Increased numbers of circulating interferon-gamma- and interleukin-4-secreting cells during normal pregnancy

Mid-pregnancy circulating cytokine levels, placental efficiency and their relationship with preterm birth

Objective

To assess a panel of cytokines and placental insufficiency with the risk of preterm delivery (PTD).

Methods

Nested case-control study into the BRISA birth cohort. Eighty-two mother-infant-placenta pairs were selected at 20+0 to 25+6 weeks. Circulating biomarker levels were performed using Luminex flowmetric xMAP technology. Cytokines classified as Th1, Th2 or Th17 and other biomarkers were selected. The ratio between birth weight and placental weight (BW/PW) was used as a proxy for placental efficiency. Spearman correlation, univariate analyses and logistic regression models were calculated. Sensitivity, specificity, positive and negative likelihood ratios were calculated using the Receiver Operating Characteristic curve.

Results

Mean gestational age was 250 days, 14,6% were small for gestational age, 4,8% large for gestational age and 13,4% stunted. Placental efficiency was higher for term newborns (p<0,001), and 18/22 (81%) preterm biomarker values were higher than the control group. Th1 cytokines were highly correlated, while the weakest correlation was observed in other biomarkers. Less education was associated with a higher risk of PTD (p = 0.046), while there was no appreciable difference in the risk of PTD for placental insufficiency. Biomarkers showed negligible adjusted OR of PTD (0.90 to 1.02). IL-6, IL-8, IL-1β, TNFβ, IL-4, IL-13, GCSF, MIP1A, VEGF, EGF, and FGF2 presented a higher sensitivity ranging from 75.56% to 91.11%.

Conclusion

IL-8, IL-12p40, IL-4, IL-13, GCSF, MIP1B, and GMSF in asymptomatic pregnant women were associated with PTD. This finding suggests an activation of maternal inflammatory response.

Maternal body mass index is associated with an altered immunological profile at 28 weeks of gestation

Healthy pregnancy is accompanied by various immunological and metabolic adaptations. Maternal obesity has been implicated in adverse pregnancy outcomes such as miscarriage, preeclampsia, and gestational diabetes mellitus (GDM), while posing a risk to the neonate. There is a lack of knowledge surrounding obesity and the maternal immune system. The objective of this study was to consider if immunological changes in pregnancy are influenced by maternal obesity. Peripheral blood was collected from fasted GDM-negative pregnant women at 26-28 weeks of gestation. Analysis was done using immunoassay, flow cytometry, bioenergetics analysis, and cell culture. The plasma profile was significantly altered with increasing BMI, specifically leptin (r = 0.7635), MCP-1 (r = 0.3024), and IL-6 (r = 0.4985). Circulating leukocyte populations were also affected with changes in the relative abundance of intermediate monocytes (r = -0.2394), CD4:CD8 T-cell ratios (r = 0.2789), and NKT cells (r = -0.2842). Monocytes analysed in more detail revealed elevated CCR2 expression and decreased mitochondrial content with increased BMI. However, LPS-stimulated cytokine production and bioenergetic profile of PBMCs were not affected by maternal BMI. The Th profile skews towards Th17 with increasing BMI; Th2 (r = -0.3202) and Th9 (r = -0.3205) cells were diminished in maternal obesity, and CytoStim™-stimulation exacerbates IL-6 (r = 0.4166), IL-17A (r = 0.2753), IL-17F (r = 0.2973), and IL-22 (r = 0.2257) production with BMI, while decreasing IL-4 (r = -0.2806). Maternal obesity during pregnancy creates an inflammatory microenvironment. Successful pregnancy requires Th2-biased responses yet increasing maternal BMI favours a Th17 response that could be detrimental to pregnancy. Further research should investigate key populations of cells identified here to further understand the immunological challenges that beset pregnant women with obesity.

T helper cell immunity in pregnancy and influence on autoimmune disease progression

Pregnancy presents the maternal immune system with a unique immunological challenge since it has to defend against pathogens while tolerating paternal allo-antigens expressed by fetal tissues. T helper (Th) cells play a central role in modulating immune responses and recent advances have defined distinct contributions of various Th cell subsets throughout each phase of human pregnancy, while dysregulation in Th responses show association with multiple obstetrical complications. In addition to localized decidual mechanisms, modulation of Th cell immunity during gestation is mediated largely by oscillations in sex hormone concentrations. Aberrant Th cell responses also underlie several autoimmune disorders while pregnancy-induced changes in the balance of Th cell immunity has been shown to exert favorable outcomes in the progression Th1 and Th17 driven autoimmune conditions only to be followed by post-partal exacerbations in disease.

Immunological Changes in Pregnancy and Its Relation to COVID-19 Infection

This chapter describes the immunological adaptation to pregnancy. A special focus is drawn on the susceptibility to viral infections, especially COVID-19. Older literature refers to the pregnancy as an immunosuppressive state, while recent studies show an immunomodulation to adapt to the growing semiallograftic fetus. Despite this, pregnant women are not susceptible to all viral infections. Regarding influenza, pregnant women are not more susceptible to the infection, but more severe maternal courses. To prevent this, influenza vaccination is recommended for pregnant women. Based on the available evidence, pregnant patients are also not more susceptible to infection with regard to COVID-19 infection. Yet, more severe courses are described throughout gestation with the onset of obstetrical complications.

Maternal Immunological Adaptation During Normal Pregnancy

The risk and severity of specific infections are increased during pregnancy due to a combination of physiological and immunological changes. Characterizing the maternal immune system during pregnancy is important to understand how the maternal immune system maintains tolerance towards the allogeneic fetus. This may also inform strategies to prevent maternal fatalities due to infections and optimize maternal vaccination to best protect the mother-fetus dyad and the infant after birth. In this review, we describe what is known about the immunological changes that occur during a normal pregnancy.

