Low prevalence of anti-annexin V antibodies in anti-phospholipid syndrome accompanied by spontaneous abortion.

Purpose. - Annexin V. a protein with potent anticoagulant activity has a ca lcium-dependent binding affinity for phospholipids. Annexin V is distribute d in many organs, especially in the placenta and endothelium. Various studi es have shown that placental annexin V is decreased in women with anti-phos pholipid syndrome. It has been suggested that annexin V might be a target o f anti-phospholipid antibodies and that the subsequent decrease in annexin V might be associated with obstetrical complications. We investigated the p resence of anti-annexin V antibodies in the plasma of women with anti-phosp holipid syndrome and obstetrical complications. Methods. - Twenty-three patients with at least one spontaneous abortion wer e included in the study. Anti-cardiolipin antibodies and lupus anticoagulan t were present in 87% and 30% of the patients, respectively. A group of 40 healthy women were included in the control group. Anti-annexin V IgG and Ig M antibodies were measured by ELISA. Results. - The IgG mean OD was 0.07 +/- 0.013 in patients and 0.042 +/- 0.0 6 in the control group. There was no significant difference between the two groups (P = NS). Only two out of the 23 patients and two out of the 40 hea lthy women were positive for IgG (OD > 0.25). The sensitivity of the assay was poor (8.7%). Even when the threshold was adjusted according to the mean OD in control subjects + 2 SD, the sensitivity was still poor, reaching on ly 13%. Conclusion. - The prevalence of anti-annexin V was low in patients with ant i-phospholipid syndrome and repetitive spontaneous abortions. Anti-annexin V assay does not appear to be sensitive enough for the identification of an ti-phospholipid antibodies that might be involved in the decrease in annexi n V leading subsequently to thrombosis risk. (C) 1999 Elsevier, Paris.