[Soluble fibrin and D-dimer at normal pregnancy and pregnancy with risk of miscarriage]

ELISA for soluble fibrin (SF) quantification has been elaborated on the basis of our fibrin-specific monoclonal antibodies (mAb). Epitope for these mAb is localized in fibrin fragment Bbeta118-134. The method was used on the blood plasma of healthy pregnant women (control group) and pregnant women with the risk of fetal loss (RFL). The increased mean values of SF concentrations were observed at pregnancy with RFL as compared to the normal pregnancy at the terms from 4 to 24 weeks (17.87 +/- 3.15 mkg/ml and 9.03 +/- 1.58 mkg/ml accordingly, p < 0.05). A weak negative correlation between SF concentration and pregnancy term was found at RFL (r = -0.201, n=35), while there was no correlation between these variables in control group (r = 0.004, n=28). The mean values of SF concentration estimated by semiquantitative test (by phosphates salting out of SF) were also higher at the pregnancy with RFL as compared to the normal pregnancy. However, the absolute values of SF concentrations determined by salting out method were essentially higher than in the case of ELISA. Immunoblot analysis with mAb 2d-2a (epitope for which in fibrin molecule encompasses peptide bond Bbeta14-15), showed that the main molecular component of SF at normal pregnancy and RFL was oligomeric fibrin desAA with possible incorporation of fibrinogen and/or fibrin desA which was not stabilized by factor XIIIa. D-dimer concentrations determined in blood plasma samples of pregnant women by ELISA varied in the range of 1-224 ng/ml at the pregnancy period from 4 to 37 weeks. There was positive correlation between D-dimer concentration and pregnancy term both at normal pregnancy and pregnancy with RFL (r = 0.765, n=33 and r = 0.712, n=44 correspondingly). The mean values of D-dimer concentration at various terms of normal pregnancy and pregnancy with RFL did not vary considerably. Thus SF but not D-dimer quantification may give useful diagnostic information at the pregnancy with RFL.