Perinatal depression: Heterogeneity of disease and in animal models

Perinatal depression (PND) can have either an antepartum or postpartum onset. Although the greatest risk factor for PND is previous depression history,de novoPND occurs with the majority of cases occurring in the postpartum. Timing of depression can impact etiology, prognosis, and response to treatment. Thus, it is crucial to study the impact of the heterogeneity of PND for better health outcomes. In this review, we outline the differences between antepartum and postpartum depression onset of PND. We discuss maternal physiological changes that differ between pregnancy and postpartum and how these may differentially impact depression susceptibility. We highlight changes in the maternal steroid and peptide hormone levels, immune signalling, serotonergic tone, metabolic factors, brain morphology, and the gut microbiome. Finally, we argue that studying the heterogeneity of PND in clinical and preclinical models can lead to improved knowledge of disease etiopathology and treatment outcomes.

Mechanisms determining the amelioration of rheumatoid arthritis in pregnancy: A systematic review

BACKGROUND

The phenomenon of pregnancy-induced remission of rheumatoid arthritis (RA) was first reported by Philip Hench in 1938. Despite extensive efforts, the underlying scientific basis has remained elusive. A number of different potential mechanisms have been investigated. We have undertaken a systematic review of the available peer-reviewed articles involving pregnant patients with RA in order to establish the depth of current scientific understanding of this important topic.

METHODS

This review was conducted according to guidelines of preferred reporting items for systematic reviews and meta-analyses. Studies were identified by a thorough search of multiple databases including Medline, PubMed and EMBASE. Search terms used were different combinations of the keywords: rheumatoid arthritis, inflammatory arthritis, pregnancy, mechanisms, disease activity, relapse and remission. Non-English language articles and studies that were not directly relevant were excluded. Two independent reviewers (CR and KA) screened the retrieved articles by reading the title and abstract to identify studies that addressed potential mechanisms determining RA activity in pregnancy. Articles were further refined after reading the full text. A data extraction sheet was developed for the purpose of this review and used by the independent reviewers.

RESULTS

After exclusion of irrelevant, duplicate and foreign language articles, a final total of 37 original articles were identified. The largest body of literature concerned glycosylation of immunoglobulins, with 9 published articles. There is evidence of an association between increasing levels of galactosylation of immunoglobulins and reduced RA disease activity in pregnancy. Other identified articles comprised 5 on cytokine changes in pregnancy, 5 on human leucocyte antigen (HLA) incompatibility, 5 on changes in peripheral blood mononuclear cell (PBMC) gene expression; 4 on changes in corticosteroids; 3 on pregnancy associated α2-glycoprotein; 2 on changes in rheumatoid factor (RF)/anti-citrullinated protein antibody (ACPA); and 1 each on microchimerism, gamma delta T cells, regulatory T cells, and mannose-binding lectin. The results of these studies were heterogenous and occasionally conflicting. Selected studies varied greatly in terms of population size, methodology and use of controls and disease activity assessments.

CONCLUSION

This systematic review has found that the cause of the pregnancy-induced amelioration of RA remains to be determined, despite extensive efforts. It is unclear which of the various transitory changes in pregnancy may be responsible for initiating downstream anti-inflammatory immunological mechanisms. We discuss limitations of the current literature and suggest areas for future study.

Intrauterine inhibition of chemokine receptor 4 signaling modulates local and systemic inflammation in ovine pregnancy

PROBLEM

Chemokines help coordinate inflammation within the fetal-maternal microenvironment during gestation. The chemokine CXCL12 signaling through its receptor CXCR4 regulates inflammatory activity, but this phenomenon is not well understood during pregnancy, and there are no reports exploring the role of this pair in peripheral immune tolerance during gestation. Herein, we hypothesize that intrauterine CXCL12-CXCR4 signaling governs local and systemic immunomodulatory dynamics during early gestation in ewes.

METHOD OF STUDY

Osmotic pumps were surgically installed for intrauterine infusion of a CXCR4 inhibitor, AMD3100, beginning on day 12 post-breeding in sheep. Endometrial tissues were collected on day 35 of gestation and evaluated for inflammatory potential, Akt pathway activation, and autophagy induction. Demonstrative of peripheral immune activity, levels of select cytokines were assessed in daily blood samples collected throughout the study, as well as in corpus luteum and spleen on day 35.

RESULTS

Anti-inflammatory IL10 was primarily localized to endometrial glandular epithelium with lower abundance when CXCR4 was antagonized. Inhibition of CXCR4 at the fetal-maternal interface resulted in less activation of Akt in endometrium, while evidence of autophagy induction was greater. Corpora lutea from ewes receiving intrauterine AMD3100 exhibited lower interferon-gamma (IFNG) expression. Blood inflammatory potential was differentially altered in a temporal fashion throughout infusion. IL10 abundance in spleen was greater following CXCR4 inhibition at the fetal-maternal interface, while IFNG was less.

CONCLUSION

Intrauterine CXCL12-CXCR4 signaling governs endometrial and systemic inflammation; disruption of this axis may have detrimental impacts on offspring and maternal health.

Lymphocytes in Placental Tissues: Immune Regulation and Translational Possibilities for Immunotherapy

Immune modulation at the fetomaternal interface is crucial to ensure that the fetal allograft is not rejected. In the present review, the focus is to describe basic functions of lymphocyte populations and how they may contribute to fetomaternal immune regulation, as well as determining what proportions and effector functions of these cells are reported to be present in placental tissues in humans. Also explored is the possibility that unique cell populations at the fetomaternal interface may be targets for adoptive cell therapy. Increasing the understanding of immune modulation during pregnancy can give valuable insight into other established fields such as allogeneic hematopoietic stem cell transplantation and solid organ transplantation. In these settings, lymphocytes are key components that contribute to inflammation and rejection of either patient or donor tissues following transplantation. In contrast, an allogeneic fetus eludes rejection by the maternal immune system.

