Spontaneous secretion of interleukin-4, interleukin-10 and interferon-gamma by first trimester decidual mononuclear cells

Human Placental Schistosomiasis-A Systematic Review of the Literature

BACKGROUND

Schistosome egg deposition in pregnant women may affect the placenta of infected mothers and cause placental schistosomiasis (PS). Histopathological examination of placental tissue is an inadequate detection method due to low sensitivity. So far, there has not been any systematic review on PS.

METHODS

We conducted a systematic literature search on PubMed, EMBASE, and Medline and included all publications that reported microscopically confirmed cases of PS, as well as the relevant secondary literature found in the citations of the primarily included publications.

RESULTS

Out of 113 abstracts screened we found a total of 8 publications describing PS with a total of 92 cases describing egg deposition of dead and/or viable eggs and worms of S. haematobium and S. mansoni in placental tissue. One cross-sectional study investigating the prevalence of PS and its association with adverse birth outcomes, found 22% of placentas to be infested using a maceration technique but only <1% using histologic examination. Additionally, no direct link to deleterious pregnancy outcomes could be shown.

CONCLUSIONS

PS is a highly unattended and underdiagnosed condition in endemic populations, due to a lack of awareness as well as low sensitivity of histopathological examinations. However, PS may play an important role in mediating or reinforcing adverse birth outcomes (ABO) such as fetal growth restriction (FGR) in maternal schistosomiasis, possibly by placental inflammation.

Maternal, placental and cord blood cytokines and the risk of adverse birth outcomes among pregnant women infected with Schistosoma japonicum in the Philippines

BACKGROUND

The objectives of this study were to 1) evaluate the influence of treatment with praziquantel on the inflammatory milieu in maternal, placental, and cord blood, 2) assess the extent to which proinflammatory signatures in placental and cord blood impacts birth outcomes, and 3) evaluate the impact of other helminths on the inflammatory micro environment.

METHODS/FINDINGS

This was a secondary analysis of samples from 369 mother-infant pairs participating in a randomized controlled trial of praziquantel given at 12-16 weeks' gestation. We performed regression analysis to address our study objectives. In maternal peripheral blood, the concentrations of CXCL8, and TNF receptor I and II decreased from 12 to 32 weeks' gestation, while IL-13 increased. Praziquantel treatment did not significantly alter the trajectory of the concentration of any of the cytokines examined. Hookworm infection was associated with elevated placental IL-1, CXCL8 and IFN-γ. The risk of small-for-gestational age increased with elevated IL-6, IL-10, and CXCL8 in cord blood. The risk of prematurity was increased when cord blood sTNFRI and placental IL-5 were elevated.

CONCLUSIONS

Our study suggests that fetal cytokines, which may be related to infectious disease exposures, contribute to poor intrauterine growth. Additionally, hookworm infection influences cytokine concentrations at the maternal-fetal interface.

CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE

ClinicalTrials.gov (NCT00486863).

The Predominant Th1 Cytokine Profile in Maternal Plasma of Preeclamptic Women Is Not Reflected in the Choriodecidual and Fetal Compartments

OBJECTIVE

Human pregnancy disorders such as preeclampsia are thought to involve variations in cytokine levels. It has been proposed that, in preeclamptic women, a balance favoring the Th1-type over the Th2-type cytokine profile determines local or systemic immunologic responses to pregnancy and that this may cause defective placental implantation and placental ischemia, which activate systemic endothelial cells. The purpose of this study was to determine whether cytokine expression differs in the maternal, choriodecidual, and fetal compartments, and between women with or without preeclampsia.

METHODS

Plasma concentrations of interferon gamma (IFNgamma), interleukin (IL)-2, IL-4, and IL-10 were measured by enzyme-linked immunosorbent assay (ELISA) in samples obtained from maternal peripheral blood (MPB), choriodecidual (CD), and fetal cord (FC) blood compartments of 17 women with preeclampsia and in 15 normotensive women. Intracellular concentrations of IFNgamma and IL-2 in T lymphocytes were assessed by flow cytometry.

