Maternal T cells and human pregnancy outcome

Are naïve T cells and class-switched memory (IgD- CD27+) B cells not essential for establishment and maintenance of pregnancy? Insights from a case of common variable immunodeficiency with pregnancy

The disruption of adaptive immune response has adverse effects on the establishment and maintenance of pregnancy. The adaptive immune system is regulated by several types of immune cells. However, there is limited information about cell hierarchy in the adaptive immune response to the establishment and maintenance of pregnancy in women. The assessment of the outcome of pregnancy in primary immunodeficiency diseases could help in understanding the cell hierarchy in the adaptive immune system during pregnancy. Common variable immunodeficiency (CVID) is a heterogeneous adaptive immune system disorder characterized by primary hypogammaglobulinemia. A few studies have previously reported the assessment of the T and B cell subpopulations in CVID patients. However, an assessment of the subpopulations of T and B cells and the outcome of pregnancy in women with CVID has not been reported till date. Most CVID patients show a general decrease in the expression of CD27 in B cells. The assessment of pregnancy and the subpopulations of T and B cells in CVID women with severe reduction in the naïve T and switched B cells could help understand whether these cells are essential for the establishment and maintenance of pregnancy in women.

Gay Male Only-Children: Evidence for Low Birth Weight and High Maternal Miscarriage Rates

Recent findings suggest that there may be a maternal immune response underpinning the etiology of sexual orientation of gay male only-children. This maternal immune response appears to be distinct from that which is purported to explain the classic fraternal birth order effect found in studies of male sexual orientation. We tested two predictions related to the hypothesized maternal immune response in mothers of gay male only-children: (1) elevated fetal loss among mothers who have had gay male only-children and (2) lower birth weight in gay male only-children. Mothers of at least one gay son (n = 54) and mothers of heterosexual son(s) (n = 72) self-reported their pregnancy histories, including the birth weights of newborns and number of fetal losses (e.g., miscarriages). Mothers of gay male only-children (n = 8) reported significantly greater fetal loss compared with mothers of males with four other sibship compositions (gay with no older brothers, gay with older brothers, heterosexual only-children, heterosexual with siblings) (n = 118). Also, firstborn gay male only-children (n = 4) had a significantly lower birth weight than firstborn children in the four other sibship compositions (n = 59). Duration of pregnancy was not significantly different among the groups of firstborn children in the birth weight analyses. Thus, this study found further support for a distinct pattern of maternal immune response implicated in the etiology of male sexual orientation. Mechanisms that may underlie this potential second type of maternal immune response are discussed.

Birth weight and two possible types of maternal effects on male sexual orientation: a clinical study of children and adolescents referred to a Gender Identity Service

This study tested predictions regarding two hypothesized maternal immune responses influencing sexual orientation: one affecting homosexual males with high fraternal birth order and another affecting firstborn homosexual individuals whose mothers experience repeated miscarriage after the birth of the first child. Low birth weight was treated as a marker of possible exposure to a maternal immune response during gestation. Birth weight was examined relative to sibship characteristics in a clinical sample of youth (N = 1,722) classified as heterosexual or homosexual based on self-reported or probable sexual orientation. No female sexual orientation differences in birth weight were found. Homosexual, compared to heterosexual, males showed lower birth weight if they had one or more older brothers--and especially two or more older brothers--or if they were an only-child. These findings support the existence of two maternal immune responses influencing male sexual orientation and possibly also cross-gender behavior and identity.

To B or not to B cells-mediate a healthy start to life

Maternal immune responses during pregnancy are critical in programming the future health of a newborn. The maternal immune system is required to accommodate fetal immune tolerance as well as to provide a protective defence against infections for the immunocompromised mother and her baby during gestation and lactation. Natural immunity and antibody production by maternal B cells play a significant role in providing such immunoprotection. However, aberrations in the B cell compartment as a consequence of maternal autoimmunity can pose serious risks to both the mother and her baby. Despite their potential implication in shaping pregnancy outcomes, the role of B cells in human pregnancy has been poorly studied. This review focuses on the role of B cells and the implications of B cell depletion therapy in pregnancy. It highlights the evidence of an association between aberrant B cell compartment and obstetric conditions. It also alludes to the potential mechanisms that amplify these B cell aberrances and thereby contribute to exacerbation of some maternal autoimmune conditions and poor neonatal outcomes. Clinical and experimental evidence suggests strongly that maternal autoantibodies contribute directly to the pathologies of obstetric and neonatal conditions that have significant implications for the lifelong health of a newborn. The evidence for clinical benefit and safety of B cell depletion therapies in pregnancy is reviewed, and an argument is mounted for further clinical evaluation of B cell-targeted therapies in high-risk pregnancy, with an emphasis on improving neonatal outcomes and prevention of neonatal conditions such as congenital heart block and fetal/neonatal alloimmune thrombocytopenia.

