Indications of an altered immune balance in preeclampsia: A decrease in in vitro secretion of IL-5 and IL-10 from blood mononuclear cells and in blood basophil counts compared with normal pregnancy

Systemic inflammatory regulators and preeclampsia: a two-sample bidirectional Mendelian randomization study

Background

Systemic inflammatory regulators have been associated with preeclampsia (PE) during pregnancy; however, there is inconsistent evidence from animal models and observational results.

Methods

Using summary data from genome-wide association studies (GWASs), we performed a bidirectional Mendelian randomization (MR) analysis of two samples of systemic inflammatory regulators (n = 8,186) and PE (n = 267,242) individuals of European ancestry. As our primary analysis, we used the random-effects inverse-variance weighted (IVW) approach. Sensitivity and pleiotropy analyses were conducted using the MR-Egger method, weighted median, MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO), and Cochran's Q test.

Results

The results indicate that there is a correlation between a higher circulating level of tumor necrosis factor alpha (TNF-α) and interleukin-9 (IL-9) and an increased risk of PE (odds ratio [OR] = 1.32, 95% confidence interval [CI] = 1.09-1.60, p = 0.004 and OR = 1.28, 95% CI: 1.02-1.62, p = 0.033, respectively). Conversely, lower levels of stem cell growth factor beta (SCGF-β) (OR = 0.89, 95% CI: 0.80-0.99, p = 0.027) and interleukin-5 (IL-5) (OR = 0.80, 95% CI: 0.65-0.98, p = 0.030) are linked to an increased risk of PE. The macrophage migration inhibitory factor (MIF) is the downstream inflammatory regulator of PE, according to reverse magnetic resonance imaging studies.

Conclusion

Our study suggests that SCGF-β, IL-5, IL-9, and TNF-α causally affect the PE risk, while PE is causally associated with MIF. Further studies are needed to validate these biomarkers in managing PE.

Association of IL-27 gene rs153109 and rs17855750 polymorphisms with preeclampsia susceptibility and severity: Meta-analysis and trial sequential analysis

BACKGROUND

The aim of this meta-analysis is to evaluate the association of interleukin-27 gene rs153109 and rs17855750 polymorphisms with preeclampsia susceptibility and severity.

METHODS

Web of Science, PubMed, Embase, CBM, WanFang Data, CNKI, and VIP database were used for retrieving. After screening with our inclusion and exclusion criteria, data extraction and quantity evaluation were performed by 2 independent authors. Included case-control studies were used for meta-analysis by RevMan 5.4, and sensitivity analysis was carried out through 1-by-1 exclusion procedure. If heterogeneity exists, then random effects model was used; otherwise, fixed effect model was used. Publication bias analysis was performed using Begg test and Egger test. Trial sequential analysis was performed using trial sequential analysis 0.9.5.10 Beta.

RESULTS

A total of 5 articles were included. The heterogeneity was high across most models during the meta-analysis. Meta-analysis results related to preeclampsia susceptibility showed that P values of all the models were higher than .05, while for meta-analysis results related to preeclampsia severity showed that P values of all the models were higher than .05 except for TT versus TG + GG and TT versus TG models of rs17855750 group. The sensitivity of the meta-analysis was high, and trial sequential analysis showed the possibility of false negative results. No obvious publication bias was found.

CONCLUSIONS

There is no obvious association between interleukin-27 gene rs153109 and rs17855750 polymorphisms and preeclampsia susceptibility or severity. However, more multi-center and large sample case-control studies are expected to be carried out to verify our conclusion in the future.

The value of eosinophil count in the diagnosis of preeclampsia among pregnant women attending the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia, 2021

BACKGROUND

Currently, studies showed that eosinophil count had clinical significance in the diagnosis and prognosis of diseases. But, the clinical significance of eosinophil count in pregnancy specifically in preeclampsia (PE) is not well studied. The main objective of the present study was to assess the diagnosis value of eosinophils counts among pregnant women with PE.

METHODS

A comparative cross-sectional study was conducted on a total of 126 pregnant women at the University of Gondar Comprehensive Specialized Hospital, using a convenient sampling technique. Socio-demographic and clinical data were collected by questionnaire and datasheet from patient's charts, respectively. A total of six ml of blood was collected from each study participant; three ml for complete cell count analysis using Sysmex XS-500i hematology analyzer and three ml for liver function tests using Humastar 200 chemistry analyzer. The data were entered into Epi-data and exported to SPSS 20 for analysis. The independent t-test was used for normally distributed data and, the Mann-Whitney U test was used for non-normally distributed data. Binary logistic regression and receiver operative curve analyses were also done to assess the diagnosis value of eosinophils count. P-value < 0.05 was considered statistically significant.

