Society for Maternal-Fetal Medicine Statement: RhD immune globulin after spontaneous or induced abortion at less than 12 weeks of gestation.

Guidelines for the management of first-trimester spontaneous and induced abortion vary in terms of rhesus factor D (RhD) testing and RhD immune globulin (RhIg) administration. These existing guidelines are based on limited data that do not convincingly demonstrate the safety of withholding RhIg for first-trimester abortions or pregnancy losses. Given the adverse fetal and neonatal outcomes associated with RhD alloimmunization, prevention of maternal sensitization is essential in RhD-negative patients who may experience subsequent pregnancies. In care settings in which RhD testing and RhIg administration are logistically and financially feasible and do not hinder access to abortion care, we recommend offering both RhD testing and RhIg administration for spontaneous and induced abortion at <12 weeks of gestation in unsensitized, RhD-negative individuals. Guidelines for RhD testing and RhIg administration in the first trimester must balance the prevention of alloimmunization with the individual- and population-level harms of restricted access to abortion.

Determination of the Predictive Roles and Potentially Pathogenic Antigen Epitopes of α-Enolase Related to the Development of Miscarriage in Females with Autoimmune Thyroiditis.

Autoimmune thyroiditis (AIT) is a common endocrine disease which causes a significantly increased risk of miscarriage. Our recent study has shown that the increased ENO1 autoantibody (ENO1Ab) expression in an experimental AIT mouse model was induced by thyroglobulin (Tg) immunization only. In this study, we explored the potential roles of ENO1Ab in miscarriage occurrence among AIT women, and the specific epitopes of ENO1 targeted by ENO1Ab. A total of 432 euthyroid pregnant participants were selected from the project of Subclinical Hypothyroid during Early Pregnancy, including 48 women with AIT and miscarriage, 96 with miscarriage but no AIT, 96 with AIT but no miscarriage, and 192 without either AIT or miscarriage. The enzyme-linked immunosorbent assay was used to determine the serum levels of total IgG against ENO1 and 18 predicted antigen epitopes of ENO1. The results showed that women with AIT and miscarriage had the highest serum levels of ENO1Ab compared to the other groups. Logistic regression analysis showed that the serum ENO1Ab was an independent risk factor for miscarriage, especially among AIT females. The serum level of total IgG against the predicted epitope peptide 6 (i.e., P6 and aa168-183) of ENO1 was significantly increased in women with AIT and miscarriage when compared with those of both the AIT non-miscarriage group and non-AIT miscarriage group. This pilot study suggests that serum ENO1Ab may have a fair predictive value for AIT-related miscarriage, and the autoantibody specific to P6 epitope may especially be more specifically related to this disorder.

IL-22 regulates endometrial regeneration by enhancing tight junctions and orchestrating extracellular matrix.

The uterine endometrium uniquely regenerates after menses, postpartum, or after breaks in the uterine layer integrity throughout women's lives. Direct cell-cell contacts ensured by tight and adherens junctions play an important role in endometrial integrity. Any changes in these junctions can alter the endometrial permeability of the uterus and have an impact on the regeneration of uterine layers. Interleukin 22 (IL-22) is a cytokine that is recognized for its role in epithelial regeneration. Moreover, it is crucial in controlling the inflammatory response in mucosal tissues. Here, we studied the role of IL-22 in endometrial recovery after inflammation-triggered abortion. Fecundity of mice was studied in consecutive matings of the same animals after lipopolysaccharide (LPS) (10 µg per mouse)-triggered abortion. The fecundity rate after the second mating was substantially different between IL-22 knockout (IL-22-/-) (9.1%) and wild-type (WT) (71.4%) mice (p < 0.05), while there was no difference between the groups in the initial mating, suggesting that IL-22 deficiency might be associated with secondary infertility. A considerable difference was observed between IL-22-/- and WT mice in the uterine clearance following LPS-triggered abortion. Gross examination of the uteri of IL-22-/- mice revealed non-viable fetuses retained inside the horns (delayed clearance). In contrast, all WT mice had completed abortion with total clearance after LPS exposure. We also discovered that IL-22 deficiency is associated with a decreased expression of tight junctions (claudin-2 and claudin-10) and cell surface pathogen protectors (mucin-1). Moreover, IL-22 has a role in the remodeling of the uterine tissue in the inflammatory environment by regulating epithelial-mesenchymal transition markers called E- and N-cadherin. Therefore, IL-22 contributes to the proper regeneration of endometrial layers after inflammation-triggered abortion. Thus, it might have a practical significance to be utilized as a treatment option postpartum (enhanced regeneration function) and in secondary infertility caused by inflammation (enhanced barrier/protector function).

