Mor, G., & Cardenas, I. (2010). The immune system in pregnancy: a unique complexity. American journal of reproductive immunology (New York, N.Y. : 1989). https://doi.org/10.1111/j.1600-0897.2010.00836.x
Mor G, Cardenas I. The immune system in pregnancy: a unique complexity. American journal of reproductive immunology (New York, N.Y. : 1989). 2010. doi:10.1111/j.1600-0897.2010.00836.x
Mor, Gil, and Ingrid Cardenas. "The immune system in pregnancy: a unique complexity." American journal of reproductive immunology (New York, N.Y. : 1989), 2010.
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RRM Academy Synopsis
Pregnancy keeps the mother's immune system active and modulated
A 2010 review from Yale University argues that pregnancy is a modulated immune state, and its three phases differ in inflammation. The authors' data suggest the placenta is an immune organ that shapes the mother's response to infection.
Key Findings
Natural killer cells make up 70% of immune cells in the decidua, the pregnant uterine lining. Macrophages make up 20–25% and dendritic cells 1.7%.
T lymphocytes make up about 3–10% of decidual immune cells, and B cells are absent.
Pregnancy has three immune phases: inflammation from implantation into the early second trimester, a calmer anti-inflammatory phase, and inflammation again at delivery.
Placental inflammation, called acute chorioamnionitis, accompanies approximately half of all preterm deliveries. Only a fraction of the fetuses show infection.
In malaria-endemic regions, pregnant women are more susceptible to malaria in the first half of pregnancy. Lassa fever case fatality was higher in pregnant women, particularly in the third trimester.
Interpretation
The paper is a narrative review. The review draws on published work and on studies from the authors' laboratory. In the authors' animal model, a virus infecting the placenta set off inflammation in the fetus, although the virus itself did not reach the fetus. The authors argue that calling pregnancy general immune suppression is misleading. They say each pathogen needs its own evaluation of how it interacts with the fetus and placenta. They also call for biomarkers that detect viral infection in pregnancy, including infection without symptoms.
RRM Context
Restorative reproductive medicine treats the body's own regulation as working by design. The review gives the same view of immunity in pregnancy. Immune cells at the implantation site are active and tightly controlled, and they support and shield the pregnancy. The phases give clinicians a normal baseline for judging inflammation.
Our editorial summary of this paper, not the article's abstract.
Abstract
Placental immune response and its tropism for specific viruses and pathogens affect the outcome of the pregnant woman's susceptibility to and severity of certain infectious diseases. The generalization of pregnancy as a condition of immune suppression or increased risk is misleading and prevents the determination of adequate guidelines for treating pregnant women during pandemics. There is a need to evaluate the interaction of each specific pathogen with the fetal/placental unit and its responses to design the adequate prophylaxis or therapy. The complexity of the immunology of pregnancy and the focus, for many years, on the concept of immunology of pregnancy as an organ transplantation have complicated the field and delayed the development of new guidelines with clinical implications that could help to answer these and other relevant questions. Our challenge as scientists and clinicians interested in the field of reproductive immunology is to evaluate many of the 'classical concepts' to define new approaches for a better understanding of the immunology of pregnancy that will benefit mothers and fetuses in different clinical scenarios.
