Redirecting reproductive immunology research toward pregnancy as a period of temporary immune tolerance

Prevalence of anti-nuclear antibodies in COVID-19 patients: a remarkable 2.5-fold rise compared to healthy controls

BACKGROUND

The SARS-CoV-2 virus, responsible for COVID-19, has the potential to induce the formation of antibodies that target self-antigens. This study aimed to investigate the prevalence of antinuclear antibodies (ANA), the most common type of autoantibody, in both healthy individuals and those recovered from COVID-19.

METHODS

This retrospective study involved 400 participants (200 with COVID-19 and 200 healthy controls), aged 18 to 60 years, without any chronic diseases, including autoimmune conditions. Analyses were performed using three different ANA ELISA test kits (anti-dsDNA, anti-ENA, and anti-Hep-2 nucleus tests) that were developed and validated.

RESULTS

Among the 200 healthy individuals, 38 (19%) tested positive for dsDNA, 37 (18.5%) for ENA, and 30 (15%) for Hep-2 nucleus antibodies. The rates of ANA positivity were significantly higher in individuals with COVID-19, with 97 (48.5%) positive for dsDNA, 81 (40.5%) for ENA, and 84 (42%) for Hep-2 nucleus antibodies (p < 0.05).

CONCLUSION

One in every two to three individuals with COVID-19 exhibited ANA positivity, indicating that the SARS-CoV-2 virus poses a significant risk regarding autoimmunity. Furthermore, the incidence of ANA in healthy individuals was observed to be higher than the literature average.

Maternal-fetal immunity and recurrent spontaneous abortion

Recurrent Spontaneous Abortion (RSA) is a common pregnancy complication, that has multifactorial causes, and currently, 40%-50% of cases remain unexplained, referred to as Unexplained RSA (URSA). Due to the elusive etiology and mechanisms, clinical management is exceedingly challenging. In recent years, with the progress in reproductive immunology, a growing body of evidence suggests a relationship between URSA and maternal-fetal immunology, offering hope for the development of tailored treatment strategies. This article provides an immunological perspective on the pathogenesis, diagnosis, and treatment of RSA. On one hand, it comprehensively reviews the immunological mechanisms underlying RSA, including abnormalities in maternal-fetal interface immune tolerance, maternal-fetal interface immune cell function, gut microbiota-mediated immune dysregulation, and vaginal microbiota-mediated immune anomalies. On the other hand, it presents the diagnosis and existing treatment modalities for RSA. This article offers a clear knowledge framework for understanding RSA from an immunological standpoint. In conclusion, while the "layers of the veil" regarding immunological factors in RSA are gradually being unveiled, our current research may only scratch the surface. In terms of immunological etiology, effective diagnostic tools for RSA are currently lacking, and the efficacy and safety of immunotherapies, primarily based on lymphocyte immunotherapy and intravenous immunoglobulin, remain contentious.

Immune Checkpoints in Recurrent Pregnancy Loss: New Insights into a Detrimental and Elusive Disorder

Recurrent pregnancy loss (RPL) refers to two or more miscarriages before 20 weeks gestation. Its prevalence is 1-2%; its pathogenesis remains unexplained in more than 50% of cases, in which the cause is thought to be abnormal immune activity during placentation leading to a lack of pregnancy-induced immune tolerance. It is unknown whether immune activity is deranged in the endometrium of women with RPL. We studied the gene expression and the quantitative tissue protein levels of three immune checkpoints (CD276, which enhances cytotoxic T-cell activity, cytotoxic T-lymphocyte-associated antigen-4 [CTL-4], which reduces Th1 cytokine production, and lymphocyte activation gene-3 [LAG-3], which shows suppressive activity on Tregs and CD4+ T-cells) in endometrial samples from 27 women with unexplained RPL and in 29 women with dysfunctional uterine bleeding and previous uneventful pregnancies as controls. RNA isolation, real-time PCR, protein isolation, and ELISA were performed. CD276 gene expression and protein tissue levels were significantly lower in the endometrium of the RPL group than in the controls, whereas both CTL-4 and LAG-3 were significantly higher. This difference suggests defective endometrial immune regulation and overactivation of immune response in women with a history of RPL, at least in relation to controls with dysfunctional uterine bleeding and previous normal reproductive history.