Changes in the Expression of Pluripotency Factor Oct-4 and Intensity of Apoptosis in the Uterus during Spontaneous and Immune-Dependent Abortions in Mice.

We studied the expression of pluripotency factor Oct-4 and the intensity of apoptosis in the uterus during spontaneous and immune abortions in mice. Increased expression of factor Bax and reduced protein Bcl-2 synthesis in cells of the decidual membrane and decreased Oct-4 expression in the myometrium and perimetrium were detected. Thus, both spontaneous and immune-dependent abortions impair the apoptosis processes in the decidua and the formation of a pool of Oct-4+ cells in the uterus. In immune-dependent abortions, the intensity of apoptosis of decidual cells was lower than in spontaneous abortion. Low expression of the transcription factor Oct-4 in the myometrium and perimetrium characterizes pregnancy failure irrespective of its mechanisms.

An imbalance of the IL-33/ST2-AXL-efferocytosis axis induces pregnancy loss through metabolic reprogramming of decidual macrophages.

During embryo implantation, apoptosis is inevitable. These apoptotic cells (ACs) are removed by efferocytosis, in which macrophages are filled with a metabolite load nearly equal to the phagocyte itself. A timely question pertains to the relationship between efferocytosis-related metabolism and the immune behavior of decidual macrophages (dMΦs) and its effect on pregnancy outcome. Here, we report positive feedback of IL-33/ST2-AXL-efferocytosis leading to pregnancy failure through metabolic reprogramming of dMΦs. We compared the serum levels of IL-33 and sST2, along with IL-33 and ST2, efferocytosis and metabolism of dMΦs, from patients with normal pregnancies and unexplained recurrent pregnancy loss (RPL). We revealed disruption of the IL-33/ST2 axis, increased apoptotic cells and elevated efferocytosis of dMΦs from patients with RPL. The dMΦs that engulfed many apoptotic cells secreted more sST2 and less TGF-ß, which polarized dMΦs toward the M1 phenotype. Moreover, the elevated sST2 biased the efferocytosis-related metabolism of RPL dMΦs toward oxidative phosphorylation and exacerbated the disruption of the IL-33/ST2 signaling pathway. Metabolic disorders also lead to dysfunction of efferocytosis, resulting in more uncleared apoptotic cells and secondary necrosis. We also screened the efferocytotic molecule AXL regulated by IL-33/ST2. This positive feedback axis of IL-33/ST2-AXL-efferocytosis led to pregnancy failure. IL-33 knockout mice demonstrated poor pregnancy outcomes, and exogenous supplementation with mouse IL-33 reduced the embryo losses. These findings highlight a new etiological mechanism whereby dMΦs leverage immunometabolism for homeostasis of the microenvironment at the maternal-fetal interface.

The Role of Dendritic Cell Subsets in Recurrent Spontaneous Abortion and the Regulatory Effect of Baicalin on It.