Cytokine profile and maternal depression and anxiety symptoms in mid-pregnancy-the FinnBrain Birth Cohort Study

Maternal prenatal psychological symptoms are associated with child health outcomes, e.g., atopic diseases. Altered prenatal functioning of the immune system is a potential mechanism linking maternal symptoms with child health. Research on prenatal distress and cytokines is warranted. The study population comprised consecutive N = 139 women from a general population-based FinnBrain Birth Cohort Study. Standardized questionnaires for depressive, overall anxiety, and pregnancy-related anxiety symptoms were used. Serum concentrations of selected cytokines were analyzed using Multiplex bead arrays from samples drawn at the gestational week 24. The concentrations of T helper (Th)2-related interleukins (IL)-9 and IL-13 and Th1-related IL-12 correlated positively with prenatal depressive and overall anxiety symptom scores (p values, range 0.011-0.029). Higher interferon (IFN)-γ/IL-4 ratio (p = 0.039) and Th2-related IL-5 (p = 0.007) concentration correlated positively with depressive symptoms. Pregnancy-related anxiety score correlated positively with IL-12 (p = 0.041), IL-13 (p = 0.025), and anti-inflammatory IL-10 (p = 0.048) concentrations. IL-6 and TNF-α concentrations were unrelated to prenatal symptoms. As a novel finding, we observed positive correlations between concentrations of potentially proallergenic cytokines and maternal prenatal psychological symptoms. Different symptom measures may yield distinct cytokine responses. This provides hypotheses for studies on mechanisms bridging prenatal stress and child health.

Elispot assay detection of cytokine secretion in multiple sclerosis patients treated with interferon-b1a or glatiramer acetate compared with untreated patients

The mechanisms behind the beneficial effects of interferon-b1a (IFN-b1a) and glatiramer acetate (GA) in the treatment of multiple sclerosis (MS) are still uncertain. A ltered cytokine patterns have been suggested including inhibition of proinflammatory cytokines like interferon-g (IFN-g) and enhancement of anti-inflammato ry cytokines such as interleukin-4 (IL-4). Twenty-nine patients with MS (10 untreated, nine treated with IFN-b1a and 10 with GA) were investigated with elispot of peripheral blood mononuclear cells. Spontaneous and myelin induced (myelin basic protein (MBP), myelin oligodendro cyte glycoprotein (MO G)-14-39 and MO G 63-87) IFN-g, IL-4, IL-5 and IL-10 secretion was studied. We found a significant reduction of spontaneous IFN-g, IL-4 and IL-5, but no difference in IL-10 secreting cells in both groups of treated patients compared with the untreated patients. Myelin-specific responses showed a significant decrease of IFN-g and an increase of IL-5, but no change in IL-4 and IL-10 secreting cells in treated compared with untreated patients. Both treatment groups revealed similar cytokine secretion patterns except for a more pronounced decrease of both spontaneous and MO G 14-39 induced IL-4 secretion in the IFN-b1a treated group. Thus, immunological effects of IFN-b1a and G A were similar showing that disease promoting Th1 (IFN-g) cells were reduced while the potentially beneficial Th2 response (IL-4) was maintained.

Preterm birth and single nucleotide polymorphisms in cytokine genes

Preterm birth (PTB) is an important issue in neonates because of its complications as well as high morbidity and mortality. The prevalence of PTB is approximately 12-13% in USA and 5-9% in many other developed countries. China represents 7.8% (approximately one million) of 14.9 million babies born prematurely annually worldwide. The rate of PTB is still increasing. Both genetic susceptibility and environmental factors are the major causes of PTB. Inflammation is regarded as an enabling characteristic factor of PTB. The aim of this review is to summarize the current literatures to illustrate the role of single nucleotide polymorphisms (SNPs) of cytokine genes in PTB. These polymorphisms are different among different geographic regions and different races, thus different populations may have different risk factors of PTB. SNPs affect the ability to metabolize poisonous substances and determine inflammation susceptibility, which in turn has an influence on reproduction-related risks and on delivery outcomes after exposure to environmental toxicants and pathogenic organisms.

Primary Sjögren syndrome presenting with hemolytic anemia and pure red cell aplasia following delivery due to Coombs-negative autoimmune hemolytic anemia and hemophagocytosis

A 36-year-old woman presented with hemolytic anemia without a reticulocyte response 38 days after delivery. A marked reduction in erythroid cells and an increase in macrophages with active hemophagocytosis were noted in the bone marrow. While conventional Coombs' tests were negative, the level of red blood cell (RBC)-bound immunoglobulin G (IgG) was increased. The patient was diagnosed with primary Sjögren syndrome (pSS) based on her symptoms, positive anti-SS-A antibodies, Coombs-negative autoimmune hemolytic anemia and pure red cell aplasia associated with RBC-bound IgG and hemophagocytosis. The unique presentation was considered to be a consequence of immunological derangement associated with pSS, pregnancy and delivery.

The Th1:th2 dichotomy of pregnancy and preterm labour

Pregnancy is a unique immunological state in which a balance of immune tolerance and suppression is needed to protect the fetus without compromising the mother. It has long been established that a bias from the T helper 1 cytokine profile towards the T helper 2 profile contributes towards successful pregnancy maintenance. The majority of publications that report on aberrant Th1:Th2 balance focus on early pregnancy loss and preeclampsia. Over the last few decades, there has been an increased awareness of the role of infection and inflammation in preterm labour, and the search for new biomarkers to predict preterm labour continues. In this paper, we explore the evidence for an aberrant Th1:Th2 profile associated with preterm labour. We also consider the potential for its use in screening women at high risk of preterm labour and for prophylactic therapeutic measures for the prevention of preterm labour and associated neonatal adverse outcomes.

