Antiprothrombin autoantibodies in severe preeclampsia and abortion

We examined the levels of autoantibodies against prethrombin-1 and fragment-1 in pregnant women to determine the type of autoantibodies that were associated with severe preeclampsia or spontaneous abortion.

We measured autoantibodies bound to prothrombin, prethrombin-1, and fragment-1 by using an enzyme-linked immunosorbent assay (ELISA) in 12 healthy nonpregnant women, 36 women with normal pregnancies, 28 pregnant women with severe preeclampsia, and 19 pregnant women who subsequently had spontaneous abortion.

Plasma samples in 10 (36%) of the 28 women with severe preeclampsia and 11 (58%) of the 19 women with spontaneous abortion were positive for antiprothrombin antibodies as compared with 3 (9%) of the 36 women with normal pregancies. All 11 of the positive samples from women who had spontaneous abortions were positive for antiprethrombin-1 antibody, but only 1 was positive for antifragment-1 antibody. The mean (+/- SD) titer of antiprethrombin-1 antibodies in patients with spontaneous abortion (36 +/- 9 U) was higher than that in women with normal pregnancies (10 +/- 4 U; P < 0.01). Antiprethrombin-1 antibody was detected in only 2 women with severe preeclampsia, whereas all 10 women with antiprethrombin antibodies were positive for antifragment-1 antibody. The antifragment-1 antibody titer in patients with severe preeclampsia (49 +/- 15 U) was higher than in women with normal pregnancies (13 +/- 6 U, P < 0.01).

There is a strong and specific association between various types of antiprothrombin antibodies with severe preeclampsia and spontaneous abortion.