Antigenic profile, prevalence, and clinical significance of antiphospholipid antibodies in women referred for in vitro fertilization.

The aim of this prospective study was to assess the prevalence of antiphospholipid antibodies (aPL) in women who had undergone in vitro fertilization (IVF) and the relationship between aPL and IVF outcome. A total of 101 infertile women with at least three unsuccessful IVF attempts were consecutively included in this study. Samples were collected in the follicular phase of a spontaneous ovarian cycle 2 months after the last ovulation induction treatment. Age-matched healthy fertile women (n = 160) were included as controls. All were evaluated for the presence of lupus anticoagulant (LA), antibodies (IgG, IgA, IgM) to cardiolipin (aCL), beta2-glycoprotein I (abeta2GPI), and phosphatidylethanolamine (aPE). Out of the 101 infertile women, 40 were persistently positive for aPL, showing a prevalence significantly higher than in controls (39.6% versus 5%, P < 0.0001). Among aPL, aPE were found with a significantly higher prevalence compared with LA, aCL, and aP2GPI (67.5% versus 0%, 15%, and 40%, respectively). Interestingly, aPE were found in 70% of the cases in the absence of the other aPL. The predominant isotype of aPL was IgA, in particular for abeta2GPI. Finally, no significant association was found between the presence of aPL and IVF outcome. This prospective study shows aPE as the most prevalent aPL in infertile women and IgA as more common than IgG and IgM. However, our results do not support an association between aPL and IVF outcome.