Immunomodulation of the mother during pregnancy

SARS-2 COVID-19-induced immunity response, a new prognostic marker for the pregnant population correlates inversely with neonatal Apgar score

Background

The COVID-19 infection has impacted pregnancy outcomes; however, few studies have assessed the association between haematological parameters and virus-related pregnancy and neonatal outcomes. We hypothesised differences in routine haematology indices in pregnant and non-pregnant COVID-19 patients as well as COVID-19-negative pregnant subjects and observed neonatal outcomes in all pregnant populations. Further, we tested if pattern identification in the COVID-19 pregnant population would facilitate prediction of neonates with a poor Apgar score.

Methods

We tested our hypothesis in 327 patients (111 COVID-19-positive pregnant females, 169 COVID-19-negative pregnant females and 47 COVID-19-positive non-pregnant females) in whom standard routine laboratory indices were collected on admission.

Results

Pregnant COVID-19-positive patients exhibited higher WBC, neutrophil, monocyte counts as well as neutrophil/lymphocyte and neutrophil/eosinophil ratio compared to non-pregnant COVID-19-positive patients (p = 0.00001, p = 0.0023, p = 0.00002, p = 0.0402, p = 0.0161, p = 0.0352, respectively). Preterm delivery was more prevalent in COVID-19-positive pregnant patients accompanied with a significantly lower birth weight (2894.37 (± 67.50) g compared with 3194.16 (± 50.61) g, p = 0.02) in COVID-19-negative pregnant patients. The COVID-19-Induced Immunity Response (CIIR) was defined as (WBC × neutrophil) / eosinophil; Apgar scores were significantly and inversely correlated with the CIIR index (r =—0.162).

Interpretation

Pregnancy appears to give rise to an increased immune response to COVID-19 which appears to protect the mother, however may give rise to complications during labour as well as neonatal concerns. CIIR is a simple metric that predicts neonatal distress to aid clinicians in determining the prognosis of COVID-19 and help provide early intensive intervention to reduce complications.

A Translational Perspective of Maternal Immune Activation by SARS-CoV-2 on the Potential Prenatal Origin of Neurodevelopmental Disorders: The Role of the Cholinergic Anti-inflammatory Pathway

The emergent Coronavirus Disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) could produce a maternal immune activation (MIA) via the inflammatory response during gestation that may impair fetal neurodevelopment and lead to postnatal and adulthood mental illness and behavioral dysfunctions. However, so far, limited evidence exists regarding long-term physiological, immunological, and neurodevelopmental modifications produced by the SARS-CoV-2 in the human maternal-fetal binomial and, particularly, in the offspring. Relevant findings derived from epidemiological and preclinical models show that a MIA is indeed linked to an increased risk of neurodevelopmental disorders in the offspring. We hypothesize that a gestational infection triggered by SARS-CoV-2 increases the risks leading to neurodevelopmental disorders of the newborn, which can affect childhood and the long-term quality of life. In particular, disruption of either the maternal or the fetal cholinergic anti-inflammatory pathway (CAP) could cause or exacerbate the severity of COVID-19 in the maternal-fetal binomial. From a translational perspective, in this paper, we discuss the possible manifestation of a MIA by SARS-CoV-2 and the subsequent neurodevelopmental disorders considering the role of the fetal-maternal cytokine cross-talk and the CAP. Specifically, we highlight the urgent need of preclinical studies as well as multicenter and international databanks of maternal-fetal psychophysiological data obtained pre-, during, and post-infection by SARS-CoV-2 from pregnant women and their offspring.

THYROID FUNCTION IN PREGNANCY: MATERNAL AND FETAL OUTCOMES WITH HYPOTHYROIDISM AND SUBCLINICAL THYROID DYSFUNCTION

Thyroid hormones are important in the development of the fetus and the placenta as well as in maintaining maternal wellbeing. Thyroid disorders are common in the population as a whole, particularly in women, and therefore are common during pregnancy and the puerperium. Biochemical derangement of thyroid function tests are present in approximately 2.5–5% of pregnant women.

