The balance of the immune system between HLA-G and NK cells in unexplained recurrent spontaneous abortion and polymorphisms analysis

HLA allele frequency of HLA-A, -B, -C, -DRB1 and -DQB1 in Indian recurrent implantation failure and recurrent pregnancy loss couples - A retrospective study

The maternal-fetal interaction has been hypothesized to involve the human leucocyte antigen (HLA). It has been suggested that excessive HLA antigen sharing between spouses is a mechanism causing maternal hyporesponsiveness to paternal antigens encountered during pregnancy and thus leading to a miscarriage. Participants in this retrospective study are RIF and RPL couples who visited Gunasheela Surgical and Maternity Hospital, Bangalore, India from November 2019 to September 2022. A total of 40 couples with RIF and 195 couples with RPL are included in the study. We observed that the DQB1*02:01:01 allele is associated with an increase in risk of both RIF and RPL, while the C*12:02:01 allele increases risk of only RPL. On the contrary, DQB1*02:02:01 and DQB1*06:03 alleles appear to be protective against both RPL and RIF. In addition, the C*07:02:01 allele was observed to be protective against RPL. In conclusion, C*12:02:01 and DQB1*02:01:01 could play a major role in RPL which is consistent with other studies, while DQB1*02:01:01 is the risk allele in our RIF group. The protective alleles C*07:02:01 in the RPL group, DQB1*02:02:01, and DQB1*06:03 in both RIF and RPL, were discovered for the first time. Allele frequencies will vary in population-based studies depending on the ethnicities of the cohort. Meta-analysis and antibody testing will provide additional insights on whether and how this data can be adopted into clinical practices.

Study on the Relationship between Unexplained Recurrent Abortion and HLA-DQ Gene Polymorphism

Objective

The study aimed to investigate the relationship between human leukocyte antigen (HLA-DQB1) gene variants and recurrent miscarriage.

Methods

HLA-DQ gene polymorphisms (PCR-SSP) were detected in 50 couples with recurrent miscarriage (URSA group) and 30 couples with normal births (control group) using sequence-specific primer-guided polymerase chain reaction.

Results

The frequency of the DQB1 ∗ 0303 allele in the URSA group (21.50%) was substantially higher than that of the control group (11.67%) (P=0.0260 0.05, RR = 1.754); however, the frequency of the DQB1 ∗ 0302 allele in the URSA group (4.00%) was substantially lower than that of the control pair (10.00%) (P=0.0318 0.05, RR = 0.400); the frequency of sharing one allele was 46.00% (23/50) in the URSA group and 0.00% (0/30) in the normal control group; the frequency of sharing two alleles was 40.00% (2/50) in the URSA group and 43.33% (13/30) in the normal control group, with no significant difference between the two groups.

Conclusion

For the Zhejiang population, HLA-DQB1 ∗ 0303 may be a susceptibility gene for recurrent miscarriage, while HLA-DQB1 ∗ 0302 may be protective against recurrent miscarriage, especially for women.

Role of polymorphisms on the Recurrent Pregnancy Loss: A systematic review, Meta-analysis and bioinformatic analysis