RESULTS

Plasma IFNgamma concentrations in both MPB and CD compartments were significantly higher in preeclamptic than in normotensive women. Maternal plasma IL-4 concentration was significantly lower in preeclamptic than in normotensive women. Intracellular IFNgamma and IL-2 concentrations did not differ significantly between preeclamptic and normotensive women.

CONCLUSIONS

The dominant Th1-type over Th2-type cytokine profile is evident in MPB, but not in the CD and FC blood compartments. This might reflect the complex cytokine networks in the fetal-placental interface and might involve trophoblasts or decidual and endothelial cells, which could account for the increased plasma IFNgamma concentration and T-helper cell number.

Maternal Schistosomiasis japonica is associated with maternal, placental, and fetal inflammation

Schistosomes infect ∼40 million women of childbearing age and result in the elaboration of proinflammatory cytokines that have been implicated in fetal growth restriction. In murine models and two observational studies in humans, schistosome infection during pregnancy was associated with reduced birth weight, although a recent treatment trial in Schistosoma mansoni did not detect this association. We conducted an observational study among 99 pregnant women living in an area of Schistosoma japonicum endemicity in the Philippines. We enrolled women at 32 weeks gestation and measured S. japonicum and geohelminth infection intensity. We collected maternal peripheral blood at 32 weeks gestation and placental and cord blood at delivery to assess inflammatory status. At delivery, we collected a placental-tissue sample and measured birth weight. In multivariate models adjusted for geohelminths, maternal schistosomiasis was associated with increased levels of inflammatory cytokines in maternal peripheral (tumor necrosis factor alpha [TNF-α] and interleukin 10 [IL-10]), placental (TNF-α, IL-6, TNF-α receptor II [RII], and IL-1β), and cord (IL-1β and TNF-α RII) blood, as well as acute subchorionitis and increased TNF-α production by syncytiotrophoblasts assessed by immunohistochemistry (all P < 0.05). After adjusting for confounders, placental IL-1β, and TNF-α production by syncytiotrophoblasts was independently associated with decreased birth weight (both P < 0.05). Our data indicate that maternal schistosomiasis results in a proinflammatory signature that is detectable in maternal, placental, and fetal compartments, and a subset of these responses are associated with decreased birth weight. This potential mechanistic link between maternal schistosomiasis and poor birth outcomes will contribute to the debate regarding treatment of maternal schistosome infections.

Glycodelin A induces a tolerogenic phenotype in monocyte-derived dendritic cells in vitro

PROBLEM

Successful mammalian pregnancy requires a delicate immunological balance at the feto-maternal interface that allows the semi-allogeneic fetus to grow, while protecting mother and child from environmental pathogens. As in other mucosal tissues, antigen-recognition and -handling by professional antigen-presenting cells such as dendritic cells (DC) determine the course of the subsequent immune response. DC at the feto-maternal interface help shape this immunological equilibrium. Endometrial tissue secretes high quantities of glycodelin A (GdA) during the so-called fertile window (i.e. the time of implantation of the blastocyst).

METHOD OF STUDY

We investigated the effect of GdA on monocyte-derived DC (moDC) regarding surface marker expression, endopinocytotic activity, cytokine profile as well as lymphoproliferative activity.

RESULTS

Upon pretreatment with GdA and subsequent maturation with tumor necrosis factor-alpha and interleukin (IL)-1beta, moDC displayed a reduced expression of costimulatory molecules, an unchanged major histocompatibility complex-II expression and persistence of DC-SIGN positive cells. GdA-pretreated moDC had a higher endopinocytotic activity, an increased IL-10 production and a dose-dependent reduction in lymphoproliferative activity. GdA incubation alone did not alter the immature phenotype.