Rethinking gender differences in health: why we need to integrate social and biological perspectives

The complexity of gender differences in health (i.e., men's lower life expectancy and women's greater morbidity) extends beyond notions of either social or biological disadvantage. Gaps remain in understanding the antecedents of such differences and the issues this paradox raises regarding the connections between social and biological processes. Our goals in this analytic essay are to make the case that gender differences in health matter and that understanding these differences requires an explanation of why rational people are not effective in making health a priority in their everyday lives. We describe some salient gender health differences in cardiovascular disease, immune function and disorders, and depression and indicate why neither social nor biological perspectives alone are sufficient to account for them. We consider the limitations of current models of socioeconomic and racial/ethnic health disparities to explain the puzzling gender differences in health. Finally, we discuss constrained choice, a key issue that is missing in the current understanding of these gender differences, and call on the social science community to work with biomedical researchers on the interdisciplinary work required to address the paradoxical differences in men's and women's health.

Inhibition of lymphocyte proliferation and activation: a mechanism used by equine invasive trophoblast to escape the maternal immune response

At days 36-38 of gestation, the equine invasive trophoblast cells migrate into the endometrium of the pregnant mare to form the endometrial cups. During their migration, they become surrounded by maternal CD4+ and CD8+ T lymphocytes, and stimulate a cytotoxic antibody response to the paternal major histocompatibility complex class I antigens that they express. Nevertheless, endometrial cup cells remain viable at the site of uterine invasion up to days 80-100 of gestation, suggesting the participation of immunomodulatory mechanisms to the maternal cellular immune response. To determine the effects of the invasive trophoblast cells on lymphocyte proliferation, an in vitro co-culture system was developed using isolated equine invasive trophoblast cells and peripheral blood lymphocytes. Fetal fibroblast cells from the same conceptuses were used as controls. The presence of invasive trophoblast cells or their pre-conditioned medium inhibited 50% or more of lymphocyte proliferation, while fetal fibroblasts had no effect. The invasive trophoblast cell inhibitory factor needed to be present constantly to affect lymphocyte proliferation, and it was ineffective if lymphocytes had been previously stimulated to proliferate. The lymphoproliferative inhibitory mechanism affected lymphocyte subpopulations similarly. In addition, lymphocyte expression of cytokine mRNA including IFNgamma, IL-2, IL-4, and IL-10 was affected compared to controls. The implication of these observations in vivo may explain, in part, the apparent equine maternal immune acceptance of the presence and development of endometrial cup cells.

N-glycans of human amniotic fluid transferrin stimulate progesterone production in human first trimester trophoblast cells in vitro

AIMS

During pregnancy, the placenta produces a variety of steroid hormones and proteins. Several of these substances have been shown to exert immunomodulatory effects. Progesterone is thought to mediate some of these effects by regulating uterine responsiveness. The aim of this study was to clarify the effect of amniotic fluid transferrin and its N-glycans on the release of progesterone by first trimester trophoblast cells in vitro.

METHODS

Cytotrophoblast cells were prepared from human first trimester placentae by trypsin-DNAse dispersion of villous tissue followed by a percoll gradient centrifugation and depletion of CD45 positive cells by magnetic cell sorting. Trophoblasts were incubated with varying concentrations (50-300 microg/ml) of transferrin from human amniotic fluid and serum as well as with N-glycans obtained from amniotic fluid transferrin. Culture supernatants were assayed for progesterone by enzyme-immunometric methods.

RESULTS

The release of progesterone increased in amniotic fluid transferrin- and N-glycan-treated trophoblast cell cultures compared to untreated trophoblast cells. There was no stimulating effect of serum transferrin on the progesterone production of trophoblast cells.

CONCLUSIONS

The results suggest that amnion-transferrin and especially its N-glycans modulate the endocrine function of trophoblasts in culture by up regulating progesterone secretion.

Human amniotic fluid glycoproteins expressing sialyl Lewis carbohydrate antigens stimulate progesterone production in human trophoblasts in vitro

BACKGROUND

Progesterone is thought to mediate immune modulator effects by regulating uterine responsiveness. The aim of the study was to clarify the effect of transferrin and glycodelin A (former name PP14) as sialyl Lewis X-expressing glycoproteins on the release of progesterone by trophoblast cells in vitro.

METHODS

Cytotrophoblast cells were prepared from human term placentas by standard dispersion of villous tissue followed by a Percoll gradient centrifugation step. Trophoblasts were incubated with varying concentrations (50-300 microg/ml) of human amniotic fluid- and serum-transferrin as well as with glycodelin A. Culture supernatants were assayed for progesterone, human chorionic gonadotropin (hCG) and cortisol by enzyme immunometric methods.

RESULTS

The release of progesterone is increased in amniotic fluid transferrin- and glycodelin A-treated trophoblast cell cultures compared to untreated trophoblast cells. There is no relation between transferrin and the hCG or cortisol production of trophoblast cells.

