Murine fetal resorption and experimental pre-eclampsia are induced by both excessive Th1 and Th2 activation

Combining RNAscope, Immunohistochemistry (IHC) and Digital Image Analysis to Assess Podoplanin (PDPN) Protein and PDPN_mRNA Expression on Formalin-Fixed Paraffin-Embedded Normal Human Placenta Tissues

The expression and function of podoplanin (PDPN) in the normal human placenta has been debated in placental evaluation. This study emphasizes the importance of a multimodal approach of PDPN expression in normal human placentas. A complete examination is performed using immunohistochemistry, RNAscope and automated Digital Image examination (DIA) interpretation. QuPath DIA-based analysis automatically generated the stromal and histological scores of PDPN expression for immunohistochemistry and RNAscope stains. The umbilical cord's isolated fibroblasts and luminal structures expressed PDPN protein and PDPN_mRNA. RNAscope detected PDPN_mRNA upregulation in syncytial placental knots trophoblastic cells, but immunohistochemistry did not certify this at the protein level. The study found a significant correlation between the IHC and RNAscope H-Score (p = 0.033) and Allred Score (p = 0.05). A successful multimodal strategy for PDPN assessment in human placentas confirmed PDPN expression heterogeneity in the full-term human normal placenta and umbilical cord at the protein and mRNA level. In placental syncytial knots trophoblastic cells, PDPN showed mRNA overexpression, suggesting a potential role in placenta maturation.

Clinical, oral immunological and microbiological shifts during and after pregnancy

OBJECTIVES

Physiological changes and shifts in the oral microbiota composition during pregnancy may affect the maternal immune system. Uncomplicated pregnancy is associated with a T-helper (Th) 2 predominant cytokine regulation (anti-inflammatory), while oral health deterioration during pregnancy is reflected by severe gingival inflammation, a primarily Th1 cytokine phenotype (pro-inflammatory), and oral microbiome alterations. This prospective observational study aimed to evaluate Th cytokine shifts and changes in the oral microbiota composition in saliva of women before and after birth.

MATERIAL AND METHODS

Saliva (n = 96) was collected before and 6 months after birth, and medical, oral health, and periodontal status were assessed. In a multiplex immunoassay, 10 cytokines were simultaneously analyzed and cumulative Th1 and Th2 cytokine levels and Th1/Th2 ratio were calculated for all groups. Putative periodontal pathogens (n = 6) were evaluated by quantitative real-time polymerase chain reaction.

RESULTS

Th2 cytokine levels were significantly lower (p = 0.014) while pro-inflammatory cytokine levels were significantly higher (p < 0.01) during pregnancy than postpartum. Similar Th1 levels were found between the groups (p = 0.143). Th1 and Th2 cytokines positively correlated with periodontal parameters (p < 0.001) and levels of studied bacteria during pregnancy (p < 0.05).

CONCLUSIONS

This study identified a significantly increased Th1/Th2 cytokine ratio during pregnancy and a positive association with putative periodontal pathogens. This immunological and microbiological deregulation in the oral milieu during pregnancy is suggestive of a destructive inflammatory periodontal profile.

STUDY REGISTRATION

Clinical Trials.gov (Record BAP-2015).

CLINICAL RELEVANCE

Understanding altered oral immunological and microbiological regulation patterns during pregnancy may help improve the inflammatory periodontal profile in pregnant women.

Cellular immune responses in the pathophysiology of preeclampsia

Preeclampsia, defined as new-onset hypertension accompanied by proteinuria occurring at 20 weeks of gestation or later, is a leading cause of perinatal morbidity and mortality worldwide. The pathophysiology of this major multi-systemic syndrome includes defective deep placentation, oxidative stress, endothelial dysfunction, the presence of an anti-angiogenic state, and intravascular inflammation, among others. In this review, we provide a comprehensive overview of the cellular immune responses involved in the pathogenesis of preeclampsia. Specifically, we summarize the role of innate and adaptive immune cells in the maternal circulation, reproductive tissues, and at the maternal-fetal interface of women affected by this pregnancy complication. The major cellular subsets involved in the pathogenesis of preeclampsia are regulatory T cells, effector T cells, NK cells, monocytes, macrophages, and neutrophils. We also summarize the literature on those immune cells that have been less characterized in this clinical condition, such as γδ T cells, invariant natural killer T cells, dendritic cells, mast cells, and B cells. Moreover, we discuss in vivo studies utilizing a variety of animal models of preeclampsia to further support the role of immune cells in this disease. Finally, we highlight the existing gaps in knowledge of the immunobiology of preeclampsia that require further investigation. The goal of this review is to promote translational research leading to clinically relevant strategies that can improve adverse perinatal outcomes resulting from the obstetrical syndrome of preeclampsia.

Association of interleukin-12B gene polymorphisms and mRNA expression with preeclampsia

OBJECTIVE

To explore the effects of functional genetic polymorphisms of the interleukin-12B (IL-12B) gene on the susceptibility to preeclampsia in northern Chinese women.

STUDY DESIGN

Maternal peripheral blood from 306 preeclamptic women and 310 control women and the placentas from 52 preeclamptic and 55 control women were collected. Two polymorphisms (rs17860508 and rs3212227) of the IL-12B gene were genotyped by polymerase chain reaction (PCR) with a direct sequencing method. The mRNA expression of IL-12B in the placentas was measured by quantitative real-time PCR (qRT-PCR).

RESULTS

Significant differences were observed between preeclamptic women and the control group in the genotype frequencies of rs17860508 (P = 0.017). Compared with the TTAGAG/TTAGAG genotype of rs17860508, the GC/GC genotype were associated with a higher risk of preeclampsia (adjusted OR: 1.95; 95% CI = 1.18-3.22; P = 0.009), especially the early-onset preeclampsia (adjusted OR: 2.40; 95% CI = 1.23-4.68; P = 0.010). The qRT-PCR results showed that the mRNA levels of IL-12B were significantly higher in the placentas of preeclampsia patients than that in the placentas of controls (P = 0.001). Moreover, the expression of IL-12B mRNA was significantly higher in the placentas of patients carrying the GC/GC genotype than in those carrying the TTAGAG/GC (P = 0.007) and TTAGAG/TTAGAG (P = 0.005) genotypes.

CONCLUSION

The GC/GC genotype of rs17860508 polymorphism may be a risk factor for the early-onset preeclampsia by upregulating the expression of IL-12B in northern Chinese women.

Maternal microbiome in preeclampsia pathophysiology and implications on offspring health

Preeclampsia is a devastating hypertensive pregnancy disorder that currently affects 2%–8% of pregnancies worldwide. It is associated with maternal and fetal mortality and morbidity and adverse health outcomes both in mom and offspring beyond pregnancy. The pathophysiology is not completely understood, and there are no approved therapies to specifically treat for the disease, with only few therapies approved to manage symptoms. Recent advances suggest that aberrations in the composition of the microbiome may play a role in the pathogenesis of various diseases including preeclampsia. The maternal and uteroplacental environments greatly influence the long‐term health outcomes of the offspring through developmental programming mechanisms. The current review summarizes recent developments on the role of the microbiome in adverse pregnancy outcomes with a focus on preeclampsia. It also discusses the potential role of the maternal microbiome in fetal programming; explores gut‐targeted therapeutics advancement and their implications in the treatment of preeclampsia.