RESULTS

The eosinophils count of PE pregnant women were significantly lower than the normotensive (NT) pregnant women (median (IQR): 50 (10-200) vs. 120 (60 - 270); (p = 0.002). The eosinophil count ≤ 55 cells/µL had an AUC of 0.66 (95% CI; 0.56-0.75) for diagnosis of PE with a sensitivity of 50.8%, specificity of 77.8%, and positive and negative predictive value of 69.6% and 61.3%, respectively. The abnormal AST and ALT results were significantly higher among PE pregnant women compared to NT pregnant women (AOR: 14.86; 95% CI: 4.97-44.4 and Fischer exact test p-value = 0.001, respectively).

CONCLUSION

The eosinophil count ≤ 55cells/µl had a reasonable/acceptable AUC which may use in the diagnosis of PE. AST and ALT were also significantly higher in PE pregnant women compared to NT pregnant women. Multicenter longitudinal studies with a large sample size are recommended to verify the role of eosinophil count in the diagnosis of PE.

Parity status and the relationship between antenatal rubella serology with obstetric outcome

Routine antenatal rubella serological testing is adopted in many countries. In a population covered by universal childhood rubella immunization for four decades, we have observed an association between pre-eclampsia with maternal rubella seronegativity among multiparous gravidae. This retrospective cohort study was further performed to elucidate the interaction between parity status and rubella seronegativity on obstetric outcome in singleton pregnancies carried to ≥ 24 weeks gestation managed from 1997 to 2019, with the data retrieved from a computerized database used for annual statistics and auditing. Of the 133,926 singleton pregnancies eligible for the study, the 13,320 (9.9%) rubella seronegative gravidae had higher mean booking weight and body mass index (BMI), but shorter height, and higher incidence of advanced age (≥ 35 years), high BMI, short stature, and lower incidence of nulliparas. Univariate analysis showed that adverse obstetric outcomes were more frequently found among the multiparas. On multivariate analysis, there was increased postdated (> 41 weeks) pregnancy irrespective of parity status, while nulliparas had reduced gestational hypertension (aRR 0.714, 95% CI 0.567-0.899) and gestational diabetes (aRR 0.850, 95% CI 0.762-0.950), and multiparas had increased pre-eclampsia (aRR 1.261, 95% CI 1.005-1.582), neonatal death (aRR 2.796, 95% CI 1.243-6.291), and perinatal death (aRR 2.123, 95% CI 1.257-3.587). In conclusion, in a population covered by universal childhood rubella immunization, antenatal rubella seronegativity is associated with increased pre-eclampsia and perinatal loss only in multiparas, suggesting that the rubella seronegativity in these women served as proxy for some form of altered immune response which increases adverse pregnancy outcome.

Differential expression of T helper cytokines in the liver during early pregnancy in sheep

Liver plays important roles in the innate and adaptive immunity, and contributes to the maternal immune adjustments during pregnancy in mice and rats. T helper 1 (Th1) and Th2 cytokines are related to immune response. However, expression of Th1 and Th2 cytokines in maternal livers is unclear during early pregnancy in sheep. In this study, livers were collected on day 16 of the estrous cycle and on days 13, 16 and 25 of pregnancy (n = 6 for each group) in ewes, and qRT-PCR, western blot and immunohistochemistry were used to analyze the expression of Th1 and Th2 cytokines in the livers. Our results showed that interferon-gamma (IFN-γ), interleukin (IL)-2, IL-4, IL-6 and IL-10 were downregulated, and IL-5 was upregulated in the livers during early pregnancy. Furthermore, there was no effect for early pregnancy on expression of TNF-β in the livers, and the IFN-γ protein was limited to the endothelial cells of the proper hepatic arteries and portal veins. In conclusion, early pregnancy exerted its effect on the liver to regulate the Th cytokines expression, but there was no evident shift from Th1 to Th2 cytokines, which may be necessary for the maternal hepatic immune adjustments during early pregnancy in sheep.