Recurrent spontaneous abortion (RSA) is a relevant complication of pregnancy. Aberrant dendritic cell (DC) activities and differentiation have been identified to be involved in RSA, but the underlying mechanisms remain unclear. Baicalin from Radix Scutellariae possesses a wide range of pharmacological and biological activities. However, the effect of baicalin on DC function in RSA has not been investigated. Here, we analyzed the changes of peripheral and maternal-fetal interface DC subsets and function in patients and mice with RSA, respectively. Then, we further treated RSA mice with baicalin and analyzed the therapeutic effect and underlying mechanism. We found that DCs from the peripheral blood and decidua of RSA patients and the maternal-fetal of RSA mice were all polarized to conventional DCs, whose proportion was positively correlated with the mice embryo absorption rate. Moreover, DCs from RSA patients and mice showed increased expression of HLA-DR/MHC-II, CD80, and CD86 but decreased expression of CD274 and 33D1. Importantly, baicalin could alleviate embryo resorption of RSA mice by reversing conventional DCs to plasmacytoid DCs and functional molecule expression via inhibiting the STAT5-ID2 pathway. Our research further proved that DCs play an important role in the pathogenesis of RSA and baicalin might be used for treating RSA.

The expression of anti-protein disulfide isomerase A3 autoantibody is associated with the increased risk of miscarriage in euthyroid women with thyroid autoimmunity.

Miscarriage frequently occurs in euthyroid women with thyroid autoimmunity (TAI), but its mechanisms remain unclear. Our previous study has found that the serum level of anti-protein disulfide isomerase A3 autoantibody (PDIA3Ab) was significantly increased in mice with TAI. This study was aimed to explore whether there could be an association between the expression of PDIA3Ab and the occurrence of miscarriage in euthyroid TAI women. It was found that the serum level of PDIA3Ab was significantly increased in euthyroid TAI women as compared with that of non-TAI controls. Especially, serum PDIA3Ab level was markedly higher in euthyroid TAI women with miscarriage than the ones without miscarriage. Furthermore, binary logistic regression analysis showed that the serum PDIA3Ab level was an independent risk factor for spontaneous abortion in euthyroid TAI women with an odds ratio of 13.457 (95% CI, 2.965-61.078). The receiver operating characteristic (ROC) analysis of serum PDIA3Ab expression for predicting the miscarriage in euthyroid TAI women showed that the area under the curve was 0.707 ± 0.05 (P < 0.001). The optimal cut-off OD450 value of serum PDIA3Ab was 0.7129 with a sensitivity of 52.5% and specificity of 86.3% in euthyroid TAI women. Trend test showed that the prevalence of spontaneous abortion was markedly increased with the rise of serum PDIA3Ab level among TAI women in a titer-dependent manner. In conclusion, serum PDIA3Ab expression may imply an increased risk of spontaneous abortion in euthyroid TAI women, and it can be used as a new predictive bio-marker.

Pregnancy Outcome in Women With APECED (APS-1): A Multicenter Study on 43 Females With 83 Pregnancies.

CONTEXT: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED; also known as autoimmune polyendocrine syndrome type 1) has a severe, unpredictable course. Autoimmunity and disease components may affect fertility and predispose to maternal and fetal complications, but pregnancy outcomes remain unknown. OBJECTIVE: To assess fetal and maternal outcomes and course of clinical APECED manifestations during pregnancy in women with APECED. DESIGN AND SETTING: A multicenter registry-based study including 5 national patient cohorts. PATIENTS: 321 females with APECED. MAIN OUTCOME MEASURE: Number of pregnancies, miscarriages, and deliveries. RESULTS: Forty-three patients had altogether 83 pregnancies at median age of 27 years (range, 17-39). Sixty (72%) pregnancies led to a delivery, including 2 stillbirths (2.4%) and 5 (6.0%) preterm livebirths. Miscarriages, induced abortions, and ectopic pregnancies were observed in 14 (17%), 8 (10%), and 1 (1.2%) pregnancies, respectively. Ovum donation resulted in 5 (6.0%) pregnancies. High maternal age, premature ovarian insufficiency, primary adrenal insufficiency, or hypoparathyroidism did not associate with miscarriages. Women with livebirth had, on average, 4 APECED manifestations (range 0-10); 78% had hypoparathyroidism, and 36% had primary adrenal insufficiency. APECED manifestations remained mostly stable during pregnancy, but in 1 case, development of primary adrenal insufficiency led to adrenal crisis and stillbirth. Birth weights were normal in >80% and apart from 1 neonatal death of a preterm baby, no serious perinatal complications occurred. CONCLUSIONS: Outcome of pregnancy in women with APECED was generally favorable. However, APECED warrants careful maternal multidisciplinary follow-up from preconceptual care until puerperium.