Psoriasis and adverse pregnancy outcomes: A nationwide case-control study in 491,274 women in Denmark

Background

The chronic systemic inflammation associated with psoriasis supposedly creates an undesirable milieu for a pregnancy, resulting in an increased risk of adverse pregnancy outcomes (APOs).

Objective

To investigate the association between psoriasis and APOs as well as how the association differs according to psoriasis severity (mild and moderate-to-severe).

Methods

This nationwide register-based case-control study collected data from 1973 to 2017. Cases were APOs (spontaneous abortion, ectopic pregnancy [EP], intrauterine fetal death, and stillbirth). Singleton live births were controls. Adjusted logistic regression models were used for statistical analyses.

Results

In total, 42,041 (8.56%) APOs and 449,233 (91.44%) controls were included. EP was the only APO that was found to be statistically associated with psoriasis (odds ratio, 1.34; 95% CI, 1.06-1.68). Odds ratio for EP was the highest for women with moderate-to-severe psoriasis (odds ratio, 2.77; 95% CI, 1.13-6.76). The absolute risk of EP was 2.48% higher for women with moderate-to-severe psoriasis compared with women without psoriasis (3.98% vs 1.50%).

Limitations

No access to clinical data confirming psoriasis severity.

Conclusion

The present study found a significant association between EP and psoriasis (absolute risk of 3.98%). As EP is the leading cause of maternal morbidity and mortality in the first trimester of pregnancy, our findings call for particular care for women of reproductive age with psoriasis.

How will our understanding of human development evolve over the next 10 years

In the next 10 years, the continued exploration of human embryology holds promise to revolutionize regenerative and reproductive medicine with important societal consequences. In this Comment we speculate on the evolution of recent advances made and describe emerging technologies for basic research, their potential clinical applications, and, importantly, the ethical frameworks in which they must be considered.

Reduced gastrointestinal worm burden following long term parasite control improves body condition and fertility in beef cows

The objective of this study was to compare effects of gastrointestinal parasite control over a long vs short term (PC-LT vs. PC-ST) on fecal parasite load, body condition and pregnancy in beef cows. On Day 0, fecal samples were collected from Angus cross cows (n = 1462) and they were assigned a body condition score (BCS: 1, emaciated; 9, Obese) and randomly divided into two groups (within location) to receive extended-release eprinomectin [PC-LT; n = 749; 50 mg/50 kg body weight (BW)] or pour-on ivermectin (PC-ST; n = 713; 25 mg/50 kg BW). All cows were synchronized with CO-Synch + CIDR [100 μg GnRH + progesterone vaginal insert (CIDR) application on Day 20, CIDR removal +25 mg PGF2a on Day 27, and artificial insemination +100 μg GnRH on Day 30 (66 h after CIDR removal)] protocol, artificially inseminated (AI; Day 30) and on Day 44, exposed to breeding bulls (1:40 bull to cow ratio) for the remainder of the 85 day breeding season. On Day 90, a second fecal sample was collected from all cows and the cows were examined to determine pregnancy/AI (P/AI). All cows were assigned a BCS on Day 180 and re-examined to determine pregnancy/breeding season (P/BS). Worm egg count per gram of feces (FEG) was determined by McMaster method. There were no differences (P > 0.1) between PC-LT and PC-ST groups on Day 0 for FEG (46.9 ± 13.1 vs 42.6 ± 15.2, respectively; mean ± SEM) or BCS (5.95 ± 0.12 vs 6.00 ± 0.20). The mean FEG (PC-LT, 12.3 ± 4.7 vs. PC-ST, 131.3 ± 10.9) on Day 90 and BCS (PC-LT, 6.04 ± 0.07 vs. PC-ST, 5.79 ± 0.13) on Day 180 differed (P < 0.05) between the two groups. Mean P/AI [PC-LT, 62.9 %; (471/749) vs PC-ST, 57.4 %; (409/713)] and P/BS [PC-LT, 92.9 % (696/749) vs PC-ST, 90.0 (642/713)] also differed (P < 0.05). Lower FEG at Day 90 resulted in moderate to good body condition at Day 180 and cows with moderate to good body condition at Day 180 had higher P/BS. In conclusion, lower worm burden with long-term parasite control reduced FEG and improved BCS, P/AI and P/BS.

