Maternal Soluble Programmed Death Ligand-1 (sPD-L1) and T-regulatory Cells (Tregs) Alteration in Preeclampsia: A Cross-Sectional Study From Eastern India

Background Studies have shown that aberrant reactions of the immune system play an important role in the pathogenesis of preeclampsia. The immune checkpoint molecules programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) system and the T-regulatory cells (Tregs) system are decisive in the regulation of immune responses and can be the target molecules in preeclampsia. In this study, an attempt has been made to evaluate the soluble PD-L1 (sPD-L1) in the serum of preeclampsia cases and correlate it with Tregs and inflammatory markers to have an insight into the link between these immunomodulatory molecules in the pathogenesis of preeclampsia. Materials and methods Ten normal fertile women, 20 trimester-matched normal pregnancy cases, and 20 preeclampsia cases were enrolled in the study. Serum sPD-L1, transforming growth factor beta 1 (TGF-β1), and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). High-sensitive C-reactive protein (hsCRP) was estimated using a clinical biochemistry autoanalyzer. Tregs were evaluated using flow cytometry. Results and discussion The immune checkpoint molecule PD-L1 inversely correlated with Tregs in preeclampsia cases. Associated inflammation was seen by raised IL-6 and hsCRP. The breakdown of immunological tolerance is mainly caused by the dysregulating the Tregs/Th17 balance, which leads to conditions of autoimmunity and chronic inflammatory disorders. PD-L1 can be the link between this immunological misbalance. Conclusion Our study, showing an increase in sPD-L1 and TGF and a decrease in Tregs with an increase in inflammatory markers like IL-6 and hsCRP levels in preeclampsia, has potential implications for early diagnosis and management of the condition. PD-L1 and Tregs can be target molecules for early management of preeclampsia.