Changes in the Th1:Th2 cytokine bias in pregnancy and the effects of the anti-inflammatory cyclopentenone prostaglandin 15-deoxy-Δ(12,14)-prostaglandin J2

Pregnancy is a complex immunological state in which a bias towards T helper 2 (Th2) protects the fetus. Evidence suggests that proinflammatory cytokines increase the risk of poor neonatal outcome, independently of the direct effect of preterm labour. The anti-inflammatory prostaglandin 15-deoxy-Δ^12,14-Prostaglandin J₂ (15dPGJ₂) inhibits nuclear factor Kappa B (NF-κB) in amniocytes and myocytes in vitro and is a ligand for the chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) receptor. Here we examine the Th1:Th2 cytokine bias in pregnancy and whether 15dPGJ₂ could be used to inhibit the production of the proinflammatory cytokines through inhibition of NF-κB while simultaneously promoting Th2 interleukin 4 (IL-4) synthesis via CRTH2 in T helper cells. Peripheral blood mononuclear cells (PBMCs) from women at 28 weeks, term pre-labour, term labour as well as non-pregnant female controls were cultured with 15dPGJ₂ or vehicle control and stimulated with phorbol myristyl acetate (PMA)/ionomycin. The percentage of CD4⁺ cells producing interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) in response to PMA/ionomycin was significantly reduced in pregnancy. 15dPGJ₂ reduced IFN-γ and TNF-α production in stimulated T helper cells, but did not alter IL-4 production in CRTH2^+ve cells. 15dPGJ₂ also reduced phospho-p65 in stimulated PBMCs. In summary, 15dPGJ₂ suppresses the Th1 response of PBMCs during pregnancy and active labour whilst maintaining the Th2 response suggesting a therapeutic benefit in reducing neonatal morbidity in inflammation-induced PTL.

Regulatory T helper cells in pregnancy and their roles in systemic versus local immune tolerance

PROBLEM

During pregnancy, the maternal immune system needs to adapt in order not to reject the semi-allogenic fetus.

METHOD

In this review, we describe and discuss the role of regulatory T (Treg) cells in fetal tolerance.

RESULTS

Treg cells constitute a T helper lineage that is derived from thymus (natural Treg cells) or is induced in the periphery (induced Treg cells). Treg cells are enriched at the fetal-maternal interface, showing a suppressive phenotype. In contrast, Treg cells are not increased in the circulation of pregnant women, and the suppressive capacity is similar to that in non-pregnant women. However, aberrations in Treg frequencies and functions, both systemically and in the uterus, may be involved in the complications of pregnancy.

CONCLUSION

Treg cells seem to have distinguished roles locally versus systemically, based on their distribution and phenotype.

Interaction of pregnancy and autoimmune rheumatic disease

During pregnancy, the fetus represents a natural allograft that is not normally rejected. While the maternal immune system retains the ability to respond to foreign antigens, tolerance mechanisms are up-regulated to protect the fetus from immunologic attacks by the mother. The profound immunologic adaptations during and after pregnancy do influence maternal autoimmune rheumatic diseases in several ways. One is triggering the onset of a rheumatic disease in the post partum period, the other influencing disease activity of established rheumatic disease. The review will discuss the mechanisms of increased susceptibility of rheumatoid arthritis (RA) in the first year post partum with a specific emphasis on the role of fetal cells or antigens persisting in the maternal circulation (so called microchimerism). Furthermore, the different influences of pregnancy on established rheumatic diseases will be highlighted. A marked beneficial effect of pregnancy is observed on RA whereas several other rheumatic diseases as ankylosing spondylitis (AS) and systemic lupus erythematosus (SLE) show either no particular effect or an aggravation of symptoms during pregnancy. Differences emerging in regard to modulation of disease symptoms during pregnancy seem related to response to hormones, the type of cytokine profile and immune response prevailing as well as further downstream interactions of molecular pathways that are important in disease pathogenesis.

Modulation of in vivo and in vitro cytokine production over the course of pregnancy in allergic and non-allergic mothers

Cytokines secreted during pregnancy may influence immune development of the foetus. This study aimed to determine if maternal allergy alters patterns of systemic cytokine production throughout and after pregnancy. Maternal plasma cytokines and allergen-specific production of interleukin (IL)-10, IL-13 and interferon (IFN)-gamma were measured in allergic (n = 63) and non-allergic (n = 70) pregnant women who had a full set of sequential peripheral blood samples collected at 20-, 30-, 36-wk gestation and 6-wk post-partum. Maternal allergy was strictly defined by both allergen sensitization and doctor-diagnosed asthma, eczema or rhinitis. IL-13 responses to allergen were higher for allergic mothers at all time-points (20 wk: p < 0.001; 30 wk: p = 0.001; 36 wk: p < 0.001; post-partum: p < 0.001). For the non-allergic group, IL-13 levels to house dust mite decreased from 20- to 36-wk gestation (Friedman ANOVA p = 0.012) and were significantly lower at 36 wk compared with post-partum (p = 0.002). In contrast, IL-13 production by allergic mothers did not change from 20 wk through to post-partum. For both allergic and non-allergic mothers, in vitro IFN-gamma production was lower at all pregnancy time-points compared with post-partum levels. Allergic women had an increased propensity for peripheral blood allergen-specific T helper-2 responses during pregnancy, and failed to downregulate these responses in comparison with non-allergic women. This may be a factor that contributes to the increased risk of atopy in infants born to allergic mothers.

[Hemophagocytic syndrome as primary manifestation in a patient with systemic lupus erythematosus after parturition]

A 33-year-old woman presented with fever, malar rash, lymphadenopathy and pancytopenia 3 weeks after parturition. Serum C3 level was decreased and antinuclear antibody, anti-dsDNA antibody and anti-SS-A antibody were positive. Serum ferritin level was elevated (3454 ng/ml), and bone marrow aspirate revealed hemophagocytosis. She was diagnosed having systemic lupus erythematosus (SLE) associated with hemophagocytic syndrome (HPS). Oral prednisolone (55 mg/day) was initiated. Clinical manifestations and pancytopenia were improved and serum ferritin level was decreased. However, elevated anti-dsDNA antibody titer and reduced C3 level continued for a month after steroid therapy. The additional therapy of tacrolimus (3 mg/day) improved clinical and laboratory findings. This is a rare SLE case associated with HPS as primary manifestation after parturition.