A prospective study of influenza vaccination and time to pregnancy

BACKGROUND

Although pregnancy planners are a priority group for influenza vaccination in the United States, little is known about the extent to which influenza vaccination affects fecundability.

METHODS

We analyzed data from Pregnancy Study Online (PRESTO), an ongoing preconception cohort study of North American pregnancy planners. During June 2013 to August 2019, 8654 female participants and 2137 of their male partners completed a baseline questionnaire and were followed until reported pregnancy, fertility treatment initiation, loss to follow-up, or 12 menstrual cycles of attempt time, whichever came first. At baseline, male and female participants reported whether they received an influenza vaccination in the past year and the date of vaccination. We used proportional probabilities regression models to estimate fecundability ratios (FR) and 95% confidence intervals (CI) comparing those who did and did not report influenza vaccination, adjusting for demographics, anthropometrics, behavioral factors, and medical history.

RESULTS

Influenza vaccination in the past year was more common among female participants than male participants (47% vs. 37%). FRs were 1.04 (95% CI: 0.98-1.10) for female vaccination and 1.03 (95% CI: 0.93-1.14) for male vaccination. Among the 2137 couples with complete data on both partners, for 40% neither partner was vaccinated, 23% had female-only vaccination, 9% had male-only vaccination, and in 28% both partners were vaccinated. Compared with couples in which neither participant was vaccinated, FRs were 1.13 for female-only vaccination (95% CI: 0.99-1.29), 0.94 for male-only vaccination (95% CI: 0.78-1.12), and 1.07 when both partners were vaccinated (95% CI: 0.94-1.21). When restricted to recent vaccination before peak influenza season, results were similar.

CONCLUSIONS

Our data indicate no adverse effect of influenza vaccination on fecundability.

The impact of disturbances in natural conception cycles

PURPOSE

Many physicians and other healthcare professionals are often asked questions on interfering factors for conception by couples with a desire for children. Such possible disturbances include, for example, the very common minor diseases, stress and also sexual intercourse during the suspected implantation period. Non-scientifically based statements about disturbances in conception cycles, as found in many layman publications and on the internet, can strongly unsettle couples with a desire for children and force them into corset of rules of conduct. Therefore, a systematic scientific evaluation of the impact of disturbances on conception is urgently needed.

METHODS

A search for possible disturbances in natural conception cycles together with up to three of the respective pre-cycles in a large cycle database from users of the symptothermal method of natural family planning in Germany was performed. Disturbances were qualified by scientific panel decision and analysed statistically with their effects on the chances of spontaneous conception. Mixed logistical regression models and survival time analyses were used.

RESULTS

A total of 237 women with a total of 747 cycles could be included in the analysis. In 61% of all 237 conception cycles, disturbances occurred. The statistical analysis shows that disturbances in natural conception cycles unexpectedly increase the likelihood of pregnancy by an overall factor of 1.32 (95% CI 1.04-1.70). Sexual intercourse in the window of implantation does not decrease the chances of conception. Relaxation states at the time of ovulation and/or during the implantation period have no representable effect and do not increase the chance of pregnancy.

CONCLUSIONS

Couples trying to conceive should at least be informed that disturbances in conception cycles, such as minor diseases, stress or sexual intercourse during the implantation period do not interfere with conception. Relaxation has no effect in favour of success. This takes away the guilty feeling of couples, fearing that they possibly did something wrong in cycles without the desired pregnancy.

Endometrial Immune Dysfunction in Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) represents an unresolved problem for contemporary gynecology and obstetrics. In fact, it is not only a relevant complication of pregnancy, but is also a significant reproductive disorder affecting around 5% of couples desiring a child. The current knowledge on RPL is largely incomplete, since nearly 50% of RPL cases are still classified as unexplained. Emerging evidence indicates that the endometrium is a key tissue involved in the correct immunologic dialogue between the mother and the conceptus, which is a condition essential for the proper establishment and maintenance of a successful pregnancy. The immunologic events occurring at the maternal-fetal interface within the endometrium in early pregnancy are extremely complex and involve a large array of immune cells and molecules with immunoregulatory properties. A growing body of experimental studies suggests that endometrial immune dysregulation could be responsible for several, if not many, cases of RPL of unknown origin. The present article reviews the major immunologic pathways, cells, and molecular determinants involved in the endometrial dysfunction observed with specific application to RPL.

