β2-glycoprotein 1 as a marker of antiphospholipid syndrome in women with recurrent pregnancy loss

Objective: To determine if beta 2-glycoprotein 1 (beta 2-GP1) antibodies are a better marker of the antiphospholipid antibody syndrome (APS) in women with recurrent pregnancy loss (RPL). Design: Evaluation and testing of sera from women with RPL. Setting: A university-affiliated reproductive endocrinology practice. Patient(s): 90 women with RPL; 45 women met criteria for APS and 45 women met criteria for RPL without antiphospholipid antibodies (APA). Both groups were of similar age and had a similar history of RPL. Intervention(s): Patient sera were obtained from women with RPL and were tested for APA and beta 2-GP1. Main Outcome Measure(s): A standard antiphospholipid antibody assay was employed to detect the presence of immunoglobulin (Ig)G, IgM, and IgA antibodies in serum against cardiolipin, phosphatidyl inositol, phosphatidyl glycerol, phosphatidyl serine, and phosphatidyl ethanolamine. Samples were also assayed with a commercial beta 2-GP1 assay for IgG antibodies. Result(s): Among the 45 women with APS, 10 (22.2%) had positive IgG antibodies for beta 2-GP1. Only 1 woman (2.2%) of 45 was positive for beta 2-GP1 among the control group of women with RPL but negative APA. There was no correlation noted among the beta 2-GP1-positive patients for a specific phospholipid antibody or isotype. Conclusion(s): These data suggest that IgG beta 2-GP1 antibodies are less sensitive than antiphospholipid antibodies for the diagnosis of APS. (C) 2000 by American Society for Reproductive Medicine.