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.