Normal pregnancy is associated with peripheral leukocyte activation

PROBLEM

Normal pregnancy has been described as both a pro-inflammatory condition and a T helper (Th)2-dominated state. Deviations in the percentage of different subpopulations of circulating leukocytes have been detected, although with conflicting results. This study was designed to analyse further the phenotype of subpopulations of peripheral blood leukocytes in normal pregnant women.

METHOD OF STUDY

Whole-blood flow cytometry was used to differentiate subsets of leukocytes using directly labeled monoclonal antibodies to specific cell surface antigens and to a panel of activation-associated markers in 33 normal pregnant women in their third trimester and in 26 non-pregnant controls.

RESULTS

We found a significant increase in the proportion of granulocytes and of CD8+ T lymphocytes during pregnancy. Up-regulation of the expression of adhesion molecules was observed on granulocytes, monocytes and T lymphocytes.

CONCLUSIONS

Pregnancy alters the representation of leukocyte subpopulations in the maternal circulation and is associated with systemic activation of leukocytes.

Lymphocyte subsets and mitogen stimulation of blood lymphocytes in preeclampsia

PROBLEM

The question of whether there are differences in systemic immune reactivity in severe preeclampsia compared with normal pregnancy was addressed.

METHOD OF STUDY

During the third trimester, blood samples were taken from 12 pregnant women with severe preeclampsia. Five of the preeclamptic pregnancies were analyzed separately because they were treated with dexamethasone before the blood samples were taken. The seven dexamethasone-treated preeclamptic pregnant women were analyzed and compared with six uncomplicated pregnancies. A control group consisted of 15 nonpregnant females. Lymphocyte subsets were identified by flow cytometry. The function of peripheral blood mononuclear cells (PBMCs) was studied as proliferative responses to mitogens alone and in combination with immunomodulating drugs.

RESULTS

An increased number of B lymphocytes (CD19+) (P < 0.05) and natural killer (NK) cells (P < 0.05) was noticed in severe preeclampsia compared with normal pregnancy. The proliferative response of PBMCs in phytohemagglutinin (PHA)-stimulated cultures in autologous serum from patients with severe preeclampsia was reduced (P < 0.05) compared with normal pregnancy. The addition of indomethacin and cimetidine significantly stimulated (P < 0.05) the proliferative responses. The enhancing effect of cimetidine was not found in dexamethasone-treated preeclamptic patients.

CONCLUSIONS

The presence of systemic immunosuppression in severe preeclampsia is demonstrated as a reduced proliferative response of PBMCs to PHA, which could be partly restituted by indomethacin or cimetidine, indicating immunosuppressor activity that is mediated by prostaglandin and histamine. Increased levels of B lymphocytes and NK cells were also noticed.

Lymphocyte subpopulations in intrauterine growth retardation in women with or without previous pregnancies

OBJECTIVE

To evaluate lymphocyte subpopulations in pregnant women with intrauterine growth retardation (IUGR).

STUDY DESIGN

Forty-two normotensive and healthy women with singleton pregnancies and intrauterine growth retardation were studied in the third trimester of pregnancy and compared with 42 normal pregnant women. Peripheral blood lymphocytes were studied using murine monoclonal antibodies and flow cytometry.

RESULTS

B-lymphocytes in both total number (312.54 vs. 163.19 cells/mm3; P = 0.000003) and percentage (11.04% vs. 7.07%; P = 0.000002) were significantly increased in patients with IUGR in comparison to normal pregnant women. Significant correlations were found between birthweight and both total number and percentage of lymphocytes B. In primigravid women, we found that women with IUGR had a higher total lymphocyte count (2749.09 vs. 2130 cells/mm3; P = 0.006), higher T-lymphocyte count (2053.77 vs. 1676.40 cells/mm3; P = 0.02), higher B-lymphocyte count and percentage (309.13 vs. 145.36 cells/mm3; P = 0.000001) (11.45 vs. 6.81%); P = 0.00001), higher CD4 lymphocyte count and percentage (1342.68 vs. 972.22 cells/mm3, P = 0.001) (49.18 vs. 44.04%; P = 0.04), lower CD8-lymphocytes percentage (28.27 vs. 32.9%; P = 0.04), and higher CD4/CD ratio (1.83 vs. 1.46; P = 0.02) than the normal control group.