Reflections upon immunological mechanisms involved in fertility, pregnancy and parasite infections

During a pregnancy, the mother accepts her semi-allogeneic fetus with no signs of immunological rejection. Therefore, some modulation of the maternal immune system must occur. Similarly, changes in the host's immune system occurs during infections with parasites. In a study conducted in an endemic area in Bolivia, it has been reported that women infected with either the helminthic parasite roundworm or hookworm were estimated to give birth to either two more, or three fewer, children than uninfected, endemic women, respectively. Immune regulation by helminthic parasites is a rather well-researched concept, but there are few reports on the effects on human fecundity. The current review focuses on mechanisms of possible importance for especially the increased fertility rates in women infected with roundworm. The host immune response to roundworm has been hypothesized to be more favourable for a successful pregnancy because it bears resemblance to the anti-inflammatory immunological responses observed in pregnancy, steering the immunological response away from a pro-inflammatory state that seem to suppress fecundity. Further research into parasitic worm interactions, fertility, and the molecular mechanisms that they unfold may widen our understanding of the immunomodulatory pathways in both helminthic infections and in fertility and pregnancy.

Endometrium immunomodulation by intrauterine insemination administration of treated peripheral blood mononuclear cell prior frozen/thawed embryos in patients with repeated implantation failure

In assisted reproductive technology (ART) programmes, approximately 10% of infertile patients have at least two or three repeated implantation failures (RIFs) after an in vitro fertilization (IVF) protocol. Successful implantation mainly depends on local immune tolerance mechanisms involving a spectrum of cytokines, interleukins and growth factors. The latter have played pivotal roles in the recruitment of immune cells (and notably T-lymphocyte cells). In total, 250 couples participating in frozen-thawed embryo transfer programme were incorporated in a randomized clinical trial (peripheral blood mononuclear cells (PBMC) subgroup: n=122; control subgroup: n=128). In the PBMC group, a blood sample was collected 5 days before the scheduled frozen-thawed embryo transfer; PBMCs were isolated using Ficoll separation and then cultured for 72 h. Two days prior to embryo transfer, 0.4 ml of cultured PBMCs were transferred into the patient's uterus. Although the clinical pregnancy rate was higher in the PBMC group (34.4%) than in the control group (23.4%), this difference was not statistically significant (P=0.05 in a chi-squared test). Nevertheless, when we limited the analysis to patients with ≥3 RIFs (n=138), there was a significant difference in the clinical pregnancy rate between the PBMC group (38.6%) and the control group (19.7%; P=0.01). Our results imply that PBMC transfer can be part of effective fertility treatment for patients with RIF.

The Tolerogenic Function of Regulatory T Cells in Pregnancy and Cancer

Regulatory T cells, a subpopulation of suppressive T cells, are potent mediators of self-tolerance and essential for the suppression of triggered immune responses. The immune modulating capacity of these cells play a major role in both transplantation, autoimmune disease, allergy, cancer and pregnancy. During pregnancy, low numbers of regulatory T cells are associated with pregnancy failure and pregnancy complications such as pre-eclampsia. On the other hand, in cancer, low numbers of immunosuppressive T cells are correlated with better prognosis. Hence, maternal immune tolerance toward the fetus during pregnancy and the escape from host immunosurveillance by cancer seem to be based on similar immunological mechanisms being highly dependent on the balance between immune activation and suppression. As regulatory T cells hold a crucial role in several biological processes, they may also be promising subjects for therapeutic use. Especially in the field of cancer, cell therapy and checkpoint inhibitors have demonstrated that immune-based therapies have a very promising potential in treatment of human malignancies. However, these therapies are often accompanied by adverse autoimmune side effects. Therefore, expanding the knowledge to recognize the complexities of immune regulation pathways shared across different immunological scenarios is extremely important in order to improve and develop new strategies for immune-based therapy. The intent of this review is to highlight the functional characteristics of regulatory T cells in the context of mechanisms of immune regulation in pregnancy and cancer, and how manipulation of these mechanisms potentially may improve therapeutic options.