Modulation of Helper T Cytokines in Thymus during Early Pregnancy in Ewes

Simple Summary

The thymus is a main organ of the immune system. Immune tolerance exists in maternal immune system during pregnancy. Helper T (Th)1 and Th2 cytokines regulate the functions of immune system. We found that early pregnancy affected the production of Th1 and Th2 cytokines in maternal thymus in sheep, which may be beneficial for normal pregnancy.

Abstract

There is an immune tolerance in maternal immune system during pregnancy, and thymus is a main organ of the immune system. Helper T (Th)1 and Th2 cytokines are involved in the regulation of immune system, but the modulation of Th cytokines in the thymus during early pregnancy is unclear in ewes. Thymuses were collected on day 16 of the estrous cycle, and on days 13, 16, and 25 of pregnancy in ewes. qRT-PCR, Western blot, and immunohistochemistry were used to analyze the expression of Th1 and Th2 cytokines in the thymuses. There was a peak in the expression of interferon-gamma (IFN-γ) on day 16 of pregnancy, an upregulation of tumor necrosis factor beta (TNF-β), and a sustained expression of interleukin-2 (IL-2) and IL-4. Furthermore, there was a peak in the expression of IL-6 on day 13 of pregnancy, no expression of IL-6 on day 16 of the estrous cycle and day 25 of pregnancy, and an upregulation of IL-5 and IL-10 in the thymuses during early pregnancy. The immunohistochemistry results revealed that the IFN-γ and IL-6 proteins were limited to the stromal cells, capillaries, and thymic corpuscles. In conclusion, early pregnancy influenced the production of Th1 and Th2 cytokines of maternal thymus in sheep.

Comparison of Th1 and Th2 cytokines production in ovine lymph nodes during early pregnancy

As a fetal allograft to the mother, early conceptus regulates the intrauterine immune and systemic immune responses during early pregnancy in sheep. However, expression of T helper 1 (Th1) and Th2 cytokines in maternal lymph nodes is unclear during early pregnancy in sheep. In this study, inguinal lymph nodes were obtained on day 16 of the estrous cycle and on days 13, 16 and 25 of pregnancy (n = 4 for each group) in ewes, and qRT-PCR, western blot and immunohistochemistry were used to compare the expression of Th1 and Th2 cytokines in the lymph nodes. Our results showed that there were the highest levels of Th1 cytokines (IFN-γ, TNF-β and IL-2) and Th2 cytokines (IL-4, IL-5, IL-6 and IL-10) in the lymph nodes on day 13 or 16 of pregnancy. Furthermore, there were a downregulation of TNF-β and IL-2 and an upregulation of IL-5 and IL-10 on day 25 of pregnancy compared with that in nonpregnancy, with no significant difference in the expression of IFN-γ, IL-4, and IL-6 between the ewes on day 25 of pregnancy and nonpregnancy. The immunohistochemistry results showed that the IL-2 and IL-10 proteins were limited to the subcapsular sinus and trabeculae in the cortex, lymph sinus. In conclusion, early pregnancy exerted its effects on the lymph node and induced a Th2-biased response, which was essential for a normal pregnancy in sheep.

The role of interleukins in preeclampsia: A comprehensive review

Preeclampsia is a multi-system hypertensive disorder of pregnancy, with significant rates of maternal and neonatal morbidity. It represents a major cause of preterm birth, as definitive treatment demands fetal delivery. Although its pathophysiology is complicated, placental hypoxia and endothelial dysfunction constitute established pathogenetic steps of the disease. Inflammation is considered to be a crucial mediator of preeclampsia process, as an imbalance between T_H 1, T_H 2, and T_H 17 immune responses is observed. The present review accumulates current knowledge about the contribution of interleukins in preeclampsia, summarizing the pathways through which each interleukin exerts its function in the disease. Also, the role of genetic polymorphisms is explored and the predictive efficacy of maternal serum interleukin levels is evaluated. Finally, recommendations about the safe interpretation of the outcomes, as well as guidance for future research, are provided.

The Role of Interleukin-10 in the Pathophysiology of Preeclampsia

PURPOSE OF REVIEW

The pathophysiology of preeclampsia is complex and not entirely understood. A key feature in preeclampsia development is an immunological imbalance that shifts the maternal immune response from one of tolerance towards one promoting chronic inflammation and endothelial dysfunction. As a key regulator of immunity, IL-10 not only has immunomodulatory activity, but also directly benefits vasculature and promotes successful cellular interactions at the maternal-fetal interface. Here we focus on the mechanisms by which the dysregulation of IL-10 may contribute to the pathophysiology of preeclampsia.