CONCLUSIONS

B-lymphocytes are increased in women with IUGR in comparison to women with normal pregnancies and there was a significant negative correlation between maternal B-lymphocytes and birthweight. With respect to T-lymphocytes, the immunological profile is different according to the presence or absence of a previous pregnancy. Fetal immunological rejection could be involved in the pathogenesis of IUGR in primigravid women, but in multigravid women there were no differences between women with IUGR and those with normal fetal growth.

Mixed maternal-paternal lymphocyte cultures before and after immunotherapy for recurrent spontaneous abortions

PROBLEM

The increased reactivity of maternal lymphocytes in reciprocal mixed-maternal-paternal lymphocyte cultures (MMPLC), observed in the presence of control serum after immunotherapy, suggests that immunization with paternal lymphocytes may induce a highly significant cell mediated immune response in specifically alloactivated maternal lymphocytes.

METHOD

Reciprocal one-way MMPLC were set up with responding maternal or paternal lymphocytes and mitomycin C-treated stimulating lymphocytes. Cultures were set up for 6 days in the presence of 15% maternal or control serum. The degree of lymphocyte stimulation was measured by tritiated thymidine uptake.

RESULTS

In maternal serum, after immunotherapy, a highly significant blocking effect on MMPLC was observed in both directions. The extent of the blocking effect in maternal serum and the stimulation in control serum was much higher, after immunotherapy, in two cases of abortions, as compared to cases with normal pregnancy outcome.

CONCLUSIONS

Although the number of cases is very small, it may be that in abortions, in the presence of maternal serum, disturbances in the balance of cytokines or/and specific antibodies could have cytotoxic effects on MMPLC and down regulate, or "block" the specific response. For a possibly better utilization of the MMPLC test in the prediction of pregnancy outcome after immunotherapy, it may be important to examine specific antibodies in maternal serum, to investigate specifically induced cytokines in MMPLC and to evaluate T cell subsets in MMPLC in the presence of maternal and control serum.

Lymphocyte subsets and autoantibodies in pregnancies complicated by placental disorders

PROBLEM

The survival of the fetoplacental unit might partly depend on down-regulation of rejection reactions. Pathological maternal cellular immune response mechanisms could therefore be of pathogenic importance in pregnancies complicated by placental disorders.

METHOD

A flow-cytometric analysis of T-cell subsets and B-cell, as well as serological tests for anticardiolipin antibodies (aCL), antinuclear antibodies (ANA), and rheumatoid factor (RF) were done on 90 women with complicated pregnancies. The results were compared with that of nonpregnant women (n = 5), and normal pregnant women (n = 5) in the third trimester.

RESULTS

Two women, suffering from severe preeclampsia and eclampsia respectively, had aCL on 12 and 13 units, respectively. ANA occurred in 11 patients with moderate and severe preeclampsia and intrauterine growth retardation. All women had negative RF tests. Within the CD4 T-helper subpopulations, the proportion of suppressor/inducer T-cell population (CD4+CD45RA+) significantly increased, while the memory and helper/inducer T-cells (CD4+CD45RO+ and CD4+CD29+) significantly decreased during normal pregnancy compared to nonpregnant controls. This deviation of CD4 subpopulations was not found, or was less pronounced, in complicated pregnancies. The proportion of cytotoxic T cells (CD8+S6F1+) was significantly reduced during normal pregnancy. This reduction was less pronounced in complicated pregnancies.

CONCLUSION

Systemic immunological deviations toward suppression or decreased activity of the immunological response as seen in normal pregnancies, was not observed in preeclampsia, intrauterine growth retardation, intrauterine fetal death, and abruptio placentae. This lack of suppression or increased T-cell activity may have a primary pathogenic role in some women with a complicated pregnancy, or it may be secondary to the placental disorders.

Listeria Monocytogenes infections

This article reviews current information regarding human infection with Listeria monocytogenes. Significant advances have occurred in regard to our knowledge of the epidemiology, pathogenesis, immunology, and treatment of this disease which was formerly believed to be of importance mainly to veterinarians. It remains a cause of high mortality in the many different groups of compromised hosts it infects unless diagnosis and treatment are rapidly established.

Viral infections in the dental setting: potential effects on pregnant HCWs

Occupational exposure of pregnant health care workers to infectious diseases may cause a variety of effects. This article reviews potential effects of viral infections in pregnant health care workers by pathogens transmittable in a dental setting.