Rift Valley Fever Virus Propagates in Human Villous Trophoblast Cell Lines and Induces Cytokine mRNA Responses Known to Provoke Miscarriage.

The mosquito-borne Rift Valley fever (RVF) is a prioritised disease that has been listed by the World Health Organization for urgent research and development of counteraction. Rift Valley fever virus (RVFV) can cause a cytopathogenic effect in the infected cell and induce hyperimmune responses that contribute to pathogenesis. In livestock, the consequences of RVFV infection vary from mild symptoms to abortion. In humans, 1-3% of patients with RVFV infection develop severe disease, manifested as, for example, haemorrhagic fever, encephalitis or blindness. RVFV infection has also been associated with miscarriage in humans. During pregnancy, there should be a balance between pro-inflammatory and anti-inflammatory mediators to create a protective environment for the placenta and foetus. Many viruses are capable of penetrating that protective environment and infecting the foetal-maternal unit, possibly via the trophoblasts in the placenta, with potentially severe consequences. Whether it is the viral infection per se, the immune response, or both that contribute to the pathogenesis of miscarriage remains unknown. To investigate how RVFV could contribute to pathogenesis during pregnancy, we infected two human trophoblast cell lines, A3 and Jar, representing normal and transformed human villous trophoblasts, respectively. They were infected with two RVFV variants (wild-type RVFV and RVFV with a deleted NSs protein), and the infection kinetics and 15 different cytokines were analysed. The trophoblast cell lines were infected by both RVFV variants and infection caused upregulation of messenger RNA (mRNA) expression for interferon (IFN) types I-III and inflammatory cytokines, combined with cell line-specific mRNA expression of transforming growth factor (TGF)-ß1 and interleukin (IL)-10. When comparing the two RVFV variants, we found that infection with RVFV lacking NSs function caused a hyper-IFN response and inflammatory response, while the wild-type RVFV suppressed the IFN I and inflammatory response. The induction of certain cytokines by RVFV infection could potentially lead to teratogenic effects that disrupt foetal and placental developmental pathways, leading to birth defects and other pregnancy complications, such as miscarriage.

Human leukocyte antigen-C and killer immunoglobulin-like receptors in reproductive medicine. / Antígeno leucocitario humano C y receptores tipo inmunoglobulina en medicina reproductiva.

Proper communication between natural killer cells and the human leukocyte antigens of the embryonic trophoblast at the maternal-fetal interface during pregnancy is essential for successful reproduction. However, specific combinations of embryonic human leukocyte antigen-C with killer immunoglobulin-like receptors on decidual natural killer cells (the immunological code of pregnancy) can be associated with obstetric morbidity and pregnancy loss. This article presents an updated review of the mechanisms underlying the interaction between embryonic human leukocyte antigen-C and maternal killer immunoglobulin-like receptors and their relevance to the physiology and pathophysiology of human reproduction.

Una adecuada comunicación entre las células asesinas naturales en la interfase materno-fetal con las moléculas de los antígenos de histocompatibilidad del trofoblasto embrionario es clave en el éxito de la reproducción. Sin embargo, combinaciones de determinados antígenos leucocitarios humanos tipo C embrionarios con los receptores tipo inmunoglobulina presentes en las células asesinas naturales deciduales (el código inmunológico del embarazo), pueden asociarse con morbilidad obstétrica y pérdidas gestacionales. En este artículo se presenta una revisión actualizada de los mecanismos subyacentes a la interacción entre el antígeno de histocompatibilidad tipo C embrionario y los receptores tipo inmunoglobulina maternos, y su relevancia tanto en la fisiología como en la fisiopatología de la reproducción humana.

Decidual IDO+ macrophage promotes the proliferation and restricts the apoptosis of trophoblasts.

