Maternal Monocytes Research Articles

Maternal Intravascular Inflammation in Preterm Premature Rupture of Membranes

Inflammatory change may be an element in preterm premature rupture of membranes (PPROM) and consequent preterm labor. It remains unclear whether any subclinical intrauterine inflammation remains localized to the site of membrane rupture or extends to the maternal compartment. The present study was planned to learn whether PPROM can be related to changes in maternal granulocytes and monocytes that are consistent with inflammation. Flow cytometry was used to identify and quantify in vivo inflammation in a prospective series of 43 women with PPROM. A comparison group included 51 normal pregnancies. Cellular phenotypes were determined in maternal blood samples using numerous cluster differentiation (CD) markers (CD11b, CD14, CD15, CD16, CD18, CD49d, CD62L, CD64, CD66b) as well as human leukocyte antigen HLA-DR. Quantities of basal intracellular reactive oxygen species (iROS) and oxidative burst also were assessed. Flow cytometric analysis showed PPROM to be associated with significantly increased mean channel brightness (MCB) for CD11b, CD14, CD64, and CD66b on granulocytes. The median MCB of CD11b was significantly increased on monocytes. Baseline values of iROS were not significantly increased in either cell type in cases of PPROM. Both the oxidative burst and the stimulation index (ratio of oxidative burst to basal iROS) were significantly increased in both granulocytes and monocytes in PPROM compared with control cases. These findings suggest that some degree of maternal intravascular inflammation is present in cases of PPROM, as reflected by phenotypic and metabolic changes in circulating granulocytes and monocytes. A systemic fetal inflammatory response has been temporally related to the spontaneous onset of preterm labor. Whether a similar relationship exists in the maternal compartment remains to be determined.

Monocytes are progressively activated in the circulation of pregnant women

Pregnancy is characterized by the presence of generalized leukocyte activation. We used flow cytometry to investigate changes in phenotype and intracellular cytokines of circulating granulocytes, monocytes, and T lymphocytes of pregnant women during gestation. We report that peripheral circulation of pregnancy is characterized by an increased percentage of granulocytes and a decrease in lymphocytes. The proportion of monocytes remains stable throughout gestation; however, a progressive up-regulation of surface markers CD11a, CD54, and CD64 was detected. Monocytes also showed higher production of interleukin (IL)-12 and IL-1beta compared with the nonpregnant state, and granulocytes had greater potential to synthesize IL-8. All these changes were particularly marked in late gestation. T lymphocytes did not have any characteristics of the activated state and showed a decreased IL-6 production. These findings demonstrate that activation of maternal monocytes and granulocytes increases during pregnancy and support the idea that pregnancy results in an elevation of the innate immune system and suppression of the adaptive immune system.

Physiological leukocytosis during pregnancy is associated with changes in glucose transporter expression of maternal peripheral blood granulocytes and monocytes.

The scarce data on glucose transporter expression of leukocytes are contradictory and nothing is known about changes accompanying physiological leukocytosis during pregnancy, which imposes acute metabolic demands on the cells. Cytospin preparations of intravascular leukocytes were searched immunocytochemically for the high affinity glucose transporters GLUT1, 3 and 4. Pregnancy-associated quantitative changes in transporter expression were assessed by flow cytometry. Granulocytes and monocytes stained for GLUT1, 3 and 4. Major changes in cell surface transporter expression during pregnancy were a 36% (P < 0.05) down-regulation of granulocyte GLUT1 at term, and an increase in monocyte GLUT3 levels to 137% (P < 0.05), paralleled by a 24% (P < 0.05) decrease in GLUT4 content in second trimester. Apart from a minor subpopulation, lymphocytes were negative for these carriers. GLUT1, 3 and 4 are abundantly expressed in granulocytes and monocytes. The particular isoforms are differentially regulated during pregnancy, suggesting an individual functional significance.

