Changes in the T-helper 1 and 2 cell populations during pregnancy in tacrolimus-treated women with repeated implantation failure and recurrent pregnancy loss

Immunomodulatory Treatment Impact on IVF Outcomes in KIR AA Genotype: Personalized Fertility Insights

Background and Objectives: Recurrent implantation failure (RIF) affects 10% of couples undergoing in vitro fertilization (IVF), spurring exploration into tailored treatments to enhance implantation rates. Maternal immune tolerance towards embryos, particularly killer-cell immunoglobulin-like receptors (KIRs) on natural killer (NK) cells, is a focal point in RIF research. Materials and Methods: This retrospective cohort study, conducted at fertility clinic in Oradea, Romania, involved 65 infertile couples undergoing IVF treatment between January 2022 and December 2023. Couples were divided into two groups: KIR AA (Group A) and KIR Bx (Group B). Results: Factors such as age, type of infertility, oocytes retrieved, embryos produced, pregnancy rates in Group A without and with immunomodulatory treatment were documented. Group A, receiving immunomodulatory treatment, achieved a pregnancy rate of 47.8%, significantly higher than the 23.73% rate without treatment (p = 0.008). Group B had a higher mean patient age than Group A. However, miscarriage rates did not significantly differ between Group A with treatment and Group B (p = 0.2457), suggesting comparable outcomes with immunomodulation. Conclusions: The impact of immunological factors on recurrent implantation failure is being more and more emphasized and warrants the attention of specialists in human reproduction. Uterine natural killers and their function though KIR receptors deserve particular attention as immunomodulatory treatment may improve pregnancy rates in patients with KIR AA haplotype.

Immunosuppressive therapy with tacrolimus is a potential drug candidate for the prevention of unexplained or preeclamptic stillbirths with Th1-dominant immune states: a case series of five patients

Some of obstetrical complications such as unexplained pregnancy loss and preeclampsia (PE) are associated with maternal-fetal immune abnormalities, leading to uteroplacental dysfunction, insufficient fetal immune tolerance, or fetal rejection. Immunosuppressants with calcineurin inhibitors could be useful for the prevention of these complications by modulating the cellular immune balance by directly inhibiting activated T-helper (Th) 1 and natural killer (NK)/NKT cells. We present our experience with the immunosuppressant tacrolimus in five pregnant women who had a previous pregnancy history of unexplained or preeclamptic stillbirth. Th1 and Th2 cell populations and NK cell activities in peripheral blood were measured as clinical parameters during pregnancy. Case 1-3 achieved suppressions of predominant Th1 immunity and live births without pregnancy-related complications. In case 4, increased tacrolimus dose after a miscarriage resulted in her first live birth; however, she developed PE and severe fetal growth restriction with elevated Th1/Th2 cell ratios at 26 weeks of gestation. Case 5 had a previous history of early onset PE and the hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome, and an emergency cesarean section was needed for maternal safety at 20 weeks of gestation. The course of the next pregnancy was stable under tacrolimus treatment; however, the HELLP syndrome recurred after PE at 33 weeks of gestation. Although an imbalance in the Th1/Th2 cell ratio was not observed during pregnancy, NK cell activity was markedly elevated before delivery. In conclusion, tacrolimus is a potential drug candidate for the prevention of unexplained or preeclamptic stillbirth with Th1-dominant immune states.

Calcineurin inhibitors in the management of recurrent miscarriage and recurrent implantation failure: Systematic review and meta-analysis