CONCLUSION

Our results suggest a model in which the human endometrium secretes high quantities of GdA during implantation and thereby helps to shape the unique immunological interaction between mother and fetus via decidual DC.

Recent findings on the pathogenesis of bronchial asthma. Part II. The role of hormonal predisposition, environmental influences and conditioning leading to bronchial asthma

In this second part of the review on the pathogenesis of asthma the hormonal factors and adverse external events are shortly reviewed which skew the balance of Th1 vs. Th2 CD4+ lymphocytes towards the latter ones and this way increase the probability of atopic diseases. Among other the role of transplacental priming, insulin, insulin-like and other growth factors, lack of the usual microbial infections in the early childhood (the so-called hygiene hypothesis), gender, diminished testosterone production, gastroesophageal reflux, adverse effects during pregnancy are discussed. A separate chapter deals with the role of central nervous system in the etiology and finally the most common allergizing and airway tissue damaging agents are listed in tabulated form.

T-cell interferon-gamma release assays for the rapid immunodiagnosis of tuberculosis: clinical utility in high-burden vs. low-burden settings

PURPOSE OF REVIEW

The utility of T-cell interferon-gamma (IFN-gamma) responses to Mycobacterium tuberculosis specific antigens [interferon-gamma release assays (IGRAs)] in high-burden settings remains unclear and there is growing evidence that IGRA performance varies across high tuberculosis (TB) burden vs. low TB burden settings. Here we review the evidence supporting the utility of IGRAs in specific subgroups and compare their performance in high-burden vs. low-burden settings.

RECENT FINDINGS

Although the IGRA, compared with the tuberculin skin test (TST), has greater specificity in BCG-vaccinated individuals, treatment of latent tuberculosis infection is not a priority in high-burden setting. Nevertheless, in high-burden settings, the TST performs reasonably well and correlates as well, or better, with proxy measures of exposure.

SUMMARY

IGRAs may still be useful in high-burden settings in specific subgroups at high risk of progression, including young children, HIV-infected individuals and healthcare workers, but this requires confirmation. Although the IGRAs cannot distinguish between latent and active TB, their utility as rule-out tests, when combined with smear microscopy or the TST, requires further study. Prospective studies are required in high-burden settings to confirm whether IFN-gamma responses are predictive of high risk of progression to active TB, particularly in HIV-infected individuals.

The anti-inflammatory limb of the immune response in preterm labor, intra-amniotic infection/inflammation, and spontaneous parturition at term: a role for interleukin-10

OBJECTIVE

The anti-inflammatory limb of the immune response is crucial for dampening inflammation. Spontaneous parturition at term and preterm labor (PTL) are mediated by inflammation in the cervix, membranes, and myometrium. This study focuses on the changes in the amniotic fluid concentrations of the anti-inflammatory cytokine interleukin (IL)- 10. The objectives of this study were to determine whether there is a relationship between amniotic fluid concentrations of IL-10 and gestational age, parturition (at term and preterm), and intra-amniotic infection/inflammation (IAI).

STUDY DESIGN

A cross-sectional study was conducted including 301 pregnant women in the following groups: (1) mid-trimester of pregnancy who delivered at term (n = 112); (2) mid-trimester who delivered preterm neonates (n = 30); (3) term not in labor without IAI (n = 40); (4) term in labor without IAI (n = 24); (5) term in labor with IAI (n = 20); (6) PTL without IAI who delivered at term (n = 31); (7) PTL without IAI who delivered preterm (n = 30); (8) PTL with IAI who delivered preterm (n = 14). IL-10 concentrations in amniotic fluid were determined by a specific and sensitive immunoassay. Non-parametric statistics were used for analysis.

