ORIGINAL ARTICLE: The Characterization of the Subpopulation of Suppressive B7H4+ Macrophages and the Subpopulation of CD25+ CD4+ and FOXP3+ Regulatory T-cells in Decidua during the Secretory Cycle Phase, Arias Stella Reaction, and Spontaneous Abortion - A

CD8+ and CD8- NK Cells and Immune Checkpoint Networks in Peripheral Blood During Healthy Pregnancy

Pregnancy involves significant immunological changes to support fetal development while protecting the mother from infections. A growing body of evidence supports the importance of immune checkpoint pathways, especially at the maternal-fetal interface, although limited information is available about the peripheral expression of these molecules by CD8+ and CD8- NK cell subsets during the trimesters of pregnancy. Understanding the dynamics of these immune cells and their checkpoint pathways is crucial for elucidating their roles in pregnancy maintenance and potential complications. This study aims to investigate the peripheral expression and functional characteristics of CD8+ and CD8- NK cell subsets throughout pregnancy, providing insights into their contributions to maternal and fetal health. A total of 34 healthy women were enrolled from the first, 30 from the second and 40 from the third trimester of pregnancy. At the same time, 35 healthy age-matched non-pregnant women formed the control group. From peripheral blood, mononuclear cells were separated and stored at -80 °C. CD8+ and CD8- NK cell subsets were analyzed from freshly thawed samples, and surface and intracellular staining was performed using flow cytometric analyses. The proportions of CD56+ NK cells in peripheral blood were similar across groups. While CD8- NKdim cells increased significantly in all trimesters compared to non-pregnant controls, CD8+ NKdim cells showed no significant changes. CD8- NKbright cells had higher frequencies throughout pregnancy, whereas CD8+ NKbright cells significantly increased only in the first and second trimesters. The expression levels of immune checkpoint molecules, such as PD-1 and PD-L1, and cytotoxic-activity-related molecules were stable, with notable perforin and granzyme B increases in CD8- NKbright cells throughout pregnancy. Our study shows that peripheral NK cell populations, especially CD8- subsets, are predominant during pregnancy. This shift suggests a crucial role for CD8- NK cells in balancing maternal immune tolerance and surveillance. The stable expression of immune checkpoint molecules indicates that other regulatory mechanisms may be at work. These findings enhance our understanding of peripheral immune dynamics in pregnancy and suggest that targeting CD8- NKbright cell functions could help manage pregnancy-related immune complications. This research elucidates the stable distribution and functional characteristics of peripheral NK cells during pregnancy, with CD8- subsets being more prevalent. The increased activity of CD8- NKbright cells suggests their critical role in maintaining immune surveillance. Our findings provide a basis for future studies to uncover the mechanisms regulating NK cell function in pregnancy, potentially leading to new treatments for immune-related pregnancy complications.

Case report: Osimertinib administration during pregnancy in a woman with advanced EGFR-mutant non-small cell lung cancer

Lung cancer (LC) is one of the most common causes of death worldwide. The identification of oncogene-addicted driving mutations suitable for targeted therapy has improved clinical outcomes in advanced diseases. Clinical trials, on the other hand, rarely involve vulnerable groups such as pregnant women. We report a 37-year-old woman with advanced non-small cell lung cancer (NSCLC) harboring an exon 19 deletion of EGFR treated with afatinib. After the initial treatment, the patient achieved a complete response and had an unplanned pregnancy. Targeted therapy was withheld during the first trimester and resumed with osimertinib in the second trimester in which the patient developed oligohydramnios and intrauterine growth restriction (IUGR) of the baby. Osimertinib was delayed at two different times during the third trimester with complete resolution of the oligohydramnios. The baby was born at 37.3 weeks of gestation (WOG) with no signs of congenital disorders. After delivery, the mother restarted osimertinib and maintained a complete response. This case suggests that osimertinib could be an acceptable option for tumor control during pregnancy in EGFR-mutant NSCLC. This information do not replace current recommendations for avoiding pregnancy and promoting contraceptive usage in patients receiving any cancer therapy.

