Prevalence of various antiphospholipid antibodies in pregnant women

Antiphospholipid antibodies (APAs) are characterized as a heterogeneous population of autoantibodies directed against different target antigens, predominantly anionic phospholipids or phospholipid-containing structures. The presence of APAs has been strongly associated with a variety of clinical disorders including adverse pregnancy complications such as spontaneous abortions, pregnancy-induced hypertension, preeclampsia and intrauterine growth retardation. The purpose of this study was to compare the prevalence of anticardiolipin antibodies (ACAs), which are routinely examined, with APAs directed against phosphatidylserine (APS), phosphatidylinositol (API), phosphatidylethanolamine (APE) and phosphatidylcholine (APC) in the sera of pregnant women. We examined 410 serum samples of pregnant women hospitalized in the department for pathological pregnancies. They underwent prenatal biochemical screening of fetal congenital abnormalities in the first and the second trimester of gravidity. Anticardiolipin IgG and IgM were measured using commercial ELISA kits (ImmuLisa Anti-Cardiolipin Antibody), whereas APS, APE, API and APC were determined by our modified ELISA kit. Among 410 pregnant women we found 21 patients (5.1%) positive for ACA IgG (>20 GPL) and 30 patients (7.3%) positive for ACA IgM (>10 MPL). It was found that 7.8% of pregnant women had at least one high-titer APA IgG and 9.8% high-titer APA IgM. One third of ACA IgG or IgM positive sera contained polyspecific autoantibodies reactive to at least two various phospholipids. In the group of IgG ACA positive women, 28.6% patients were positive for APS, 28.6% were positive or moderately positive for API, 23.8% for APC and 19% for APE. In the group of IgM ACA positive women, 33.3% were also positive for APS, 26.7% for APE, 26.7% for API and 23.3% for APC were present. IgG and IgM ACA negative patients exhibited a significantly lower incidence of other APA than the group of ACA positive pregnant women. It still remains to clarify if the routine examination of APA reacting with other anionic and zwitterionic antigens other than cardiolipin would improve the probability of identifying women liable to adverse pregnancy complications.