RESULTS

(1) IL-10 was detectable in amniotic fluid and its median concentration did not change with gestational age from mid-trimester to term. (2) Patients in labor at term had a significantly higher median amniotic fluid IL-10 concentration than that of patients at term not in labor (p = 0.04). (3) Women at term in labor with IAI had a significantly higher median amniotic fluid IL-10 concentration than that of patients at term in labor without IAI (p = 0.02). (4) Women with PTL and IAI who delivered preterm had a significantly higher median amniotic fluid concentration of IL-10 than those without IAI who delivered preterm and than those who delivered at term (p = 0.009 and p < 0.001, respectively). (5) Among patients with preterm labor without IAI, those who delivered preterm had a significantly higher median amniotic fluid IL-10 concentration than those who delivered at term (p = 0.03).

CONCLUSIONS

The anti-inflammatory cytokine IL-10 is detectable in the amniotic fluid of normal pregnant women. Spontaneous parturition at term and in preterm gestation is associated with increased amniotic fluid concentrations of IL-10. IAI (preterm and at term) is also associated with increased amniotic fluid concentrations of IL-10. We propose that IL-10 has a role in the regulation of the immune response in vivo by initiating actions that dampen inflammation.

Maternal plasma cytokines in early- and mid-gestation of normal human pregnancy and their association with maternal factors

Few studies have assessed longitudinal changes in circulating cytokine levels during normal pregnancy. We have examined the natural history of maternal plasma cytokines from early- to mid-pregnancy in a large, longitudinal cohort. Multiplex flow cytometry was used to measure interleukin (IL)-2, IL-6, IL-12, tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma and granulocyte-macrophage colony-stimulating factor (GM-CSF) in early- (median [IQR]: 8.5 weeks [7.1, 10.0]) and mid-pregnancy (25.0 [24.1, 26.1]) from 1274 Danish women delivering singleton term infants. GM-CSF decreased from early- to mid-pregnancy (median percent change [95% CI]: -51.3% [-59.1%, -41.8%]), while increases were observed in IL-6 (24.3% [4.6%, 43.9%]), IL-12 (21.3% [8.9%, 35.7%]) and IFN-gamma (131.7% [100.2%, 171.6%]); IL-2 (-2.8% [-11.5%, 0.0%]) and TNF-alpha (0% [-5.9%, 25.6%]) remained stable. Positive correlations were found between all cytokines, both in early- and mid-pregnancy (all p<0.001). Early- and mid-pregnancy levels were rank-correlated for IL-2, IL-12, TNF-alpha and GM-CSF, but not IL-6 and IFN-gamma; these correlations were generally weaker than correlations between different cytokines at a single time point in pregnancy. Women with a pre-pregnancy BMI <18.5 had reduced levels of IFN-gamma and GM-CSF compared to women in other BMI categories, while women aged >or=35 years had elevated IL-2, IL-6, TNF-alpha and IFN-gamma. Early-pregnancy levels of TNF-alpha were higher in women with a prior preterm delivery. Cytokine levels were not associated with gravidity. In conclusion, cytokines were detected in plasma during early- and mid-pregnancy, with IL-6, IL-12, IFN-gamma and GM-CSF concentrations varying over pregnancy. Concentrations may depend on BMI, maternal age and prior preterm delivery.

NK cells and human pregnancy--an inflammatory view

For several years, reproductive immunology has been dominated by the 'Th1/Th2' hypothesis, in which the fetus avoids maternal T-cell rejection through a bias towards T-helper (Th)2 cytokine production. The discovery that normal pregnancy is a controlled state of inflammation, at an early stage at the implantation site and also later systemically, has challenged this concept, as has the finding that the predominant immune interactions in the decidua are between the placental trophoblast and maternal natural killer (NK) cells instead of T cells. Here, we extend this concept to the interaction between the trophoblast and NK cells in the maternal circulation. We suggest novel ways in which the trophoblast might stimulate the maternal systemic inflammatory response, and how dysfunctional NK-cell activation could result in the maternal syndrome of pre-eclampsia.