Indoleamine 2, 3-dioxygenase (IDO), a tryptophan-catabolizing enzyme, is essential in physiological immunoregulation. The present research was conducted to elucidate the expression and roles of IDO in decidual macrophages (dMφ) during early pregnancy. Here, we observed a remarkable decrease of IDO+ dMφ from patients with unexplained recurrent spontaneous abortion (URSA). IDO+ dMφ displayed M2 phenotype with higher CD206, CD209 and CD163, and lower CD86. Interestingly, treatment with 1-methyl-d-tryptophan (1-MT, an IDO pathway inhibitor) led to the M1 bias of dMφ. Further analysis of the cytokine array and the qPCR showed decreased levels of trophoblast proliferation or invasion-related molecules (e.g., CXCL12 and BMP2) in 1-MT-treated dMφ. The data of co-culture system showed that 1-MT-pretreated dMφ decreased the proliferation and the expression of Ki-67 and Bcl-2, and increased cell apoptosis of HTR-8/Snveo cells. Additionally, the expression of IDO in U937 cells was up-regulated by decidual stromal cells (DSC) and HTR-8/Snveo cells in vitro, as well as estradiol and medroxyprogesterone. These data suggest that endocrine environment, DSC and trophoblasts should contribute to the high level of IDO in dMφ, and IDO+ dMφ with M2 dominant phenotype promote the survival of trophoblasts during early pregnancy. The abnormal lower level of IDO should trigger the dysfunction of dMφ, further suppress the survival of trophoblasts and increase the risk of miscarriage.

Ureaplasma parvum alters the immune tolerogenic state in placental tissue and could cause miscarriage.

OBJECTIVE: To study the inflammatory profile and genes involved in the response to bacterial infections in women who developed spontaneous abortion in the presence of Ureaplasma parvum. DESIGN: Cross-sectional study. SETTING: A maternal and child referral center. PATIENT(S): Eighty-nine women with spontaneous abortion and 20 women with normal vaginal delivery (control group) were studied. INTERVENTION(S): Samples of biopsied placental tissue were collected for Mollicutes detection. MAIN OUTCOME MEASURE(S): The samples were subjected to histologic analysis, immunohistochemical evaluation for macrophages and lymphocytes, cytokine quantification, and quantitative polymerase chain reaction array to evaluate the expression of 84 genes related to the innate and adaptive immune responses. RESULT(S): The presence of U. parvum in the abortion group was positively associated with the influx of polymorphonuclear cells in the placental tissue and increased concentrations of interleukin-6 and interleukin-12p70. U. parvum caused downregulation of genes involved in the immune response, such as attraction of immune cells, activation of an inflammatory response, T-helper cell 17 response activation, and activation of the complement system at the beginning and end of pregnancy. CONCLUSION: The direct action of U. parvum on placental tissue altered the gestational tolerogenic state, reducing the immune response against pathogens and activating the extrinsic apoptotic pathway, causing spontaneous abortion.

CD91 Derived Treg Epitope Modulates Regulatory T Lymphocyte Response, Regulates Expression of Costimulatory Molecules on Antigen-Presenting Cells, and Rescues Pregnancy in Mouse Pregnancy Loss Model.

The loss of immune tolerance to fetal antigens may result in reproductive failure. The downregulated number and activity of T regulatory lymphocytes, which are critical for the establishment of immune tolerance to fetal antigens, during pregnancy may lead to miscarriage. The adoptive transfer of Tregs prevents fetal loss in abortion-prone mice. Recently, we demonstrated that the administration of tregitopes, which are short peptides found in human and mouse immunoglobulins (IgGs), decreased the incidence of abortions in female CBA/J mice mated with DBA/2J mice. Here, two non-IgG source peptides (SGS and LKD) that can potentially bind to the major histocompatibility complex II (MHC II) with high affinity and induce Treg expansion were designed in silico. The immune dysregulation-induced pregnancy failure mouse model was used to evaluate the effect of SGS and LKD on immune response and pregnancy outcome. The fetal death rate in the SGS-treated group was lower than that in the phosphate-buffered saline-treated group. SGS and LKD upregulated the splenic pool of Tregs and modulated the T-helper cell (Th1)/Th2-related cytokine response at the preimplantation stage. Additionally, SGS and LKD downregulated the expression of CD80 and MHC class II molecules in splenic CD11c+ antigen-presenting cells. Thus, SGS treatment can result in beneficial pregnancy outcomes. Additionally, SGS peptide-mediated immunomodulation can be a potential therapeutic strategy for immune dysregulation-induced pregnancy failure.

