Interleukin-12 and pre-eclampsia

Comparison of maternal serum levels of interleukin-10, interleukin-12, and interleukin-2 in normal and preeclamptic pregnancies

OBJECTIVE

The aim of this study was 2 fold: (1) to compare the maternal serum levels of IL-10, IL-12, and IL-2 in preeclamptic and normal pregnant women, and (2) to study the serum levels of these cytokines in preeclamptic pregnancies with and without intrauterine growth retardation.

STUDY DESIGN

Forty women with singleton pregnancies complicated by preeclampsia (32 severe and 8 mild) and 29 normotensive healthy pregnant women were included in the study. Preeclamptic patients were further divided into 2 groups according to the presence or absence of intrauterine growth retardation. Maternal serum levels of IL-10, IL 12, and IL-2 were compared between these groups using enzyme-linked immunosorbent assays.

RESULTS

Maternal serum levels of IL-10 were significantly higher in the preeclampsia group than in controls (p<0.001). There were no statistically significant differences in maternal serum concentrations of IL-2 and IL-10 between the study and control groups (p>0.05). Serum levels of IL-2 and IL-10 in the patients with preeclampsia complicated by IUGR were elevated in comparison with the uncomplicated preeclampsia group. These differences were statistically significant (p<0.05 for both).

CONCLUSIONS

IL-10 may be involved in the pathologic process of preeclampsia. Increased serum levels of IL-10 and IL-2 in preeclampsia complicated with IUGR suggests a possible role of these cytokines in IUGR.

Is preeclampsia an autoimmune disease?

Preeclampsia is a life-threatening hypertensive disease of pregnancy. The condition is characterized by the presence of autoantibodies that activate the major angiotensin receptor, AT(1). Research conducted during the past decade has shown that these autoantibodies activate AT(1) receptors on a variety of cell types and provoke biological responses that are relevant to the pathophysiology of preeclampsia. The introduction of these autoantibodies into pregnant mice results in hypertension, proteinuria and a variety of other features of preeclampsia including small fetuses and placentas. These findings demonstrate the pathophysiological role of these autoantibodies in preeclampsia. The biological properties of these autoantibodies can be blocked by a 7-amino acid peptide that corresponds to a specific sequence associated with the second extracellular loop of the AT(1) receptor. The fact that autoantibodies from different individuals are directed to a common epitope provides obvious diagnostic and therapeutic opportunities. Research reviewed here raises the intriguing possibility that preeclampsia may be a pregnancy-induced autoimmune condition characterized by the presence of disease-causing angiotensin receptor activating autoantibodies.

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

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

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

It has been suggested that maladaptation of the maternal immune response during pregnancy might be a causal factor for preeclampsia. This study was designed to examine the systemic immune status at both the innate level and the adaptive level in pregnancies complicated by preeclampsia (n=15) and normal pregnancies (n=15). Spontaneous and in vitro-induced secretion of IL-5, IL-6, IL-10, IL-12, IL-13 and TNF-alpha, in response to paternal blood cells and the vaccination antigens purified protein derivate of tuberculin (PPD) and tetanus toxoid (TT), was detected in cell culture supernatants from blood mononuclear cells by ELISA. Preeclamptic women showed reduced numbers of basophil granulocytes in the blood (p=0.004) and lower spontaneous secretion of IL-5 from blood mononuclear cells (p=0.016). In addition, paternal antigen-induced secretion of IL-10 was decreased in preeclampsia compared with normal pregnancy (p=0.012). No further differences between preeclampsia and normal pregnancy were found for any stimuli or cytokines. The present findings of reduced basophil numbers and lower spontaneous in vitro secretion of IL-5 in preeclampsia compared with normal pregnancy indicate a decrease in systemic Th2 immunity in preeclampsia. Furthermore, the decrease in paternal antigen-induced secretion of the immunosuppressive cytokine IL-10 in preeclampsia indicates a fetus-specific decrease in immunosuppression mediated by blood mononuclear cells. Whether these systemic changes are a cause or a consequence of preeclampsia remains to be elucidated.