Animal Models of Preeclampsia: Causes, Consequences, and Interventions

Preeclampsia is a common pregnancy complication, affecting 2% to 8% of pregnancies worldwide, and is an important cause of both maternal and fetal morbidity and mortality. Importantly, although aspirin and calcium are able to prevent preeclampsia in some women, there is no cure apart from delivery of the placenta and fetus, often necessitating iatrogenic preterm birth. Preclinical models of preeclampsia are widely used to investigate the causes and consequences of preeclampsia and to evaluate safety and efficacy of potential preventative and therapeutic interventions. In this review, we provide a summary of the published preclinical models of preeclampsia that meet human diagnostic criteria, including the development of maternal hypertension, together with new-onset proteinuria, maternal organ dysfunction, and uteroplacental dysfunction. We then discuss evidence from preclinical models for multiple causal factors of preeclampsia, including those implicated in early-onset and late-onset preeclampsia. Next, we discuss the impact of exposure to a preeclampsia-like environment for later maternal and progeny health. The presence of long-term impairment, particularly cardiovascular outcomes, in mothers and progeny after an experimentally induced preeclampsia-like pregnancy, implies that later onset or reduced severity of preeclampsia will improve later maternal and progeny health. Finally, we summarize published intervention studies in preclinical models and identify gaps in knowledge that we consider should be targets for future research.

Splenocyte transfer exacerbates salt-sensitive hypertension in rats

NEW FINDINGS

What is the central question of this study? Recruitment of immune cells to the kidney potentiates hypertensive pathology, but more refined methods are needed to assess these cells functionally. Adoptive transfer studies of immune cells have been limited in rat models and especially in the study of salt-sensitive hypertension. We tested the hypothesis that splenocyte transfer into T-cell-deficient rats is sufficient to exacerbate salt-sensitive hypertension. What is the main finding and its importance? We demonstrate that transfer of splenocytes into T-cell-deficient animals exacerbates salt-sensitive hypertension, and an enrichment in the CD4⁺ compartment specifically induces this phenomenon.

ABSTRACT

Increasing evidence of immune system activation during the progression of hypertension and renal injury has led to a need for new methods to study individual cell types. Transfer of immune cells serves as a powerful tool to isolate effects of specific subsets. Transfer studies in Rag1^-/- mice have demonstrated an important role of T-cell activation in hypertension, but this approach has yielded limited success in rat models. Using the T-cell-deficient Dahl salt-sensitive (SS) rat, SS^CD247-/- , we hypothesized that splenocyte transfer from SS wild-type animals into SS^CD247-/- animals would populate the T-cell compartment. The Dahl SS background provides a model for studying salt-sensitive hypertension; therefore, we also tested whether the dietary salt content of the donor would confer differential salt sensitivity in the recipient. To test this, donors were maintained on either a low-salt or a high-salt diet, and at postnatal day 5 the recipients received splenocyte transfer from one of these groups before a high-salt diet challenge. We showed that splenocyte transfer elevated blood pressures while rats were fed low salt and exacerbated the salt-sensitive increase in pressure when they were fed fed high salt. Furthermore, transfer of splenocytes conferred exacerbated renal damage. Lastly, we confirmed the presence of T cells in the circulation and in the spleen, and that infiltration of immune cells, including T cells, macrophages and B cells, into the kidney was elevated in those receiving the transfer. Interestingly, the source of the splenocytes, from donors fed either a low-salt or a high-salt diet, did not significantly affect these salt-sensitive phenotypes.

Circulating soluble endoglin modifies the inflammatory response in mice

Inflammation is associated with every health condition, and is an important component of many pathologies such as cardiovascular diseases. Circulating levels of soluble endoglin have been shown to be higher in the serum of patients with cardiovascular diseases with a significant inflammatory component. The aim of this study was to evaluate the implication of circulating soluble endoglin in the inflammatory response. For this purpose, a transgenic mouse expressing human soluble endoglin (sEng+) was employed, and three different inflammatory approaches were used to mimic inflammatory conditions in different tissues. This study shows that control sEng+ mice have a normal inflammatory state. The lung and kidney injury induced by the inflammatory agents was reduced in sEng+ mice, especially the intra-alveolar and kidney infiltrates, suggesting a possible reduction in inflammation induced by soluble endoglin. To deepen into this possible effect, the leukocyte number in the bronchoalveolar lavage and air pouch lavage was evaluated and a significant reduction of neutrophil infiltration in LPS-treated lungs and ischemic kidneys from sEng+ with respect to WT mice was observed. Additionally, the mechanisms through which soluble endoglin prevents inflammation were studied. We found that in sEng+ animals the increment of proinflammatory cytokines, TNFα, IL1β and IL6, induced by the inflammatory stimulus was reduced. Soluble endoglin also prevents the augmented adhesion molecules, ICAM, VCAM and E-selectin induced by the inflammatory stimulus. In addition, vascular permeability increased by inflammatory agents was also reduced by soluble endoglin. These results suggest that soluble endoglin modulates inflammatory-related diseases and open new perspectives leading to the development of novel and targeted approaches for the prevention and treatment of cardiovascular diseases.

10 workshops on Immunology of preeclampsia

For the 10th issue of the « island workshops », now the Reunion Workshops, organised by Pierre Yves Robillard since the first one in Tahiti challenging the "vascular disease only" theory of pre eclampsia and introducing the primipaternity concept, we examined the reasons for considering an Immunological approach to the disease. This (brief) overview thus examines several important topics in an Immunological framework. I have chosen to present here the evolution of the main themes rather than a purely chronological vision.

Pre-eclampsia has an adverse impact on maternal and fetal health

Pre-eclampsia (preE) is a multifaceted complication found uniquely in the pregnant patient and one that has puzzled scientists for years. PreE is not a single disorder, but a complex syndrome that is produced by various pathophysiological triggers and mechanisms affecting about 5% of obstetrical patients. PreE is a major cause of premature delivery and maternal and fetal morbidity and mortality. PreE is characterized by de novo development of hypertension and proteinuria after 20 weeks of gestation and affects nearly every organ system, with the most severe consequences being eclampsia, pulmonary edema, intrauterine growth restriction, and thrombocytopenia. PreE alters the intrauterine environment by modulating the pattern of hormonal signals and activating the detrimental cellular signaling that has been transported to the fetus. The fetus has to adapt to this intrauterine environment with detrimental signals. The adaptive changes increase the risk of disease later in life. This review defines the predisposition and causes of preE and the cellular signaling detrimental to maternal health during preE. Moreover, the risk factors for diseases that are transmitted to the offspring have been addressed in this review. The detrimental signaling molecules that have been overexpressed in preE patients raises the possibility that those signals could be therapeutically blocked one day.