The Role of Immune Cells in Recurrent Spontaneous Abortion.

Recurrent spontaneous abortion affects approximately 1-2% of women of childbearing, and describes a condition in which women suffer from three or more continuous spontaneous miscarriages. However, the origin of recurrent spontaneous abortion (RSA) remains unknown, preventing effective treatment and placing stress upon patients. It has been acknowledged that successful pregnancy necessitates balanced immune responses. Therefore, immunological aberrancy may be considered a root cause of poor pregnancy outcomes. Considerable published studies have investigated the relationship between various immune cells and RSA. Here, we review current knowledge on this area, and discuss the five main categories of immune cells involved in RSA; these include innate lymphocytes (ILC), macrophages, decidual dendritic cells (DCs), and T cells. Furthermore, we sought to summarize the impact of the multiple interactions of various immune cells on the emergence of RSA. A good understanding of pregnancy-induced immunological alterations could reveal new therapeutic strategies for favorable pregnancy outcomes.

The decidual expression of Interleukin-7 is upregulated in early pregnancy loss.

BACKGROUND: Maternal immunological rejection of the semi-allogenic fetus is discussed as one of the significant factors involved in early pregnancy loss. An array of cytokines secreted by both maternal and fetal cells is involved in generating a delicate maternal immune tolerance. Interleukin-7 (IL-7) is discussed to play a key role in pro-inflammatory processes, but there is still limited insight into the pathophysiological input on placentation and embryonic development in early pregnancy loss. PATIENTS AND METHODS: Cytokine level differences were identified with quantitative real-time PCR in placental tissue from spontaneous abortions (SA) (n = 18), recurrent spontaneous abortions (RSA) (n = 15), and healthy pregnancies (n = 15) at gestational weeks 7 to 14. Protein expression of IL-7 in the decidua was investigated by immunohistochemistry. IL-7-expressing cells were identified with double-immunofluorescence. RESULTS: Decidua of women with RSA expressed almost 51-times higher values of IL-7 in gene expression analysis. Immunohistochemistry identified a significant upregulation of IL-7 in the decidua of RSA specimens (p = .013) and in the decidua of women with SA (p = .004). Double-immunofluorescence confirmed decidual stroma cells as IL-7-expressing cells. CONCLUSION: Significantly elevated IL-7 values in the decidua of spontaneous and recurrent miscarriages imply a crucial role of the cytokine in the signaling at the feto-maternal interface of the placenta. An overexpression of IL-7 could result in early pregnancy loss by inducing a pro-inflammatory environment. Proven to be valuable in other autoimmune diseases, targeting IL-7 signaling therapeutically may prove to be a very beneficial treatment option for RSA patients.

Risk factors for pregnancy morbidity in women with antiphospholipid syndrome.

