Natural killer cell activity in women with recurrent miscarriage: Etiology and pregnancy outcome

High doses of intravenous immunoglobulin stimulate regulatory T cell and suppress natural killer cell in women with recurrent pregnancy loss

The aim was to evaluate whether natural killer (NK) cells and regulatory T (Treg) cells were involved in mechanisms underlying beneficial effects of a high dose of intravenous immunoglobulin (IVIG) on recurrent pregnancy losses (RPL) of unexplained etiology. In a double-blind, randomized, placebo-controlled trial of IVIG (400 mg/kg, for 5 days in 4-6 weeks of gestation) in women with RPL, blood samples were collected pre-infusion, one week after infusion (1 w), and eight weeks of gestation/when miscarried (8 w). Levels of NK and Treg cells in peripheral blood were compared between women with IVIG (n = 50) and placebo (n = 49), and between women with IVIG who gave live birth (n = 29) and those who had miscarriage with normal chromosome (n = 12). Effector Treg cell percentages in IVIG group at 1 w (mean 1.43 % vs. 1.03 %) and at 8 w (1.91 % vs. 1.18 %) were higher than those in placebo group (p < 0.01). Total Treg cell percentages in IVIG group at 1 w (4.75 % vs. 4.08 %) and at 8 w (5.55 % vs. 4.47 %) were higher than those in placebo group (p < 0.05). In women with live birth, total Treg cell percentages increased at 8 w (5.52 %, p < 0.001) compared with pre-infusion (4.54 %) and 1 w (4.47 %), while NK cell activity decreased at 1 w (20.18 %, p < 0.001) compared with pre-infusion (26.59 %). IVIG increased Treg cell percentages and suppressed NK cell activity very early in pregnancy, and these were associated with subsequent live birth. Stimulation of Treg cells and suppression of NK cell activity very early in pregnancy may be a mechanism of pharmacological effects of high dose IVIG.

Assessment of the risk of unexplained recurrent spontaneous abortion based on the proportion and correlation of NK cells and T cells in peripheral blood

BACKGROUND

Unexplained recurrent spontaneous abortion (URSA) is difficult to diagnose and treat clinically due to its unknown causeOBJECTIVE: Changes in natural killer (NK) cells, T lymphocytes, and Th1(IFNγ)/Th2(IL-4) cytokines were investigated in the peripheral blood of patients with URSA to examine the pathogenesis, clinical diagnosis, and inform potential treatment strategies for this condition.

METHODS

For this study, we selected patients with URSA as the case group and included normal women in the control group. Flow cytometry was performed to detect lymphocytes and cytokines in the peripheral blood of all subjects.

RESULTS

The proportion of NK cells, Th1 cells, and the Th1/Th2 ratio were significantly higher in the URSA group compared to the control group; whereas the proportion of CD3+T cells was lower. Pairwise correlation analysis revealed a positive correlation between the percentage of NK cells and CD3+T cells, as well as CD3+CD4+T cells. Canonical correlation analysis indicated a significant correlation between NK cells and T cells, including their subgroups.

CONCLUSION

Patients with URSA have immune balance disorders, characterised by an increased proportion of peripheral blood NK cells, Th1, and Th1/Th2 ratio along with a decreased proportion of CD3+T cells. The proportion of NK cells and CD3+T may serve as predictive factors for URSA, while NK cells are closely related to the regulation of CD3+T cells and their subsets. By regulating the level of IFN-γ, NK cells can influence the proportion of CD3+T cells and induce a Th1 (IFNγ)/Th2 (IL-4) imbalance.

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.

Intravenous immunoglobulin treatment in women with four or more recurrent pregnancy losses: A double-blind, randomised, placebo-controlled trial

BACKGROUND

There is no effective treatment for women with unexplained recurrent pregnancy loss (RPL). We aimed to investigate whether treatment with a high dose of intravenous immunoglobulin (IVIG) in early pregnancy can improve pregnancy outcomes in women with unexplained RPL.