Lipopolysaccharide-Induced Profiles of Cytokine, Chemokine, and Growth Factors Produced by Human Decidual Cells Are Altered by Lactobacillus rhamnosus GR-1 Supernatant

The aim of this study was to assess the effects of bacterial lipopolysaccharide (LPS) and Lactobacillus rhamnosus GR-1 supernatant (GR-1SN) on secretion profiles of cytokines, chemokines, and growth factors from primary cultures of human decidual cells. Lipopolysaccharide significantly increased the output of proinflammatory cytokines (interleukin [IL]-1B, IL-2, IL-6, IL-12p70, IL-15, IL-17A, interferon gamma [IFN-γ], and tumor necrosis factor [TNF]); anti-inflammatory cytokines (IL-1RN, IL-4, IL-9, and IL-10); chemokines (IL-8, eotaxin, IFN-inducible protein 10 [IP-10], monocyte chemoattractant protein 1 [MCP-1], macrophage inflammatory protein-1α [MIP-1α], macrophage inflammatory protein-1β [MIP-1β], and regulated on activation normal T cell expressed and secreted [RANTES]); and growth factors (granulocyte colony-stimulating factor [CSF] 3, CSF-2, and vascular endothelial growth factor A [VEGFA]). Lactobacillus rhamnosus GR-1SN alone significantly increased CSF-3, MIP-1α MIP-1β, and RANTES but decreased IL-15 and IP-10 output. The GR-1SN also significantly or partially reduced LPS-induced proinflammatory cytokines TNF, IFN-γ, IL-1β, IL-2 IL-6, IL-12p70, IL-15, IL-17, and IP-10; partially reduced LPS-induced anti-inflammatory cytokines IL-1RN, IL-4 and IL-10, and LPS-induced VEGFA output but did not affect CSF-3, MIP-1α, MIP-1β, MCP-1, IL-8, and IL-9. Our results demonstrate that GR-1SN attenuates the inflammatory responses to LPS by human decidual cells, suggesting its potential role in ameliorating intrauterine infection.

Cytokines, neurophysiology, neuropsychology, and psychiatric symptoms

Recent research has overcome the old paradigms of the brain as an immunologically privileged organ, and of the exclusive role of neurotransmitters and neuropeptides as signal transducers in the central nervous system. Growing evidence suggests that the signal proteins of the immune system - the cytokines - are also involved in modulation of behavior and induction of psychiatric symptoms. This article gives an overview on the nature of cytokines and the proposed mechanisms of immune-to-brain interaction. The role of cytokines in psychiatric symptoms, syndromes, and disorders like sickness behavior, major depression, and schizophrenia are discussed together with recent immunogenetic findings.

Is inflammation the cause of pre-eclampsia?

It has been proposed that either excessive inflammation or an imbalance in angiogenic factors cause pre-eclampsia. In the present review, the arguments for and against the role of inflammation and/or angiogenic imbalance as the cause of pre-eclampsia are discussed on the basis of the Bradford–Hill criteria for disease causation. Although both angiogenic imbalance and systemic inflammation are implicated in pre-eclampsia, the absence of temporality of inflammatory markers with pre-eclampsia challenges the concept that excessive inflammation is the cause of pre-eclampsia. In contrast, the elevation of anti-angiogenic factors that precede the clinical signs of pre-eclampsia fulfils the criterion of temporality. The second most important criterion is the dose–response relationship. Although such a relationship has not been proven between pro-inflammatory cytokines and pre-eclampsia, high levels of anti-angiogenic factors have been shown to correlate with increased incidence and disease severity, hence satisfying this condition. Finally, as the removal of circulating sFlt-1 (soluble Fms-like tyrosine kinase receptor-1) from pre-eclamptic patients significantly improves the clinical outcome, it fulfils the Hill's experiment principle, which states that removal of the cause by an appropriate experimental regimen should ameliorate the condition. In contrast, treatment with high doses of corticosteroid fails to improve maternal outcome in pre-eclampsia, despite suppressing inflammation. Inflammation may enhance the pathology induced by the imbalance in the angiogenic factors, but does not by itself cause pre-eclampsia. Development of therapies based on the angiogenic and cytoprotective mechanisms seems more promising.

Plasma IL-4, IL-8, IL-12, interferon-γ and CRP levels in pregnant women with preeclampsia, and their relation with severity of disease and fetal birth weight

OBJECTIVE

The aim of the present study was to evaluate the hypothesis that preeclampsia is associated with increased systemic inflammatory responses of Th1-type as well as decreased Th2-type responses compared with normal pregnancy. We also sought to determine whether there was a correlation between these markers with severity of preeclampsia and fetal birth weight.

METHODS

The study population consisted of maternal age, gestational age, and body mass index matched 138 pregnant women; 56 normotensive healthy pregnant women (group 1), 42 women with mild preeclampsia (group 2), 40 women with severe preeclampsia (group 3).

RESULTS

Plasma interleukin (IL)-8 and C-reactive protein (CRP) levels were significantly higher in group 3 than group 1 (p<0.05). Plasma IL-4, IL-12, and interferon (IFN)-γ levels were similar in all groups. Although plasma IL-8 and CRP levels of mild preeclamptic group were higher than control group and lower than severe preeclamptic group, the differences were not statistically significant. There was a positive correlation between IL-12 and fetal birth weight in severe preeclamptic group (p<0.05).

CONCLUSIONS

Elevated maternal serum pro-inflammatory cytokine IL-8 and CRP in severe preeclamptic women compared with normal pregnant women supports the hypothesis that preeclampsia is associated with increased inflammatory responses.

Chronic anti-phencyclidine monoclonal antibody therapy decreases phencyclidine-induced in utero fetal mortality in pregnant rats

Illicit drug use during pregnancy is a serious social and public health problem inflicting an array of deleterious effects on both mother and offspring. We investigated the hypothesis that a murine anti-phencyclidine (PCP) monoclonal antibody (mAb6B5; K(D)=1.3 nM) can safely protect mother and fetus from PCP-induced adverse health effects in pregnant rats. Pregnant Sprague-Dawley rats (n=4-5) were intravenously administered bolus injections of PCP (1mg/kg) on multiple days during pregnancy. They were also chronically treated with anti-PCP mAb6B5 at 45 mg/kg as a PCP antagonist. This dose provided one mAb-PCP binding site for every four PCP molecules. Therapeutic and safety study endpoints included pregnancy outcome (litter size, number of live vs. dead pups), maternal hemodynamic status and locomotor activity. Maternal hemodynamic changes (i.e., blood pressure and heart rate) and locomotor activity were measured in dams from gestation days 6-21 (one day antepartum) using a radiotelemetry-tracking device with a femoral arterial pressure catheter. This mAb6B5 treatment regimen significantly (p=0.008) reduced the number of PCP-induced in utero fetal deaths (odds ratio=3.2; 95%CI 1.3 to 7.9) and significantly (p<0.05) reduced acute PCP-induced maternal locomotor effects in the second trimester. Maternal hemodynamic responses to PCP were not significantly affected by mAb6B5 treatment. In conclusion, these data suggest that anti-PCP mAb treatments administered during pregnancy can safely protect a mother and her fetus(es) from PCP-related morbidity and mortality even when the mAb dose is too low to significantly prevent other PCP-induced maternal pharmacological effects.