Cytokine secretion in decidual mononuclear cells from term human pregnancy with or without labour: ELISPOT detection of IFN-gamma, IL-4, IL-10, TGF-beta and TNF-alpha

Cytokines are believed to be important in maintaining pregnancy and in the process of labour induction in humans. The aim of this study was to investigate the secretion of the cytokines interferon-gamma (IFN-gamma), interleukin-4 (IL-4), IL-10, transforming growth factor-beta (TGF-beta) and tumour necrosis factor-alpha (TNF-alpha) in decidual tissue with or without labour. Decidual tissue was collected from 32 healthy women undergoing elective caesarean sections before the onset of labour (n=17) or after normal vaginal delivery (n=15). Mononuclear cells were analysed for cytokine secretion with ELISPOT. To validate the widely used method of tissue collected at caesarean sections and after vaginal deliveries as a representative of before and after labour, respectively, placenta biopsies were collected from 12 healthy women to study the expression of the prostaglandin pathway enzymes cyclooxygenase-2 (COX-2) and microsomal prostaglandin E(2) synthase (mPGES). Decidual mononuclear cells from term human pregnancy spontaneously secrete IFN-gamma, IL-4, IL-10, TGF-beta and TNF-alpha. No difference was seen in cytokine secretion with or without labour, indicating that decidual leukocytes are not the main cell population responsible for plausible cytokine regulation in the process of termination of pregnancy. Placental tissues obtained after vaginal delivery showed a higher mRNA expression of the prostaglandin regulating molecules COX-2 and mPGES than tissues from caesarean sections before the onset of labour, validating that the model can be used as a representative of the state before and after labour.

Synergistic induction of apoptosis in primary rat decidual cells by INF-γ and TNF

In the rat, in response to blastocyst implantation, stromal cells of the endometrium proliferate and differentiate into decidual cells, forming the decidua. After reaching its maximum development, the decidua undergoes regression. This phenomenon appears to be due to an active process involving apoptosis. As there is sparse knowledge concerning the mechanisms of induction of decidual cell death, the potential role of cytokines present in the uterine environment during pregnancy, such as tumor necrosis factor (TNF) and interferon-gamma (INF-gamma) was explored in primary cultures of rat decidual cells. The effects of these factors upon cellular viability, nuclear morphologic alterations, expression, and enzymatic activities of the effector caspases-3/7 were evaluated. The results obtained demonstrated that in contrast to TNF, which did not induce any alteration, INF-gamma and in association with TNF caused a decrease in cell viability and an increase in the appearance of apoptotic bodies in a time-dependent manner that was augmented in the co-presence of TNF. An increase in caspase-3/7 activities after 12 hr of TNF/INF-gamma treatment was also observed. These findings suggest that INF-gamma expressed in the uterine environment may play an important role in regulating apoptosis through potential synergistic mechanisms with TNF and thereby modulate decidual stability and regression during pregnancy.

The role of apoptosis in the regulation of trophoblast survival and differentiation during pregnancy

Apoptosis is important for normal placental development, but it may also be involved in the pathophysiology of pregnancy-related diseases. Normal placental development is dependent upon the differentiation and invasion of the trophoblast, the main cellular component of the placenta. Trophoblast apoptosis increases in normal placentas as gestation proceeds, and a greater incidence of trophoblast apoptosis has been observed in pregnancies complicated by preeclampsia or intrauterine growth retardation (IUGR). In response to different stimuli, apoptosis may be initiated extrinsically by the death receptor pathway or intrinsically by the mitochondrial pathway. The central executioners of apoptosis are the caspases, which cleave numerous vital cellular proteins to affect the apoptotic cascade. By inhibiting caspase activation, several endogenous inhibitors, including flice-like inhibitory proteins (FLIPs), inhibitors of apoptosis (IAPs), and antiapoptotic Bcl-2 family members, can prevent further propagation of the death signal. Macrophages present at the maternal-fetal interface may also contribute to trophoblast survival by removing apoptotic cells and producing cytokines and growth factors, which influence the progression of the apoptotic cascade. This review focuses on the role of apoptosis in trophoblast development and differentiation, the molecular mechanisms by which normal trophoblast apoptosis can occur, and how it is regulated to prevent excessive trophoblast apoptosis and possible pregnancy complications.

