnosising APS in pregnant women. More antiphospholipid antibodies could be found in patients with thrombosis than those without thrombosis, and the levels of these antibodies are higher in the patients with thrombosis than in the without thrombosis.