Total and allergen-specific IgE levels during and after pregnancy in relation to maternal allergy

Type 2 T-helper cell (Th2)-skewed immunity is associated with successful pregnancy and the ability to easily direct immune responses to a Th2-polarised profile may be an evolutionary benefit. The Th2-like immunity associated with allergic disease might generate favourable effects for the maintenance of pregnancy, but could also promote development of Th2-like immune responses and allergic disease in the offspring. The aim of this study was to explore, by using IgE as a stable proxy for Th2, the Th1/Th2 balance in allergic and non-allergic women by measuring allergen-specific and total IgE antibody levels in plasma during pregnancy and after delivery. Specific and total IgE antibody levels were determined by ImmunoCAP technology at five occasions during pregnancy (gestational weeks 10-12, 15-16, 25, 35 and 39), as well as at 2 and 12 months after delivery. Thirty-six women without and 20 women with allergic symptoms were included, of whom 13 were sensitised with allergic symptoms and 30 were non-sensitised without allergic symptoms. The levels of total IgE, but not allergen-specific IgE, were increased during early pregnancy when compared to 12 months after delivery in the sensitised women with allergic symptoms, but not in the non-sensitised women without allergic symptoms (p<0.01). This increase in total IgE levels during early pregnancy only in the sensitised women with allergic symptoms indicates that allergy is associated with an enhanced Th2 deviation during pregnancy.

Gestational effects on host inflammatory response in normal and pre-eclamptic pregnancies

OBJECTIVE

Pre-eclampsia (PET) remains a leading cause of maternal and neonatal morbidity and mortality. Although its pathophysiology involves an underlying inflammatory dysfunction, it is unclear how this may be affected by increasing gestational age, particularly in relation to the time of onset of disease. Murine studies have indicated that a progressive increase in serum inflammatory profile is a physiological feature of normal gestation. The present study aimed to investigate this phenomenon in women in relation to normal and pre-eclamptic pregnancies.

STUDY DESIGN

Control and PET groups (each n=20) were divided into early and late pregnancy (before and after 34 weeks gestation, respectively). Whole blood was diluted 1:1 with RPMI 1640 medium with/without 1 microg/ml lipopolysaccharide at 37 degrees C for 24 h under a humidified 5% CO(2) atmosphere. Samples were collected at 0, 2, 6 and 24 h and analysed for interleukin (IL)-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p70), IL-13, IL-17, granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage-colony stimulating factor (GM-CSF), interferon (IFN)-gamma, monocyte chemotactic protein (MCP-1), macrophage inflammatory protein (MIP)-1beta and tumour necrosis factor (TNF)-alpha by fluid-phase multiplex immunoassay.

RESULTS

This study confirms that pregnancy features an increasing inflammatory response with advancing gestational age, which was seen in both control and PET pregnancies (P<0.01).

CONCLUSIONS

This increase in inflammatory responsiveness with advancing gestation may provide an explanation for the incidence of late onset PET in the absence of placental pathology, as well as serving as a potential physiological priming mechanism geared towards increasing maternal sensitivity to the fetal triggers of labour.

Regulation of maternal serum and amniotic fluid cytokine profiles in the mouse: Possible roles in the onset of labour

Murine pregnancy is characterised by marked increases in serum cytokine profiles with advancing gestation, but whether these changes reflect concentrations in amniotic fluid is unknown. This study therefore profiled 23 cytokines by fluid-phase multiplex immunoassay of amniotic fluid and serum collected from naturally mated mice during mid- and late pregnancy (days 11 and 18, respectively). The marked increase in serum profile of many cytokines from days 11 to 18 was not reflected in amniotic fluid, wherein most cytokine concentrations were lower on day 18. Serum and amniotic fluid cytokine concentrations were largely inversely related, indicating separate, localised regulatory mechanisms geared towards the maintenance of pregnancy, modulation of immune effector cell function and optimisation of fetal development. We suggest that, while maternal systemic inflammatory priming prepares the mother for birth, the amniotic compartment exhibits a tightly regulated inflammatory quiescence. These findings are discussed in relation to the onset of labour, which ultimately results in the elevated cytokine amniotic levels traditionally associated with the final stages of pregnancy.

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.

The remission of rheumatoid arthritis during pregnancy

Rheumatoid arthritis (RA) is an autoimmune disease that is favorably influenced by pregnancy but relapses after delivery. A variety of circulating factors has been considered as candidates for inducing gestational improvement of RA; however, the factors/pathways responsible remain still elusive. This review discusses recent research on the effect of pregnancy on RA with a focus on immunregulation, cytokine secretion, HLA antigens, microchimerism, and innate immunity. The complex hormonal and immunological alterations of pregnancy may temporarily correct the disturbed immunregulation of RA.

CD4+ CD25+ regulatory T cells in human pregnancy: development of a Treg-MLC-ELISPOT suppression assay and indications of paternal specific Tregs

The current study was aimed at developing a one-way mixed leucocyte culture-enzyme-linked immunospot (MLC-ELISPOT) assay for the study of CD4(+) CD25(+) regulatory T (T(reg)) cells and applying this method in the study of antifetal immune reactions during human pregnancy. Twenty-one pregnant women and the corresponding fathers-to-be, and 10 non-pregnant control women and men, participated in the study. CD4(+) CD25(+) cells were isolated from peripheral blood mononuclear cells (PBMC) by immunomagnetic selection. Maternal/control PBMC were stimulated with paternal or unrelated PBMC in MLC. Secretion of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) from responder cells, with or without the presence of autologous T(reg) cells, was analysed by ELISPOT. PBMC from pregnant women showed increased secretion of IL-4 compared to controls. In pregnant and non-pregnant controls, T(reg) cells suppressed IFN-gamma reactivity against paternal and unrelated alloantigens. Interestingly, T(reg) cells suppressed IL-4 secretion against paternal but not unrelated alloantigens during pregnancy. We have successfully developed a model for studying T(reg) cells in antifetal cytokine reactions during pregnancy. Results indicate that T(reg) cells contribute to strict regulation of both T helper type 1-like and type 2-like antifetal immune reactions. Interestingly, T helper type 2-like cells specific to unrelated alloantigens are able to escape the suppression of T(reg) cells, which would allow for IL-4, alongside CD4(+) CD25(+) T(reg) cells, to control potentially detrimental IFN-gamma reactions during pregnancy.