Autonomic dysfunction may be an under-recognized cause of female fertility disorders

Female conditions of impaired fertility comprise a heterogeneous group of disorders that are attributed to various anatomic, hormonal and immunologic disturbances. We hypothesize that autonomic dysfunction may be a previously unrecognized factor in female fertility disorders. Emerging physiologic and molecular evidence suggests that autonomic balance varies during normal menstrual cycles with a shift to sympathetic bias during the luteal phase. Furthermore, many diseases associated with autonomic dysfunction show catamenial variations in patterns consistent with a shift to sympathetic bias occurs during the second half of normal menstrual cycles. The shift to sympathetic bias during the normal luteal phase may be an evolutionary adaptation to address the immunologic and physiologic demands for successful implantation and gestation. Through direct modulation of the lymphoid system and activation of the cortisol pathway, sympathetic bias promotes a shift to relative T helper (Th)-2 biased immunity which may favor maternal tolerance of the embryo by attenuating Th-1 mediated interference of implantation. Indeed, a growing body of evidence has implicated abnormal Th balance in fertility disorders, but the link has been attributed to factors other than autonomic function, such as hormonal factors. After implantation, maternal sympathetic bias may further support gestation through physiologic changes necessary to maintain placental perfusion pressure. We propose that insufficient shift to sympathetic bias during the luteal phase, which manifests in inadequate shift towards Th-2 bias and down-regulation of Th-1 function, may be the mechanism of impaired fertility in certain patients. Our hypothesis portends new potential methods to treat fertility disorders by modulating autonomic balance.

T Helper Cell Cytokine Profiles in Preterm Labor

PROBLEM

To compare concentrations of T-helper cell cytokines in women with preterm labor (PTL) to normal pregnancies.

METHOD OF STUDY

Fourteen women with PTL and 13 women with normal pregnancies from 24 to 34 weeks were enrolled in this pilot study. Peripheral blood mononuclear cells (PBMCs) and cervical secretions were collected. PBMCs were cultured and stimulated with mitogens. Culture supernatants and cervical secretions were assayed for type 1 (interferon-gamma, IL-12) and type 2 cytokines (IL-4, IL-5, IL-10 and IL-13) using enzyme-linked immunosorbent assays.

RESULTS

There were no intergroup differences in median cytokine concentrations in PBMC cultures, or in ratios of type 1/type 2 cytokines. In cervical secretions, the median concentration of IL-4 was significantly higher in control patients.

CONCLUSIONS

PTL patients appeared to have an altered T-helper cytokine balance in cervical secretions. Further study of the role of cytokines produced in the adaptive response appears warranted.

Cytokine secretion patterns of NK cells and macrophages in early human pregnancy decidua and blood: implications for suppressor macrophages in decidua

PROBLEM

Local immune modulation has been shown to be of considerable importance for the maintenance of successful pregnancy. We have previously reported the secretion of interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and IL-10 in human decidua from early normal pregnancy. The aim of this study was to investigate the cellular source of cytokine secretion in the decidua, and compare this to secretion patterns in peripheral blood.

METHOD OF STUDY

Decidual tissue and peripheral blood was collected from 20 women undergoing surgical abortion during first trimester pregnancy. Monocytes/macrophages and NK cells were enriched by immunomagnetic cell separation and cytokine secretion was detected by enzyme-linked immunosorbent spot-forming cell assay.

RESULTS

Decidual and peripheral monocytes/macrophages and NK cells spontaneously secrete IFN-gamma, IL-4 and IL-10. The number of IL-10 secreting cells was significantly higher in decidual macrophages compared with decidual non-monocytic cells as well as compared with blood monocytes/macrophages. These differences were not seen for IFN-gamma or IL-4.