METHODS

In a double-blind, randomised, placebo-controlled trial, women with primary RPL of unexplained aetiology received 400 mg/kg of IVIG daily or placebo for five consecutive days starting at 4-6 weeks of gestation. They had experienced four or more miscarriages except biochemical pregnancy loss and at least one miscarriage of normal chromosome karyotype. The primary outcome was ongoing pregnancy rate at 22 weeks of gestation, and the live birth rate was the secondary outcome. We analysed all women receiving the study drug (intention-to-treat, ITT) and women except those who miscarried due to fetal chromosome abnormality (modified-ITT). This study is registered with ClinicalTrials.gov number, NCT02184741.

FINDINGS

From June 3, 2014 to Jan 29, 2020, 102 women were randomly assigned to receive IVIG (n = 53) or placebo (n = 49). Three women were excluded; therefore 50 women received IVIG and 49 women received placebo in the ITT population. The ongoing pregnancy rate at 22 weeks of gestation (31/50 [62·0%] vs. 17/49 [34·7%]; odds ratio [OR] 3·07, 95% CI 1·35-6·97; p = 0·009) and the live birth rate (29/50 [58·0%] vs. 17/49 [34·7%]; OR 2·60, 95% CI 1·15-5·86; p = 0·03) in the IVIG group were higher than those in the placebo group in the ITT population. The ongoing pregnancy rate at 22 weeks of gestation (OR 6·27, 95% CI 2·21-17·78; p < 0·001) and the live birth rate (OR 4·85, 95% CI 1·74-13·49; p = 0·003) significantly increased in women who received IVIG at 4-5 weeks of gestation as compared with placebo, but these increases were not evident in women who received IVIG at 6 weeks of gestation. Four newborns in the IVIG group and none in the placebo group had congenital anomalies (p = 0·28).

INTERPRETATION

A high dose of IVIG in very early pregnancy improved pregnancy outcome in women with four or more RPLs of unexplained aetiology.

FUNDING

The Japan Blood Products Organization.

In vitro fertilization-embryo transfer in patients with unexplained recurrent pregnancy loss

Background:

Empiric therapy for patients with unexplained recurrent pregnancy loss (URPL) is not precise. Some patients will ask for assisted reproductive technology due to secondary infertility or advanced maternal age. The clinical outcomes of URPL patients who have undergone in vitro fertilization-embryo transfer (IVF-ET) require elucidation. The IVF outcome and influencing factors of URPL patients need further study.

Methods:

A retrospective cohort study was designed, and 312 infertile patients with URPL who had been treated during January 2012 to December 2015 in the Reproduction Center of Peking University Third Hospital were included. By comparing clinical outcomes between these patients and those with tubal factor infertility (TFI), the factors affecting the clinical outcomes of URPL patients were analyzed.

Results:

The clinical pregnancy rate (35.18% vs. 34.52% in fresh ET cycles, P = 0.877; 34.48% vs. 40.27% in frozen-thawed ET cycles, P = 0.283) and live birth rate (LBR) in fresh ET cycles (27.67% vs. 26.59%, P = 0.785) were not significantly different between URPL group and TFI group. URPL group had lower LBR in frozen-thawed ET cycles than that of TFI group (23.56% vs. 33.56%, P = 0.047), but the cumulative LBRs (34.69% vs. 38.26%, P = 0.368) were not significantly different between the two groups. The increased endometrial thickness (EMT) on the human chorionic gonadotropin day (odds ratio [OR]: 0.848, 95% confidence interval [CI]: 0.748–0.962, P = 0.010) and the increased number of eggs retrieved (OR: 0.928, 95% CI: 0.887–0.970, P = 0.001) were protective factors for clinical pregnancy in stimulated cycles. The increased number of eggs retrieved (OR: 0.875, 95% CI: 0.846–0.906, P < 0.001), the increased two-pronucleus rate (OR: 0.151, 95% CI: 0.052–0.437, P < 0.001), and increased EMT (OR: 0.876, 95% CI: 0.770–0.997, P = 0.045) in ET day were protective factors for the cumulative live birth outcome.

Conclusion:

After matching ages, no significant differences in clinical outcomes were found between the patients with URPL and the patients with TFI. A thicker endometrium and more retrieved oocytes increase the probability of pregnancy in fresh transfer cycles, but a better normal fertilization potential will increase the possibility of a live birth.

