Immunological Indicators of Recurrent Pregnancy Loss: A Mendelian Randomization Study

Recurrent pregnancy loss (RPL) is thought to be related to maternal-fetal immune tolerance disorders. Immune monitoring of RPL patients mainly involves two aspects: inflammatory factors and immune cells. However, most observational studies have reported controversial findings. This study aimed to confirm whether abnormal inflammatory factors and immune cells in peripheral blood may lead to RPL, and guide clinical immune monitoring. We demonstrated causality using two-sample Mendelian randomization. Sensitivity analysis, reverse Mendelian randomization and meta-analysis were used to enhance the effectiveness of the results. There was a causal relationship between the level of IL-12 (OR = 1.78, 95% CI = 1.25-2.55; P = 0.00149) and RPL for 41 inflammatory factors. We screened 5 groups of immune cell subtypes that were causally associated with RPL: switched memory B-cell absolute count (OR = 0.66, 95% CI = 0.49-0.87, P = 0.00406), IgD + CD24 + B-cell absolute count (OR = 0.69, 95% CI = 0.53-0.88, P = 0.00319), CD39 + resting CD4 regulatory T-cell %CD4 regulatory T-cell (OR = 0.86, 95% CI = 0.78-0.95, P = 0.00252), activated & resting CD4 regulatory T-cell %CD4 regulatory T-cell (OR = 0.89, 95% CI = 0.82-0.97, P = 0.00938) and CD45 RA + CD28-CD8 + T-cell %CD8 + T-cell (OR = 0.99, 95% CI = 0.98-1.00, P = 0.01231). In terms of inflammatory factors, a causal relationship between IL-12 and RPL in peripheral blood was confirmed. We also identified five immune cell phenotypes that play a protective role. This suggests that there may be protective B cells and CD8 + T-cell subsets in peripheral blood, and the protective effect of Tregs was proved again. Immune monitoring of peripheral blood in patients with RPL seems to be necessary and the foundation for precision medicine.

Treatment with low-dose prednisone in refractory obstetric antiphospholipid syndrome: A retrospective cohort study and meta-analysis

BACKGROUND

Glucocorticoids have been suggested as a potential therapy in refractory obstetric antiphospholipid syndrome (oAPS). Our aims were to describe a cohort of patients with oAPS treated with low-dose glucocorticoids and to perform a systematic review and meta-analysis evaluating the effects of additional glucocorticoids on the pregnancy outcomes in oAPS patients.

METHODS

Retrospective study that included 11 women diagnosed with primary antiphospholipid syndrome. The meta-analysis was conducted by fitting random effects models and was checked for heterogeneity.

RESULTS

All women had suffered from early pregnancy losses and two also had a history of fetal deaths. We studied 47 pregnancies that resulted in 32 abortions (68.1%) and 3 fetal deaths (6.4%). Twenty-six pregnancies were under treatment, mainly LDA and LMWH. Low-dose glucocorticoids were indicated in 13 pregnancies (always in association with LDA and LMWH). There was a decrease in pregnancy loss in those patients treated with LDA and LMWH. Treatment with glucocorticoids significantly increased the rate of successful pregnancy (38.5% abortions in treated vs 85.3% abortions in non-treated pregnancies; p=0.003). After multivariate GEE analysis, only glucocorticoids remained inversely associated with pregnancy loss (OR=0.157, (CI 0.025-0.968, p=0.046)). The meta-analysis showed that glucocorticoids tended to improve the frequency of successful pregnancy (OR= 0.509 (0.252-1.028), p=0.06). Three cases of gestational diabetes and one of preeclampsia were observed in our cohort. The meta-analysis, which mostly included studies using high-dose steroids, showed that glucocorticoids increased not only the frequency of preeclampsia and gestational diabetes, but also the rate of pre-term birth.

CONCLUSIONS

The efficacy of low-dose glucocorticoids in addition to the standard therapy in patients with refractory oAPS should be confirmed in well-designed clinical trials. However, high doses of steroids significantly increase the frequency of maternal and fetal morbidities, making their use strongly inadvisable.

Maternal and fetal safety of intravenous immunoglobulin in women with reproductive failure

PROBLEM

Intravenous immunoglobulin G (IVIG) is an emerging regimen for women with reproductive failures (RF) during- or pre-pregnancy who have aberrant cellular immune reactions. Studies investigating teratogenicity of IVIG have been limited. Herein, we evaluated the fetal teratogenicity of IVIG and IVIG-related obstetric complications.