Animal models of pre-eclampsia

The cardinal features of human pre-eclampsia, hypertension and proteinuria, are mimicked in animal models. Increasingly, the accuracy of inducing 'pure' systemic endothelial dysfunction is regarded as critical in differentiating mechanisms of pre-eclampsia from other conditions which induce hypertension (e.g. glomerulonephritis, renal denervation or manipulation of the renin-angiotensin system). A recent study in baboons has identified the timing of induction of maternal endothelial damage after acute uteroplacental ischaemia (UPI). The endothelial changes in the glomerulus are indicative of a direct endothelial toxin and mimic the lesions seen in human pre-eclampsia; the extent of hypertension and proteinuria are also similar. This animal model identifies systemic and placental sFLT-1 (soluble fms-like tyrosine kinase-1) as a potential mediator of endothelial damage. This research involving primates with haemomonochorial placentas makes translation of these results to humans very compelling for understanding the mechanisms of human disease. Similar endothelial dysfunction has been identified in baboons treated with anti-inflammatory inhibitors. Similar studies in rodents have identified a relationship between angiotensin II agonistic antibodies, UPI/reduced uteroplacental perfusion pressure, angiogenic markers, and cytokines. We can now identify vasoconstrictive mediators of the hypertensive and endothelial response such as endothelin 1, the renin-angiotensin system, or other hormones such as oestrogens in primate models.

Association of monocyte chemotactic protein-1 and CC chemokine receptor 2 gene variants with preeclampsia

Preeclampsia complicates 10% of pregnancies in developing countries. It is one of the leading causes of maternal and fetal/neonatal mortality and morbidity worldwide. It has been suggested that maladaptation of the maternal immune response during pregnancy might be a causal factor for preeclampsia. According to immune maladaptation hypothesis, preeclampsia is due to an inappropriate regulation of normally Th2-deviated maternal immune responses, leading to a shift toward harmful Th1 immunity. Several studies indicate that monocyte chemotactic protein-1 (MCP-1) and CC chemokine receptor 2 (CCR2) are involved in Th1 and Th2 immunity. In this study, we investigated the association between MCP-1 A-2518G and CCR2-V64I polymorphisms and preeclampsia. One hundred eighty preeclamptic pregnant women and 145 healthy controls were included in the study. We observed that in preeclamptic women, MCP-1 G: CCR2 Val haplotype was significantly higher when compared with other haplotypes. In conclusion, we stated that MCP-1 and CCR2 gene variants might be associated with preeclampsia.

Lipopolysaccharide (LPS)-induced Interferon (IFN)-gamma production by decidual mononuclear cells (DMNC) is interleukin (IL)-2 and IL-12 dependent

PROBLEM

Th1-shifted immune response is believed to be harmful for successful pregnancy because of activation of maternal cytotoxic T lymphocytes and natural killer cells. However, its effects on Toll-like receptor (TLR)-mediated innate immune response are so far unknown and this study has been undertaken to address the issue.

METHOD OF STUDY

decidual tissues were obtained from 16 pregnant women undergoing elective termination during the first trimester pregnancy for socioeconomic reasons. Decidual Mononuclear Cells (DMNC) were stimulated with suboptimal doses of IL-2 and IL-12 with/without LPS, considered to be a TLR4 ligand, for 48 hr. Productions of IFN-γ and tumor necrosis factor (TNF)-α in culture supernatant were measured with ELISA.

RESULTS

(i) IFN-γ production was induced with LPS alone which was strongly up-regulated in the presence of IL-2 and IL-12. (ii) TNF-α was also induced by LPS but was not affected by the presence of IL-2 and IL-12.

CONCLUSION

IL-2 and IL-12 up-regulated the production of IFN-γ in DMNC through increasing their susceptibility to LPS. TNF-α production is independent of such a mechanism.

Developmental and reproductive toxicology studies in IL-12p40 knockout mice

BACKGROUND

Interleukin (IL)-12 is a cytokine that can exert regulatory effects on T and NK cells. This study was designed to identify potential developmental and reproductive hazards associated with IL-12p40 knockout in mice.

METHODS

In the combined fertility and teratology study, female F0 C57/BL6 wild-type control mice and female F0 C57/BL6 IL-12p40 homozgyous knockout mice were assessed for estrous cyclicity, sperm, and mating parameters. Pregnant females were euthanized on gestation day (GD) 18 and their fetuses were assessed for external, visceral, and skeletal development. In the peri and postnatal development study, the F1 wild-type control and IL-12p40 knockout mice were assessed for developmental landmarks, sexual development, passive avoidance, motor activity, and morris water maze.

RESULTS

The IL-12p40 knockout male mice exhibited decreased testis weights when compared to the wild-type control group; however, this finding was not considered adverse, as it had no apparent functional effects on mating, fertility, and pregnancy rates or sperm motility. The IL-12p40 knockout group exhibited effects on estrous cycle length, passive avoidance, morris water maze, and motor activity when compared to the wild-type control group. However, since these findings were small in magnitude, transient and/or had no apparent effects on subsequent growth and development, they were not considered adverse.

CONCLUSIONS

These results demonstrate that although IL-12p40 homozygous knockout in mice exhibited effects on developmental and reproductive parameters, these effects were relatively minor and were not considered adverse.

Sera from preeclampsia patients elicit symptoms of human disease in mice and provide a basis for an in vitro predictive assay

Early diagnosis and treatment of preeclampsia would significantly reduce maternal and fetal morbidity and mortality. However, its etiology and prediction have remained elusive. Based on the hypothesis that sera from patients with preeclampsia could function as a "blueprint" of causative factors, we describe a serum-based pregnancy-specific mouse model that closely mirrors the human condition as well as an in vitro predictive assay. We show that a single administration of human preeclampsia serum in pregnant IL-10-/- mice induced the full spectrum of preeclampsia-like symptoms, caused hypoxic injury in uteroplacental tissues, and elevated soluble fms-like tyrosine kinase 1 and soluble endoglin, markers thought to be related to the disease. The same serum sample(s) induced a partial preeclampsia phenotype in wild-type mice. Importantly, preeclampsia serum disrupted cross talk between trophoblasts and endothelial cells in an in vitro model of endovascular activity. Disruption of endovascular activity could be documented in serum samples as early as 12 to 14 weeks of gestation from patients who subsequently developed preeclampsia. These results indicate that preeclampsia patient sera can be used to understand the pregnancy-specific disease pathology in mice and can predict the disorder.

Functional changes of human peripheral B-lymphocytes in pre-eclampsia

PROBLEM

The aim of our study was to investigate the functional changes of human peripheral B-lymphocytes in healthy and pre-eclamptic pregnancies.

METHOD OF STUDY

Twenty patients with pre-eclampsia and 15 healthy third-trimester pregnant women were recruited in this study. Peripheral blood mononuclear cells (PBMCs) were isolated and directly stained with fluorescein isothiocyanate (FITC)-labeled anti-CD27 monoclonal antibody (mAb) and phycoerythrin (PE)-labeled anti-CD38 mAb. The percentages of the individual B-cell subsets were estimated out of total lymphocytes by flow cytometric analysis. Additionally, the enriched PBMCs were cultured with or without the stimulation of pokeweed mitogen (PWM) for 5 days. Then morphologic observation of plasma cells was analysed by Wright-Giemsa stain, and antibody-producing cells were detected by enzyme-linked immunospot assay.