The ratio of interleukin (IL)-18 to IL-12 secreted by peripheral blood mononuclear cells is increased in normal pregnant subjects and decreased in pre-eclamptic patients

Interleukin (IL)-18 acts in synergy with IL-12 to promote development of T helper 1 (Th1) responses. On the other hand, IL-18 alone has the capacity to induce Th2 responses. Here, we have measured IL-18 and IL-12 secretion by non-stimulated peripheral blood mononuclear cells (PBMC) from 17 non-pregnant women, 21 healthy pregnant women, 9 mildly pre-eclamptic patients and 15 severely pre-eclamptic patients. Th1/Th2 ratios in PBMC were determined by flow cytometry. PBMC from healthy pregnant subjects secreted more IL-18 and less IL-12 than non-pregnant women. PBMC from severely pre-eclamptic patients secreted more IL-12 than those from healthy pregnant women, while IL-18 secretion in mildly pre-eclamptic patients resembled that in normal pregnancy. The ratios of IL-18 to IL-12 were significantly higher in healthy pregnant women than non-pregnant women. These ratios were significantly lower in severely pre-eclamptic cases than in normal pregnancy subjects, while these ratios in mild pre-eclampsia resembled those in normal pregnancy. Interestingly, Th1/Th2 ratios were negatively correlated with the ratios of IL-18/IL-12. These results suggest that elevated IL-18 secretion and decreased IL-12 secretion by PBMC may induce Th2 dominance in normal pregnancy, while elevated secretion of both IL-18 and IL-12 by PBMC may cause Th1 dominance in severe pre-eclampsia.

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

PROBLEM

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

Interleukin-18 in the plasma of women with preeclampsia

OBJECTIVE

Interleukin-18 (IL-18) is a proinflammatory cytokine capable of stimulating interferon gamma and tumor necrosis factor-alpha production. Our purpose was to determine whether abnormal levels of IL-18 in maternal plasma correlate with the diagnosis of preeclampsia.

STUDY DESIGN

A case control study design was used to enroll 61 patients: controls (n = 31) and preeclamptic women (n = 30). A standard enzyme-linked immunosorbent assay measured plasma IL-18. Statistical methods included Student t tests and chi(2) tests.

RESULTS

Mean IL-18 levels were lower in preeclampsia than in controls (185 +/- 74 pg/mL vs 224 +/- 75 pg/mL, P =.053). Administration of betamethasone (BMZ) and/or hydralazine (HYD) was significantly associated with a lower IL-18 compared with controls (159 +/- 50 pg/mL vs 224 +/- 75 pg/mL, P =.002). After women who received BMZ or HYD were excluded, levels of IL-18 in preeclampsia were similar to those of controls (213 +/- 87 pg/mL, P =.69). There was no association between gestational age and IL-18.

CONCLUSION

Lower IL-18 was associated with administration of either BMZ or HYD. After patients receiving these medications were excluded, IL-18 levels were similar in controls and preeclamptic women. IL-18 was not associated with gestational age.