Immunological Changes in Pregnancy and Prospects of Therapeutic Pla-Xosomes in Adverse Pregnancy Outcomes

Stringent balance of the immune system is a key regulatory factor in defining successful implantation, fetal development, and timely parturition. Interference in these primary regulatory mechanisms, either at adolescence or prenatal state led to adverse pregnancy outcomes. Fertility restoration with the help of injectable gonadotrophins/progesterone, ovulation-inducing drugs, immunomodulatory drugs (corticosteroids), and reproductive surgeries provides inadequate responses, which manifest its own side effects. The development of a potential diagnostic biomarker and an effectual treatment for adverse pregnancy outcomes is a prerequisite to maternal and child health. Parent cell originated bi-layered-intraluminal nano-vesicles (30-150 nm) also known as exosomes are detected in all types of bodily fluids like blood, saliva, breast milk, urine, etc. Exosomes being the most biological residual structures with the least cytotoxicity are loaded with cargo in the form of RNAs (miRNAs), proteins (cytokines), hormones (estrogen, progesterone, etc.), cDNAs, and metabolites making them chief molecules of cell-cell communication. Their keen involvement in the regulation of biological processes has portrayed them as the power shots of cues to understand the disease's pathophysiology and progression. Recent studies have demonstrated the role of immunexosomes (immunomodulating exosomes) in maintaining unwavering immune homeostasis between the mother and developing fetus for a healthy pregnancy. Moreover, the concentration and size of the exosomes are extensively studied in adverse pregnancies like preeclampsia, gestational diabetes mellitus (GDM), and preterm premature rupture of membrane (pPROMs) as an early diagnostic marker, thus giving in-depth information about their pathophysiology. Exosomes have also been engineered physically as well as genetically to enhance their encapsulation efficiency and specificity in therapy for cancer and adverse pregnancies. Successful bench to bedside discoveries and interventions in cancer has motivated developmental biologists to investigate the role of immunexosomes and their active components. Our review summarizes the pre-clinical studies for the use of these power-shots as therapeutic agents. We envisage that these studies will pave the path for the use of immunexosomes in clinical settings for reproductive problems that arise due to immune perturbance in homeostasis either at adolescence or prenatal state.

COVID-19 in pregnancy: What we know from the first year of the pandemic

The COVID-19 pandemic has infected nearly 178 million people and claimed the lives of over 3.8 million in less than 15 months. This has prompted a flurry of research studies into the mechanisms and effects of SARS-CoV-2 viral infection in humans. However, studies examining the effects of COVID-19 in pregnant women, their placentae and their babies remain limited. Furthermore, reports of safety and efficacy of vaccines for SARS-CoV-2 in pregnancy are limited. This review concisely summarises the case studies and research on COVID-19 in pregnancy, to date. It also reviews the mechanism of infection with SARS-CoV-2, and its reliance and effects upon the renin-angiotensin-aldosterone system. Overall, the data suggest that infection during pregnancy can be dangerous at any time, but this risk to both the mother and fetus, as well as placental damage, increases during the third trimester. The possibility of vertical transmission, which is explored in this review, remains contentious. However, maternal infection with SARS-CoV-2 can increase risk of miscarriage, preterm birth and stillbirth, which is likely due to damage to the placenta.

Immunology and the immunological response to pregnancy

The immune system in humans is a complex system capable of discriminating self from non-self, and mounting appropriate allogenic immune responses to protect themselves from foreign organisms. This system is made up of two arms of defense: the first one is a non-specific arm (innate), in which humans are born with and do not require antigenic recognition. The second one is specific arm (humoral) involving B and T cells that are capable of mounting responses to particular antigen with immense specificity. Both of these systems importantly interact with each other to protect humans in the most effective and efficient manner. Defects or malfunctions in these systems can result in a variety of illnesses and conditions. The immunology of pregnancy is a very unique, highly controlled system, which allows for survival of a fetus (semi-allograft), whilst simultaneously protecting a pregnant woman. There are immune shifts in pregnancy, which are well established to facilitate maternal-fetal tolerance. This promotes the concept that the immune system is not suppressed, but instead modulated to facilitate a pregnancy and explain the differential response to various pathogens in pregnancy. During pregnancy, the development of a fetal immunological system also occurs with intricate interaction between the maternal and fetal interface. The mechanism is preterm and term birth is poorly understood, but the immunological response has been well documented for both the pathological and physiological scenarios.