Recurrent miscarriage (RM) affects up to 2.5% of couples of reproductive age. Up to 10% of couples using assisted reproductive technology experience recurrent implantation failure (RIF). Immunosuppressive drugs, such as calcineurin inhibitors (CNIs), has been proposed for RM and RIF management. This systematic review and meta-analysis (SRMA) aimed to evaluate the efficacy and safety of CNIs in RM and RIF treatment. We searched in the three databases. Review Manager 5.4.1 was used for statistical analysis. This review included 8 studies involving 1042 women (485 women in the CNIs group and 557 women in the control group). CNI treatment (cyclosporine [CsA] and tacrolimus [TAC]) increases live birth rate (LBR, odds ratio [OR]: 2.52; 95% confidence interval [CI]: 1.93-3.28, p < 0.00001) and clinical pregnancy rate (OR: 2.25; 95% CI: 1.54-4.40, p < 0.0001) and decreases miscarriage rate (OR: 0.45 95% CI: 0.32-0.63, p < 0.00001) when compared to the control. Side effects and obstetric and neonatal complications was similar in both groups. In conclusion, CNIs increased LBR in women with RM and RIF but there is a moderate risk of bias. Subgroup analysis revealed that CNIs improved LBR in women with RM with a low risk of bias. However, in women with RIF, with moderate to high risk of bias. The use of CsA and TAC, in low doses and for a short period, for managing reproductive failures in women seems to be safe, not causing serious side effects nor increasing the risk of obstetric and neonatal complications.

Multicenter, 2-dose single-group controlled trial of tacrolimus for the severe infertility patients

INTRODUCTION

Infertility is estimated to affect 8% to 12% of reproductive-aged couples worldwide. While approximately 85% of infertile couples have an identified cause, the remaining 15% suffer physically and emotionally from unexplained intractable infertility. In recent years, maternal-to-fetal immunological abnormalities have attracted attention as mechanisms that differ from the conventional factors contributing to infertility and pregnancy loss. A T-helper 2 (Th2)-dominant immune state has been proposed as a maternal immune alteration to eliminate rejection and induce tolerance to a semi-allogeneic fetus. An imbalance in Th1 responses would not induce adequate maternal immune tolerance to the fetus or early embryos. Tacrolimus, widely used as an immunosuppressant agent in solid organ transplant recipients, is expected to suppress maternal rejection and promote tolerance to early embryos after assisted reproductive technology by modulating the immunological environment of the preimplantation endometrium. We planned an exploratory clinical trial to determine the efficacy, safety, and dosage of tacrolimus in women with intractable infertility.

METHODS AND ANALYSIS

This is a multicenter, 2-dose, single-group controlled trial in infertile women who failed to achieve a chemical pregnancy despite multiple in vitro fertilization (IVF) and embryo transfer (ET) treatment cycles. The following 2 key selection criteria were set: no underlying factors of infertility despite appropriate evaluation and presence of Th1-dominant immune state, defined as a Th1/Th2 cell ratio ≥ 10.3 in the peripheral blood. A total of 26 eligible participants are randomly assigned (in a 2:1 ratio) to receive immunosuppressive therapy with oral tacrolimus at a daily dose of 2 mg or 4 mg. Tacrolimus is administered for 16 days starting from 2 days before ET. The primary endpoint is the presence of clinical pregnancy 3 weeks after IVF/ET treatment, and the secondary endpoint is the presence of biochemical pregnancy 2 weeks after IVF/ET treatment. Safety evaluation and biomarker discovery for tacrolimus treatment in infertile women will be conducted simultaneously.

TRIAL REGISTRATION NUMBER

Japan Registry of Clinical Trials (jRCT; jRCTs031220235).

The Diagnostics and Treatment of Recurrent Pregnancy Loss

Recurrent pregnancy loss is a common problem in the reproductive age population of women. It can be caused by many different conditions. This problem is addressed in international guidelines that take a slightly different approach to its diagnosis and treatment. The guidelines used in this review mainly use the guidelines of the Royal College of Obstetricians and Gynaecologists (RCOG), American Society of Reproductive Medicine (ASRM) and European Society of Human Reproduction and Embryology (ESHRE). This review shows how much the approach to miscarriages has changed and how much more needs to be explored and refined. The review also addresses the topic of unexplained pregnancy loss, which continues to be a challenge for clinicians.