Increased Th1/Th2 (IFN-gamma/IL-4) Cytokine mRNA ratio of rat embryos in the pregnant mouse uterus

Somatic cell nuclei can be dedifferentiated in ooplasm from another species, and interspecies cloned embryos can be implanted into the uteri of surrogates. However, no full pregnancies have been achieved through interspecific mammalian cloning. Rat blastocysts transferred into mouse uteri provide a unique model for studying the causes of interspecific pregnancy failure. In this study, intraspecific pregnancy (mouse-mouse) and interspecific pregnancy (rat-mouse) models were established. On Day 9 of pregnancy, the fetoplacental units were separated from the uterine implantation sites and the expression of messenger (m)RNA was quantitated by real-time PCR. We compared the mRNA expression levels of type-1 T helper (Th1) and type-2 T helper (Th2) cytokines, interferon-gamma (IFN-gamma), and interleukin-4 (IL-4) in fetoplacental units between intraspecific and interspecific pregnancy groups. The mRNA expression of IFN-gamma in the fetoplacental units of the interspecific pregnancy group was significantly higher than that of the intraspecific pregnancy group (P<0.05). The mRNA expression of IL-4 in the interspecific pregnancy group was significantly lower than that in the intraspecific pregnancy group (P<0.05). We also analyzed the ratio of IFN-gamma/IL-4 mRNA, and an increased IFN-gamma/IL-4 mRNA ratio was observed in the interspecific pregnancy compared with that in the intraspecific pregnancy group. The IFN-gamma and IL-4 mRNA expressions indicate that there is a Th1/Th2 imbalance in the feto-maternal interface of interspecific pregnancies. Bias of Th1 cytokine dominance may be a barrier to reproductive success between species.

Adoptive Transfer of Paternal Antigen-Hyporesponsive T Cells Facilitates a Th2 Bias in Peripheral Lymphocytes and at Materno-Fetal Interface in Murine Abortion-prone Matings

PROBLEM

To investigate the Th1/Th2 cytokine changes in abortion-prone recipient mice adoptively transferred by the paternal antigen-hyporesponsive T cells.

METHOD OF STUDY

The paternal antigen-hyporesponsive T cells were generated by the anti-B7 monoclonal antibody (mAb) treatment and adoptively transferred into pregnant CBA/J mice of abortion-prone matings on day 4 of gestation. The intracellular expressions of Th1 cell-derived cytokine, tumor necrosis factor-alpha, gamma-interferon and interleukin-2 (IL-2) and Th2 cell-derived cytokine, IL-4 and IL-10 in the maternal spleen were analyzed by flow cytometry, and secretions of the Th1 and Th2 cytokines in supernatant of the feto-placental unit culture were analyzed by an enzyme-linked immunosorbent assay.

RESULTS

Our findings showed the increased secretion of Th1 cytokines and the decreased secretion of Th2 cytokines in abortion-prone matings. Treatment with anti-B7 mAbs on day 4 of gestation enhanced Th2 and reduced Th1 cytokine production in abortion-prone matings. Similarly, adoptive transfer of paternal antigen-hyporesponsive T cells induced maternal tolerance to the fetus and displayed a Th2 bias both in the peripheral lymphocytes and at the materno-fetal interface of the abortion-prone matings.

CONCLUSIONS

These findings indicate that the Th2 cytokine bias and an increase in fetal viability induced by the anti-B7 mAb treatment can be transferred to other pregnant mice of the abortion-prone matings.

Cytokines and Pregnancy in Rheumatic Disease

Cytokines are important mediators involved in the successful outcome of pregnancy. The concept of pregnancy as biased toward a Th2 immune response states that Th1 type cytokines are associated with pregnancy failure and that Th2 cytokines are protective and counteract pregnancy-related disorders. Studies at the level of the maternal-fetal interface, in the maternal circulation and in cells of peripheral blood have shown that the Th2 concept of pregnancy is an oversimplification. Both Th1 and Th2 type cytokines play a role at different stages of pregnancy and are adapted to the localization and function of cells and tissues. The changes of local and systemic cytokine patterns during pregnancy correspond to neuroendocrine changes with hormones as powerful modulators of cytokine expression. Several autoimmune disorders show a modulation of disease activity during and after pregnancy. In rheumatic diseases with a predominance of a Th1 immune response, a shift to a Th2 type immune response during pregnancy has been regarded as beneficial. Studies of pregnant patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) have shown a cytokine expression similar to that found in healthy pregnant women. Significant differences were present only for a few cytokines and seemed related to the activity of the underlying disease. Interestingly, a gestational increase of cytokine inhibitors interleukin 1 receptor antagonist (IL-1ra) and soluble tumor necrosis factor receptor (sTNFR) in the circulation corresponded to low disease activity in RA. The influence of hormones and cytokines on autoimmune disease is an issue for further study.

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".

Neospora caninum: Quantification of DNA in the blood of naturally infected aborted and pregnant cows using real-time PCR

This study quantified Neospora caninum DNA in the blood and brain of pregnant and aborted heifers by monitoring PCR product formation in real-time using SYBR Green I, a double-stranded DNA-binding dye. Primers were designed to amplify a 188 bp product specific to N. caninum from the Nc-5 gene fragment of N. caninum. Similarly, a 71 bp product was amplified from the 28S rRNA gene of bovine genomic DNA that served as a control. Agarose gel electrophoresis and analysis of the melting curve for PCR products showed that both primer pairs were specific to their targets. Standard curves were generated for both bovine and N. caninum genomic DNA, and were used to compute the relative concentration of parasite to bovine DNA in the test samples. The concentration of N. caninum DNA in 1 ng of bovine genomic DNA obtained from blood ranged between 0.097 ng at the 1st week of the observation and 0 ng at the 15th week in aborted cows. In pregnant cows, the values ranged between 0.080 ng at the 1st week and 0.155 ng at the 15th week of observation. There was a sustained decrease of DNA concentration in the aborted group after abortion and an increase in DNA concentration in the pregnant group. Comparison of parasite DNA in blood and brain of infected heifers showed a higher DNA concentration in brain than in blood. This study shows that N. caninum DNA can be quantified to obtain the relative concentration of parasite DNA to host genomic DNA in blood. This technique allows testing of a large number of samples at one time and can be done without the need for slaughter of tested animals.

