Bedeutung natürlicher Killerzellen in der Frühschwangerschaft

Background: Natural killer (NK) cells play a pivotal role in the establishment of a successful pregnancy. They are found in peripheral blood (peripheral NK cells) as well as in the endometrium and decidua (uterine NK cells). Objective: This article aims to provide an overview of the origin, function, and diagnostics of NK cells, as well as to highlight possible therapeutic options. Results: Different types of NK cells differ significantly in their cytotoxicity. About 90% of uterine NK cells show low cytotoxicity with high cytokine production, whereas peripheral NK cells show high cytotoxicity and low cytokine production. Elevated uterine and peripheral NK cells are associated with miscarriage, hypertension, preeclampsia, and fetal growth restriction. Conclusion: A detailed understanding of the various mechanisms of implantation and (early) pregnancy is paramount to improving the success rates of reproductive interventions, as well as to prevent pregnancy complications. There is a growing number of studies on immunomodulatory therapies for NK cell changes investigating, e.g., corticosteroids, lipid infusions, and immunoglobulins. However, the studies are heterogeneous in design, methodology, intervention, and study population, which makes not only comparison and interpretation difficult, but also the development of evidence-based therapeutic strategies.