Alteration of the immune cell profiles in the pathophysiology of tubal ectopic pregnancy

Tubal ectopic pregnancy (TEP) refers to implantation of conceptus in the fallopian tube. It makes up over 98% of ectopic pregnancy (EP), which is the leading cause of maternal morbidity and mortality in the first trimester of pregnancy. Immune cells at the maternal-fetal interface play important roles in the process of embryo implantation, stroma decidualization, and early placental development. Alterations in the composition, phenotype, and activity of the immune cells in the fallopian tubes contribute toward the onset of TEP. In this review, we compare the leukocytic proportions in decidua of normal pregnancy, and in decidua and fallopian tubes of TEP. The possible functions of these immune cells in the pathophysiology of TEP are also discussed.

Microbial Vertical Transmission during Human Pregnancy

Congenital infections with pathogens such as Zika virus, Toxoplasma gondii, Listeria monocytogenes, Treponema pallidium, parvovirus, HIV, varicella zoster virus, Rubella, Cytomegalovirus, and Herpesviruses are a major cause of morbidity and mortality worldwide. Despite the devastating impact of microbial infections on the developing fetus, relatively little is known about how pathogens associated with congenital disease breach the placental barrier to transit vertically during human pregnancy. In this Review, we focus on transplacental transmission of pathogens during human gestation. We introduce the structure of the human placenta and describe the innate mechanisms by which the placenta restricts microbial access to the intrauterine compartment. Based on current knowledge, we also discuss the potential pathways employed by microorganisms to overcome the placental barrier and prospects for the future.

Models of vertical cytomegalovirus (CMV) transmission and pathogenesis

Despite the considerable clinical impact of congenital human cytomegalovirus (HCMV) infection, the mechanisms of maternal-fetal transmission and the resultant placental and fetal damage are largely unknown. Here, we discuss animal models for the evaluation of CMV vaccines and virus-induced pathology and particularly explore surrogate human models for HCMV transmission and pathogenesis in the maternal-fetal interface. Studies in floating and anchoring placental villi and more recently, ex vivo modeling of HCMV infection in integral human decidual tissues, provide unique insights into patterns of viral tropism, spread, and injury, defining the outcome of congenital infection, and the effect of potential antiviral interventions.

Imitating a stress response: a new hypothesis about the innate immune system's role in pregnancy

Recent research challenges long-held hypotheses about mechanisms through which pregnancy induces maternal immune suppression or tolerance of the embryo/fetus. It is now understood that normal pregnancy engages the immune system and that the immune milieu changes with advancing gestation. We suggest that pregnancy mimics the innate immune system's response to stress, causing a sterile inflammatory response that is necessary for successful reproduction. The relationship between external stressors and immunomodulation in pregnancy has been acknowledged, but the specific mechanisms are still being explicated. Implantation and the first trimester are times of immune activation and intensive inflammation in the uterine environment. A period of immune quiescence during the second trimester allows for the growth and development of the maturing fetus. Labor is also an inflammatory event. The length of gestation and timing of parturition can be influenced by environmental stressors. These stressors affect pregnancy through neuroendocrine interaction with the immune system, specifically through the hypothalamic-pituitary-adrenal (HPA) axis and the hypothalamic-pituitary-ovarian axis. Trophoblastic cells that constitute the maternal-fetal interface appear to harness the maternal immune system to promote and maximize the reproductive success of the mother and fetus. Pregnancy is a time of upregulated innate immune responses and decreased adaptive, cell-mediated responses. The inflammatory processes of pregnancy resemble an immune response to brief naturalistic stressors: there is a shift from T helper (Th) 1 to T helper (Th) 2 dominant adaptive immunity with a concomitant shift in cytokine production, decreased proliferation of T cells, and decreased cytotoxicity of natural killer (NK) cells. Inclusion of both murine and human studies, allows an exploration of insights into how trophoblasts influence the activity of the maternal innate immune system during gestation.