METHOD OF STUDY

Women who used IVIG during pregnancy due to RF with cellular immune aberrances were enrolled from four medical centers in Korea. The pregnancy outcomes were collected.

RESULTS

A total of 370 RF women who used IVIG during their pregnancy were enrolled. Most of the patients started the IVIG therapy before 12 weeks of gestation and 229 women continued IVIG treatment beyond 12 weeks of gestation. The mean age of the subjects was 34.8 years and the mean total dosage of IVIG was 125.3 g. A total of 307 women had livebirths and six of them were twins. Of 301 singleton livebirths, obstetric complications were developed as follows: preterm births (12.0%), gestational diabetes (7.0%), preeclampsia (4.0%), placental abruption (1.3%), placenta previa (4.3%), and placenta accrete (1.7%). Total six cases (1.99%) had major fetal anomalies in livebirths. The incidence of birth defects is similar to those of the general population in Korea and the previous report in infertile women. No IVIG -related viral contamination was noted.

CONCLUSION

IVIG use during pregnancy did not increase obstetric complications and fetal teratogenicity. This study can be an evidence of maternal and fetal safety of IVIG administration during pregnancy.

A novel update on vitamin D in recurrent pregnancy loss (Review)

Recurrent pregnancy loss (RPL) is usually characterized as ≥3 miscarriages before 20 weeks of gestation. Patients with RPL may have autoimmune abnormalities or alloimmune problems. Vitamin D has a major function on the mechanism of immunomodulation at the maternal-fetal interface. However, whether vitamin D can be used as an effective method to treat patients with RPL requires investigation. It has been reported that vitamin D could prevent the occurrence of antiphospholipid syndrome (APS) by reducing the expression levels of anti-β2 glycoprotein and tissue factor in RPL cases with APS. In addition, there is an opposite relationship between vitamin D and thyroid peroxidase antibody levels in autoimmune thyroid disease cases with RPL. Vitamin D changes the ratio of T helper (Th) 1/Th2 and regulatory T cell/Th17 to a certain extent, as well as affects the activity of natural killer cells and the production of cytokines to reduce the incidence of RPL. The objective of the current review was to address the research progress of vitamin D in RPL in recent years, which could facilitate the use of vitamin D treatment to enhance the pregnancy outcome of RPL. Collectively, it was suggested that vitamin D may be used as an important and effective immunotherapeutic agent for patients with RPL.

Role of Low Molecular Weight Heparin in the Management of Unexplained Recurrent Pregnancy Loss: A Review of Literature

Recurrent pregnancy loss remains a significant challenge in gynecological practice, accounting for about 2%-4% of pregnancies. In some patients, the etiology is unknown. Unexplained recurrent pregnancy loss (URPL) refers to the spontaneous loss of three or more consecutive pregnancies without an identifiable risk factor, accounting for about 40%-50% of pregnancy losses. The review aims to understand the role of low molecular weight heparin (LMWH) in the treatment of URPL. Articles for this review have been found in the PubMed database, and studies published more than ten years before the review excluded. The articles were reviewed to determine the effect of LMWH on live birth rates, reduced late pregnancy complications, and adverse drug reactions following its use. Many studies show improved live birth rates in women treated with LMWH compared to the control, while some studies show no improvement. There was no statistically significant difference in reducing late pregnancy complications, such as preeclampsia, intrauterine growth restriction, preterm labor, and low birth weight, in either study and control groups. Adverse drug reaction was rare among women treated with LMWH and, if present, was mild and self-limiting, thus making it a safe therapy. More studies, preferably large multicenter randomized controlled trials, need to be conducted on the use of LMWH to establish a consensus guideline on the treatment of URPL.

Prednisone for patients with recurrent implantation failure: study protocol for a double-blind, multicenter, randomized, placebo-controlled trial

Background

Recurrent implantation failure (RIF) brings great challenges to clinicians and causes deep frustration to patients. Previous data has suggested that prednisone may play a promising role in the establishment of pregnancy and help improve the pregnancy outcome in women with RIF. But there is insufficient evidence from randomized clinical trials that had adequate power to determine if prednisone can enhance live births as the primary outcome.