Role of Decidual Natural Killer Cells in Human Pregnancy and Related Pregnancy Complications

Pregnancy is a unique type of immunological process. Healthy pregnancy is associated with a series of inflammatory events: implantation (inflammation), gestation (anti-inflammation), and parturition (inflammation). As the most abundant leukocytes during pregnancy, natural killer (NK) cells are recruited and activated by ovarian hormones and have pivotal roles throughout pregnancy. During the first trimester, NK cells represent up to 50–70% of decidua lymphocytes. Differently from peripheral-blood NK cells, decidual natural killer (dNK) cells are poorly cytolytic, and they release cytokines/chemokines that induce trophoblast invasion, tissue remodeling, embryonic development, and placentation. NK cells can also shift to a cytotoxic identity and carry out immune defense if infected in utero by pathogens. At late gestation, premature activation of NK cells can lead to a breakdown of tolerance of the maternal–fetal interface and, subsequently, can result in preterm birth. This review is focused on the role of dNK cells in normal pregnancy and pathological pregnancy, including preeclampsia, recurrent spontaneous abortion, endometriosis, and recurrent implantation failure. dNK cells could be targets for the treatment of pregnancy complications.

Interplay of immune components and their association with recurrent pregnancy loss

Maintenance and progression of pregnancy is an intricate process governed by a variety of developmental cues. Recurrent pregnancy loss (RPL) is a complication experienced by expecting mothers that is defined as three or more consecutive pregnancy losses. This review focuses on the dysfunctions of the immune system as one of the key contributors towards RPL. The current data suggests that the alloimmune and autoimmune factors contribute to the loss of fetus. Such causes despite being recognized as a definitive reason for recurrent pregnancy loss, are still under extensive investigation with new parameters being discovered and scrutinized for their association with RPLs. More in-depth and high throughput studies are required for devising better diagnostic tools and management strategies for the affected female so that they can carry their pregnancy to term.

Single-cell Immune Landscape of Human Recurrent Miscarriage

Successful pregnancy in placental mammals substantially depends on the establishment of maternal immune tolerance to the semi-allogenic fetus. Disorders in this process are tightly associated with adverse pregnancy outcomes including recurrent miscarriage (RM). However, an in-depth understanding of the systematic and decidual immune environment in RM remains largely lacking. In this study, we utilized single-cell RNA-sequencing (scRNA-seq) to comparably analyze the cellular and molecular signatures of decidual and peripheral leukocytes in normal and unexplained RM pregnancies at the early stage of gestation. Integrative analysis identifies 22 distinct cell clusters in total, and a dramatic difference in leukocyte subsets and molecular properties in RM cases is revealed. Specifically, the cytotoxic properties of CD8⁺ effector T cells, nature killer (NK), and mucosal-associated invariant T (MAIT) cells in peripheral blood indicates apparently enhanced pro-inflammatory status, and the population proportions and ligand–receptor interactions of the decidual leukocyte subsets demonstrate preferential immune activation in RM patients. The molecular features, spatial distribution, and the developmental trajectories of five decidual NK (dNK) subsets have been elaborately illustrated. In RM patients, a dNK subset that supports embryonic growth is diminished in proportion, while the ratio of another dNK subset with cytotoxic and immune-active signature is significantly increased. Notably, a unique pro-inflammatory CD56⁺CD16⁺ dNK subset substantially accumulates in RM decidua. These findings reveal a comprehensive cellular and molecular atlas of decidual and peripheral leukocytes in human early pregnancy and provide an in-depth insight into the immune pathogenesis for early pregnancy loss.