Recurrent miscarriage (RM) is a major reproductive health issue. RM is a multi-factorial disease, and is affected by environmental, genetic, and epigenetic factors. Genetics has a common role in recurrent miscarriage occurrence. It seems that molecular genetics has a great role in RSA incidence. So, in these years, RM has become for a major subject of genetics research. There are many genes that are involved in each phase for successful reproduction. This research aimed to evaluate the effect of all studied polymorphisms in studies on RSA that have not been included in any meta-analysis. PubMed, Scopus, and Web of Science databases were recruited to investigate the related articles. The systematic review results identified 143 studies worldwide. Thirteen genes have been included in assessing the case-control studies. Sixty-four SNPs were recruited to assess the association between genetic factors and RSA susceptibility. Ninety-two studies containing twenty two SNPs (from 10 genes) were included in the quantitative analysis. Bioinformatic analysis indicated that rs12722482 showed "Damaging Status" by double servers, and rs315952 and rs854560 had "Possibly damaging" status in the PolyPhen-2 server. MethPrimer server indicated that there is "CpG Island" in the rs10895068, rs1130355, and rs41557518 variants, and rs10895068-G allele makes a CpG dinucleotide which can change the gene methylation and result in altering the gene expression. So, further studies on rs12722482 and rs10895068 can demonstrate valuable results. To the best of our knowledge, this systematic review has covered the all studied polymorphisms of HLA-C, HLA-G, PON1, AGTR1, TAFI, FAS, FAS-L, ESR1, PGR, CTLA-4, MMP-2, MMP-3, MMP-9, and IL1RN for the first time. Also, we did a novel meta-analysis for AGTR1 rs5186, TAFI rs1926447, rs3742264, HLA-G rs1063320, rs1233334, rs1736936, rs2249863, PON1 rs662, rs854560, FAS rs2234767, rs1800682, FAS-L rs763110, ESR1, rs9340799, rs3798759, PGR rs1042838, CTLA4 rs4553808, rs5742909, rs231775, rs3087243, and MMP-2 rs243865 and updated statistical finding for rs2234693 and rs371194629. Rs2234693, rs9340799, rs231775, and rs371194629 demonstrated a significant association with RSA risk. Some variations showed significant association, while further studies are suggested to confirm the results. Finally, Rs4553808 and rs5742909 revealed no significant deviation in the results. It is suggested that these SNPs may be excluded from subsequent case-control studies or other analyses.

CD4+CD25+Foxp3+ regulatory T cells regulate immune balance in unexplained recurrent spontaneous abortion via the Toll-like receptor 4/nuclear factor-κB pathway

Objective

The present study aimed to evaluate the effects of cluster of differentiation (CD)4⁺CD25⁺ forkhead box p3 (Foxp3)⁺ regulatory T cells (Tregs) on unexplained recurrent spontaneous abortion (URSA) and the associated mechanisms.

Methods

The proportion of CD4⁺CD25⁺Foxp3⁺ Tregs and inflammatory cytokine concentrations in the peripheral blood of women with URSA were measured by flow cytometry and enzyme-linked immunosorbent assay, respectively. CBA/JxDBA/2J mating was used to establish an abortion-prone mouse model and the model mice were treated with the Toll-like receptor 4 (TLR4) antagonist E5564 and the TLR4 agonist lipopolysaccharide.

Results

The proportion of CD4⁺CD25⁺Foxp3⁺ Tregs was decreased and the inflammatory response was increased in women with URSA. In the abortion-prone mouse model, E5564 significantly increased the proportion of CD4⁺CD25⁺Foxp3⁺ Tregs, decreased the inflammatory response, and increased Foxp3 mRNA and protein expression. Lipopolysaccharide had adverse effects on the abortion-prone model.

Conclusions

These data suggest that CD4⁺CD25⁺Foxp3⁺ Tregs regulate immune homeostasis in URSA via the TLR4/nuclear factor-κB pathway, and that the TLR4 antagonist E5564 may be a novel and potential drug for treating URSA.

Expression and significance of PD-1 and PD-L1 in patients with recurrent spontaneous abortion: A protocol for systematic review and meta-analysis

BACKGROUND

Recurrent spontaneous abortion (RSA) accounts for the most common complication of early pregnancy in humans. As an immune checkpoint pathway, programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) can be exploited by tumor cells to evade immuno-surveillance. Many studies have shown that the expression of PD-1/PD-L1 is involved in RSA. However, the correlation between the expression of PD-1/PD-L1 and RSA is still controversial. We conducted meta-analysis to further explore the correlation between the expression of PD-1/PD-L1 and RSA, to provide a basis for clinical prevention and treatment.

METHODS

We will search PubMed, Embase, Web of Science, Google Scholar, Chinese National Knowledge Infrastructure, Chinese VIP Information, Wanfang Database, and Chinese Biomedical Literature Database for related published studies before February 2021. Two review authors will search and assess relevant studies independently. Case control studies and cohort studies will be included. The Revman 5.3 software was applied to carry out the meta-analysis for the included literature.