Productive HIV-1 infection of human cervical tissue ex vivo is associated with the secretory phase of the menstrual cycle

Cervical tissue explants (CTEs) from 22 HIV-1 seronegative women were exposed to R5 HIV-1 ex vivo. Eight CTEs were productively infected in terms of HIV-1 p24Gag release in culture supernatants, whereas 14 were not. Nonetheless, both accumulation of HIV-1gag DNA and of p24Gag(+) CD4(+) T cells and macrophages occurred in both productive and, at lower levels, in nonproductive CTEs. Nonproductive CTEs differed from productive CTEs for higher secretion of C-C motif chemokine ligand 3 (CCL3) and CCL5. A post-hoc analysis revealed that all productive CTEs were established from women in their secretory phase of the menstrual cycle, whereas nonproductive CTEs were derived from women either in their secretory (28%) or proliferative (36%) menstrual cycle phases or with an atrophic endometrium (36%). Thus, our results support the epidemiological observation that sexual HIV-1 transmission from males to women as well as from women to men is more efficient during their secretory phase of the menstrual cycle.

Specific infiltration pattern of FOXP3+ regulatory T cells in chronic histiocytic intervillositis of unknown etiology

INTRODUCTION

Chronic histiocytic intervillositis of unknown etiology (CIUE) is a rare placental lesion characterized by an intervillous mononuclear inflammatory infiltrate of maternal origin. Although the mechanism and origin of these lesions are currently not understood, they appear to be related to an immune conflict between mother and fetus cells.

AIM

To clarify the inflammatory cell profile and evaluate the T regulatory lymphocyte (Treg) status in CIUE.

MATERIALS AND METHODS

All cases of CIUE that occurred over an 8-year period were analyzed using immunohistochemistry.

RESULTS

The inflammatory profile of CIUE was characterized by a clearly predominant component of histiocytic cells (80% ± 6.9) associated with some T cells (24% ± 5.7). The ratio of CD4+ versus CD8+ T cells was close to 1. This profile differs from infectious disease and chronic histiocytic villitis, the main differential diagnoses of CIUE. As for normal pregnancies most regulatory T cells were localized in the decidua basalis. Nevertheless, their appearance was also noted in the intervillous space. In both the intervillous space and the deciduas the number of Tregs gradually increased from grade 1 to 3.

CONCLUSION

We found that CIUE is associated with an increase in Treg lymphocytes in the decidua basalis and the intervillous space. Contrary to previously published data on human miscarriage, this result appears to be specific to CIUE and would support the hypothesis of an immunopathological disorder for CIUE.

The presence of B7-H4+ macrophages and CD25+CD4+ and FOXP3+ regulatory T cells in the microenvironment of nasal polyps - a preliminary report

The nasal polyp (NP) seems to represent the end-stage of longstanding inflammation in patients with chronic rhinosinusitis. The aim of our study has been to evaluate the presence of two regulatory cell populations in the microenvironment of NP: CD4+CD25high Foxp3+ (Treg) cells and B7-H4-expressing macrophages. Treg cells are actively able to inhibit T lymphocytes, while the population of B7-H4-expressing macrophages has recently been described as characterized by a regulatory function similar to that of Treg cells. For our study, we evaluated 14 NP tissue samples. The samples were divided into two main groups, eosinophilic (NP) and lymphocytic (NP), according to the predominant type of immune cell infiltration. The presence of Treg cells and B7-H4 positive macrophages in the samples was analyzed by FACS. Treg cells and B7-H4-expressing macrophages were identified in all the examined nasal polyps. The percentages of both Treg cells and of B7H4 positive cells found in the eosinophilic nasal polyps were higher than those found in the lymphocytic nasal polyps. Treg cells and B7H4+ macrophage subpopulations were present in the NP microenvironment and the alterations in their percentages were related to a distinct pattern of immune cell infiltration.