Myeloid and lymphoid dendritic cells in normal pregnancy and pre-eclampsia

The aim of our study was to estimate the populations of peripheral blood myeloid and lymphoid dendritic cells (CD1c+, BDCA-2+) and the CD1c+ : BDCA-2+ ratio in normal pregnant women and in patients with pre-eclampsia. Fifteen women in the first, second and third trimesters of normal pregnancy, and 25 patients with pre-eclampsia were included in the study. The dendritic cells were isolated from peripheral blood, stained with monoclonal antibodies against blood dendritic cell antigens (anti-CD1c, anti-BDCA-2) and estimated using the flow cytometric method. CD1c+ and BDCA-2+ dendritic cells were present in women during all trimesters of physiological pregnancy and in pre-eclamptic patients. It was observed that the numbers of dendritic cells were significantly lower in the second trimester when compared with the first and third trimesters of normal pregnancy. Furthermore, in the second trimester, CD1c+ : BDCA-2+ ratio was higher than in the other trimesters of physiological pregnancy. All populations of dendritic cells and CD1c+ : BDCA-2+ ratio did not differ in the first and third trimesters of normal pregnancy. The percentage of BDCA-2+ dendritic cells was significantly lower in pre-eclampsia in comparison with healthy women in the third trimester of physiological pregnancy, while CD1c+ : BDCA-2+ ratio was significantly higher in pre-eclamptic patients when compared with control groups. We concluded that dendritic cells may be involved in the immune regulation during physiological pregnancy. CD1c+ and BDCA-2+ cells can influence the Th2 phenomenon which is observed during physiological pregnancy. Furthermore, it seems possible that lower BDCA-2+ cells percentage and higher CD1c+ : BDCA-2+ ratio can be associated with increased Th1-type immunity in patients with pre-eclampsia.

Interleukin-12 secretion by peripheral blood mononuclear cells is decreased in normal pregnant subjects and increased in preeclamptic patients

PROBLEM

It has been reported that T-helper (Th) 2 dominance in normal pregnancy shifts to Th1 dominance in preeclampsia. Peripheral blood mononuclear cell (PBMC) production of interleukin (IL)-12, which induce Th1 responses, has not been compared between these clinical states.

METHOD OF STUDY

Peripheral blood mononuclear cell from 35 non-pregnant women, 35 healthy pregnant women, 12 mildly preeclamptic patients, and 15 severely preeclamptic patients were cultured for 24 hr. IL-12 secretion was determined by enzyme-linked immunosorbent assay (ELISA). Th1/Th2 ratios in PBMC were determined flow-cytometrically, and the amounts of HLA-DR and CD14 expression on the monocytes were obtained by flow cytometry.

RESULTS

Peripheral blood mononuclear cell from healthy pregnant subjects secreted less IL-12 than non-pregnant women. PBMC from severely preeclamptic patients secreted more IL-12 than those from healthy pregnant subjects, while IL-12 secretion in mild preeclampsia resembled secretion in normal pregnancy. Th1/Th2 ratios correlated were positively with IL-12. Increased HLA-DR antigens and reduced CD14 expression, suggesting monocyte activation, were observed in preeclamptic patients, although monocyte counts were unchanged.

CONCLUSION

Decreased IL-12 secretion by PBMC may cause Th2 dominance in normal pregnancy, while increased IL-12 secretion by activated monocytes may cause Th1 dominance in preeclampsia.

Cytokine levels in midtrimester amniotic fluid in normal pregnancy and in the prediction of pre-eclampsia

Midtrimester amniotic fluid cytokines may reflect the function of the maternal immune system in the maternal-fetal interface and thus be predictive of pre-eclampsia. We determined the concentrations of interleukin (IL)-6, IL-8, IL-10, IL-11, IL-12, IL-15, tumour necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta in amniotic fluid at 14-16 weeks of gestation from women with normal pregnancies and from those who subsequently developed severe pre-eclampsia. The concentrations of the cytokines in amniotic fluid did not significantly differ between patients and normal controls. The median concentration of IL-6 was 950 pg/ml in normal pregnant women and 578 pg/ml in the patient group. The median concentration of IL-8 was 606 pg/ml in normal controls and 294 pg/ml in the patient group. The levels of IL-6, IL-8 and TGF-beta correlated positively with each other. TNF-alpha concentrations were low and similar in both groups. IL-10 and IL-12 were detected at very low levels in 37 and 7% of the samples, respectively. No difference was found in IL-15 concentrations between the groups. IL-11 was found only at low levels in both groups. Although none of the cytokines measured was predictive of pre-eclampsia, this study provides information of cytokines in amniotic fluid during the period when the spiral arteries are remodelled.