Maternal intravascular inflammation in preterm premature rupture of membranes

Objective: Intrauterine inflammation has been implicated in the mechanisms responsible for preterm premature rupture of membranes (PROM). However, it is unclear whether this inflammatory process remains localized to the uterus, at the site of membrane rupture, or extends to the maternal compartment. Flow cytometric analysis is a sensitive method to assess the presence and magnitude of in vivo inflammation. This study was conducted to determine whether preterm PROM is associated with changes in the phenotypic and metabolic characteristics of maternal granulocytes and monocytes consistent with the presence of maternal intravascular inflammation. Study design: A prospective cross-sectional study was performed including patients with preterm PROM (n = 43) and with a normal pregnancy (n = 51). Maternal inflammation was assessed by flow cytometric analysis of maternal plasma. Intravascular inflammation was studied using flow cytometry. Maternal blood was assayed to determine granulocyte and monocyte phenotypes using monoclonal antibodies, which included cluster differentiation (CD) markers CD11b, CD14, CD15, CD16, CD18, CD49d, CD62L, CD64, CD66b and human leukocyte antigen (HLA)-DR. The presence of basal intracellular oxygen radical species (iROS) and oxidative burst was assessed. Statistical analysis was conducted with the use of non-parametric methods. A p value < 0.01 was considered significant. Results: Preterm PROM was associated with a significant increase in the median mean channel brightness (MCB) of CD11b, CD14, CD64 and CD66b on granulocytes and median MCB of CD11b on monocytes. The ratio of oxidative burst over basal iROS in both granulocytes and monocytes was higher in preterm PROM than in normal pregnancy (p < 0.01). Conclusion: Preterm PROM is associated with a maternal intravascular inflammatory response.

Maternal intravascular inflammation in preterm premature rupture of membranes

Objective: Intrauterine inflammation has been implicated in the mechanisms responsible for preterm premature rupture of membranes (PROM). However, it is unclear whether this inflammatory processremains localized to the uterus, at the site of membrane rupture, or extends to the maternal compartment. Flow cytometric analysis is a sensitive method to assess the presence and magnitude of in vivoinflammation. This study was conducted to determine whether preterm PROM is associated with changes in the phenotypic and metabolic characteristics of maternal granulocytes and monocytes consistent withthe presence of maternal intravascular inflammation.Study design: A prospective cross-sectional study was performed including patients with preterm PROM (n = 43) and with a normal pregnancy(n = 51). Maternal inflammation was assessed by flow cytometric analysis of maternal plasma. Intravascular inflammation was studied using flow cytometry. Maternal blood was assayed to determine granulocyteand monocyte phenotypes using monoclonal antibodies, which included cluster differentiation (CD) markers CD11b, CD14, CD15, CD16, CD18, CD49d, CD62L, CD64, CD66b and human leukocyte antigen (HLA)-DR. Thepresence of basal intracellular oxygen radical species (iROS) and oxidative burst was assessed. Statistical analysis was conducted with the use of non-parametric methods. A p value < 0.01 wasconsidered significant.Results: Preterm PROM was associated with a significant increase in the median mean channel brightness (MCB) of CD11b, CD14, CD64 and CD66b on granulocytes and medianMCB of CD11b on monocytes. The ratio of oxidative burst over basal iROS in both granulocytes and monocytes was higher in preterm PROM than in normal pregnancy (p < 0.01).Conclusion:Preterm PROM is associated with a maternal intravascular inflammatory response.

Phenotypic and metabolic characteristics of maternal monocytes and granulocytes in preterm labor with intact membranes

Objective: Experimental and clinical studies support a role for the fetus in the control of the onset of labor. Fetal systemic inflammation, but not a maternal inflammatory response, has been linked to the onset of preterm labor and delivery on the basis of the determination of inflammatory cytokines in fetal and maternal blood. We propose that parturition requires fetomaternal cooperation and that inflammation is an integral part of the parturitional process. This study used flow cytometry, a sensitive technique for the detection of intravascular inflammation, to assess whether maternal inflammation is present in preterm labor. Study Design: A prospective cross-sectional study was performed including patients with preterm labor (n = 55) and women with normal pregnancy (n = 50). Intravascular inflammation was studied by using flow cytometry. Maternal blood was assayed to determine granulocyte and monocyte phenotype by using monoclonal antibodies, which included the following cluster of differentiation (CD) markers: CD11b, CD14, CD15, CD16, CD18, CD49d, CD62L, CD64, CD66b, and HLA-DR. Oxidative burst and generation of basal intracellular oxygen radical species were assessed. Statistical analysis was conducted with the use of nonparametric methods. A P value of <.01 was considered statistically significant. Results: Preterm labor was associated with a significant increase in the median mean channel brightness of CD11b, CD15, and CD66b on granulocytes and median mean channel brightness of CD11b and CD15 on monocytes. The ratio of oxidative burst over basal intracellular oxygen radical species in both granulocytes and monocytes was increased in preterm labor (P <. 01). Conclusion: Preterm labor with intact membranes is associated with phenotypic and metabolic changes of maternal granulocytes and monocytes. (Am J Obstet Gynecol 2001;185:1124-9.)