RESULTS

The percentage of CD27(-)CD38(-) naïve B-cells and CD27(-)CD38(+) plasma cells did not differ between study groups (P > 0.05). The percentage of CD27(+)CD38(-) memory B-cells and CD27(+)CD38(+) plasma cell precursors increased in pre-eclamptic women compared with the controls (P < 0.05). Irrespective of whether the PBMCs were stimulated with or w/o PWM in vitro, the mean percentages of generated plasma cells were significantly higher in pre-eclamptic group than in the controls (P < 0.05). There were more antibody-producing cells in pre-eclamptic women following the activation of PWM than those in the controls (P < 0.01).

CONCLUSION

Our findings implicate that the functional changes of human circulating B-cells might contribute to the etiology of pre-eclampsia.

Comparison of murine thymic stromal lymphopoietin- and polyinosinic polycytidylic acid-mediated placental dendritic cell activation

We confirmed previously the existence of thymic stromal lymphopoietin (TSLP)-positive cells in murine placenta by flow cytometry. To compare the characteristics of Toll-like receptor 3 (TLR3)- and TSLP-mediated placental dendritic cell (DC) activation, pregnant BALB/c mouse mated with C57BL/6 male were used as a model of allogenic gestation. Placental CD11c(+) DCs were potently activated by the TLR3-agonist polyinosinic polycytidylic acid [poly (I:C)], subsequently causing increased expression of co-stimulatory molecules. Accordingly, increased intracellular production of interleukin (IL)-12 and interferon (IFN)-gamma, but not IL-4 or IL-10, were detected after stimulation by poly (I:C). In the case of TSLP-stimulation, although increased expression of co-stimulatory molecules was also detected, there was no substantial increase of intracellular production of IL-12, IFN-gamma, IL-4 or IL-10. In contrast, the expression of the Th2 cell-attracting chemokine, the thymus and activation-regulated chemokine (TARC) or CCL17, was significantly boosted in response to TSLP induction, whereas no significant increase of CCL17 was observed when triggering TLR3 with its specific agonist poly (I:C). The data were further supported by a CD4(+)IL-10(+) cell migratory assay. These results suggest that TSLP-TSLP receptor interaction may result in a Th2-type microenvironment at the feto-maternal interface by inducing the production of Th2 cell-attracting chemokine and modulating the immigration of Th2-type cells.

Cytokine production by monocytes, NK cells, and lymphocytes is different in preeclamptic patients as compared with normal pregnant women

OBJECTIVE

To measure cytokine production in ex vivo stimulated leukocyte populations of women with normal pregnancy and those with preeclampsia.

METHODS

Whole blood from preeclamptic and normal pregnant women was stimulated with LPS or PMA/Ca-ionophore. The percentages of IFN gamma and IL-2, 4, and 10 producing lymphocytes and NK cells and the percentages of TNFalpha, IL-1 beta, and IL-12 producing monocytes were measured by flowcytometry.

RESULTS

In women with preeclampsia, there was a significantly increased percentage IL-4 producing cytotoxic T cells. Also, a significant decreased percentage IL-2 producing T helper cells and IL-12 producing monocytes was seen as compared with normal pregnancy.

CONCLUSION

Th1 cytokine production of lymphocytes and monocytes appears to be decreased in our group of preeclamptic patients compared with normal pregnant women.

T helper 1/t helper 2 cell immunity in preeclamptic twin pregnancy

Preeclampsia has been classified into two types on the basis of the T helper (Th)1/Th2 balance: Th1-predominant type and Th2 predominant type. In this study, we examined the Th1/Th2 ratio in peripheral Th cells in 11 patients with preeclamptic twin pregnancies, 11 normal (nonpreeclamptic) twin pregnancies, 11 preeclamptic singleton pregnancies, and 11 normal singleton pregnancies. The average Th1/Th2 ratio in the patients with preeclamptic twin pregnancy was 8.3 +/- 3.4 (mean +/- SD), which was similar to those in patients with normal singleton and twin pregnancies and significant lower than that in patients with preeclamptic singleton pregnancies (p = 0.003). The present results suggest that the mechanisms of preeclampsia differ between singleton and twin pregnancies.

Cytokines: Important for implantation?

PROBLEM

Cytokines are obviously very important in an established pregnancy, but what about human embryo implantation?

METHODS

Literature review.

RESULTS

We first discuss the necessity and limits of animal models, and then review the few cytokines which have been demonstrated by knock-out methods to be absolutely necessary for embryo implantation using in animal models. We then review what is known or discussed about the role of other cytokines as deduced from quantitative and/or qualitative dysregulation in animals and in humans.

CONCLUSIONS

Cytokines are indeed involved in implantation as they are in ongoing pregnancy and delivery. Relevance to infertility and recurrent pregnancy loss is discussed.

Murine Pre-Eclampsia Induced by Unspecific Activation of the Immune System Correlates with Alterations in the eNOS and AT1 Receptor Expression in the Kidneys and Placenta

It remains arguable if an animal model can be of use in pre-eclampsia (PE) studies, as it is clearly a human disease not observed spontaneously in other species. The aim of this study was to investigate whether PE-like signs in mice inoculated with activated Th1 cells were accompanied by abnormal expression of molecules related to the regulation of blood pressure, viz. nitric oxide synthase enzymes (eNOS and iNOS) and angiotensin (Ang) II receptors (AT1R and AT2R), in order to analyse the relevance of this model for human disease. In this model, C57/BL6-mated BALB/c females received lymphocytes crosslined with anti-CD3 and cultured with interleukin (IL)-2 and IL-12 to mimic PE pathology. Control mice received PBS. eNOS, iNOS and AT1R but not AT2R expression was augmented in the kidneys of PE-mice compared with control pregnant mice. The expression of eNOS but not of iNOS was augmented at the fetal-maternal interface of PE-mice as compared with the controls. NOSs regulate the synthesis of NO, a blood pressure and parturition mediator. As its expression is increased in PE patients, our data suggest that the Th1 cells-induced signs in this model are due to similar mechanisms as in humans. AT1R and AT2R mediate the effect of Ang II, and particularly the AT1R appears to be involved in the pathogenesis of human PE. The increased AT1R expression in the kidneys of PE-mice reinforces the theory that Th1 cells elicit a pathological situation closely resembling the human PE. All together, our data support the use of this animal model to study mechanisms underlying clinically overt PE.

The role of the immune system in preeclampsia

Recent data demonstrate that an altered immune response may play a key role in the development of preeclampsia. Some epidemiological findings and animal models support this idea. In this article, we review the innate immune system and adaptive immune system in preeclampsia and discuss the pathophysiology of preeclampsia from an immunological viewpoint. The most characteristic immunological finding in preeclampsia is the activation of both the innate and adaptive immune system. Activated neutrophils, monocytes, and NK cells initiate inflammation which induce endothelial dysfunction, and activated T cells may support inadequate tolerance during pregnancy. The cytokine profile in preeclampsia shows that the production of type 1 cytokines, which induce inflammation, is dominant while the production of type 2 cytokines, which regulates inflammation, is suppressed. Furthermore, the immunoregulatory system is down-regulated in preeclampsia and persistent inflammation reduces regulatory T cell function. Therefore, systematical immunoactivation may be one cause of preeclampsia.