Update on the Use of Intravenous Immunoglobulin in Pregnancy

Intravenous immunoglobulin (IVIG) was first administered to humans in the 1980s. The mechanism of action of IVIG is still a subject of debate but the pharmacokinetics have been well characterized, albeit outside of pregnancy. IVIG has been used in pregnancy to treat several nonobstetrical and obstetrical-related conditions. However, current evidence suggests that IVIG use during pregnancy can be recommended for 1) in utero diagnosis of neonatal alloimmune thrombocytopenia; 2) gestational alloimmune liver disease; 3) hemolytic disease of the fetus and newborn for early-onset severe intrauterine disease; 4) antiphospholipid syndrome (APS) when refractory to or contraindicated to standard treatment, or in catastrophic antiphospholipid syndrome; and 5) immune thrombocytopenia when standard treatment is ineffective or rapid increase of platelet counts is needed. All recommendations are based on case series and cohort studies without randomized trials usually because of the rare prevalence of the conditions, the high incidence of adverse outcomes if left untreated, and ethical concerns. In contrast, IVIG therapy cannot be recommended for recurrent pregnancy loss, and the use of IVIG in subgroups of those with recurrent pregnancy loss requires further investigations. For non-obstetrical-related conditions, we recommend using IVIG as indicated for nonpregnant patients. In conclusion, the use of IVIG during pregnancy is an effective treatment in some obstetrical-related conditions with rare serious maternal side effects. However, the precise mechanisms of action and the long-term immunologic effects on the fetus and neonate are poorly understood and merit further investigations.

Novel predictive and therapeutic options for better pregnancy outcome in frozen embryo transfer cycles

Since 1978, in the first decades of in vitro fertilization (IVF), the use of ovarian hyperstimulation allowed for the development and transfer of multiple embryos. As IVF technology improved, the number of multiple pregnancies increased, which led to gradual reduction in the number of embryos that were transferred. Embryo freezing (vitrification) was recommended to allow subsequent transfer if the fresh cycle was unsuccessful. However, experimentation has continued to improve pregnancy outcomes. We discuss here the significance of frozen embryo transfer cycle and the impact of uterine and peripheral immunity dominated by NK cells and regulatory T cells and human chorionic gonadotropin on pregnancy outcome in this innovative mode of IVF therapy.

Parental human leukocyte antigen-C allotypes are predictive of live birth rate and risk of poor placentation in assisted reproductive treatment

OBJECTIVE

To study the pregnancy, miscarriages, and live birth rates (LBRs) according to maternal killer cell immunoglobulin-like receptor (KIR) genes expressed by uterine natural killer cells and paternal or oocyte donor human leukocyte antigen-C (HLA-C) genes expressed by trophoblast cells in patients with recurrent reproductive failure.

DESIGN

Prospective observational cohort study.

SETTING

Private infertility center.

PATIENT(S)

Participants included 204 women with recurrent miscarriage or recurrent implantation failure.

INTERVENTION(S)

The KIR and HLA-C genotypes of all women and HLA-C of their partners, gamete donors, miscarriage tissue, and babies were analyzed.

MAIN OUTCOME MEASURE(S)

All clinical variables (pregnancy, miscarriage, and LBRs) were analyzed and categorized based on KIR, oocyte origin, and single embryo transfer (SET)/double embryo transfer (DET).

RESULT(S)

A higher miscarriage rate was observed after DETs in KIR AA mothers (47.8% egg donation and 37.5% in vitro fertilization [IVF]) compared with KIR AB (10.5% egg donation and 12.5% IVF) or KIR BB (6.7% egg donation and 0% IVF). A significantly decreased LBR was observed after DETs with oocyte donation in KIR AA patients (4.3%) compared with KIR AB (26.3%) or BB (46.7%). The LBR decreased significantly as the fetal HLA-C2 load increased in KIR AA women.

CONCLUSION(S)

Elective SET improves the reproductive outcomes compared with DET. An increased embryo HLA-C2 load has a negative impact on the LBR in KIR AA patients. The selection of HLA-C1 over HLA-C2 donors could have a positive impact on the LBR in KIR AA patients.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04052438.

Euploid miscarriage is associated with elevated serum C-reactive protein levels in infertile women: a pilot study

Purpose

Increased serum C-protein (CRP) levels reduce fecundity in healthy eumenorrheic women with 1–2 pregnancy losses. Subclinical systemic inflammation may impede maternal immune tolerance toward the fetal semi-allograft, compromising implantation and early embryonic development. Some miscarriages with normal karyotypes could, therefore, be caused by inflammation. Whether pre-pregnancy CRP relates to karyotypes of spontaneously aborted products of conception (POCs) was investigated.

Methods

A study cohort of 100 infertile women with missed abortions who underwent vacuum aspirations followed by cytogenetic analysis of their products of conception tissue was evaluated at an academically affiliated fertility center. Since a normal female fetus cannot be differentiated from maternal cell contamination (MCC) in conventional chromosomal analyses, POC testing was performed by chromosomal microarray analysis. MCC cases and incomplete data were excluded. Associations of elevated CRP with first trimester pregnancy loss in the presence of a normal fetal karyotype were investigated.