The impact of the use of immunosuppressive treatment after an embryo transfer in increasing the rate of live birth

The tolerance of the immune system for the semi-allogeneic embryo is promoted by several factors and the cells involved in the immune system and factors in the mother during pregnancy. The dysregulation of the immune responses between the mother and fetus is a risk factor that raises the likelihood of rejection of the embryo and reproductive failure. To safeguard embryos and prevent immunological attacks, it is critical to suppress immunological rejection and encourage immunological tolerance. Based on current medical literature, it seems that immune cell management through immunosuppressive therapies can address reproductive failures. Immunosuppressive treatment has demonstrated encouraging results in terms of enhancing outcomes related to pregnancy and rates of live birth by regulating the immune responses of mothers and positively impacting the reproductive processes of humans. Currently, there is scarcity of high-quality data regarding the safety and efficacy of immunosuppressive therapies for children and mothers. Therefore, it is important to exercise caution while selecting use of any immunosuppressive therapy in pregnancy. This mini review provides a comprehensive overview of the existing literature regarding the impact of Calcineurin Inhibitors and anti-TNF treatment on improving the live birth rate following embryo transfer.

Co-administration of tacrolimus and low molecular weight heparin in patients with a history of implantation failure and elevated peripheral blood natural killer cell proportion

AIM

To investigate the therapeutic effect of co-administration of tacrolimus (TAC) and low-molecular-weight heparin (LMWH) or LMWH only on pregnancy outcomes in the female with a history of implantation failure and elevated peripheral blood natural killer (pNK) cell proportion in frozen-thawed embryo transfer cycles.

METHODS

To evaluate the pregnancy parameters for 249 patients with ≥2 implantation failures and pNK cell proportion ≥12% by analyzing a retrospective observational cohort study. Sixty patients had received the co-administration TAC and LMWH (TAC & LMWH group), 85 others had only taken LMWH (LWMH group), and the rest did not take any particular drugs (control group).

RESULTS

The experimental finding indicated that the TAC & LMWH group and the LMWH group showed higher clinical pregnancy rates than the control group (p < 0.05), and TAC & LMWH group had a much higher live birth rate. According to the binary logistic regression analysis, the combination of TAC and LMWH was conducive to clinical pregnancy and live birth rate and reduced the possibility of miscarriage. It would not affect the result of spontaneous abortion and live birth, although the LMWH was only beneficial to clinical pregnancy. In addition, these findings were similar for these three groups' obstetrical and neonatal outcomes.

CONCLUSIONS

The combination of TAC and LMWH can improve clinical pregnancy and live birth rates and reduce the risk of spontaneous miscarriage in patients with a history of implantation failure and elevated pNK ratio. LMWH is also beneficial to clinical pregnancy.

Immune alterations in recurrent implantation failure

A failure to achieve pregnancy after three or more embryo transfer cycles with high-quality blastocysts is referred to as recurrent implantation failure (RIF). RIF can be due to altered uterine factors or male factors or embryo factors. Disrupted endometrial receptivity, altered expression of genes in several pathways, immunologic disturbances in the peripheral blood and/or the endometrium, and epigenetic alterations are associated with RIF. Amongst the immunologic disturbances, altered Th1/Th2 ratio, altered NK cell and macrophage numbers are observed in women with RIF. However, not all women with RIF have the same kind of immune dysfunction suggesting that RIF is a heterogeneous condition associated with varied immune responses and one size may not fit all. Thus, personalized therapies based on the immune status of the patient are being tested in women with RIF. In general, women with a high Th1/Th2 ratio are offered Tacrolimus, while intravenous IgG is recommended in women with high NK cell numbers/HLA mismatch. Women with hyperactivated immune status in the uterus are offered progesterone support, prednisolone, vitamin E, and intralipid treatment to suppress inflammation and oxidative stress, while endometrial scratching and intrauterine hCG administration are offered to women with hypo-active immune status. There is a need for standardized tests for evaluation of immune status in patients and sufficiently powered randomized controlled trials for personalized therapies to determine which of these will be beneficial in women with RIF. Till then, the ART community should limit the use of such add-on interventions in women with RIF.