RESULTS

The findings of this systematic review will be disseminated in a peer-reviewed publication and/or presented at relevant conferences.

CONCLUSION

This study will provide a new theoretical basis for the prevention and treatment of RSA.

TRIAL REGISTRATION NUMBER

DOI 10.17605/OSF.IO/CZD23.Ethics and dissemination: Formal ethical approval is not required, as the data are not individualized.

Systematic biological and proteomics strategies to explore the regulation mechanism of Shoutai Wan on recurrent spontaneous Abortion's biological network

ETHNOPHARMACOLOGICAL RELEVANCE

Shoutai Wan (STW) is a classic herbal formula for the treatment of recurrent spontaneous abortion (RSA), and clinical studies have shown the effectiveness of STW on RSA. However, the molecular mechanism of STW treatment of RSA is still unclear.

METHODS

(1) Animal experiments: The normal pregnancy model was established with CBA/J*BALB/C, and the RSA model was established by CBA/J*DBA/2. The RSA model CBA/J*DBA/2 pregnant mice were randomly divided into four groups (RSA model group, STW low, medium and high dose groups) according to the order of pregnancy, respectively. The drug administration starts from the first day of pregnancy to the 14th day of pregnancy. The embryo loss rate (ELR) of each group was calculated. (2) Proteomic analysis of decidual tissue: The total protein of decidual tissue of each group was isolated by solid phase pH gradient 2-DE technique. The differentially expressed protein spots were analyzed and identified by PDQuest images; the peptide quality fingerprinting (PMF) was obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Then, the proteins were identified by Mascot software searching, their functions were identified by bioinformatics strategy. (3) The expression of HSP27, α-enolase and Transferrin was detected by Western blotting and the expression of Annexin A2 and Transferrin was detected by immunohistochemistry. (4) The differential proteins and potential targets were analyzed by systematic biological strategy.

RESULTS

(1) Compared with the normal group, the ELR in the RSA model group was significantly higher (P < 0.01). Compared with the model group, the ELR in the STW high, medium dose groups was lower (P < 0.01). (2) A 2-DE map of the decidual tissue of the RSA model group, normal pregnancy group, STW low, medium and high dose groups was established. Thirty proteins were identified. (3) The results of western blot showed that the expression of HSP27 and a-enolase in the RSA model group was higher than that in the normal group, and the expression of transferrin was lower (P < 0.01). Compared with the model group, the expression of HSP27 and a-enolase in STW high, medium dose groups was decreased (P < 0.01); Compared with the model group, the expression of Transferrin in the STW high dose group was increased (P < 0.01). (5) A lot of RSA treatment-related targets, biological processes and pathways were found after the systematic biological analysis.

CONCLUSION

(1) STW may reduce the ELR of the RSA mice. (2) The results of proteomics suggest that RSA is a complex process involving multiple proteins. STW can regulate the expression of various proteins in the decidual tissue of RSA mice, suggesting that it can act on multiple targets. (3) The results of western blotting of HSP27, a-enolase, transferrin were consistent with the results of proteomic analysis. (4) STW may achieve therapeutic effects by interfering with the targets, biological processes and signaling pathways discovered in this study.

ATP6V1G3 Acts as a Key Gene in Recurrent Spontaneous Abortion: An Integrated Bioinformatics Analysis

