Normal expression of tissue factor, thrombomodulin, and annexin V in placentas from women with antiphospholipid syndrome

OBJECTIVE: Placentas from pregnancies complicated by antiphospholipid syndr ome often show thromboses and infarction, which may result from aberrations in placental coagulant pathways. We tested the hypothesis that alterations in tissue factor, thrombomodulin, and annexin V expressions contribute to poor pregnancy outcome associated with antiphospholipid syndrome. STUDY DESIGN: Frozen sections from random biopsy samples of the basal plate s of placentas from patients with primary antiphospholipid syndrome (n = 9) , patients with secondary antiphospholipid syndrome (n = 3), and gestationa l age-matched control subjects (n = 10) were immunostained for tissue facto r, thrombomodulin, and annexin V. Intensity of immunostaining was assessed by means of quantitative image analysis. Annexin V protein expression was e valuated with Western blotting techniques. RESULTS: Tissue factor was expressed in the perivascular cells of the villo us vasculature. Thrombomodulin and annexin V immunostaining was localized t o the syncytiotrophoblast. There were no differences in the intensity of im munostaining for tissue factor, thrombomodulin, and annexin V between place ntas from women with antiphospholipid syndrome and those from control subje cts. Western blot analysis of annexin V expression showed no differences be tween study patients and control subjects. CONCLUSION: Alterations in placental coagulant pathways involving tissue fa ctor, thrombomodulin, and annexin V do not contribute to poor pregnancy out come associated with antiphospholipid syndrome.