Methods/design

This trial is a prospective, multicenter, randomized, double-blind, placebo-controlled clinical trial (1:1 ratio of prednisone versus placebo). Infertile patients with RIF who intend to undergo frozen-thawed embryo transfer (FET) after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) or pre-implantation genetic testing for aneuploidy (PGT-A) will be enrolled and randomly assigned to two parallel groups. Participants will be given the treatment of prednisone or placebo from the start of endometrial preparation till the end of the first trimester of pregnancy if pregnant. The primary outcome is live birth rate.

Discussion

The results of this study will provide evidence for the effect of prednisone on pregnancy outcomes in patients with RIF.

Trial registration

Chinese Clinical Trial Registry, ChiCTR1800018783. Registered on 9 October 2018.

Decreased HLA-C1 alleles in couples of KIR2DL2 positive women with recurrent pregnancy loss

Specific killer cell immunoglobulin-like receptor (KIR) in women with recurrent pregnancy loss (RPL) and HLA ligands in couples invoke a susceptibility to RPL. However, the relationship between KIR2DL2 and its cognate ligand HLA-C1 has not been explored. In this prospective cohort study, 160 Caucasian women with RPL and 99 partners were included. KIR/HLA-C typing, NK assay, Th1/Th2 intracellular cytokine ratios, 25-(OH)-vitamin D level, and the presence of autoantibodies were analyzed. KIR2DL2 positive women (P = 0.023) and their partners (P = 0.017) had lower allele frequencies of HLA-C1 than those of KIR2DL2 negative women. KIR2DL2 positive women had significantly lower genotype frequency of HLA-C1C1 as compared to the North American Caucasian population controls (P < 0.05). In the partners of KIR2DL2 positive women, there was a substantially higher frequency of HLA-C2C2 than controls (P = 0.016). Besides, KIR2DL2 negative women had a higher prevalence of anti-ssDNA antibody as compared with that of KIR2DL2 positive women (P = 0.043). There were no differences in the distribution of HLA-C genotypes based on KIR2DL2, regardless of pregnancy outcome in women with RPL and their partners while on immunomodulation treatment. In conclusion, decreased ligands for inhibitory KIRs (inhKIR) could lead to insufficient inhibition of maternal uterine NK cells toward the trophoblast, thereby contributing to the pathogenesis of RPL. Specific KIR and HLA-C genotyping may predict the reproductive outcome of women with RPL.

Uterine Radial Artery Resistance Index Predicts Reproductive Outcome in Women with Recurrent Pregnancy Losses and Thrombophilia

Uterine radial artery resistance index (URa-RI) by Doppler ultrasound may reflect the changes in the uteroplacental circulation and be associated with adverse events in early pregnancy. Recurrent pregnancy losses (RPL) are associated with thrombophilia, and anticoagulation treatment with low molecular weight heparin improves pregnancy outcome in women with RPL and thrombophilia. A retrospective cohort study was conducted in 139 pregnant women with 3 or more RPL and thrombophilia. The relationship between pregnancy outcome and dynamic changes of URa-RI was analyzed in 116 women who delivered a liveborn infant and 23 who miscarried the index pregnancy. Patients were on preconception low molecular weight heparin, low-dose aspirin (81mg per day), and prednisone treatment. URa-RI was measured during periovulation time, at the time of positive pregnancy test, and then repeated every two weeks until 32-week gestation or the time of miscarriage. The URa-RI at 8-week gestation was significantly higher in women who miscarried the index pregnancy than those who delivered alive born infant (0.51±0.08 vs. 0.42±0.03, P<0.001). Receiver operating characteristic curve analysis demonstrated that URa-RI of 8 wk gestation effectively distinguished women who miscarried from those who had a live birth with an area under the curve of 82.6% (95% CI 69.01-97.17). After adjusting for covariates including age, BMI, and number of miscarriages, multiple logistic regression models showed that each 0.1 unit increase of URa-RI of 8 wk gestation was associated with 18.70-point increase in the risk of miscarriage (OR19.70, 95%CI 4.26-91.1, P<0.001), and women with an URa-RI≥0.45 had an OR of 49.48 (95% CI 8.01-307.95; P<0.001) for miscarriage compared to those who had URa-RI<0.45. In women with RPL and inherited thrombophilia, increased URa-RI at 8-week gestation was associated with spontaneous abortion independent of other risk factors while they were on anticoagulation treatment.

