Soluble PD-L1 and B7-H4 serum levels during the course of physiological pregnancy

Problem: The aim of this study was to evaluate the soluble programmed death-ligand (sPD-L1) and soluble B7-H4 (sB7-H4) serum concentration levels longitudinal throughout the three trimesters of uncomplicated pregnancies. Method of the study: sPD-L1 and sB7-H4 levels were determined with enzyme-linked immunosorbent assay (ELISA). The patients (n = 26) were divided into three groups according to the pregnancy trimester. Among 26 women involved in the study 14 had longitudinal sB7-H4 and sPD-L1 measurements in each trimester of pregnancy. Results: During the course of pregnancy, the sB7-H4 blood serum levels were significant higher in second trimester than in first and third trimester, whereas sPD-L1 levels increased significantly over the course of pregnancy. Conclusion: The highest serum levels of sPD-L1 in the third trimester suggest increasing suppression of maternal immunity throughout pregnancy, whereas elevated sB7-H4 concentration levels in second trimester suggests different profile of T-cell regulation in physiological pregnancy.