Monocytes adhering by LFA-1 to placental syncytiotrophoblasts induce local apoptosis via release of TNF-α. A model for hematogenous initiation of placental inflammations

Placental inflammations (villitis) are accompanied by loss of the syncytiotrophoblast, which is the cellular barrier separating maternal blood from fetal tissue in the villous placenta. We propose that syncytiotrophoblast loss is mediated by adhesion of activated maternal monocytes. This hypothesis was tested with a co-culture model of peripheral blood monocytes and placental syncytiotrophoblasts. We find that LPS-activated monocytes adhere to interferon-gamma (IFN-gamma)-treated syncytiotrophoblasts via monocyte LFA-1 for >48 h, during which time the monocytes induce trophoblast apoptosis and subsequent damage of the trophoblast layer. Optimal monocyte-mediated syncytiotrophoblast death requires both lipopolysaccharide (LPS) and IFN-gamma and is inhibited by either anti-tumor necrosis factor (TNF) antibody or epidermal growth factor. Syncytiotrophoblast damage is largely limited to culture surfaces in the vicinity of bound monocytes. These results show that activated maternal monocytes bound to the placental barrier can induce focal damage mediated by the inflammatory cytokine TNF-alpha and suggest a route for maternal leukocyte infiltration into the fetal stroma.

Immunohistochemical Study of the Inflammatory Infiltrate in Villitis of Unknown Etiology: A Qualitative and Quantitative Analysis

Villitis is characterized by an inflammatory infiltrate within the substance of the chorionic villi. Quantitative and qualitative analyses of the mononuclear infiltrate in areas of villitis were performed in placentas with villitis of unknown etiology (VUE). We used a panel of monoclonal antibodies and immunoperoxidase technique in paraffin sections from 17 placentas with VUE and 8 without VUE. Macrophages followed by T lymphocytes were the predominant inflammatory cells in areas of villitis in virtually all cases. B lymphocytes were not observed and monocytes were present usually in small number in 58 per cent of the cases. Mononuclear cells which expressed HLA-DR antigens were found in 75 per cent of the cases. In areas of villitis with trophoblastic necrosis, we found monocytes and some T lymphocytes adhered to them. These cells apparently had migrated from the maternal circulation. We suggest that in areas of villitis with destruction of the trophoblast and its basal membrane the inflammatory infiltrate might have a mixture of fetal and maternal cells. The maternal monocytes and T lymphocytes might be attracted to these sites of trophoblastic necrosis and activated due to exposure to fetal MHC antigens of the villous stroma.

The effects of betamethasone on maternal cellular resistance to infection

Antenatal administration of glucocorticoids is often used to facilitate fetal lung maturation in cases of prematurity; however, the effects of betamethasone on maternal immune function have not been established. Therefore maternal immune function was assessed with the use of in vitro techniques. Transient and incomplete suppression of the proliferative response to the T-cell mitogen phytohemagglutinin was demonstrated as early as 24 hours after administration of betamethasone. The magnitude and duration of suppression showed a corresponding increase with advancing gestational age, but these effects were not cumulative and were always short-lived (<72 hours). No such suppression of the B-cell mitogen lipopolysaccharide was detected. The nonspecific cellular resistance to infection of maternal monocytes was determined through coincubation with the facultative intracellular pathogen Listeria monocytogenes. Increased phagocytic activity with a normal bactericidal effect was measured in the cell preparations obtained from recipients versus nonrecipients of betamethasone. Taken together, these findings clearly show that both specific and nonspecific immune function are intact in the preterm gravid woman after administration of betamethasone and should allay concerns over its use for reasons of infection control alone.

Interleukin-1β in human colostrum

The two forms of interleukin-1, IL-1α and IL-1β respectively, and tumour necrosis factor (TNF) are polypeptides sharing different biological activities which are often associated with host defence mechanisms. Because of the well-recognized benefits of breast feeding for newborns, colostrum from 9 healthy lactating women was analysed for the presence of these 3 cytokines. Specific radioimmunoassay revealed that colostrum contains a significant amount of IL-1β (mean ± SEM values of 1,130 ± 259 pg/ml). The concentrations of IL-1α and TNF were negligible. Colostral leukocytes are able to produce IL-1 since high activity was found after stimulation with Staphylococcus epidermidis. In addition, these cells produced IL-1 spontaneously in vitro, in contrast to resting maternal blood monocytes. As IL-1 increases resistance to infection, the presence of this cytokine represent a beneficial aspect of breast feeding.