Modulation and recruitment of inducible regulatory T cells by first trimester trophoblast cells

PROBLEM  The specialized regulatory T-cells (Treg) population, essential for maternal tolerance of the fetus, performs its suppressive actions in the critical peri-implantation phase of pregnancy. In the present work, we investigated whether trophoblast cells are able to induce Treg recruitment, differentiation, and whether these mechanisms are modified by a bacterial or viral infection. METHOD OF STUDY  Human T-regulatory cells were differentiated from naïve CD45RA(+) CCR7(+) cells obtained from peripheral blood mononuclear cells cultured with IL-2 and TGFβ over 5 days. Induction of iTregs (CD4(+)  Foxp3(+) cells) was evaluated using low serum conditioned media (LSCM), obtained from two first trimester trophoblast cell lines, Swan-71 and HTR8. Coculture experiments were carried out using transwell assays where trophoblast cells were in the absence or presence of PGN, LPS, or Poly [I:C]. Cytokine production was measured by multiplex analysis. RESULTS  Trophoblast cells constitutively secrete high levels of TGFβ and induced a significant increase of Foxp3 expression accompanied by a specific T-reg cytokine profile. Moreover, trophoblast cells were able to recruit iTregs in a specific manner. CONCLUSION  We demonstrate that trophoblast cells have an active role on the recruitment and differentiation of iTregs, therefore, contributing to the process of immune regulation at the placental-maternal interface.

The distribution of immune cells and macrophages in the endometrium of women with recurrent reproductive failure I: Techniques

Recurrent miscarriage affects approximately 1% of the population and in half of these cases no cause is found. Abnormally functioning immunocompetent cells, including natural killer (NK) cells, in the endometrium, are thought to be responsible for many such cases and treatment trials including oral prednisolone and intravenous immunoglobulins are now underway. Despite these encouraging developments, there is neither adequate standardization of counting uterine NK cells nor consensus as to what constitutes an abnormal level. To address this issue, immunohistochemistry was used to examine the presence and distribution of selected immune cells and macrophages in the endometrium from 222 women who had a routine endometrial biopsy for investigation of recurrent miscarriage or IVF failure, at various stages of the menstrual cycle, and accessioned prospectively over a 7-month period. Biopsies were examined by H+E and immunostained for CD8(+) T-cells, CD163(+) macrophages, CD56(+) NK cells, and CD57(+) cells. Cell numbers (expressed as immunopositive cells per mm(2)) were determined in the stroma of the functional layer of endometrium and the relative concentrations of some cell types (CD163(+) macrophages, CD56(+) NK cells) were expressed as a percentage of all stromal cells. Routine H+E sections revealed 12 patients with focal "endometritis" without plasma cells. CD8(+) T-cells showed focal perivascular aggregates in most instances, and non-random but scattered cells in all cases, with a twofold increase in the luteal phase. CD163(+) cells were distributed evenly throughout the superficial endometrial stroma and also present as single or clustered macrophages within the lumens of superficial glands, mostly in the luteal phase. CD56(+) NK cells showed "diffuse" but variable distribution throughout the functional layer and perivascular aggregates of various sizes in two thirds of cases. Raw cell counts were low and relatively stable in the proliferative phase, but increased somewhat during the first half of the secretory phase, while in the second half of secretory phase they increased six to tenfold. Percentage counts rose from approximately 5% of stromal cells in the early part of the secretory phase of the cycle to over 35% in premenstrual endometrium. CD57(+) cells were present in very low numbers in most cases. The study illustrates the complexity and variability of immune cell infiltration of endometrium. We stress the need for strict counting protocols and attention to histological criteria if any immunological perturbations potentially responsible for recurrent reproductive failure are to be identified. Reference ranges for individual cell types are only valid for individual "days" of a normalized menstrual cycle.