Effect of cryopreservation on expression of Th1 and Th2 cytokines in blood mononuclear cells from patients with different cytokine profiles, analysed with three common assays: an overall decrease of interleukin-4

Studies on cytokine expression in blood cells are commonly performed on cryopreserved cells. Previous studies show that cryopreservation affects cytokine expression, but the findings are not consistent. This may be due to divergent effects of freezing on different cytokines, different stimuli, and different patient groups or to the use of different assays in the studies. This study was designed to investigate the effect of freezing on spontaneous, auto-antigen, allergen, and mitogen induced cytokine secretion from peripheral blood mononuclear cells from several groups of patients expressing different cytokine profiles; multiple sclerosis, atopic children, non-atopic children, and pregnant women. The expression of IFN-gamma, IL-4, IL-5, IL-9, IL-10, and IL-13 was analysed with ELISA, ELISPOT and/or real time RT-PCR. Our data provide evidence that the process of cryopreservation and thawing does affect the expression of cytokines, both at the protein and the mRNA level. Moreover, the effect varied among different cytokines, different stimuli, and different patient groups, which partly may be explained by differences in optimal freezing conditions for non-activated and activated cells. An increase of allergen and PHA stimulated IFN-gamma secretion in atopic children was found following cryopreservation, but no such increase in auto-antigen induced IFN-gamma was seen in MS-patients. The most consistent finding was that expression of IL-4 was generally decreased in spontaneous and auto-antigen/allergen induced expression in cryopreserved cells. In conclusion, this study points out the importance of investigation of the effects of freezing for each cytokine, stimuli and patient group before using frozen cells in studies of in vitro cytokine secretion.

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.

Expression of IL-4, IL-8 and IL-18 messenger RNAs in maternal peripheral blood and relationships with the HbF-gamma chain mRNA in it

PROBLEM

This study was designed to examine immunological changes in maternal peripheral blood and the relationship of these changes with the amount of fetal cells in the blood.

METHOD OF STUDY

The expression of interleukin-4 (IL-4), IL-8, IL-18 and fetal hemoglobin gamma chain (HbF-gamma chain) messenger RNAs (mRNAs) in maternal peripheral blood was measured by a quantitative reverse transcription-polymerase chain reaction method.

RESULTS

In maternal peripheral blood, the expression of IL-4 mRNA was up-regulated from the second gestational month (GM) to delivery. The expression of IL-8 and IL-18 mRNAs was down-regulated from the third or fourth GM until the eighth or ninth GM, respectively, and both increased before the onset of labor, though IL-4 mRNA decreased. The expression of IL-8 and IL-18, but not IL-4, mRNAs was correlated with that of HbF-gamma chain mRNA.

CONCLUSIONS

Immunological interactions between maternal peripheral immune cells and fetal cells appear to be related to the onset of labor.

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.

Expression of nuclear factor of activated T cells mRNA in maternal peripheral blood cells

PROBLEM

In T lymphocytes, nuclear factor of activated T cells (NF-AT) regulates the induction of cytokine genes upon antigenic stimulation. This study was designed to analyse the relationship between NF-AT and pregnancy.

METHOD OF STUDY

With informed consent, peripheral blood cells (PBCs) were obtained from non-pregnant (n = 114), pregnant (n = 604), and puerperal women (n = 52). The expression of NF-AT2 and NF-AT3 mRNAs in PBCs was measured by a quantitative reverse transcriptase-polymerase chain reaction method.

RESULTS

In the early pregnancy period, in successful pregnancy, both NF-AT2 and NF-AT3 mRNAs increased significantly, whereas in cases of spontaneous abortion they did not change significantly. After peaking, they decreased gradually and were re-elevated in the ninth and tenth gestational month. In the puerperal period, NF-AT3 mRNAs decreased, but NF-AT2 mRNA showed a comparatively high expression level.

CONCLUSION

These findings suggested that in humans NF-AT signal transduction might be involved in alloantigenic recognition and tolerance and play important roles, especially in the early and late period of pregnancy.

Interleukin-13 and tumor necrosis factor-beta differentially regulate the production of cytokines by cultured human endometrial stromal cells

OBJECTIVE

To evaluate the effects of interleukin (IL)-13, a T-helper (Th)2 cytokine, and tumor necrosis factor (TNF)-beta, a Th1 cytokine, on the production of IL-6 family cytokines and chemokines by endometrial stromal cells (ESC).

DESIGN

The effects of IL-13 and TNF-beta, on the production of IL-6, IL-11, leukemia inhibitory factor (LIF), IL-8, growth-regulated oncogene alpha (GROalpha), monocyte chemoattractant protein-1 (MCP-1), regulated on activation, T-cell expressed and secreted (RANTES), and eotaxin were investigated.

SETTING

Research laboratory at a medical university.

PATIENT(S)

Thirteen endometrial specimens in the late proliferative phase were used.

INTERVENTION(S)

The ESC were incubated for 24 hours with recombinant human IL-13 and recombinant human TNF-beta.

MAIN OUTCOME MEASURE(S)

The concentration of IL-6, IL-11, LIF, IL-8, GROalpha, MCP-1, RANTES, and eotaxin in the culture media was measured using ELISA.

RESULT(S)

The increase in levels of IL-6, IL-8, MCP-1, and eotaxin in the culture media of ESC paralleled the addition of increasing amounts of IL-13 and TNF-beta, whereas the levels of IL-11 and LIF were decreased with increasing amounts of IL-13, but were increased with increasing amounts of TNF-beta. Tumor necrosis factor-beta enhanced the production of GROalpha and RANTES in dose-dependent manner; however, IL-13 did not affect the expression of GROalpha or RANTES.

CONCLUSION(S)

These results suggest that IL-13 and TNF-beta secreted in the cyclic endometrial tissue and in the decidua may differentially regulate the production of IL-6 family cytokines and chemokines by ESC. The controlled expression of these cytokines in the endometrium may contribute to the modulation of the immune reaction during the menstrual cycle and in early pregnancy by the regulation of leukocyte trafficking and functions.

