Dorien Feyaerts, from the research group of Van der Molen, theme Inflammatory diseases, showed that pregnancy induces a memory phenotype on endometrial natural killer cells. However, previous CMV infection is a prerequisite for this memory induction.They published their findings in Cellular and Molecular Immunology: link.
During pregnancy, local uterine natural killer (NK) cells play an important regulatory role by ensuring correct placentation and successful pregnancy. It is known that pregnancy complications of poor placentation are at increased risk in first pregnancies. Since it has become clear that NK cells possess immune memory, it has been suggested that pregnancy could induce memory in uterine NK cells.
The researchers report that previous pregnancy indeed induces an increase of endometrial NK cells with a memory phenotype (LILRB1+ expression on NKG2C+ NK cells) but only when women had a CMV positive status. Multigravidae women with a CMV negative status did not show memory-like NK cells in their endometrium. This suggests that CMV seropositivity might be a prerequisite for the induction of these pregnancy-induced memory endometrial NK cells.
These finding opens up the exciting hypothesis that CMV primes the induction of pregnancy trained eNK cells. This prompts further research to determine how this CMV priming works and whether the observed changes would alter NK cell function in a manner beneficial for future gestations.