Antiphospholipid syndrome (APS) increases the risk of obstetric complications, but risk factors for pregnancy morbidity in women with APS remain incompletely characterized. This retrospective study included pregnant women with APS and a control group without APS admitted to Peking University People's Hospital between January 2013 and September 2019. Clinical data were extracted from medical records. Univariate and multivariate logistic regression analyses were used to identify factors associated with adverse pregnancy outcomes (fetal loss, premature birth, fetal growth restriction [FGR], preeclampsia and neonatal death). We included 64 pregnancies in 59 patients with APS (age, 32.3 ± 4.3 years) and 256 pregnancies in 256 women without APS (age, 30.4 ± 3.3 years). Compared with the control group, the APS group had higher incidence rates of preeclampsia (10.9 % vs. 2.3 %, P = 0.002), premature rupture of membranes (17.2 % vs. 3.9 %, P < 0.001), postpartum hemorrhage (23.4 % vs. 4.3 %, P < 0.001), fetal loss (4.7 % vs. 0.8 %, P = 0.024) and premature delivery at ≤34 weeks (7.8 % vs. 2.3 %, P = 0.047). The incidence rates of hypertension during pregnancy, HELLP syndrome, gestational diabetes, oligohydramnios and FGR were similar in both groups. Multivariate logistic regression revealed that three or more prior spontaneous miscarriages (odds ratio [OR], 6.162; 95 % confidence interval [CI], 1.271-29.882; P = 0.024) and double-positivity for antiphospholipid antibodies (OR, 4.024; 95 %CI, 1.025-15.794; P = 0.046) were independently associated with adverse pregnancy outcomes. APS increases the risks of adverse maternal and fetal outcomes during pregnancy. Three or more spontaneous miscarriages and double-positivity for antiphospholipid antibodies are risk factors for adverse pregnancy outcomes in women with APS.

Human Herpesviruses 6A and 6B in Reproductive Diseases.

Human herpesviruses 6A (HHV-6A) and human herpesvirus 6B (HHV-6B)-collectively, HHV-6A/B-are recently-discovered but ancient human viruses. The vast majority of people acquire one or both viruses, typically very early in life, producing an ineradicable lifelong infection. The viruses have been linked to several neurological, pulmonary and hematological diseases. In early human history, the viruses on multiple occasions infected a germ cell, and integrated their DNA into a human chromosome. As a result, about 1% of humans are born with the full viral genome present in every cell, with uncertain consequences for health. HHV-6A may play a role in 43% of cases of primary unexplained infertility. Both the inherited and acquired viruses may occasionally trigger several of the factors that are important in the pathogenesis of preeclampsia. Transplacental infection occurs in 1-2% of pregnancies, with some evidence suggesting adverse health consequences for the child. While emerging knowledge about these viruses in reproductive diseases is not sufficient to suggest any changes in current practice, we write this review to indicate the need for further research that could prove practice-changing.

Changes in the Distribution of Intrauterine Microbiota May Attribute to Immune Imbalance in the CBA/J×DBA/2 Abortion-Prone Mice Model.

Background: Female Genital Tract (FGT) is an important micro-ecological area of human body. Microbiota in the lower reproductive tract may subsequently invade the uterine cavity during embryo implantation and produce immune responses. CBA/J×DBA/2 mating combination has been widely used as an abortion-prone mice model but whether microbiota existed in their uterine cavity remains unclear. In this context, the role of the microbial communities in immune response deserves attention. Objective: To investigate the relationship between the distribution of microbiota in the uterine cavity of CBA/J×DBA/2 abortion-prone mouse model and the immune imbalance of the maternal-fetal interface. Methods: In this study, female CBA/J mice were paired with male DBA/2 mice to develop an abortion-prone model (BA group), and with male BALB/c mice to build a standard pregnancy model (BC group). The non-pregnant female mice were served as the control group (C group). Uterine flushing fluid and sera were collected on day 13.5 of pregnancy. 16S rRNA sequencing technology was used to analyze the distribution of intrauterine microbiota. Phylogenetic Investigation of Communities were conducted to predict the microbiota functions by Reconstruction of Unobserved States (PICRUST) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The serum IL 10, INF-γ, and TNF-α levels were examined using Enzyme-linked immunosorbent assay (ELISA) method. Results: All samples were detected with microbial communities. The α diversity (p = 0.00077) had significant differences among three groups. Proteobacteria was the most dominant phylum in C group (mean = 83.21%) and BA group (mean = 43.23%). Firmicutes was dominant in BC group (mean = 46.4%), as well as the second dominant one in C group (mean = 12.63%) and BA group (mean = 40.55%). Microbiota functions were associated with metabolism and immune response through the NOD-like receptor signaling pathway. The serum IL 10 level in BA group were significantly lower than that in BC group (10.14 ± 1.90 pg/ml, n = 8; vs. 19.03 ± 1.82 pg/ml, n = 10; p = 0.004). The serum TNF-α and INF-γ level in BA group were also significantly higher than that in BC group (523.1 ± 58.14 pg/ml, n = 8 vs. 310.3 ± 28.51 pg/ml, n = 10, p = 0.0029; 69.22 ± 5.38 pg/ml, n = 8 vs. 50.85 ± 2.45 pg/ml, n = 10, p = 0.0042). Conclusion: Microbial communities were colonized in uterine cavity of CBA/J mice both at non-pregnant stage and pregnant stage when mated with both BALB/c and DBA/2 male mice. The differentially abundant microbiome may be attributed to the immune tolerance through binding to the NOD-like receptor.