Prednisone may rebuild the immunologic homeostasis: Alteration of Th17 and Treg cells in the lymphocytes from rats' spleens after treated with prednisone-containing serum

Background

This study aimed to investigate alterations of T helper 17 (Th17), regulatory T (Treg) cells and relative cytokines after treating with prednisone‐contained serum. Lymphocytes were isolated from female rats' spleens.

Methods

The splenic lymphocytes were divided into four groups: which were treated with normal rats' serum (control); prednisone‐containing rats' serum (PDN); normal rats' serum and cytokines (CTK); cytokines and prednisone‐containing rats' serum (PDN + CTK). The mRNA expression level of RORC, Foxp3 and interleukin‐17 (IL‐17) was examined by reverse transcription‐polymerase chain reaction. The quantities of Th17 and Treg cells were tested by flow cytometry, and the concentrations of IL‐17 and IL‐10 were detected by enzyme‐linked immunosorbent assay.

Results

Higher mRNA expression level of Foxp3, percentages of Treg/CD4⁺, and concentrations of IL‐10, lower mRNA expressions of RORC and IL‐17, concentrations of IL‐17 and percentages of Th17/CD4⁺ in PDN group were detected, compared with control group (all p < 0.01). Similar trend was detected in PDN + CTK group, compared with CTK group (all p < 0.01).

Conclusion

Our results suggest that prednisone may rebuild the immunologic homeostasis and may be used in human diseases with changes in the imbalance immune system such as unexplained recurrent spontaneous abortion (URSA), hepatitis B infection, or other autoimmune diseases.

Immune modulation of i.v. immunoglobulin in women with reproductive failure

Background

The mechanism of maternal immune tolerance of the semi‐allogenic fetus has been explored extensively. The immune reaction to defend from invasion by pathogenic microorganisms should be maintained during pregnancy. An imbalance between the immune tolerance to the fetus and immune activation to the pathogenic organisms is associated with poor pregnancy outcomes. This emphasizes that the immune mechanism of successful reproduction is not just immune suppression, but adequate immune modulation.

Methods

In this review, the action of i.v. immunoglobulin G (IVIg) on the immune system and its efficacy in reproductive failure (RF) was summarized. Also suggested is the indication of IVIg therapy for women with RF.

Main findings (Results)

Based on the mechanism of the immune regulation of IVIg and following confirmation of the immune modulation effects of it in various aberrant immune parameters in patients with RF, it is obvious that IVIg is effective in recurrent pregnancy losses and repeated implantation failures with immunologic disturbances.

Conclusion

The authors recommend IVIg therapy in patients with RF with aberrant cellular immunologic parameters, including a high natural killer cell proportion and its cytotoxicity or elevated T helper 1 to T helper 2 ratio, based on each clinic's cut‐off values. Further clinical studies about the safety of IVIg in the fetus and its efficacy in other immunologic abnormalities of RF are needed.

Prednisone may induce immunologic tolerance by activating the functions of decidual immune cells in early pregnancy

The objective of this study was to investigate alterations in human first-trimester decidual immune cells (DICs) and relevant cytokines after treatment with prednisone. Decidual lymphocytes were treated with prednisone alone, cytokines alone or the combination of prednisone and cytokines. Levels of STAT3, STAT5, RORC and FOXP3 mRNA were assayed using quantitative real-time PCR, proportions of CD4⁺ T helper 17 (Th17) and CD4⁺ T regulatory (Treg) cells were measured using flow cytometry, and concentrations of interleukin (IL)-17A and IL-10 were determined using enzyme-linked immunosorbent assay. After treatment with prednisone alone, levels of STAT5 and FOXP3 mRNA were significantly higher than in untreated control cells (both P < 0.01), while levels of RORC mRNA were significantly lower than in controls (P < 0.05). Levels of STAT3 mRNA did not vary significantly with treatment. After treatment with prednisone alone, proportions of Th17/CD4⁺ cells and levels of IL-17A were significantly lower than in control cells, and proportions of Treg/CD4⁺ cells and levels of IL-10 significantly higher than in controls (all P < 0.01). Our results suggest that prednisone may improve pregnancy outcomes by restoring immunological homeostasis through up-regulation of STAT5 and FOXP3, induction of DIC differentiation into Treg cells, inhibition of DIC differentiation into Th17 cells, reduction of IL-17A secretion and induction of IL-10 secretion.