Expected advances in human fertility treatments and their likely translational consequences

BACKGROUND

Due to rapid research progress in reproductive biology and reproductive clinical endocrinology, many human infertility treatments are close to potential breakthroughs and translational applications. We here review current barriers, where such breakthroughs will likely come from, what they will entail, and their potential clinical applications.

MAIN TEXT

The radical nature of change will primarily benefit older women, reduce fertility treatment costs and thereby expand access to treatment. A still widely overlooked prerequisite for implantation and normal pregnancy maintenance is timely development of maternal immunological tolerance toward an implanting paternal semi-allograft, if malfunctioning associated with implantation failure and pregnancy loss, while premature termination of tolerance appears associated with premature labor, pre-eclampsia/eclampsia and gestoses of pregnancy. Common denominators between pregnancy and invasive malignancies have again been attracting attention, suggesting that, like in malignant tumors, degrees of embryo aneuploidy may affect invasiveness and ability to "disarm" the immune system's innate response against implanting embryos. Linking tolerance to implantation, we offer evidence that the so-called "implantation window" is likely immunological rather than hormonally defined.

CONCLUSIONS

Because many here outlined treatment changes will disproportionally benefit older women, they will exert a pronounced effect on society, as increasing numbers of women at grandparental ages will become mothers.

Complex Analysis of Total and Fetal DNA and Cytokines in Blood Plasma of Pregnant Women with Preeclampsia

We performed a complex analysis of total and fetal extracellular DNA, 8 cytokines (IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-macrophage CSF, IFNγ, and TNFα) in blood plasma obtained from women with preeclampsia prior to labor onset. Total (sensitivity 89.47%, specificity 93.75%) and fetal extracellular DNA (sensitivity 73.68%, specificity 87.5%) were the most accurate parameters determining preeclampsia. We revealed a high correlation (p=3×10^-6) between total and fetal extracellular DNA levels in the group of preeclampsia. Preeclampsia significantly increased the levels of macrophage factors IL-10 and IL-6. These cytokines significantly correlated with the levels of total and fetal extracellular DNA in the preeclampsia group. In the control group, such correlations were not observed. These findings obtained suggest that preeclampsia develops upon increased macrophage activity, leading to destruction of the placenta trophoblast cells.

Placenta immune infiltrates and perinatal outcomes

Pregnancy is a state of immunotolerance and loss of this immunotolerance may lead to fetal rejection, pregnancy complications, and neonatal complications. Immunobiology of pregnancy is complex and involves unique immune cell populations specific to pregnancy, changes in mucosal immune cells and peripheral immune system, and reciprocal adaptations between the mother and the fetus. The mechanisms required for sustaining a healthy feto-placental barrier and a healthy pregnancy such as activation of regulatory immune responses with a predominance of regulatory T cells lead to immune evasion and propagation of cancer. It is intriguing to note that the immune pathways which are effective in limiting or eliminating cancer form the very basis for loss of feto-maternal tolerance. In this article, we aim to compare and contrast immunobiology of healthy and pathological pregnancies mirroring with cancer immunobiology with a focus on immune checkpoint receptors.

Immunological Tolerance, Pregnancy, and Preeclampsia: The Roles of Semen Microbes and the Father

Although it is widely considered, in many cases, to involve two separable stages (poor placentation followed by oxidative stress/inflammation), the precise originating causes of preeclampsia (PE) remain elusive. We have previously brought together some of the considerable evidence that a (dormant) microbial component is commonly a significant part of its etiology. However, apart from recognizing, consistent with this view, that the many inflammatory markers of PE are also increased in infection, we had little to say about immunity, whether innate or adaptive. In addition, we focused on the gut, oral and female urinary tract microbiomes as the main sources of the infection. We here marshall further evidence for an infectious component in PE, focusing on the immunological tolerance characteristic of pregnancy, and the well-established fact that increased exposure to the father's semen assists this immunological tolerance. As well as these benefits, however, semen is not sterile, microbial tolerance mechanisms may exist, and we also review the evidence that semen may be responsible for inoculating the developing conceptus (and maybe the placenta) with microbes, not all of which are benign. It is suggested that when they are not, this may be a significant cause of PE. A variety of epidemiological and other evidence is entirely consistent with this, not least correlations between semen infection, infertility and PE. Our view also leads to a series of other, testable predictions. Overall, we argue for a significant paternal role in the development of PE through microbial infection of the mother via insemination.