Granzyme B-expressing γδ-T and NK cells as a predictor of clinical pregnancy failure in patients with unexplained repeated implantation failure.

The limited cytotoxicity of immune cells facilitates a successful establishment of pregnancy. However, the association between cytotoxic granules and unexplained repeated implantation failure (uRIF) remains unkown. Twenty-one fertile controls and 54 patients with uRIF were included in this study. The pregnancy outcomes were monitored at different gestational periods. The peripheral blood lymphocytes were detected using specific monoclonal antibodies by flow cytometry. The percentage of perforin+ (Pfr+), granzyme B+ (GrB+), or granulysin+ (Gnly+) lymphocytes was not significantly different among fertile controls, uRIF patients with successful pregnancy outcomes, and uRIF patients with pregnancy failure. The percentage of GrB+ γδ-T cells in lymphocytes was markedly higher in uRIF patients with implantation failure and clinical pregnancy failure than that in uRIF patients with a corresponding successful pregnancy outcome. A four-tier risk model showed that the risk of suffering clinical pregnancy failure in uRIF patients among high risk tier (83.3 %), normal risk tier (65.0 %) and low risk tier (39.1 %) was elevated by 2-4 fold compared with uRIF patients among lowest risk tier (20.0 %). In addition, the percentage of GrB+ NK cells in lymphocytes tended to decrease in uRIF patients with pregnancy failure. The AUC of the combined indicator with GrB+ γδ-T cells and GrB+ NK cells was increased than that of GrB+ γδ-T cells and GrB+ NK cells for predicting clinical pregnancy failure. In conclusion, the frequency of GrB-expressing γδ-T and NK cells in peripheral blood could serve as a predictor of clinical pregnancy failure in patients with uRIF.

Mesenchymal stem cells induce expansion of regulatory T cells in abortion-prone mice.

Recurrent pregnancy loss (RPL) is one of the most common complications of early pregnancy associated in most cases with local or systemic immune abnormalities such as the diminished proportion of regulatory T cells (Tregs). Mesenchymal stem cells (MSCs) have been shown to modulate the immune responses by de novo induction and expansion of Tregs. In this study, we analyzed the molecular and cellular mechanisms involved in Treg-associated pregnancy protection following MSCs administration in an abortion-prone mouse mating. In a case-control study, syngeneic abdominal fat-derived MSCs were administered intraperitoneally (i.p) to the DBA/2-mated CBA/J female mice on day 4.5 of pregnancy. Abortion rate, Tregs proportion in spleen and inguinal lymph nodes, Ho1, Foxp3, Pd1 and Ctla4 genes expression at the feto-maternal interface were then measured on day 13.5 of pregnancy using flow cytometry and quantitative RT-PCR, respectively. The abortion rate in MSCs-treated mice reduced significantly and normalized to the level observed in normal pregnant animals. We demonstrated a significant induction of Tregs in inguinal lymph nodes but not in the spleen following MSCs administration. Administration of MSCs remarkably upregulated the expression of Ho1, Foxp3, Pd1 and Ctla4 genes in both placenta and decidua. Here, we show that MSCs therapy could protect the fetus in the abortion-prone mice through Tregs expansion and upregulation of Treg-related genes. These events could establish an immune-privileged microenvironment, which participates in the regulation of detrimental maternal immune responses against the semi-allogeneic fetus.