CONCLUSIONS

Our results indicate that decidual macrophages subserve important suppressive functions in the pregnant uterus.

Systemic Th1/Th2 Cytokine Responses to Paternal and Vaccination Antigens in Preeclampsia: No Differences Compared with Normal Pregnancy

PROBLEM

A Th1-shift has been suggested to be involved in the pathogenesis of preeclampsia. This study was designed to compare Th1/Th2 related cytokine secretion in blood between women with preeclampsia (n = 15) and normal pregnancies (n = 15), using a high-sensitivity technique for cytokine detection.

METHODS OF STUDY

Spontaneous as well as 'fetus-specific' and recall antigen-specific (purified protein derivate of Mycobacterium tuberculosis, tetanus toxoid and lipopolysaccharide) secretion of interferon-gamma, interleukin (IL)-4, IL-10 and IL-12 in peripheral blood mononuclear cells (PBMC) was detected by enzyme-linked immunosorbent spot-forming cell assay (ELISPOT). Fetus-specific secretion was induced by stimulation with paternal PBMC in a mixed leukocyte culture assay.

RESULTS

All cytokines were secreted by PBMCs both from women with preeclampsia and women with normal pregnancies. No differences in the number of cytokine-secreting cells were found between the two groups.

CONCLUSIONS

No evidence was found for a shift in the systemic Th1/Th2 responses, in preeclampsia compared with normal pregnancy. This does, however, not exclude differences in the local immune responses related to the fetoplacental unit.

Immunomodulatory function of seminal catecholamines may be an adaptation for reproduction

Catecholamines are found at high concentrations in seminal fluid. The exact functional significance of seminal catecholamines is unknown. We hypothesize that seminal catecholamines perform important immunomodulatory functions that support reproductive success. Specifically, we propose that catecholamines contribute to a local adaptive shift of T helper (Th) balance to Th2 dominance in the maternal reproductive tract to enable the gametes, and possibly the nascent zygote, to evade immune surveillance of the female. Our hypothesis suggests that the Th2 effects of catecholamines are independent of the direct immunomodulatory effects of seminal cytokines such as prostaglandin E2 and transforming growth factor beta1. Potential immunomodulatory functions of other seminal constituents such as aldosterone, oxytocin, vasopressin, and angiotensin remain unexplored and represents a topic of future interest. Seminal stress hormones may play a role in mating dynamics since alpha males typically live in a state of high hormonal stress, Mating with adrenalized alpha males may represent an adaptive Darwinian strategy by females to maximize their reproductive fitness.

Menstrual variation of autonomic balance may be a factor in exacerbations of certain diseases during the menstrual cycle

Exacerbation of certain medical conditions during specific phases of the menstrual cycle has long been recognized. Mechanisms of the cyclic variations are poorly understood, but are often attributed to fluctuations in reproductive hormones. We hypothesize that normal variations in autonomic balance during the menstrual cycle, which likely evolved as adaptations for reproduction, may contribute to catamenial variations in diseases independent of hormonal variations. Emerging evidence suggests that autonomic balance shifts towards sympathetic bias during the second half of the menstrual cycle. This shift can be seen as an evolutionary adaptation to address the immunologic and physiologic demands for successful implantation and gestation. Through direct modulation of lymphoid system and activation of the cortisol pathway, sympathetic bias promotes a shift to relative T helper (Th)-2-biased immunity which may favor maternal tolerance of the embryo by attenuating Th-1-mediated interference of implantation. Immune variance during the menstrual cycle has been implicated in menstrual fluctuations of many diseases, but until now the immune variance has been attributed to female hormonal changes. We propose that shifts in autonomic balance independently contribute to fluctuations in diseases by modulating the immune system. Still further, we propose that many other diseases fluctuate due to the direct nervous system actions of shifts in autonomic balance. Our hypothesis portends new therapeutic paradigms based on cyclical modulation of autonomic balance to address catamenial variations of medical conditions.

