Rinat Hackmon

HLA-G Antigen and Parturition: Maternal Serum, Fetal Serum and Amniotic Fluid Levels during Pregnancy

Objective: To determine whether soluble HLA-G1 (sHLA-G1) concentrations in maternal serum and in amniotic fluid are lower at term than in the second trimester. Methods: In this prospective study amniotic fluid and maternal serum samples were aspirated from 21 pregnant women during genetic amniocentesis at 16–20 weeks’ gestation, and from 19 women undergoing a cesarean section at term. In the latter group arterial umbilical cord blood was aspirated as well. sHLA-G1 levels were determined using ELISA assay. This assay included the anti-HLA-G monoclonal antibodies 87G and 16G1, both as capture antibodies and horseradish-peroxidase-labeled rabbit anti-human β2-microglobulin antibodies, as the detection antibody. The relative concentrations of sHLA-G1 were measured from the absorbancy of the blue product at 650 nm. Student’s t test was used for statistical analysis. Results: sHLA-G1 levels in amniotic fluid were significantly lower at term than in the second trimester (0.160 ± 0.05 vs. 0.272 ± 0.150 OD units; p < 0.05). Levels of sHLA-G1 in maternal serum declined toward term, but the difference from the second trimester was not statistically significant (0.266 ± 0.157 vs. 0.205 ± 0.120 OD units; p = 0.193). There was a strong correlation of sHLA-G1 concentrations between cord serum and maternal serum (R2 = 0.79; p < 0.001), but not between cord serum and amniotic fluid (R2 = 0.00004) or amniotic fluid and maternal serum (R2 = 0.02). Conclusions: sHLA-G1 antigen expression is higher in amniotic fluid than in maternal-fetal compartments and significantly decreases toward term. We speculate that the declining amniotic fluid sHLA-G1 levels may stimulate a maternal immunological response against the fetus and contribute to the initiation of parturition.

Definitive class I human leukocyte antigen expression in gestational placentation: HLA‐F, HLA‐E, HLA‐C, and HLA‐G in extravillous trophoblast invasion on placentation, pregnancy, and parturition

The extravillous trophoblasts (EVT) express HLA‐C and HLA‐G, but HLA‐E and HLA‐F are the subject of conflicting reports. In this study, we define the HLA expression profile during active EVT placental implantation, pregnancy development, and parturition.

The association of maternal BMI with fetal echogenic intracardiac foci and echogenic bowel

Objectives. To evaluate the impact of maternal body mass index (BMI) as well as maternal ethnicity on the detection of either echogenic intra-cardiac focus (EIF) or echogenic bowel (EB). Methods. This prospective study identified 74 uncomplicated singleton fetuses in which EIF and/or EB were detected between 18 and 21 weeks of gestation (i.e. study group). Seventy four consecutively scanned fetuses without EIF or EB, at the same gestational age, were selected as controls. The differences in maternal BMI and maternal ethnicity were compared between the two groups using the χ2 test, Fishers exact test, and the Student t-test. A multivariable logistic regression model was constructed to control for confounders. Odds ratios (OR) and their 95% confidence interval (CI) were computed. Results. The mean maternal BMI was significantly lower in the study group as compared to controls (22.9 ± 3.1 vs. 28.0 ± 7.5 kg/m2, respectively; p < 0.0001). Patients with fetal EIF and/or EB were significantly more likely to be Asians (20.3% vs. 5.4%, OR = 4.5; 95% CI 1.3–16.9). Using a multivariable analysis, controlling for ethnicity, the association between maternal BMI and fetal EIF or EB remained significant (OR = 0.83; 95% CI 0.76–0.91). However, based on this model Asian ethnicity was not an independent risk factor for the detection of EIF and/or EB (OR = 2.6; 95% CI 0.8–8.9). Conclusions. Our data suggests an inverse relationship between the maternal BMI and the detection of fetal EIF and/or EB. Moreover, it appears that low maternal BMI, and not Asian ethnicity, is an independent risk factor for the detection of these echogenic fetal findings.