Inflammation and pregnancy: the role of the immune system at the implantation site

The concept that pregnancy is associated with immune suppression has created a myth of pregnancy as a state of immunological weakness and, therefore, of increased susceptibility to infectious diseases. A challenging question is whether the maternal immune system is a friend or a foe of pregnancy. In this review, we discuss data associated to the role of the immune system during pregnancy. We propose a new paradigm in terms of the fetal-maternal immune interaction as well as the immunological response of the mother to microorganism. Our challenge is to better understand the immunology of pregnancy in order to deliver the appropriate treatment to patients with pregnancy complications as well as to determine public policies for the protection of pregnant women during pandemics.

The immunohistochemical analysis of RCAS1, HLA-G, and B7H4-positive macrophages in partial and complete hydatidiform mole in both applied therapeutic surgery and surgery followed by chemotherapy

INTRODUCTION

The suppressive microenvironment developing around the implantating ovum in normal pregnant women may correlate with the development in cancer patients of a suppressive microenvironment of neoplasmatic cells derived from trophoblasts, such as occurs in molar lesions. Macrophages are suitable candidates for mediating not only the balance of the maternal defensive immune responses to external antigens, but also a tolerance to tumor cells. The aim of our study has been to gain information about the expression of RCAS1, B7H4, and HLA-G within the macrophages present in the microenvironment of the molar lesion.

METHODS

We analyzed the immunoreactivity of such antigens as B7H4, RCAS1, and HLA-G on the macrophages present in tissue samples derived from patients on whom curettage was performed after a diagnosis of molar pregnancy. These patients were then divided into two subgroups according to whether or not they required chemotherapy after the surgical procedure.

RESULTS

We observed a statistically significant increase in the RCAS1-positive macrophage infiltration within the microenvironment of the molar lesions in patients with partial hydatidiform mole in comparison with those patients who exhibited complete hydatidiform mole. There were no such differences, however, in the infiltration of HLA-G- and B7H4-positive macrophages between the two groups of patients. Additionally, we showed that RCAS1- and HLA-G-positive macrophages are more distinct in those cases of complete molar pregnancy where chemotherapy was necessary after surgical treatment while no such differences with respect to B7H4-positive macrophages were observed.

CONCLUSION

The immune-suppressive endometrial microenvironment represented by suppressive macrophages may have an influence on the clinical course of hydatidiform mole.

The frequency of CD25+CD4+ and FOXP3+ regulatory T cells in ectopic endometrium and ectopic decidua

BACKGROUND

The presence of regulatory T (Treg) cells in human endometrium is crucial for maintaining immunological homeostasis within the uterus. For this study we decided to evaluate the subpopulations of Treg cells in conditions where a disturbance in the immunological equilibrium in ectopic endometrium and decidua has been observed, such as in cases of ovarian endometriosis (involving local immune cell suppression) and ectopic pregnancy (involving an increase in local immune system activity). We then compared these findings to what we observed in the normal eutopic endometrium of women during the secretory phase of the menstrual cycle (with immune cells under individual control).

METHODS

The endometrium tissue samples evaluated in our study were obtained from 47 women during one of two kinds of laparoscopic procedures. 16 of the women underwent laparoscopies due to Fallopian tube pregnancies (EP), and 16 due to ovarian endometrioma, while 15 women made up a control group. The presence of regulatory T cells in these tissue samples was evaluated by FACS.

RESULTS

In our study, the percentages of FOXP3+ cells within the subpopulation of CD4+ T lymphocytes found in the decidua of the patients treated for Fallopian tube pregnancies were statistically significantly lower than both those observed in the ovarian endometriosis tissue samples and those found in the secretory eutopic endometrium samples of the control group.

CONCLUSION

The disturbance in the immunological equilibrium observed in ectopic endometrium and decidua would seem to be related to the alteration in the Treg cell population that occurs in these ectopic tissues.

The immune system in pregnancy: a unique complexity

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.