Results

Mean patients’ age was 39.9 ± 5.8 years; they demonstrated a BMI of 23.9 ± 4.6 kg/m² and antiMullerian hormone (AMH) of 1.7 ± 2.4 ng/mL; 21.3% were parous, 19.1% reported no prior pregnancy losses, 36.2% 1–2 and 6.4% ≥ 3 losses. Karyotypes were normal in 34% and abnormal in 66%. Adjusted for BMI, women with elevated CRP were more likely to experience euploid pregnancy loss (p = 0.03). This relationship persisted when controlled for female age and AMH.

Conclusions

Women with elevated CRP levels were more likely to experience first trimester miscarriage with normal fetal karyotype. This relationship suggests an association between subclinical inflammation and miscarriage.

NK cell subsets in idiopathic recurrent miscarriage and renal transplant patients

The present review article compares NK cell subsets and cytokine patterns determined in the peripheral blood as well as results of functional in-vitro assays using peripheral NK cells of idiopathic recurrent miscarriage (iRM) patients with corresponding results obtained in female healthy controls and female renal transplant recipients with good long-term graft function. Immune mechanisms, inducing transplant rejection in long-term transplant recipients might also be able to induce rejection of semi-allogeneic fetal cells in patients with iRM. Consequently, the immune status of transplant recipients with good stable long-term graft function should be different from the immune status of iRM patients. iRM patients show a strong persistent cytotoxic NK cell response in the periphery. Simultaneously, immunostimulatory Th1 as well as immunosuppressive Th2 type lymphocytes in the blood are strongly activated but plasma levels of immunosuppressive Th2 type cytokines are abnormally low. In-vitro, unstimulated NK cell cultures of iRM patients show a strong spontaneous TGF-ß1 release in the supernatant but lower TGF-ß1 levels after stimulation with tumor cell line K562, suggesting strong consumption of TGF-ß1 by pre-activated NK cells of iRM patients that might contribute to the low systemic Th2 type plasma levels. iRM patients do not show a systemic switch to a Th2 type cytokine pattern and one might hypothesize that low TGF-ß plasma levels indicate low TGF-ß levels in the micromilieu immediately before fetal rejection. Persistent TGF-ß deficiency implies a persistent unfavorable micromilieu for pregnancy resulting in failing tolerance induction due to lack of TGF-ß, a condition that might contribute to iRM.

17-Hydroxyprogesterone caproate improves T cells and NK cells in response to placental ischemia; new mechanisms of action for an old drug

Preeclampsia (PE) is new onset hypertension during pregnancy associated with increased uterine artery resistance (UARI) and an imbalance among CD4 + T lymphocytes and natural killer (NK) cells. We have shown an important role for 17-hydroxyprogesterone caproate (17-OHPC) to improve hypertension and fetal demise in the RUPP rat model of PE. However we have not examined a role for 17-OHPC to improve NK cells and CD4⁺TH2 cells as possible mechanisms for improved fetal weight and hypertension. Therefore, we hypothesized that 17-OHPC lowers NK cells while improving the T cell ratio in the RUPP rat. RUPP was surgically induced on gestational day 14 in pregnant rats. 17-OHPC (3.32 mg/kg) was administered intraperitoneal on day 15, UARI was measured on day 18. Blood pressure (MAP), blood and tissues were collected on GD 19. MAP in NP rats (n = 9) was 100 ± 2, 104 ± 6 in Sham rats (n = 8), 128 ± 2 in RUPP (n = 11) and 115 ± 3 mmHg in RUPP + 17-OHPC (n = 10), p < 0.05. Pup weight and UARI were improved after 17-OHPC. Total and cytolytic placental NK cells were 38 ± 5, and 12 ± 2% gate in RUPP rats which decreased to 1.6 ± 0.5 and 0.4 ± 0.2% gate in RUPP + 17OHPC rats. CD4⁺ T cells were 40 ± 3 in RUPP rats, which significantly decreased to 7 ± 1 RUPP + 17-OHPC rats. Circulating and placental TH2 cells were 6.0 ± 1, 0.3 ± 0.1% gate in RUPP rats and 12 ± 1%, 2 ± 0.5% gate in RUPP + 17-OHPC rats, p < 0.05 This study identifies new mechanisms whereby 17-OHPC improves outcomes in response to placental ischemia.

