Soluble CEACAM1 and CEACAM6 are differently expressed in blood serum of pregnant women during normal pregnancy

Problem: CEACAM1 and CEACAM6 belong to the carcinoembryonic antigen (CEA) family and may play an immune-modulatory role during pregnancy. The aim of the study was to determine the blood serum levels of soluble CEACAM1 and CEACAM6 over the course of pregnancy and postpartum. Method of study: CEACAM1 and CEACAM6 levels were determined with customized in-house Sandwich-enzyme-linked immunosorbent assay (ELISA) systems. The study population (n=125) was divided into four groups according to the pregnancy trimester and postpartum. Additionally, samples of non-pregnant women (n=14) were analyzed. Results: Serum levels of CEACAM1 in healthy pregnant women were much lower than in non-pregnant women, a difference not seen for CEACAM6. Comparison between the trimesters and postpartum revealed a significant difference in CEACAM1 serum levels. The highest CEACAM1 levels were detected in third trimester. These levels were statistically significantly different from the CEACAM1 levels in first trimester and second trimester. The lowest levels were observed in the second trimester. Postpartum CEACAM1 serum concentrations were slightly lower than in the third trimester, but higher than in the first trimester and significantly higher compared to levels in the second trimester. Conclusion: Decreased concentration of CEACAM1 during the pregnancy suggests its regulatory role in the immune tolerance during the course of pregnancy.