RECENT FINDINGS

Dysregulation of IL-10 has been demonstrated in various animal models of preeclampsia. Decreased IL-10 production in both placenta and peripheral blood mononuclear cells has been reported in human studies, but with inconsistent results. The significance of IL-10 in preeclampsia has shifted from a key biomarker to one with therapeutic potential. As such, a better understanding of the role of this cytokine in the pathophysiology of preeclampsia is of paramount importance.

Multivariate analysis of cytokine profiles in pregnancy complications

PROBLEM

The immunoregulation to tolerate the semiallogeneic fetus during pregnancy includes a harmonious dynamic balance between anti- and pro-inflammatory cytokines. Several earlier studies reported significantly different levels and/or ratios of several cytokines in complicated pregnancy as compared to normal pregnancy. However, as cytokines operate in networks with potentially complex interactions, it is also interesting to compare groups with multi-cytokine data sets, with multivariate analysis. Such analysis will further examine how great the differences are, and which cytokines are more different than others.

METHODS

Various multivariate statistical tools, such as Cramer test, classification and regression trees, partial least squares regression figures, 2-dimensional Kolmogorov-Smirmov test, principal component analysis and gap statistic, were used to compare cytokine data of normal vs anomalous groups of different pregnancy complications.

RESULTS

Multivariate analysis assisted in examining if the groups were different, how strongly they differed, in what ways they differed and further reported evidence for subgroups in 1 group (pregnancy-induced hypertension), possibly indicating multiple causes for the complication.

CONCLUSION

This work contributes to a better understanding of cytokines interaction and may have important implications on targeting cytokine balance modulation or design of future medications or interventions that best direct management or prevention from an immunological approach.

Exposure to vitamin D from fortified margarine during fetal life and later risk of pre-eclampsia: the D-tect Study

OBJECTIVE

To examine if fetal exposure to a small dosage of extra vitamin D from food fortification was associated with a decrease in the risk of pre-eclampsia later in life.

DESIGN

Cancellation of the mandatory vitamin D fortification of margarine in 1985 created a societal experiment, with entire adjacent birth cohorts exposed or unexposed to extra vitamin D during fetal development. The Danish national medical health registries allowed the identification of pre-eclampsia cases later in life among all exposed and unexposed female individuals.

SETTING

Denmark.

SUBJECTS

Women born between June 1983 and August 1988, who gave birth to their first child at age 14·5-27·5 years (n 32 621).

RESULTS

OR (95 % CI) for pre-eclampsia among women exposed v. unexposed to extra vitamin D from fortification during fetal development was 0·86 (0·76, 0·97). Exposure to extra vitamin D was associated with further reduced odds of pre-eclampsia (0·49 (0·34, 0·72)) among current smokers, but not among former smokers and non-smokers.

CONCLUSIONS

Additional vitamin D in fetal life from food fortification seems to reduce the risk of pre-eclampsia later in life. The risk reduction may be particularly strong among women who smoke during pregnancy.

Maternal rubella immunity status and pre-eclampsia

PROBLEM

To determine if maternal immune maladaptation associated with pre-eclampsia is reflected in the rubella immunity status.

METHOD OF STUDY

Incidence of pre-eclampsia was compared between rubella non-immune and immune gravidae carrying a singleton pregnancy beyond 24 weeks, taking into account maternal characteristics and reported risk factors for pre-eclampsia.

RESULTS

The 9870 (10.4%) rubella non-immune gravidae among the 95 024 in the cohort exhibited no difference in incidence of underlying medical disorders, but they were slightly but significantly older, shorter, heavier, and had more pre-eclampsia (OR 1.24, 95% CI 1.05-1.47) despite having fewer nulliparas. Regression analysis confirmed an overall association between rubella non-immunity with pre-eclampsia (aOR 1.27, 95% CI 1.06-1.54), which was related to multiparas (aOR 1.42, 95% CI 1.05-1.91) and carrying a male fetus (aOR 1.37, 95% CI 1.06-1.78).

CONCLUSION

The association between rubella non-immunity and pre-eclampsia reflects immune maladaptation in multiparas and toward a male fetus.