Immune cells in uteroplacental tissues throughout pregnancy: a brief review

In a brief introduction, this review states why the presence of immune cells at the interface poses problems for an immunologist (Medawar paradigm). Different types of placentation are then discussed, and the various interactions with leukocytes, the extreme being with the equids where a certain degree of 'attack' is often seen. The limits of animal models when dealing with the human situation are emphasized. It is then stated why the various phases of pregnancy are different, and an analysis made of the cellular movements at the implantation, peri-implantation, immediate post-implantation and resorption windows in rodents. Details of the cellular components involved are given, as are hints for the human situation. The Th1/Th2 paradigm is described, with clinical examples, and its limits. Thus, the newly appraised dual role of natural killer (NK) cells is discussed, with examples in rodents and in humans (pre-eclampsia, implantation failure, abortion systems). Clinical data on the IL-12/IL-18/NK tripod and implantation failure in humans are detailed.

Immunological analogy between allograft rejection, recurrent abortion and pre-eclampsia - the same basic mechanism?

There are still controversies concerning the role of immunological mechanisms engaged both in recurrent abortions (RA) and pre-eclampsia (PE). According to some opinions, recurrent miscarriage is comparable to organ-specific autoimmune disease. Analysis of immune reactions shows that graft rejection shares many similar mechanisms with RA and PE. This fact allows us to conclude that rejection of transplanted alloantigenic organs and pregnancy loss have probably the same evolutionary origin. Subsets and functions of immunocompetent cells (T CD4, suppressor gammadeltaT, cytotoxic T CD8, Treg, Tr1, uterine NK cells), over-activation of innate immunity (activation of NK cytotoxic cells, macrophages, neutrophils and complement), changes of Th1/Th2 cytokine balance (IL-2, IL-12, IL-15, IL-18, IFNgamma, TNFalpha vs. IL-4, IL-10, TGFbeta), importance of HLA-G molecule, CD200/CD200R interaction, over-expression of adhesion molecules, fgl2 prothrombinase activation and stimulation of IDO and HO expression, all suggest that RA and PE are syndromes of fetal allograft rejection, and not organ-specific autoimmune diseases. According to that supposition, an analogy might exist between acute graft rejection and recurrent abortion, and between chronic graft rejection and pre-eclampsia.

Possible interactions of genetic and immuno-neuro-endocrine regulatory mechanisms in pathogenesis of congenital anomalies

The process of organogenesis depends on genetic and environmental factors. Besides genetic background, congenital anomalies can also be influenced by micro environmental changes, which are related to maternal-foetal interactions followed by the production of cytokines, hormones, neurotransmitters, growth factors and biochemical mediators, and stress proteins. Pre-natal maternal stress, including infections, psychological stress and other teratogens, can influence a disregulation of maternal immune, endocrine and nervous systems, during pregnancy. This is a crucial condition for the abnormal growth and development of the foetus. Activated maternal immune system can alter the cytokine network and make it inadequate for normal embryogenesis and organogenesis. Heat-shock proteins play an important role in stress physiology repairing DNA errors or activating pro-inflammatory response. Regarded from this aspect, the altered cytokine network suggests aetiopathogenetic basis of congenital anomalies in neonates. It is our wish to point out our potentially harmful conditions in the development of congenital anomalies, as well as their control by using pre-natal and pre-conceptional diagnostics and treatment.

Cytokine production of in vitro stimulated peripheral lymphocytes during the course of pregnancy and pseudopregnancy in the rat

PROBLEM

Does maternal lymphocyte cytokine production after in vitro stimulation vary with the stage of pregnancy in the rat?

METHOD OF STUDY

Blood samples were taken during the estrus cycle in rats (n = 11). Thereafter, rats were rendered pregnant (n = 6) or pseudopregnant (n = 5) and blood samples were taken at days 4, 8, 11, 15, and 20 of pregnancy and pseudopregnancy. White blood cell (WBC) count was measured and whole blood was stimulated with phorbol 12-myristate 13-acetate and calcium ionophore; interferon-gamma (IFNgamma) and interleukin-4 (IL-4) production as well as (sub)populations of lymphocytes were measured using flow cytometry.

RESULTS

We observed an increase of WBC in the second week of pregnancy and a slowly decreasing percentage of lymphocytes during the course of pregnancy. The percentage IFNgamma producing T-lymphocytes after in vitro stimulation was increased during pregnancy (for Th-lymphocytes only in the second week of pregnancy, for Tc-lymphocytes at all days). This increased IFNgamma production in pregnant T-lymphocytes was accompanied by an increase during pseudopregnancy, and therefore may result from increased sex hormone concentrations. The percentage IFNgamma producing natural killer (NK) cells after in vitro stimulation was decreased on day 20 of pregnancy. No effect of pregnancy or pseudopregnancy was seen on percentage IL-4 producing lymphocytes after in vitro stimulation.

CONCLUSION

In the rat the IFNgamma production after in vitro stimulation varies during pregnancy and is increased, rather than decreased, during pregnancy.

Th1/Th2 cytokines balance--yin and yang of reproductive immunology

For years conception of Th2 overbalance during pregnancy has been a paradigm for immunology of reproduction, while Th1 activity has been presented as unwanted component. Studies concerning Th1/Th2 balance in physiological and complicated pregnancy have been reviewed. Th1 activity during early peri-implantation period, premature and term labour not only accompanies but even predominates over Th2 activity. Th1 activity plays important role in promotion of Th2 response, regulation of placentation process, defense against infections and initiation of delivery. Together with Th2 activity it is necessary component of immunological reactions during pregnancy, both activities being inseparable like yin and yang. So paradigm of "Th1-Th2 cooperation" is much closer to reality than "Th2 phenomenon".

T cells in normal pregnancy and recurrent pregnancy loss

This review focuses on the possible role of T cells in successful pregnancy and in unexplained recurrent abortion. The functions exhibited by Th1 and Th2 cells have suggested, perhaps in a simplistic way, that Th1-type cytokines, which promote allograft rejection, may compromise pregnancy, whereas the Th2-type cytokines, by inhibiting Th1 responses, promote allograft tolerance and therefore may improve fetal survival. However, Th1 cytokines are not always detrimental for pregnancy development. Th1 cytokines, depending on their time of expression, stage of gestation and relative concentrations, could have a positive role in successful pregnancy. Other cytokines (LIF, M-CSF) produced by T cells seem to be important for the maintenance of pregnancy. Hormones present in the microenvironment of the decidual T cells could be responsible, at least in part, for the cytokine profile of the T cells. Indeed, progesterone is a potent inducer of Th2-type cytokines (e.g. IL-4 and IL-5), LIF and M-CSF production by T cells, whereas relaxin induces T cells to produce IFNgamma. Of course, the success of pregnancy depends on many mechanisms induced by different type of cells. Th2 cells could be one of these.