BACKGROUND The molecular mechanism of recurrent spontaneous abortion is unclear. It has been suggested that dysregulated genes participate in the pathogenesis of recurrent spontaneous abortion. The aim of this study was to identify the differentially expressed genes (DEGs) and pathways in recurrent spontaneous abortion. MATERIAL AND METHODS Gene expression data series of GSE22490 and GSE26787 were obtained from the GEO database to identify the differentially expressed genes between patients with recurrent miscarriage (Case group) and patients with uncomplicated pregnancies matched for gestational age (Control group). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEEG) were applied to enrich the biological functions and pathways of the identified differentially expressed genes. A protein-protein interaction (PPI) network was constructed thorough the STRING database. Thirty-one cases of recurrent spontaneous abortion (Case group) and 30 cases of artificial abortion (Control group) were included in the study. The protein expression of hub genes in the villi and decidua tissue of the 2 groups was detected by immunohistochemical assay. RESULTS Forty-six DEGs were identified with the enriched biological function mainly in the aspects of glutamate secretion and positive regulation of synapse assembly. KEGG pathway analysis indicated the dysregulated genes were only enriched in the glutamatergic synapse pathway. In the PPI network, 83 nodes and 273 edges with the average node degreed of 6.58 were enriched. The hub gene (ATP6V1G3) of the included 46 genes was identified using Cytohubba software. In the Case group, the high expression of ATP6V1G3 protein was detected in 13 (43.3%) and 10 (33.3%) for placental villus and decidual tissue, respectively. However, the high expression rate in the Control group was 23.3% and 16.7% for placental villus and decidual tissue, respectively. The ATP6V1G3 protein high expression rate was not significantly different between the Case and Control groups (P>0.05). CONCLUSIONS We found differential gene expression profiles in villous and decidual tissues between patients with recurrent miscarriage vs. those with uncomplicated pregnancies. Upregulation of the ATP6V1G3 gene may play an important role in the development of recurrent miscarriage.

Frequency of the rs 14035 polymorphism of RAN gen in recurrent pregnancy loss: A case-control study

Background

Genetic factors could account for recurrent pregnancy loss (RPL). The RAN gene is a member of the "large RAS family" and a small GTPase that is essential for the translocation of Ribonucleic acid (RNA) and proteins through the nuclear pore. Mutation in the RAN constitutive gene could stop DNA synthesis and alter the expression of genes in the uterus, likely playing a role in recurrent miscarriage.

Objective

The aim was to investigate the frequency of RAN (rs 14035) polymorphism in women with RPL compared with women without abortion history.

Materials and Methods

In this case-control study, 100 women with at least two consecutive miscarriages before the 20th wk of gestation and having spouses with karyotype and normal sperm parameters as the case group and 100 women with no history of abortion and having at least one successful pregnancy and normal delivery as the control group. The groups were age matched (20-40 yr). The rs 14035 polymorphism of RAN gene was investigated by Polymerase Chain Reaction-Restriction Fragment Length poly morphism technique and the frequency of which was compared between the two groups.

Results

The frequency of TT, TC, and CC genotypes of RAN gene polymorphism in the case group were 9%, 40%, and 51%, respectively, and in the control group were 11%, 38%, and 51%, respectively. There was no significant difference in the genotypes between two groups (p = 0.882).

Conclusion

According to our results, it seems that RAN polymorphism (rs 14035) is not associated with the risk of RPL in this study population.

Pregnancy immune tolerance at the maternal-fetal interface

Pregnancy is a natural process that poses an immunological challenge because non-self fetus must be accepted. During the pregnancy period, the fetus as 'allograft' inherits maternal and also paternal antigens. For successful and term pregnancy, the fetus is tolerated and nurtured enjoying immune privileges that minimize the risk of being rejected by maternal immune system. Multiple mechanisms contribute to tolerate the semi-allogeneic fetus. Here, we summarize the recent progresses on how the maternal immune system actively collaborates to maintain the immune balance and maternal-fetal tolerance.

Genetics of recurrent pregnancy loss among Iranian population

Background

Recurrent pregnancy loss (RPL) is one of the most common reproductive disorders which is defined as the occurrence of recurrent miscarriage before 24 weeks of gestation and is observed among 1%–5% of women.

Methods

Various factors are associated with RPL such as immunological disorders, maternal age, obesity, alcohol, chromosomal abnormality, endocrine disorders, and uterine abnormalities. About half of the RPL cases are related with chromosomal abnormalities. Therefore, RPL genetic tests are mainly limited to karyotyping. However, there is a significant proportion of RPL cases without any chromosomal abnormalities that can be related to the single‐gene aberrations. Therefore, it is required to prepare a diagnostic panel of genetic markers besides karyotyping.