Quantitative analysis of peripheral blood Th0, Th1, Th2 and the Th1:Th2 cell ratio during normal human pregnancy and preeclampsia

We calculated the percentage of Th1, Th2, Th0 cells and the Th1:Th2 cell ratio of peripheral blood from normal pregnant subjects and preeclampsia patients using flow cytometry which can analyse both the surface marker, CD4, and intracellular cytokines, interleukin (IL)-4 and interferon (IFN)-gamma. In normal pregnancy, the percentage of Th1 cells was significantly lower in the third trimester, and the ratios of Th1:Th2 were significantly lower in the second and third trimester than in nonpregnant subjects. In contrast, the percentage of Th1 cells and the ratios of Th1:Th2 in preeclampsia were significantly higher than in normal third trimester pregnant subjects. The percentage of Th2 cells in preeclampsia was significantly lower than in third trimester of normal pregnancy. Additionally, peripheral blood mononuclear cells from these subjects and patients were cultured with phytohemagglutinin stimulation, and IL-4 and IFN-gamma concentrations were determined in the supernatant by enzymed linked immunosorbent assays. The percentage of Th1 and Th2, and the ratios of Th1:Th2 were correlated with cytokine (IFN-gamma and IL-4) secretion level. These results demonstrated that Th2 cells were predominant in the second and third trimesters of normal pregnancy, but Th1 cells predominated in preeclamptic patients.

Hormonal regulation of tumor necrosis factor-alpha, interleukin-12 and interleukin-10 production by activated macrophages. A disease-modifying mechanism in rheumatoid arthritis and systemic lupus erythematosus?

Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) frequently develop and progress in settings in which sympathoadrenomedullary and gonadal hormone levels are changing, e.g., during pregnancy, postpartum period, menopause, estrogen administration. This paper addresses the view that adrenal and gonadal hormonal deficiency facilitates excessive macrophage production of TNF-alpha and IL-12 that characterizes RA, whereas excessive estrogen action is suggested to play an essential role in the production of IL-10 in patients with SLE. Disease activity in SLE, in contrast to RA, appears to be associated with high-level production of IL-10, relative to the proinflammatory cytokines, TNF-alpha and IL-12. Accumulating data suggest that novel therapeutic approaches may ultimately be developed from continued investigation of the role of the neuroendocrine factors in RA and SLE.

Increased T-helper-1-type immunity and decreased T-helper-2-type immunity in patients with preeclampsia

PROBLEM

To examine whether preeclampsia involves type-1 T-helper (TH1) immune hyperactivity.

METHOD OF STUDY

Expression of HLA-DR, a cell-surface marker of activation, was analyzed on CD3+, CD4+, and CD8+ T cells in 15 preeclamptic patients and 15 normal pregnant women using flow cytometry. Additionally, peripheral blood mononuclear cells from preeclamptic patients and normal pregnant women were cultured with or without phytohemagglutinin (PHA) stimulation, and interleukin (IL)-2, IL-4, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha concentrations were determined in the supernatant by immunoassays.

RESULTS

HLA-DR antigen was expressed more strongly on CD3+ T cells in preeclamptic patients than in normal subjects. In preeclampsia, HLA-DR was expressed more strongly in CD8+ T cells than in CD4- T cells. More TNF-alpha, IL-2, and IFN-gamma were produced by unstimulated and stimulated cultured peripheral blood mononuclear cells from preeclampsia patients than by those from normal subjects. TNF-alpha/IL-4, IL-2/IL-4, and IFN-gamma/IL-4 ratios were higher in preeclamptic patients than in the normal group. Significant positive correlations were observed between mean blood pressure and concentrations of the Th-1 type cytokines IL-2, IFN-gamma, and TNF-alpha.

CONCLUSION

Up-regulation of Th1 responses and down-regulation of Th2 responses occur in preeclampsia.