Persistency of high proinflammatory cytokine levels from colostrum to mature milk in preeclampsia

OBJECTIVES

Recent evidence suggests a role of an excessive maternal inflammatory response in the pathogenesis of preeclampsia. Whether this imbalance can be transferred from mother to breast milk remains to be established.

DESIGN AND METHODS

15 preeclamptic and 15 healthy pregnant women were recruited in this study. Colostrum and milk samples were collected postpartum in the first 48 h and at 30 days, respectively. Samples were analyzed for interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor (TNF)-alpha and soluble IL-2R (sIL-2R) levels with chemiluminescence enzyme immunometric assays.

RESULTS

Colostrum cytokine levels corrected for gestational age and type of delivery were not significantly different in the two groups. Cytokine levels significantly decreased in mature milk versus colostrum in the control group (P < 0.05), but did not significantly decrease in the preeclampsia group (P > 0.05), except for TNF-alpha (P < 0.05). Mature milk IL-8 and TNF-alpha levels were higher in the preeclampsia group versus controls (P < 0.05).

CONCLUSION

Results of this study show that proinflammatory cytokines in breast milk exhibit biological variation at different periods of human lactation. In preeclampsia, high cytokine levels persist at least for 30 days. These results suggest that preeclampsia may affect milk cytokine balance and offer an immunological signal for the host defense in high-risk neonates.

Increased levels of tumor necrosis factor-alpha and decreased levels of interleukin-12 p 70 in tracheal aspirates, within 2 hrs after birth, are associated with mortality among ventilated preterm infants

OBJECTIVE

To determine the association of antibacterial interleukin (IL)-12 p 70 levels as well as the pathogen-induced proinflammatory cytokine response in tracheal aspirate (TA) to respiratory failure and mortality among ventilated preterm infants.

DESIGN

A prospective observational clinical cohort study with measurements of cytokine levels and microbial cultures of TA from ventilated preterm neonates. Interleukin (IL)-1 beta, IL-8, IL-6, IL-10, IL-12 p 70, and tumor necrosis factor (TNF)-alpha were measured in TA within 2 hrs of birth, and comorbidity characteristics were recorded prospectively. The association between cytokine levels in TA and neonatal mortality was determined, with correction for comorbidity factors by means of multivariate stepwise logistic regression.

SETTING

A single tertiary neonatal intensive care unit at the University Hospital of Antwerp, Belgium.

PATIENTS

One hundred forty-one neonates born before a gestational age of 31 wks and who required ventilation were enrolled in the study; 31 (22%) died and 37 (26%) had airway colonization.

MEASUREMENTS AND MAIN RESULTS

The airway colonization rate was significantly greater among deceased neonates (45% vs. 21%; chi-square, 7.4; p=.007). Neonates who died had a significantly lower IL-12 p 70 cytokine level (6 pg/mL vs. 11 pg/mL; p<.05) in their TA. Neonates with a low IL-12 p 70 cytokine level had more pronounced respiratory failure (significantly higher oxygenation index, higher degree of radiologic respiratory distress syndrome, higher critical index for babies score, and more surfactant use). Multivariate analysis revealed that, after correction for severity of disease by critical index for babies score, the degree of intraventricular hemorrhage (odds ratio, 5.0 [95% confidence interval, 2.6-9.7]), low IL-12 p 70 levels (odds ratio, 4.9 [95% confidence interval, 2.1-11.7]), and high TNF-alpha levels in TA (odds ratio, 3.5 [95% confidence interval, 1.6-7.5]) were significantly associated with neonatal mortality.

CONCLUSIONS

Pathogen-induced excessive production of the proinflammatory cytokine TNF-alpha and lack of antibacterial IL-12 p 70 response in the TA are associated with increased neonatal mortality among ventilated preterm infants.

Placental imbalance of Th1- and Th2-type cytokines in preeclampsia

OBJECTIVES

To characterize the changes in the level of T helper 1 (Th1)- [interleukin (IL)-2 and tumor necrosis factor (TNF)-alpha] and Th2-type cytokine (IL-10) and the ratios of Th1/Th2 (IL-2/IL-10 and TNF-alpha/IL-10) in placentae from women with preeclampsia and women with gestational hypertension.

METHODS

Placental levels of IL-2, TNF-alpha, and IL-10 were determined with radioimmunoassay and Th1/Th2 ratios (IL-2/IL-10 and TNF-alpha/IL-10) calculated in the placentae from 22 women with preeclampsia, 15 women with gestational hypertension, and 32 normal term pregnant women.

RESULTS

Although preeclampsia had the trend of the increase in the placental levels of IL-2 and TNF-alpha and the trend of the decrease in placental IL-10, there were not significant difference in placental levels of IL-2, IL-10, and TNF-alpha among preeclampsia, gestational hypertension, and normal pregnancy (P > 0.05 for all). Placental ratios of IL-2/IL-10 and TNF-alpha/IL-10 were significantly higher in preeclampsia than in normal pregnancy (P = 0.035 and P = 0.005, respectively). No differences of Th1/Th2 ratios were found between preeclampsia and gestational hypertension and between gestational hypertension and normal pregnancy (P > 0.05 for all).

CONCLUSIONS

Alterations of placental balances of cytokines with Th1 predominance were demonstrated in preeclampsia. These associations may offer insights into the pathogenesis of preeclampsia.

Diesel exhaust affects immunological action in the placentas of mice

We investigated the effect of diesel exhaust (DE) on pregnancy and fetal development in mice at day 14 postcoitum (pc) with a special focus on the placenta. The number of absorbed fetuses increased in groups exposed to DE, and congestion was observed in histological sections of placentas. During placental absorption expression of CYP1A1 mRNA decreased to undetectable levels, whereas expression of TNF alpha mRNA increased approximately twofold over that of the control. Levels of CYP1A1 mRNA in normal placentas from DE-exposed mice were unchanged. mRNA levels of inflammatory cytokines IL-2, IL-5, IL-12 alpha, IL-12 beta, and GM-CSF increased in placentas exposed to DE (0.3 and 3.0 mg diesel exhaust particles (DEP)/m3). Expression of IL-5 mRNA was markedly increased in DE-exposed placentas, although levels were barely detectable in control placentas. IL-6 mRNA expression was increased approximately 10-fold in placentas exposed to DE (3.0 mg DEP/m3). It has been reported that expression of mRNA encoding proteins involved in immune function in the placenta is increased during fetal absorption in mice. In the present study, expression of such mRNA by the placenta was increased by DE exposure. Because it is believed that expression of mRNA in the placenta also affects fetal development, DE may promote fetal absorption. These findings suggest that in mice exposure to DE affects fetal absorption and placental function by modifying expression of immune-related genes during early gestation and expression of endocrine-related genes during late gestation.

Immunological Similarities between Implantation and Pre-eclampsia

PROBLEM

Cytokines are involved in implantation success and failure. We envisage that they could be similarly involved in pre-eclampsia (PE).

MATERIALS AND METHODS

First, we review the primipaternity and primiparity concepts and then why natural killer (NK) cells are involved in implantation. We stress that the common event in all PE is vascular remodelling.