CONCLUSION

The results suggest that sialyl Lewis carbohydrate antigen-expressing amniotic fluid glycoproteins modulate the endocrine function of trophoblasts in culture by upregulating progesterone production.

T helper-2 type of interleukins with de novo germinal center formation in the spleen during murine pregnancy

PROBLEM

Murine pregnancy is characterized by transient thymic atrophy and splenomegaly. Although some reports on the thymus are available, little is known about the role of the spleen. In the present study, sequential changes in the spleen have been evaluated during murine syngeneic pregnancy.

METHOD OF STUDY

Formation of germinal centers (GCs), immunoglobulin positive (Ig+) cells and interleukin (IL)-2, IL-4, and IL-6 were immunolocalized in the spleen during pregnancy and compared with a control group of virgin mice.

RESULTS

Initiation of T-cell dependent B-cell response with the induction of peanut agglutinin (PNA+) GCs correlated with decrease in IL-2 and maintenance of IL-4 and IL-6 on day-1 pregnancy followed by an increase in Ig+ cells.

CONCLUSION

The immune response observed in the syngeneically pregnant mother is not directed to paternal major histocompatibility complex antigens. Present studies demonstrate for the first time the role of the spleen in initiating a T-cell dependent B-cell response with a shift of systemic immune response from T helper 1 to T helper 2 type.

Pregnancy and multiple sclerosis

In this review, we summarize the available information on the short- and long-term effects of pregnancy on the course of multiple sclerosis (MS). Published studies that used established criteria for the diagnosis of MS were given more weight than studies in which the criteria for diagnosis were unstated or unclear. Population-based studies were emphasized more than clinic-based studies, unless the clinic base was well defined and thought to be reasonably representative of the MS population in the geographic area. For completeness, small studies were also included but weighted accordingly in our overall conclusions. Methodologic limitations and biases inherent in the study methods are discussed. We conclude that patients with relapsing MS have an increased risk of relapse during the initial 6-month postpartum period. This increased risk does not seem to have a detrimental effect on the rate of developing sustained disability. In fact, a full-term pregnancy may increase the time interval to reaching a common disability endpoint-walking with the aid of a cane or crutch--or to having a secondarily progressive course. Evidence indicates that pregnancy may alter T-lymphocyte functions and cause clinically relevant consequences. The specific biochemical mechanisms responsible for these observations, however, remain undefined. Because of limitations of current knowledge, our conclusions are tentative at best. The data are most applicable to patients with relapsing-remitting MS in its early stages. MS is an unpredictable disease and is only one of many factors that patients must consider when a pregnancy is contemplated.

Lymphocyte subsets and mitogen stimulation of blood lymphocytes in normal pregnancy

PROBLEM

In normal pregnancy the maternal immune system should be directed towards tolerance or suppression in order not to reject the partly foreign feto-placental unit. The aim of this investigation was to find hallmarks of systemic immunosuppression during normal pregnancy.

METHODS

Five healthy primigravidae were examined during pregnancy and postpartum with flow cytometric analysis to define T and B lymphocyte subsets in peripheral blood. In addition, we studied the proliferative response of lymphocytes to mitogens or interleukin-2 (IL-2) alone or in combination with immunomodulating drugs or interleukin-4 (IL-4). The results were compared to healthy, non-pregnant women.

RESULTS

During pregnancy and early puerperium we noted an immune balance in favour of suppression, as measured by increased numbers of T "helper/suppressor" (CD4+CD45RA+) and "suppressor"/effector T cells (CD8+S6F1-), and decreased numbers of T "helper/inducer" (CD4+CD29+), T "helper/memory" (CD4+CD45RO+), killer/effector T cells (CD8+S6F1+), and Natural Killer cells (CD56+), as well as decreased numbers of activated lymphocytes expressing IL-2 receptor (CD25+) and T cells expressing HLA-DR (HLA-DR+CD3+). During pregnancy, lymphocyte proliferation was impaired in autologous serum with concanavalin A (ConA), phytohemagglutinin (PHA), or IL-2. A difference in proliferative response to PHA or IL-2 between cultures with AB serum and autologous serum is suggestive of an immunosuppressor factor in serum during pregnancy. Indomethacin significantly increased lymphocyte proliferation in autologous serum with ConA, indicating PGE2 mediated suppressor activity during pregnancy. Chlorambucil and cimetidine modulated the proliferative response to ConA, indicating an alkylating agent sensitive and a histamine dependent suppressor activity during pregnancy.