Regulatory T-cells and preeclampsia: an overview of literature

Regulatory T-cells (Tregs) are key players in successful pregnancy and their deficiencies are implicated in pregnancy complications such as preeclampsia (PE), but the results are inconsistent among studies. This study aims to compile an overview of the studies about the associations of Tregs and PE risk and to provide recommendations for future research. A sensitive search of three databases including PubMed, Scopus and Google scholar (from 1995 to January 9, 2015) identified 636 unique titles. An accurate process of study selection, data extraction and method qualification were independently conducted by authors on retrieved papers. Seventeen papers met the inclusion criteria and were included in quality assessment. Regarding the source of Tregs, 14 studies assessed Tregs in peripheral blood, 2 studies in peripheral blood and decidua and one study in peripheral blood and umbilical cord blood. Despite variation in the combinations of markers and other aspects of the studies designs, remarkable constancy in the results of studies that measured Tregs as CD4+FoxP3+ or CD4+CD25+FoxP3+ cells (but not CD4+CD25(high/low)FoxP3+ markers) was found, which in broad terms showed a shift towards fewer Treg cells in PE. This review revealed an association between lower percentage of circulating CD4+FoxP3+ or CD4+CD25+FoxP3+ Tregs and the risk of PE. Given the above issue and regarding the high consistency of studies on reduction of suppressive activity of Tregs in PE, we have proposed a model in which the Tregs deficiency is a reflection of immune endocrine imbalance, which reverses maternal tolerance and results in development of preeclampsia.

Hypertension, preeclampsia and eclampsia among HIV-infected pregnant women from Latin America and Caribbean countries

OBJECTIVES

To evaluate the incidence of and risk factors for hypertensive disorders in a cohort of HIV-infected pregnant women.

METHODS

Hypertensive disorders (HD) including preeclampsia/eclampsia (PE/E) and pregnancy induced hypertension, and risk factors were evaluated in a cohort of HIV-infected pregnant women from Latin America and the Caribbean enrolled between 2002 and 2009. Only pregnant women enrolled for the first time in the study and delivered at ≥20 weeks gestation were analyzed.

RESULTS

HD were diagnosed in 73 (4.8%, 95% CI: 3.8%-6.0%) of 1513 patients; 35 (47.9%) had PE/E. HD was significantly increased among women with a gestational age-adjusted body mass index (gBMI) ≥25 kg/m(2) (OR = 3.1; 95% CI: 1.9-5.0), hemoglobin (Hg) ≥11 g/dL at delivery (OR = 2.1; 95% CI: 1.2-3.6) and age ≥35 years (OR = 1.8; 95% CI: 1.1-3.2). PE/E was increased among women with a gBMI ≥25 kg/m(2) (OR = 3.0; 95% CI: 1.5-6.0) and Hg ≥11 g/dL at delivery (OR = 2.8; 95% CI: 1.2-6.5). A previous history of PE/E increased the risk of PE/E 6.7 fold (95% CI: 1.8-25.5). HAART before conception was associated with PE/E (OR = 2.3; 95% CI: 1.1-4.9).

CONCLUSIONS

HIV-infected women, with a previous history of PE/E, a gBMI ≥25 kg/m(2), Hg at delivery ≥11 g/dL and in use of HAART before conception are at an increased risk of developing PE/E during pregnancy.

Disturbed sleep and inflammatory cytokines in depressed and nondepressed pregnant women: an exploratory analysis of pregnancy outcomes

OBJECTIVE

Disturbed sleep and depression are potential risk factors for pregnancy complications. Both conditions are known to dysregulate biological pathways responsible for maintaining homeostatic balance and pregnancy health. Depression during pregnancy is associated with poor sleep. Thus, we explored whether disturbed sleep was associated with inflammatory cytokines and risk for adverse pregnancy outcomes, as well as whether depression augmented the sleep-cytokine relationship, thereby additively contributing to risk for adverse outcomes.

METHODS

Interview-assessed sleep and plasma cytokine concentrations were evaluated in a cohort of depressed and nondepressed pregnant women (n = 168) at 20 and 30 weeks' gestation. Outcomes evaluated included preterm birth, birth weight, and peripartum events.

RESULTS

Among depressed women, short sleep duration (<7 hours) was associated with higher interleukin (IL)-8 across time (β = 0.506, p = .001), poor sleep efficiency (<85%) was associated with higher IL-6 (β = 0.205, p = .006), and daytime naps were associated with higher tumor necrosis factor α (β = 0.105, p = .024). Aspects of poor sleep were associated with having a lower weight baby (p values <.053). Among depressed women, interferon-γ increased risk for preterm birth (odds ratio = 1.175, p = .032). Trends for IL-6 and higher birth weight (β = 105.2, p = .085), interferon-γ and lower birth weight (β = -19.92, p < .069), and increased IL-8 and babies weighing less than 4000 grams (odds ratio = 0.72, p < .083) were observed.