Yellow fever vaccination and pregnancy: a four-year prospective study

During an outbreak of yellow fever (YF) in Nigeria in 1986-1987, women at various stages of pregnancy were vaccinated against YF, either because those pregnancies were not known at the time or because they requested vaccination out of fear of acquiring the disease. This offered an opportunity to assess the safety and efficacy of YF vaccine in pregnant women and the effect of this vaccine on their newborn children. Pre-vaccination and post-vaccination serum samples from the vaccinated pregnant women were tested by enzyme-linked immunosorbent assay and by neutralization tests for antibody to YF virus. The results showed that the antibody responses of these pregnant women were much lower than those of YF-vaccinated, non-pregnant women in a comparable control group. Follow-up of these women and their newborn children for 3-4 years showed no abnormal effect that could be attributed to the YF vaccine, which suggests that vaccination of pregnant women, particularly during a YF epidemic, may not be contraindicated.

Immunology of pregnancy: towards a unifying hypothesis

The variable findings of hormonal-immunoregulation and the variable cellular and humoral immune responses in pregnancy have been considered in relationship to the physiological response. From such considerations it appears that the peripheral blood lymphocyte/leukocyte response in pregnancy is not important, but rather the local uterine immune response at implantation and throughout pregnancy. It is proposed, and evidence is presented, that a normal allogeneic immune response is initiated at the time of implantation of the blastocyst. This immune response regulates the invasive nature of the trophoblast and initiates the first stage of parturition. The initiation and maintenance of this immune response is based on an interplay between maternal and paternal HLA and trophoblast antigens. In the case of HLA-incompatible donor-recipient blastocyst transplants, a more pivotal role for immunoregulation by trophoblast antigens is proposed. This is because it is considered that the local uterine immune response suppresses the expression of allogeneic HLA. This concept is further developed in terms of haploid HLA suppression on maternal and fetal lymphocytes that cross the placenta. This is considered to allow the interaction of these lymphocytes with each other and explains maternal transfer of cell-mediated immunity.

A possible mechanism of immunotherapy for patients with recurrent spontaneous abortions

The mechanism of the beneficial effect of immunotherapy for human reproductive wastage remains to be elucidated. Induction of blocking antibodies such as anti-HLA class II antibodies and anti-idiotypic antibodies was investigated as the mechanism of specific immunosuppression in pregnancy. We reported the changes in the mixed lymphocyte reaction (MLR), T-cell subsets, and generation of anti-idiotypic antibodies after immunotherapy compared to before immunotherapy. MLR was significantly (P less than 0.001) inhibited after the immunization. The mean inhibition rate was 50.2%, suggesting that MLR blocking antibodies were induced by immunotherapy. Binding of autoantibodies to alloactivated maternal lymphoblasts against the paternal lymphocytes was detected in postimmunization cases in two-color flow-cytometric experiments. This suggests that anti-idiotypic antibodies were induced by the immunotherapy. The percentage of cytotoxic T-cells was significantly decreased (P less than 0.05) and the percentage of suppressor T-cells was significantly increased (P less than 0.01) after the immunotherapy, suggesting that a cell-mediated immune response was induced by the immunotherapy.

Cytotoxic antibody against trophoblast and lymphocytes present in pregnancy with intrauterine fetal growth retardation and its relation to anti-phospholipid antibody

To elucidate immunological mechanisms involved in the genesis of intra-uterine fetal growth retardation (IUGR), an in vitro cytotoxicity assay against normal trophoblast and lymphocytes was performed. The data demonstrated the existence of cytotoxic antibody directed against trophoblast exclusively in the IgG fraction of the sera of 9 out of 15 mothers with IUGR, but in none of the sera from normal pregnant women. This antibody showed differential reactivity patterns that may be indicative women. This antibody showed differential reactivity patterns that may be trophoblast in common. Out of 9 IUGR mothers with this cytotoxic antibody, in 6 cases (66.7%) chronic villitis was evident upon microscopic examination of the placenta, the frequency being significantly higher than that in IUGR mothers without cytotoxicity or in control mothers (P less than 0.02). It is suggested that in situ inflammatory change triggered by this antibody might lead to IUGR through chronic villitis. This antibody showed cross-reactivity with anti-negatively charged phospholipid antibody, as confirmed by an absorption experiment, indicating that the trophoblast antigenic stimuli in pregnancy can induce the production of various autoantibodies including anti-phospholipid antibodies. These results are of interest in relation to the pathogenesis of autoimmune diseases.