CONCLUSIONS

During normal pregnancy, a state of systemic suppression of the maternal immune system seems to be present.

Listeria monocytogenes infection in pregnant mice: abnormalities in the function of non-adherent accessory light density dendritic cells

Pregnant A/J mice were found to be more susceptible to the lethal effect of Listeria monocytogenes bacteria than virgin females. However, during the first four days of post-infection there was no difference in the elimination of Listeria from the spleens of pregnant and virgin mice. This suggests that the increase in the susceptibility of pregnant mice to pathogenic activity of L. monocytogenes was related to the diminution in Listeria-specific cellular reactions. Indeed, we found that non-adherent light density dendritic cells (DCs) from pregnant mice showed a marked reduction in the ability to form clusters with L. monocytogenes immune T lymphocytes and it is known that cell cluster formation between antigen presenting cells (APC) and responding T cells is required for antigen recognition as well as for cell proliferation. DCs from pregnant mice also demonstrated the decrease and an instability in the expression of H-2 class II molecules which play a crucial role in the recognition of exogenous antigens. The abnormalities demonstrated in the function of the light density dendritic cells from the spleens of pregnant mice could compromise cellular reactions to L. monocytogenes bacteria possibly resulting in increased susceptibility of pregnant mice to experimental listeriosis.

Psychosocial and medical factors in pregnancy outcomes: a case study of Israeli women

Building on a body of research which confirms that psychosocial factors have an important influence on health in general and on pregnancy outcomes in particular, we carried out a prospective study of pregnant women in Israel. We hypothesized that medical pregnancy and delivery outcomes are mediated by psychosocial coping resources and risks. Resources were defined as social ties, and risks as life events self-reported as stressful. The population studied included 233 women who responded to questionnaires after the second trimester of pregnancy. Medical data on the delivery were collected from hospital archives. The questionnaire measured biomedical risks, including general medical and obstetrical history, as well as health behaviours, social ties, and perceived stress. Pregnancy outcomes were classified according to medical measures of abnormalities in mother and child at birth. Our findings show that resources such as the variety of social ties (family, friends, neighbours and colleagues) interacted significantly with biomedical risk. It was found that low scores for social ties anticipated 3.6 times higher negative medical outcome in otherwise healthy women than in those with higher scores for social ties. The findings of the study are discussed in terms of their implications for relating to social competence as a determining element in health and health behaviour.

Lymphocyte subsets and autoantibodies in pregnancies complicated by placental disorders

PROBLEM

The survival of the fetoplacental unit might partly depend on down-regulation of rejection reactions. Pathological maternal cellular immune response mechanisms could therefore be of pathogenic importance in pregnancies complicated by placental disorders.

METHOD

A flow-cytometric analysis of T-cell subsets and B-cell, as well as serological tests for anticardiolipin antibodies (aCL), antinuclear antibodies (ANA), and rheumatoid factor (RF) were done on 90 women with complicated pregnancies. The results were compared with that of nonpregnant women (n = 5), and normal pregnant women (n = 5) in the third trimester.

RESULTS

Two women, suffering from severe preeclampsia and eclampsia respectively, had aCL on 12 and 13 units, respectively. ANA occurred in 11 patients with moderate and severe preeclampsia and intrauterine growth retardation. All women had negative RF tests. Within the CD4 T-helper subpopulations, the proportion of suppressor/inducer T-cell population (CD4+CD45RA+) significantly increased, while the memory and helper/inducer T-cells (CD4+CD45RO+ and CD4+CD29+) significantly decreased during normal pregnancy compared to nonpregnant controls. This deviation of CD4 subpopulations was not found, or was less pronounced, in complicated pregnancies. The proportion of cytotoxic T cells (CD8+S6F1+) was significantly reduced during normal pregnancy. This reduction was less pronounced in complicated pregnancies.

CONCLUSION

Systemic immunological deviations toward suppression or decreased activity of the immunological response as seen in normal pregnancies, was not observed in preeclampsia, intrauterine growth retardation, intrauterine fetal death, and abruptio placentae. This lack of suppression or increased T-cell activity may have a primary pathogenic role in some women with a complicated pregnancy, or it may be secondary to the placental disorders.

Listeria Monocytogenes infections

This article reviews current information regarding human infection with Listeria monocytogenes. Significant advances have occurred in regard to our knowledge of the epidemiology, pathogenesis, immunology, and treatment of this disease which was formerly believed to be of importance mainly to veterinarians. It remains a cause of high mortality in the many different groups of compromised hosts it infects unless diagnosis and treatment are rapidly established.