CONCLUSIONS

Although speculative, disturbed sleep may disrupt normal immune processes and contribute to adverse pregnancy outcomes. Exploratory analyses indicate that depression modifies these relationships.

Inflammatory disturbances in preeclampsia: relationship between maternal and umbilical cord blood

Preeclampsia (PE) is one of the main causes of maternal and fetal mortality and morbidity. PE is associated with an inflammatory state and with oxidative stress, in maternal circulation. Our aim was to evaluate and compare the levels of oxidative stress and inflammatory markers in maternal and umbilical cord blood (UCB), in normal and PE pregnancies. We measured acute-phase proteins (CRP and α1-antitrypsin), proinflammatory cytokines (IL-6 and TNF-α), leukocyte activation (elastase, lactoferrin, sL-selectin, sVCAM, sPECAM), total antioxidant status (TAS), thiobarbituric acid reactive substances (TBARS), and uric acid levels. We studied 42 healthy pregnant women, 46 PE women, and their neonates. The concentrations of IL-6, TNF-α, α1-antitrypsin, CRP, sVCAM, uric acid, and TBARS were significantly higher, and sL-selectin was significantly lower in PE pregnant women as compared with normotensive pregnant women. In newborns uric acid, α1-antitrypsin, and CRP values were significantly higher in PE; leukocyte count, sL-selectin, lactoferrin, and the ratio elastase/α1-antitrypsin were significantly lower. Our data suggest that PE pregnancy is associated with an enhanced maternal inflammatory condition, which is reflected in fetal circulation. This enhanced inflammatory state seems to be related to endothelial dysfunction and increased cytokine synthesis, rather than with neutrophil activation.

The predictive value of leukocyte parameters for hypertensive disorders of pregnancy in south China

OBJECTIVE

To evaluate the predictive values of the leukocyte parameters for hypertensive disorders in pregnancy (HDP).

METHODS

A total of 523 HDP patients and 853 normal pregnancies were included in the present study. The leukocyte parameters in different stages of pregnancy were compared among the groups, and the efficiency of clinical diagnosis was calculated to analyze the predictive value of these parameters to HDP.

RESULTS

Women with HDP presented significantly higher leukocyte parameters in the second trimester and significantly lower values in the last trimester as compared to the normal gravidas. An evident increase of several parameters was observed preceding the clinical syndromes of HDP; and the odds ratio of increased neutrophil (NEU) and basophil (Baso) for predicting HDP were 1.02 and 1.16 (p < 0.01), respectively. The sensitivity of NEU was 71.95% when it was higher than 6.12 × 10(9)/L, and the specificity of Baso was 71.01% when it was higher than 0.053 × 10(9)/L for the prediction of HDP in 13-20 weeks.

CONCLUSION

The NEU and Baso are helpful for predicting HDP during the presymptom period.

Maternal serum soluble CD30 is increased in normal pregnancy, but decreased in preeclampsia and small for gestational age pregnancies

OBJECTIVE

Women with preeclampsia and those who deliver small for gestational age (SGA) neonates are characterized by intravascular inflammation (T helper 1 (Th1)-biased immune response). There is controversy about the T helper 2 (Th2) response in preeclampsia and SGA. CD30, a member of the tumor necrosis factor receptor superfamily, is preferentially expressed in vitro and in vivo by activated T cells producing Th2-type cytokines. Its soluble form (sCD30) has been proposed to be an index of Th2 immune response. The objective of this study was to determine whether the maternal serum concentration of sCD30 changes with normal pregnancy, as well as in mothers with preeclampsia and those who deliver SGA neonates.

METHODS

This cross-sectional study included patients in the following groups: (1) non-pregnant women (N = 49); (2) patients with a normal pregnancy (N = 89); (3) patients with preeclampsia (N = 100); and (4) patients who delivered an SGA neonate (N = 78). Maternal serum concentration of sCD30 was measured by a specific and sensitive enzyme-linked immunoassay. Non-parametric tests with post-hoc analysis were used for comparisons. A p value <0.05 was considered statistically significant.