Soluble HLA-DR levels in the maternal circulation of normal and pathologic pregnancy

OBJECTIVE

The purpose of this study was to determine that circulating HLA-DR molecules are important candidates for the monitoring of maternal immunostimulation and immunosuppression.

STUDY DESIGN

Concentrations of soluble HLA-DR molecules were estimated in EDTA plasma samples of 61 nonpregnant women, 123 healthy pregnant women in the second trimester, 66 healthy women who were delivered at term, and 136 women who were delivered because of complications such as uncontrollable preterm intrauterine activation, abruptio placentae, intrauterine growth retardation, preeclampsia, and HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome.

RESULTS

In comparison to nonpregnant women, the normal course of pregnancy was associated with strongly increasing levels of soluble HLA-DR from second trimester on until term. In comparison to women who were delivered preterm because of uncontrollable intrauterine activation, increased soluble HLA-DR concentrations were detected in case of HELLP syndrome (P <.05), although decreased levels were detected in the case of intrauterine growth retardation, preeclampsia (P <.01), and abruptio placentae (P <.01).

CONCLUSION

Dysregulation of the maternal immune response to pregnancy may play an important role in the cause of complicated pregnancies.

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.

Non-MHC driven exacerbation of experimental thyroiditis in the postpartum period

Many human autoimmune diseases, including those of the thyroid gland, are affected by immune changes during pregnancy and the postpartum period. To investigate this influence, we have developed an animal model of pregnancy thyroiditis by using thyroglobulin (Tg)-induced experimental autoimmune thyroiditis (EAT). We now report a study of the post-partum period in mice with EAT. At 5 weeks postpartum, which was 9 weeks after the completion of a Tg immunization regime, the mean thyroiditis grade was significantly increased in the postpartum group from 0.23 to 0.43 (p<0.05) and the thyroiditis Index, which reflected both the frequency and severity of thyroiditis, was similarly increased compared to controls (29.0 vs 9.0). When Tg immunized CBA/J (H-2k) female mice were mated with BALB/c (H-2d) males, there was a similar increase in the severity of thyroiditis in the postpartum period as seen with CBA/J males suggesting that allogeneic factors were not able to further this postpartum exacerbation. Spleen cell IL-4 secretion was enhanced in the postpartum but only in the presence of thyroiditis indicating enhanced activity of Th2 immune responses. There were no differences in IFN-gamma secretion, titers of anti-Tg, CD8+ & CD4+ T cells and T cell chemokine receptor (CCR5, CCR3) expression between non-pregnant control mice with thyroiditis and postpartum thyroiditis. In summary, we found that the severity of EAT during the postpartum was significantly greater than in non-pregnant control mice and was associated with enhanced Th2 immune responses. The allogenicity of the pregnancy had no influence on these findings. The lack of allogenic impact was in contrast to earlier observations in pregnancy itself where an exacerbation of thyroiditis was male strain-dependent and involved primarily Th1 responses. This indicated that the postpartum exacerbation of autoimmune thyroid disease was not a simple response to fetal antigens but secondary to unique postpartum factors.

Cytokine production in natural killer cells and lymphocytes in pregnant women compared with women in the follicular phase of the ovarian cycle

OBJECTIVE

To test whether peripheral natural killer (NK) cells, helper T cells, and cytotoxic lymphocytes of pregnant women shift from a type 1 cytokine production toward a type 2 cytokine production as compared with these cells in women in the follicular phase.

DESIGN

Prospective study.

SETTING

Outpatient clinic.

PATIENT(S)

Healthy nullipara at 30 weeks' amenorrhea and healthy nonpregnant women in their follicular phase.

INTERVENTION(S)

Samples of whole blood were stimulated with phorbol myristate acetate (PMA; Sigma Chemical Co., St. Louis, MO) and Ca-ionophore in the presence of monensin (Sigma). Lymphocytes were stained with alpha-CD3, alpha-CD8, and alpha-interferon gamma (IFN-gamma) alpha-interleukin 2 (IL-2), IL-4, or IL-10. Analysis was performed by flow cytometry. Statistical evaluation was done with the Mann-Whitney U test.

MAIN OUTCOME MEASURE(S)

Percentage NK cells, helper lymphocytes, and cytotoxic lymphocytes that were producing IFN-gamma, IL-2, IL-4, or IL-10.

RESULT(S)

There is a statistically significant decrease in the percentage of NK cells, and helper and cytotoxic lymphocytes that produced IFN-gamma in pregnant women when compared with women in the follicular phase. There is also a statistically significant decrease in the percentage of helper lymphocytes producing IL-2 in pregnant women compared with nonpregnant women.

CONCLUSION(S)

We found a decrease in type 1 cytokine production with no change in type 2 cytokine production after in vitro stimulation of "pregnant" NK cells and lymphocytes as compared with "nonpregnant" NK cells and lymphocytes. We suggest that NK cell and lymphocyte response are shifted away from a type 1 immune response during pregnancy.

Immunology of pregnancy-pregnancy as a remission inducing agent in rheumatoid arthritis

A variety of hormonal and immunological alterations are induced by pregnancy in order to protect the semi-allogeneic fetus from rejection. Systemic effects of altered immunoregulation induced by pregnancy influence the activity of rheumatoid arthritis (RA) and other autoimmune diseases. Pregnancy induces improvement or even remission of disease activity in 75% of RA patients. This phenomenon has still not been explained, however, several attractive hypotheses related to the immunology of pregnancy emerge. Pregnancy polarizes the immune response towards a TH2 response, which may counterbalance the augmented TH1 response observed in RA. The increase of circulating inhibitors of proinflammatory cytokines occurring in pregnancy could act as a potent anti-inflammatory agent in joint inflammation. In what way the induction of T cell tolerance to fetal antigens or maternal-fetal HLA disparity modulates disease activity of RA has not been studied. The concept of regulatory T cells has been discussed in the context of pregnancy, but until now has not been substantiated by experimental data. In conclusion, pregnancy influences the signs and symptoms of RA, but not the underlying autoimmune process. It remains to be investigated if a single event like neutralisation of proinflammatory cytokines or an interplay between circulating and cellular mechanisms is the key to remission.