The evolution of MHC restrictions in antigen recognition by T cells in a haploidentical bone marrow transplant recipient.

We have longitudinally followed the major histocompatibility complex (MHC) restrictions that govern the response of T lymphocytes to specific Ag in a child with severe combined immunodeficiency who was successfully transplanted by using T cell depleted haploidentical maternal bone marrow cells and immunized shortly afterwards with tetanus toxoid (TT) Ag. In the first year post-transplant, monocytes were of both donor and recipient origin whereas T and B cells were of donor origin. Three years after transplant, all monocytes and T and B cells were of donor origin. T lymphocytes taken from the child at that time and depleted in vitro of alloreactivity to paternal Ag proliferated in response to TT presented by maternal as well as paternal monocytes. A TT-specific T cell line established from these cells in the presence of maternal monocytes cooperated with maternal but not with paternal monocytes, whereas a TT-specific T cell line established in the presence of paternal monocytes cooperated with paternal but not with maternal monocytes and with monocytes derived from a paternal uncle who shared the haplotype inherited by the recipient from her father. These results show that long-term memory T cells restricted to recipient MHC Ag not shared with the bone marrow donor continue to circulate long after the disappearance of accessory cells of recipient origin. These T cells could potentially participate in a secondary immune response because they were shown to recognize TT presented by recipient fibroblasts induced to express class II MHC molecules following treatment with IFN-gamma.

T cell response to anti-CD3 antibody in Down's syndrome.

The non-specific mitogen phytohaemagglutinin (PHA) and an anti-CD3 (OKT3) monoclonal antibody were used to measure the lymphocyte proliferative response in blood samples from 15 subjects with Down's syndrome. Blood from 15 healthy controls closely matched for age and sex was also assayed. The mean blastogenic value in PHA stimulated patient lymphocyte cultures was similar to that calculated in the controls. In contrast, the mitogenic response of lymphocytes from patients with Down's syndrome to anti-CD3 stimulation was on average significantly reduced. Immunofluorescence studies and additional experiments carried out by using semiallogeneic (maternal) monocytes as a source of antigen presenting cells showed that the impaired anti-CD3 induced mitogenesis in Down's syndrome could not be ascribed either to a lack of binding of the antibody to the trisomic cells, or to a defective monocyte-T cell interaction. These findings help to explain the cellular basis of the immune defect in Down's syndrome.

Studies of the Teratogenic Potential of Exposure of Rats to 6000-MHz Microwave Radiation: I. Morphologic Analysis at Term

Thirty-six pregnant Wistar strain albino rats were exposed throughout pregnancy to 6000-MHz microwave radiation at a power density level of 35 mW/cm2 or were used as controls. The irradiation did not cause a significant increase in maternal body temperature as measured by a rectal thermocouple. The rats were randomly assigned to one of four groups: home cage control (5), anechoic chamber control (10), sham-irradiated concurrent control (10), and irradiated (11). All animals were killed on the 22nd day of gestation, and maternal tissues were removed and weighed and maternal blood samples were taken. The 384 resultant fetuses and their placentas were individually weighed, fixed, and dissected to determine normality. Teratologic evaluation included the following parameters: maternal weight and weight gain; mean litter size; maternal organ weight and organ weight/body weight ratios; body weight ratios of brain, liver, kidneys, and ovaries; maternal peripheral blood parameters including hematocrit, hemoglobin, and white cell counts; number of resorptions and resorption rate; number of abnormalities and abnormality rate; mean term fetal weight. The irradiated fetuses exhibited slight but statistically significant growth retardation at term. Term maternal monocyte count was also significantly depressed. No other parameters differed between the control groups and the irradiated group.

Presentation of antigen by human newborn monocytes to maternal tetanus toxoid-specific T-cell blasts

The requirement for linked HLA-D antigen recognition for the proliferation of antigen-specific T-cell blasts provides a method for testing antigen presentation of human monocytes. We used maternal tetanus toxoid-specific T-cell blasts to show that human newborn monocytes can process and present antigen at least as well as maternal monocytes. These results suggest that human monocytes are relatively more mature at birth than those of newborn rats and mice. A major role for monocyte-macrophage immaturity in limiting the immune responses of human newborns is therefore unlikely.