RESULTS

(1) The median sCD30 serum concentration of pregnant women was significantly higher than that of non-pregnant women (median 29.7 U/mL, range 12.2-313.2 vs. median 23.2 U/mL, range 14.6-195.1, respectively; p = 0.01). (2) Patients with preeclampsia had a significantly lower median serum concentration of sCD30 than normal pregnant women (median 24.7 U/mL, range 7.6-71.2 vs. median 29.7 U/mL, range 12.2-313.2, respectively; p < 0.05). (3) Mothers with SGA neonates had a lower median concentration of sCD30 than normal pregnant women (median 23.4 U/mL, range 7.1-105.3 vs. median 29.7 U/mL, range 12.2-313.2, respectively; p < 0.05). (4) There was no significant correlation (r = -0.059, p = 0.5) between maternal serum sCD30 concentration and gestational age (19-38 weeks) in normal pregnant women.

CONCLUSIONS

(1) Patients with preeclampsia and those who deliver an SGA neonate had a significantly lower serum concentration of sCD30 than normal pregnant women. (2) This finding is consistent with the view that preeclampsia and SGA are associated with a polarized Th1 immune response and, perhaps, a reduced Th2 response.

The link between the epidemics of obesity and allergic diseases: does obesity induce decreased immune tolerance?

There is increasing epidemiological evidence that obesity increases the risk of asthma, atopic, and autoimmune diseases. We hypothesize that the increase in these diseases is caused, at least in part, by decreased immunological tolerance as a consequence of immunological changes induced by adipokines (e.g. leptin and adiponectin) and cytokines [e.g. interleukin 6 (IL6) and tumor necrosis factor alpha (TNFalpha)] secreted by white adipose tissue. The increasing body weight increases the levels of circulating IL6, leptin, and TNFalpha. IL6 and leptin down-regulate the activity of regulatory T-lymphocytes (Tregs). Additionally, adiponectin, which decreases with increasing obesity, down-regulates the secretion of IL10 from macrophages and adipocytes. These changes in IL6, leptin, and IL10 decrease the regulatory effect of Tregs resulting in decreased immunological tolerance to antigens. In pregnant women, these obesity-induced immunological changes might be transmitted to the fetus by epigenetic inheritance thereby increasing the risk of atopic disease. We propose that obesity results in immunological changes resulting in decreased immunological tolerance to antigens and skewing of the immune system towards a Th2 cytokine profile increasing the risk of allergy and other immune-mediated diseases. Furthermore, this hypothesis offers a unifying explanation for the observation that older siblings appear to confer protection against atopic diseases, preeclampsia, and certain autoimmune diseases. More studies are definitely needed to explore further the immunological effects of obesity and its possible effects on allergic disease.

Role of placentally produced inflammatory and regulatory cytokines in pregnancy and the etiology of preeclampsia

Human pregnancy is a metabolic and immune challenge for the mother who has to accommodate in her womb a semi-allogeneic fetus whose energy needs increase tremendously with gestation. Recent compelling research has suggested that proper inflammatory changes and oxidative balance are a requisite for successful pregnancy. The placenta is an integral component of this inflammatory response as it actively produces a variety of cytokines and immunomodulatory hormones. In preeclampsia, a life-threatening disorder of pregnancy that is characterized by widespread damage and dysfunction of the maternal endothelium, placental oxidative stress and aberrant cytokine expression induces an exaggerated maternal systemic inflammatory response to pregnancy.

The role of the immune system in preeclampsia

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

Inflammatory Changes in Preeclampsia: Current Understanding of the Maternal Innate and Adaptive Immune Response

Preeclampsia is characterized by generalized endothelial dysfunction as a result of an inappropriate maternal immune response against the fetus. It has been postulated that the adaptive immune system plays a key role in the etiology of preeclampsia by generating a pro-inflammatory Th1 type immune reaction. In this review, recent studies on Th1 and Th2 type cytokine mapping in preeclampsia are reviewed, as well as on the sources of pro-inflammatory cytokines and the role of regulatory cytokines and chemokines. In addition, we discuss the possible role of Toll-like receptors of the innate immune system in the pathophysiology of preeclampsia.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to summarize the newer concepts related to the pathogenesis of preeclampsia and explain the role of the maternal immune system and the role of pro-inflammatory and regulatory cytokines and chemokines in the pathophysiology of the disease.

Does paternal antigen-induced secretion of interleukin-10 by T regulatory cells mediate the birth order effect?