Placental Trophoblast from Successful Human Pregnancies Expresses the Tolerance Signaling Molecule, CD200 (OX-2)*

PROBLEM

Th1 cytokine-dependent abortions in the CBA x DBA/2 mouse model have been linked to down-regulation of expression of the CD200 (OX-2) 'tolerance' signal on trophoblast and in decidua prior to onset of the abortion process. Abortions could be prevented by administration of a soluble CD200. Is CD200 expressed on trophoblast in successful human pregnancy?

METHOD OF STUDY

As one cannot easily obtain trophoblasts in large quantities from successful human pregnancies in the first trimester prior to the onset of the abortion process at 6 weeks gestation, we examined as a first step, trophoblast isolated from term placentae (i.e. successful pregnancies). CD9- trophoblasts were isolated by affinity column and stained for intracellular cytokeratin, and surface CD200 using PE-anti-human CD200 monoclonal antibody. mRNA was extracted from CD9+ and CD9- cells and tested by reverse transcription-polymerase chain reaction for CD200 mRNA. CD9- placental cells were separated by velocity sedimentation and test for CD200-dependent suppression of an allogeneic human mixed lymphocyte culture where cytotoxic T cell (CTL) generation, and Thl --> Th2 cytokine production shift were measured.

RESULTS

CD9- but not CD9+ placental cell populations contained cells with mRNA for CD200, both a normal length transcript and a truncated transcript. Flow cytometry showed a CD200+ cytokeratin+ moderate-to-large-sized cell population compatible with trophoblasts and a smaller subset of cytokeratin- cells that expressed CD200 at normal and at high levels. The moderate-sized population proved most potent at inhibiting CTL generation and caused a Th1 --> Th2 cytokine shift. These effects were blocked by monoclonal anti-CD200.

CONCLUSIONS

A subpopulation of cytokeratin+ placental trophoblasts express bioactive CD200 able to alter maternal immune responses in a favorable (Th2 > Th1) direction. Two populations of CD200+ small- and medium-small-sized cytokeratin- placental cells remain to be identified. Studies of karyotyped first trimester elective termination and spontaneous miscarriage tissues are needed.

In-situ detection of both inflammatory and anti-inflammatory cytokines in resting peripheral blood mononuclear cells during pregnancy

INTRODUCTION

Local and possibly systemic curtailment of the maternal immune response is important for a successful pregnancy. Although the local milieu at the utero-placental interface is likely to harbor the most prominent alterations, it is suggested, at least in mice, that systemic immunity is also tolerized during pregnancy. In the present study, we investigated mRNA expression of the key immunomodulatory cytokines; interleukin (IL)-4, IL-10, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma during normal pregnancy.

MATERIAL AND METHODS

In-situ hybridization (ISH) of cytokine mRNA in resting peripheral blood mononuclear cells (PBMCs) was used to detect the number of cells spontaneously expressing cytokines. Eleven women with normal gestations were followed during pregnancy as well as 8 weeks postpartum, and compared with 10 non-pregnant healthy controls.

RESULTS

The numbers of IFN-gamma and IL-4 mRNA expressing cells were found to be significantly increased during pregnancy and postpartum compared with non-pregnant controls. Pregnant women and non-pregnant controls did not differ in their expression of TNF-alpha and IL-10.

CONCLUSION

Our studies demonstrated increased numbers of both IFN-gamma and IL-4 mRNA expressing cells in blood suggesting that systemic immunomodulation, albeit partial, takes place during normal pregnancy. It is proposed that enhanced IL-4 expression, possibly in concert with other elevated anti-inflammatory immunomodulatory cytokines, curtail the potentially hazardous effects of IFN-gamma on systemic immunity during pregnancy.