Characterization of cofactor activity for factor I: cleavage of complement C4 in human syncytiotrophoblast microvilli

A predictive model of pregnancy loss using pre-pregnancy endocrine and immunological parameters in women with abnormal glucose/lipid metabolism and previous pregnancy loss

OBJECTIVE

To investigate the clinical and endocrine risk factors for pregnancy loss in women with abnormal glucose/lipid metabolism and a history of pregnancy loss, and to develop a predictive model to assess the risk of pregnancy loss in these women's subsequent pregnancies.

METHODS

Patients with a history of pregnancy loss who had abnormal glucose/lipid metabolism were retrospectively included in this study, and their pre-pregnancy baseline and clinical characteristics were collected. A predictive nomogram was constructed based on the results of the multivariable logistic regression model analysis, and its calibration and discriminatory capabilities were evaluated. The internal validation was then performed and the net benefits were assessed by the clinical decision curve.

RESULTS

The predictive model was eventually incorporated eight variables, including maternal age, previous pregnancy losses, anticardiolipin antibody (aCL) IgG, aCL IgM, thyroid peroxidase antibody, complement 4, free thyroxine and total cholesterol. The area under the curve (AUC) of the nomogram was 0.709, and Chi-square value and P value of the Hosmer-Lemeshow test were 12.786 and 0.119, respectively, indicating that the nomogram had a satisfactory calibration and discriminatory performance. The validation cohort showed a similar result for the discrimination of the nomogram (AUC = 0.715). The clinical decision curve demonstrated the nomogram had good positive net benefits.

CONCLUSIONS

This is the first study to predict the risks of subsequent pregnancy loss in women with abnormal glucose/lipid metabolism and history of pregnancy loss using pre-pregnancy clinical and endocrine parameters. This predictive nomogram may provide clinicians assistance to personalize the management of subsequent pregnancies in these patients.

HLA and complement factors alleles sharing in Italian couples with recurrent spontaneous abortions

Recurrent Spontaneous Abortion (RSA) is postulated to be due to several factors including immunogenetic mechanisms. Many studies have been conducted on the effect of the MHC region in the reproductive phenomena suggesting an immunological or genetic involvement in RSA. We studied couples with 3 or more abortions among a larger group of couples in which female partners were anti-cardiolipin antibodies negative, resulting in a population of 43 couples typed for HLA-A, B, C, DR, DQ. In 16 of these 43 couples, complement factors C4A, C4B, and Bf were typed. The data shows a statistically significant increase of C4B*Q0 in RSA patients (N = 32) compared with the control population (N = 44) (pc = .00147) and also a statistically significant increase of C4B*Q0 sharing in aborting couples (43.75%) against the expected sharing rate in the control population (1.86%) (p < .001). Frequency increase of C4B*Q0 allele in aborting population leads to the hypothesis that an imbalance of complement factors expression and activity can have detrimental effects on implantation and embryo survival. Additionally, the significant sharing rate of C4B*Q0 in couples with RSA could indicate the existence of a gene in linked to this allele predisposing to RSA and acting in a recessive manner if present in double copies in the fetus.

Alloantibody responses to antigens recognized by rabbit antitrophoblast antisera in trophoblast and mononuclear cell (MNC) membranes by primary aborting women before and after paternal leukocyte immunization

PROBLEM

Because shared allogeneic antigens are expressed on peripheral blood lymphocytes, as well as trophoblasts, it has been proposed that lymphocyte transfusions may appropriately sensitize recurrent spontaneous aborters (RSA) to trophoblast and lead to pregnancy conservation. The degree to which these responses are affected by this treatment, however, has not been defined.

METHOD

SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analyses were used to study the alloantibody responses in RSA patients both before and after immunization with paternal leukocytes (MNC) against membrane proteins isolated from peripheral blood mononuclear cells (MNC), first trimester and full term chorionic villi (CV).

RESULTS

A distinct set of antigens with apparent molecular weights of 32, 36, 41, 63, 65, and 85 kDa was identified in both MNC and trophoblast membranes by rabbit anti-trophoblast antisera. In addition, a 55 kDa protein was recognized by MNC membranes. Thirty-eight percent of primary RSA sera recognized this 55 kDa protein. After paternal MNC immunization, all primary RSA samples displayed increased reactivity or produced antibodies to this 55 kDa protein when compared with preimmunization sera. The protein was identified as MCP using a rabbit polyclonal anti-MCP antisera. In contrast, reactivity to the other antigens present in the membrane preparations decreased after paternal MNC immunization.

CONCLUSION

Changes in immune reactivity in RSA patients after paternal MNC immunization suggest that immunization alters serum immune reactivity to MNC and trophoblast shared antigens.