Relationships between maternal malaria and malarial immune responses in mothers and neonates

Immune responses of 97 Gambian women and their neonates were studied. New methods distinguished between active and previous placental malaria, were used to examine relationships between maternal malaria and neonatal immune responses. Many placentas (61%) had active or previous malarial infection. Maternal and cord malarial IgG levels correlated (P < 0.001). Malarial IgG was raised in cord blood in active placental malaria; IgM was not detected. Mean lymphoproliferation and the proportion of responders to soluble P. falciparum antigens (F32) and conserved regions of p190 expressed on trophozoites and schizonts (190L and 190N) were higher in neonates than mothers. There was no clear relationship between maternal malaria and neonatal mean lymphoproliferation to malarial antigens, although fewer neonates responded when mothers were actively infected. Matched maternal and neonatal lymphoproliferation responses did not correlate. However, first born neonatal lymphoproliferation to PPD and malarial antigens appeared lower than other neonates, in agreement with lower lymphoproliferation in primigravidae compared with multigravidae. Also in common with mothers, autologous plasma suppressed neonatal lymphoproliferation to PPD and malarial antigens, suggesting common immunoregulation. Higher cortisol or other circulating factors in first pregnancies may be implicated. The relevance of cell-mediated malarial immune responses detected at birth remains to be established.

Maternal infections influence infection susceptibility in childhood

The proposed hypothesis suggests that the types of infections commonly experienced in pregnancy and in childhood are linked. The suggestion is made that maternal infections leave an impression on the developing fetal immune system and modulate future responsiveness to infection and/or vaccination challenge. A number of factors are explored which may influence this process, namely immunoregulation in pregnancy and infection type, gestation, maturity of the fetal immune system, and parity.

Effect of pregnancy on proteoglycan-induced progressive polyarthritis in BALB/c mice: remission of disease activity

Proteoglycan-induced arthritis is a murine autoimmune model displaying many similarities to human rheumatoid arthritis and ankylosing spondylitis, as has been documented by clinical, immunological and histopathological studies. Since the onset of arthritis correlates with the serum antibody level to mouse cartilage proteoglycan (PG), it is believed that these autoreactive antibodies may play crucial roles in the pathological mechanisms of PG-induced arthritis. We have found that fertility in these PG-induced arthritic mice had been reduced but, unlike collagen-induced arthritis, had not been completely lost. Moreover, pregnancy had a beneficial effect upon the clinical symptoms with very little or no influence on serum antibody levels. Although fertility was retained and arthritic mothers delivered healthy offspring, the birth frequency was significantly less than in non-arthritic age-matched controls. Furthermore, the presence of anti-PG autoantibodies (predominantly IgG1 subclass) transmitted from arthritic mothers to infants transplacentally and by milk during the lactation period did not render these offspring either resistant or more sensitive to subsequent induction of arthritis. Subsequent immunization of infants with 'arthritogenic' PG revealed an unaltered susceptibility to arthritis induction.

The pineal gland and spontaneous abortions: implications for therapy with melatonin and magnetic field

Spontaneous abortion, the termination of pregnancy prior to 20 weeks of gestation, is estimated to occur in 40%-50% of all pregnancies and in 12%-15% of identified pregnancies. The causes of spontaneous abortion can be divided into two main categories: those arising from chromosomal anomalies and those arising from abnormalities in the intrauterine environment. In the following communication, we propose that deficient pineal melatonin functions in early pregnancy may be causally related to the development of spontaneous abortions in cases where chromosomal anomalies or structural abnormalities of the uterus have been excluded. This hypothesis is based on the findings that: (a) melatonin plasma levels normally increase by 200%-300% in the first 20 weeks of pregnancy; (b) melatonin decreases uterine contractility in the rat; (c) melatonin stimulates the secretion of progesterone, which decreases uterine contractility and prevents immunological rejection of the trophoblast; (d) melatonin inhibits the synthesis of prostaglandins, which are potent inducers of uterine contractility and labor, and (e) pinealectomy increases the number of spontaneous abortions in pregnant rats. In addition, since melatonin is a hormone with immunosuppressant properties, we propose that the increased melatonin production in early pregnancy may contribute to a state of "transplantation immunity" to the paternal histocompatibility antigens preventing immunological rejection of the trophoblast. If this hypothesis is correct, then plasma melatonin, levels during early pregnancy could be used as an indicator for increased risk of spontaneous abortions.(ABSTRACT TRUNCATED AT 250 WORDS)