Granulysin‐mediated apoptosis of trophoblasts in blighted ovum and missed abortion

Problem Granulysin ( GNLY ) is a cytotoxic molecule mostly present in decidual natural killer ( NK ) cells. Blighted ovum ( BO ) and missed abortion ( MA ) represent the early pathological pregnancies with hindered development of the embryoblast or a dead embryo. We investigated the GNLY ‐mediated apoptotic mechanism potentially responsible for delayed termination of pregnancy. Method of study We performed immunohistological and immunofluorescence labeling of decidual tissues ( GNLY , Apaf‐1, NF ‐κB). NKG 2A expression was analyzed by flow cytometry and GNLY mRNA by RT ‐ qPCR . Results The GNLY labeling intensity ( H score) was lower in the nuclei of trophoblast cells in BO and MA . GNLY gene levels were inversely detected in BO and MA . A decreased decidual NK cell percentage was found in MA . NK cells from pathological pregnancies expressed lower NKG 2A levels. The highest frequency of Apaf‐1 was found in trophoblast cells of MA . NF ‐ kB was highly expressed in decidual cells of BO . Conclusion The reduced activation of GNLY ‐mediated killing might be implicated in the slower rejection of trophoblast cells in BO and MA . A decreased authentic decidual NK cell number could be responsible for low cytotoxicity against trophoblast cells in MA . In BO , trophoblast cells have a higher survival potential due to increased NF ‐ kB expression.