Glycodelin regulates the numbers and function of peripheral natural killer cells

Natural killer (NK) cells comprise of ∼70% of the immune cell population in the maternal decidua and ∼15% of the mononuclear cells in the peripheral blood. The decidual NK cells capable of producing high levels of cytokines are functionally distinct from the peripheral NK cells that exhibit high cytotoxicity. The numbers of peripheral NK cells and their cytotoxicity potential have been correlated with pregnancy outcome. In the same context, glycodelin, an immunomodulatory protein, has been recognized to be essential for the establishment and maintenance of pregnancy, and its' reduced levels are associated with recurrent spontaneous abortions. We investigated the effect of glycodelin on the peripheral NK cells. Our results reveal that glycodelin suppresses the cytotoxicity of peripheral NK cells via downregulating perforin, granzyme B and IFNγ. Glycodelin also induces caspase-dependent death in only activated peripheral NK cells, the effect suggested to be mediated by glycodelin upon engaging with the CD7 cell surface receptor. Thus, during pregnancy, glycodelin modulates the function and the number of cytotoxic NK cells that pose a deleterious effect on the fetus, a semi-allograft. This study provides insights into the mechanism of the regulatory effect of glycodelin on NK cells and could possibly be exploited for the management of miscarriages.

Clinical factors associated with pregnancy outcome in women with recurrent pregnancy loss

The aim of this prospective cohort study was to evaluate clinical factors associated with pregnancy outcomes in women with recurrent pregnancy loss (RPL). Women with a history of two or more pregnancy losses underwent workups for clinical factors of RPL and their pregnancies were followed-up with informed consent. Two hundred eleven (81.5%) of 259 women with RPL became pregnant. The multivariable analyses demonstrated that age (p < .01, OR 0.9, 95%CI 0.97-0.83), uterine abnormality (p < .05, OR 0.3, 95%CI 0.11-0.8), and protein C (PC) deficiency (p < .01, OR 0.14, 95%CI 0.03-0.6) were independent factors for becoming pregnancy in women with RPL. The number of previous pregnancy loss (p < .01, OR 0.57, 95%CI 0.43-0.75) and natural killer (NK) cell activity ≥33% (p < .01, OR 0.31, 95%CI 0.13-0.73) were independent factors for live birth in the subsequent pregnancy. Advanced age, the presence of uterine abnormality, and PC deficiency were risk factors for reduced pregnancy rate in women with RPL. Increased number of previous pregnancy loss and high NK cell activity were risk factors for miscarriage in the subsequent pregnancy. These results involve important information and are helpful for clinical practitioners.

Gestational and perinatal outcomes in recurrent miscarriages couples treated with lymphocyte immunotherapy

Objective

This study aims to elucidate which types of recurrent miscarriage (RM) patients experienced a livebirth after paternal lymphocyte immunotherapy (LIT) and to evaluate the perinatal outcome.

Study design

Retrospective analysis of a multicenter, observational study which enrolled 1096 couples with a history of two or more spontaneous miscarriages without any intercalated delivery. We conducted an intention-to-treat analysis of couples with RM treated with or without LIT regarding to gestational and perinatal outcomes. We compared groups by using the Student’s t-test or Kruskal–Wallis test, Fisher’s exact-test and χ² test when appropriate.

Results

The success of gestation was significantly higher in the LIT group (60.1% vs. 33.1%; p <  0.001). A sub-analysis of four different immune disorder groups revealed a significantly higher success in the LIT group in all immune categories, except in patients who had autoantibodies positive. We observed no significant differences in perinatal outcomes such as gestational age at birth, preterm and extreme preterm birth, and birth weight in successful pregnancy in both groups. The success rate was significantly higher when LIT was administrated before and during pregnancy and only during pregnancy compared to only before pregnancy (p <  0.01).

Conclusions

Careful laboratory test phenotyping of RM patients may identify subgroups most likely to benefit and exclude those with little likelihood of benefit, and LIT during a pregnancy may significantly improve success rates.