RESULTS AND CONCLUSION

We conclude that PE could involve cytokine and/or NK dysfunctions, and propose a working hypothesis.

Th2/Th3 cytokine genotypes are associated with pregnancy loss

Cytokines are critical immunoregulatory molecules, responsible for determining the nature of an immune response. It has been proposed that Th2/Th3 immune reactions support normal pregnancy, while Th1 immunity is considered detrimental to the fetus. Since cytokine production is partly under genetic control, it is possible that women suffering from a high incidence of abortions are genetically predisposed to mount a type of immune response inappropriate for pregnancy maintenance. This study investigated the frequencies of cytokine gene polymorphisms in abortion-prone women and women with successful pregnancies. We investigated the role of Th1/Th2/Th3 cytokine gene polymorphisms, such as TGF-beta1 codon 10 (TGFbetac10; C to T), TGF-beta1 codon 25 (TGFbetac25; G to C), TNFalpha promoter-308 (G to A), IL-6 promoter-174 (G to C), IL-10 promoter-1082 (G to A), IL-10 promoter-819 (C to T), IL-10 promoter-592 (C to A), and IFNgamma intron 1 +874 (A to T) in abortion-prone female patients. Our results support the importance of Th2/Th3 immune responses in pregnancy loss, and suggest that an individual's immunogenetic profile indicative of imbalances in Th2/Th3 cytokines is associated with pregnancy loss. Our results suggest that abortive events are determined by genetic factors, reflected in the female patient's immunogenetic profile.

Effects of Interleukin-12 Administration during the Pre- and Peri-Implantation Period on Mouse Embryofetal Development

PROBLEM

The immunological success of pregnancy is thought to depend upon the establishment of a balance between favorable and deleterious cytokines, the current paradigm viewing pregnancy as a T helper (Th)2 cytokine-dependent phenomenon. In this context, a particular attention should be directed to the potential role of interleukin (IL)-12, which promotes the development of Th1 responses, in the induction of adverse pregnancy-related phenomena. Indeed, very few data linked the Th1-inducer IL-12 to the event of abortion.

METHODS

In this study, we have investigated the maternal and fetal effects of exogenous administration of IL-12 to CD1 (BR) ICR mice during the pre- and peri-implantation period (day 2-6 of pregnancy). Animals have been evaluated for parameters of reproductive performance, embryo and fetal developmental toxicity and maternal toxicity.

RESULTS

Intraperitoneal administration of IL-12 at concentrations from 2.5 to 10 microg/kg daily did not result in an increase in the murine abortion rate. A statistically significant, although minimal, decrease in the number of somites were found in the embryos of animals treated with IL-12 at a dose of 10 microg/kg/day. However, developmental parameters at birth were similar between the two groups of animals suggesting that alteration of somites might be a transitory state during treatment. An increased body weight gains and reduced feed and water consumption were observed in the mothers treated with the cytokine.

CONCLUSION

In the present experimental conditions and in this specific strain of mice, IL-12 does not exert adverse effects on reproductive performance and induces an only modest harmful action on mothers and embryos.

Cytokines, implantation and early abortion: re-examining the Th1/Th2 paradigm leads to question the single pathway, single therapy concept

PROBLEM

Human in vitro fertilization (IVF) embryo transfer is accompanied by a low implantation rate even after a very successful IVF, and there are a certain number of 'idiopathic sterilities' which are due to repeated implantation failures. In the very same vein, the question of improving implantation rates is of prime importance in agricultural research to improve the management of livestock. Preimplantation prenatal diagnosis cannot be accomplished in individuals who have a high rate of implantation failure, whether women undergoing IVF, or animals, during genetic cloning. Implantation cytokine networks need to be known in such a perspective.

METHODS

We review the evolution and theories in reproductive immunology, briefly deal with the complexity of implantation as a step by step developmental event, and then present some of our recent data in mice and human.

CONCLUSIONS

We conclude that the T helper cell type 1/2 (Th1/ Th2) paradigm, as useful as it has been to explain pregnancy, is no longer sufficient in view of the emerging complexity of the cytokine network at the materno-fetal interface. This is peculiarly true for implantation, which, as a step by step developmentally regulated process, involving inflammatory molecules, cannot fit into such a scheme.

Serum granulysin is a marker for Th1 type immunity in pre-eclampsia

Recent studies suggest that pre-eclampsia is associated with a Th1 predominant state and may be considered a failure of tolerance. Granulysin is a cytotoxic granule protein of natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). Recently, we developed an enzyme-linked immunosorbent assay (ELISA) system for detecting serum granulysin, and reported that serum granulysin is a useful marker to evaluate the cell-mediated immunity. In this study, we show that the serum levels of granulysin were significantly elevated in pre-eclamptic patients compared with those in normal pregnancy subjects. In addition, the serum granulysin levels in pre-eclamptic patients were well associated with mean blood pressure, percentage of peripheral blood Th1 cells and Th1/Th2 ratios. The present results suggest that the serum granulysin levels would be a useful and novel serum marker to evaluate the Th1/Th2 balance, especially Th1 type immunity in pre-eclampsia.

Anti-fetal immune response mechanisms may be involved in the pathogenesis of placental abruption

Placental abruption is an unpredictable severe complication in pregnancy. In order to investigate the possibility that the activation of the fetal nonadaptive immune system may be involved in the pathogenesis of this disease, IL-6 release from cord blood monocytes was examined by intracellular cytokine staining and flow cytometric analysis. Our results demonstrate that preterm placental abruption (n = 15) in contrast to uncontrollable preterm labor (n = 33) is associated with significantly (P < 0.001) increased release of IL-6 from the fetal monocytes. The same holds true for rhesus disease (n = 9, P < 0.001) that is characterized by a maternal production of antibodies against the rhesus-D antigen expressed by the fetal erythrocytes. This suggests that during rhesus disease, IL-6 release of monocytes is induced by antibody-mediated cross-linking of these cells to the erythrocytes in the fetal circulation. Hence, this assumption favors the idea that also in case of placental abruption, an increased maternal antibody production against paternal antigens leads to an elevated IL-6 release by the fetal monocytes. To elucidate this potential mechanism, the presence of anti-HLA-antibodies was assessed in the maternal circulation of patients with placental abruption (n = 17) and patients with uncontrollable preterm labor (n = 29). The percentage of women producing anti-paternal HLA-antibodies was significantly (P < 0.01) increased in the group of women with preterm placental abruption (47%) in comparison to women with uncontrollable preterm labor (14%). Therefore, our results suggest that an increased humoral immune response of the mother against the fetus may be decisively involved in the pathogenesis of placental abruption.

Th1/Th2 balance in preeclampsia

The syndrome of preeclampsia has previously been ascribed to generalized maternal endothelial dysfunction, poor placentation and excessive maternal inflammatory response. Recent reports suggest that preeclampsia is associated with a Th1 predominant profile and may be considered as a failure of the tolerance system allowing the second physiological trophoblastic invasion. In this review, we discuss that Th1 predominant immunity is closely related to inflammation, endothelial dysfunction and poor placentation.