Serum hCG-β levels of postovulatory day 12 and 14 with the sequential application of hCG-β fold change significantly increased predictability of pregnancy outcome after IVF-ET cycle

PURPOSE

To investigate hCG-β level on postovulatory day (POD) 12 and its fold increase as predictors for pregnancy outcome after in vitro fertilization (IVF) cycles.

METHODS

A retrospective cohort study was performed in total 1408 fresh and 598 frozen cycles between November 2008 and October 2011, which resulted in biochemical pregnancy, early pregnancy loss, or live birth of singleton pregnancy. The serum hCG-β levels of POD 12 and 14 were compared among biochemical pregnancy, early pregnancy loss, and live birth groups. The cutoff values of POD 12 and 14 hCG-β levels and the degree of hCG-β increase from POD 12 to 14 were determined for each pregnancy outcome.

RESULTS

POD 12 and 14 hCG-β levels stratified based on pregnancy outcomes were significantly different among the biochemical pregnancy, early pregnancy loss, and live birth in both fresh and frozen cycles. Serum hCG-β levels of POD 12 and 14 and the fold increase of hCG-β levels from POD 12 to 14 significantly predict pregnancy outcomes after fresh and frozen cycles. Among these, the cutoff value of POD 14 hCG-β had the highest sensitivity and positive predictive value (PPV). In fresh cycles, the cutoff values of POD 12 and 14 serum hCG-β levels for clinical pregnancies were 30.2 mIU/mL (sensitivity 81.3 %, specificity 79.6 %, and PPV 92.3 %) and 70.5 mIU/mL (sensitivity 88.4 %, specificity 85.2 %, and PPV 94.7 %). In pregnancies with POD 12 serum hCG-β levels ≥30.2 mIU/mL, the cutoff level of increase of hCG-β for clinical pregnancy was 2.56 (sensitivity 73.6 %, specificity 72.4 %, and PPV 97.8 %). Sequential application of cutoff values such as POD 12 hCG-β and fold increase of hCG-β improved predictability of pregnancy outcome as compared with that of POD 12 hCG-β alone. The cutoff values of POD 12 and 14 serum hCG-β levels for live birth were 40.5 mIU/mL (sensitivity 75.2 %, specificity 72.6 %, PPV 78.9 %) and 104.5 mIU/mL (sensitivity 80.3 %, specificity 74.1 %, PPV 80.8 %). In the frozen cycles, the cutoff values of POD 12 and 14 serum hCG-β level for clinical pregnancy were 31.5 IU/L (sensitivity 80.4 %, specificity 71.1 % and PPV 90 %) and 43.5 mIU/mL (sensitivity 72.6 %, specificity 71.7 %, PPV 77.2 %). In pregnancies with POD 12 serum hCG-β level ≥31.5 mIU/mL, the cutoff value for fold increase of hCG-β was 2.38 for clinical pregnancy (sensitivity 81.6 %, specificity 71.4 % and PPV 87.9 %). The cutoff values of POD 12 and 14 for live birth were 43.5 mIU/mL (sensitivity 72.6 %, specificity 71.7 %, PPV 77.2 %) and 101.6 mIU/mL (sensitivity 79.6 %, specificity 71.1 %, PPV 78.4 %). Sequential application of cutoff values for POD 12 hCG-β level and fold increase of hCG-β significantly increased PPV for live birth but not clinical pregnancy in frozen cycles.

CONCLUSIONS

Early prediction of pregnancy outcome by using POD 12 and 14 cutoff levels and sequential application of cutoff value of fold increase could provide appropriate reference to health care providers to initiate earlier management of high-risk pregnancies and precise follow-up of abnormal pregnancies.

Immunological modes of pregnancy loss: inflammation, immune effectors, and stress

Inflammatory immune response plays a key role in reproductive failures such as multiple implantation failures (MIF), early pregnancy loss, and recurrent pregnancy losses (RPL). Cellular immune responses particularly mediated by natural killer (NK), and T cells are often dysregulated in these conditions. Excessive or inappropriate recruitment of peripheral blood NK cells to the uterus may lead to cytotoxic environment in utero, in which proliferation and differentiation of trophoblast is hampered. In addition, inadequate angiogenesis by uterine NK cells often leads to abnormal vascular development and blood flow patterns, which, in turn, leads to increased oxidative stress or ischemic changes in the invading trophoblast. T-cell abnormalities with increased Th1 and Th17 immunity, and decreased Th2 and T regulatory immune responses may play important roles in RPL and MIF. A possible role of stress in inflammatory immune response is also reviewed.