Childhood allergy constitutes a significant burden of disease in the Western world. The prevalence of this condition is highest in first born children, an as yet unresolved phenomenon called the "birth order effect". The hygiene hypothesis attempted to explain this differential risk by stating that less exposure to microbial agents at an early age of first born children would result in reduced activation of the immune system and subsequent polarization towards a Th2 phenotype. However, no conclusive evidence for or against the hygiene hypothesis has been found so far. Another, not necessarily conflicting, theory states that the birth order effect is already established during prenatal life and that the fetal-maternal interaction changes during successive pregnancies. Combining this theory with research on preeclampsia, another disease originating in pregnancy and also related to birth order, could suggest clues about the mechanisms underlying the birth order effect. Recent research on preeclampsia showed that preeclamptic women have higher levels of pro-inflammatory IL-6 and lower paternal antigen-induced secretion of IL-10 compared to normal pregnant women, indicating a lower number or lower functional activity of T regulatory (Treg) cells. These Treg cells play an important role in maintaining tolerance to fetal antigens in pregnancy and they are found in high numbers at the maternal-fetal interface. We hypothesize that nulliparous women have a lower activity of Treg cells specific to paternal antigens compared to parous women, either in peripheral blood or in the decidua (maternal part of the fetal-maternal interface). If this hypothesis is true, this would mean that the allergen suppressor mechanism of Treg cells is sub-optimal in first born children. This would explain at least a part of the mechanism of the birth order effect and would give us directions for developing preventive measures to prevent possibly 30% of future childhood allergies.

Antiretroviral therapy-associated modulation of Th1 and Th2 immune responses in HIV-infected pregnant women

A successful pregnancy is characterised by an increase in Th2 cytokines and suppression of Th1 cytokine production. A Th1 to Th2 cytokine shift is also observed in the disease progression of HIV infection. Highly active antiretroviral therapy (HAART) suppresses HIV viremia, increases CD4+ cell counts and counteracts the Th1 to Th2 shift. We hypothesised that the increased risk of premature delivery reported in HIV-infected, HAART-treated pregnant women is mediated through changes in the cytokine environment in pregnancy. Here, we present results relating to levels of interleukin (IL)-2 (Th1) and IL-10 (Th2) in peripheral blood mononuclear cells (PBMCs) measured three times during pregnancy in 49 HIV-infected women. Slope values representing the trend of repeated cytokine (IL-2-PHA, IL-2-Env, IL-10-PHA and IL-10-Env) measurements within women during pregnancy were estimated and median values compared by prematurity and HAART use. Multiple regression adjusted for HAART and cytokine slope clarified the additional and independent effect of HAART on prematurity risk. Results showed favourable immunomodulation induced by HAART with increased IL-2 and decreased IL-10. HAART use and IL-10-Env slopes were not significantly associated with prematurity risk, but each unit increase in IL-2-PHA slope was associated with an 8% increased risk of premature delivery (AOR, 1.08; 95% CI, 1.0-1.17; p=0.005). HAART use in pregnancy provides significant benefits in delaying HIV disease progression and reducing the risk of mother-to-child-transmission, but may be counterproductive in terms of successful pregnancy outcome.

Cytokine mapping of sera from women with preeclampsia and normal pregnancies

INTRODUCTION

Preeclampsia is a pregnancy-specific syndrome. The immune system in preeclampsia is changed with an increased innate activity and there is a hypothesis of a shift towards Th1-type immunity. The aim of this study was to determine a spectrum of soluble immunological factors denoting different aspects of immune activation in third trimester sera from women with preeclampsia (N=15) and compare with levels in sera from normal pregnant women (N=15).

MATERIAL AND METHODS

IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12 p40, IL-13, IL-15, IL-17, IFN-alpha, IFN-gamma, TNF-alpha, GM-CSF, MIP-lalpha, MIP-1beta, MCP-1, eotaxin and RANTES were measured in serum using multiplex bead arrays. The levels of soluble CD14 and soluble IL-4 receptor were measured by enzyme-linked immunoassay (ELISA).

RESULTS

Preeclamptic women had significantly increased levels of circulating IL-6 (p=0.002), IL-8 (p=0.003) and soluble IL-4R (p=0.037), compared to women with normal pregnancies.

CONCLUSION

This study supports the hypothesis of increased inflammatory responses in preeclampsia, illustrated by the increased levels of IL-6 and IL-8. The finding of increased levels of soluble IL-4 receptor is an intriguing finding with several interpretations, which may partly support the hypothesis of a Th1 shift in preeclampsia.