Results

In the present review, we have summarized all the significant reported genes until now which are associated with RPL among Iranian women. We categorized all the reported genes based on their cellular and molecular functions in order to determine the molecular bases of RPL in this population.

Conclusion

This review paves the way of introducing a population‐based diagnostic panel of genetic markers for the first time among Iranian RPL cases. Moreover, this review clarifies the genetic and molecular bases of RPL in this population.

Vitamin D, autoimmunity and recurrent pregnancy loss: More than an association

Recurrent pregnancy loss (RPL) affects close to 1% of couples; however, the etiology is known in only about 50% of the cases. Recent studies show that autoimmune dysregulation is a probable cause of RPL, which in some cases may be overlooked. In order for a pregnancy to proceed to term, early modulation of immunologic response is required to induce tolerance to the semi-allogenic fetus. Certain subsets of both the innate and adaptive immune responses play a role in the induction of fetomaternal tolerance. A relatively predominant T-cell helper (Th) 2 and T regulatory (Treg) cell population seem to favor a better pregnancy outcome, whereas Th1 and Th17 cell populations appear to have an opposite effect. Lately, the role of vitamin D in the modulation of immune response was established. Vitamin D has been shown to promote a more favorable environment for pregnancy through various mechanisms, such as enhancement of the shift toward Th2 cells and regulation of immune cell differentiation and cytokine secretion. Therefore, it seems that vitamin D deficiency sways the balance toward a worse outcome and may play a part in recurrent pregnancy loss. This review sheds light on the immunologic changes, which occur in early pregnancy and the regulatory role vitamin D has in the maintenance of this delicate balance.

Evaluation of HLA-G 14-bp ins/del and +3142G>C polymorphisms with susceptibility to recurrent spontaneous abortion

OBJECTIVE

HLA-G is critically important for successful implantation during pregnancy. Increasing evidence supposed that HLA-G plays a key role in tolerance of the semi-allogeneic graft in pregnancy by inhibiting the cytotoxic functions of T and NK cells. The present study aimed to evaluate the impact of HLA-G rs1063320 (+3142G>C) and 14-bp insertion (ins)/deletion (del) polymorphisms on recurrent spontaneous abortion (RSA).

MATERIALS AND METHODS

Genomic DNA from 93 RSA patients and 93 normal fertile women was isolated using the salting out method. Genotyping of HLA-G +3142G>C and 14-bp ins/del variants was done by polymerase chain reaction restriction fragment length polymorphism (PCR-RFP) and PCR method, respectively.

RESULTS

The HLA-G +3142G>C polymorphism increased the risk of RSA in codominant (OR = 2.39, 95%CI = 1.27-4.49, p = 0.010, GC vs GG; OR = 3.28, 95%CI = 1.16-9.72, p = 0.040, CC vs GG) and dominant (OR = 2.52, 95%CI = 1.37-4.64, p = 0.004, GC + CC vs GG) tested inheritance models. HLA-G rs1063320 C allele was associated with increased risk of RSA (OR = 1.84, 95%CI = 1.20-2.83, p = 0.007). The del/del genotype as well as del allele of 14-bp ins/del variant increased that risk of RSA (OR = 3.02, 95%CI = 1.23-7.41, p = 0.025 and OR = 1.65, 95%CI = 1.09-2.50, p = 0.022, respectively).

CONCLUSION

In summary, our results showed that HLA-G gene polymorphisms significantly increased the risk of RSA in a sample of the Iranian population.

HLA-G coding region polymorphism is skewed in autistic spectrum disorders

Different isoforms of HLA-G protein are endowed with a differential ability to induce allogenic tolerance during pregnancy. As prenatal immune activation is suggested to play a role in the onset of autistic spectrum disorders (ASD), we evaluated HLA G*01:01-*01:06 allelic polymorphism in a cohort of Italian children affected by ASD (N=111) their mothers (N=81), and their healthy siblings (N=39). DNA sequencing analysis of HLA-G exon 2, 3 and 4 was used to obtain HLA-G allelic frequencies; alleles distribution was compared with that of two control groups of Caucasoid couples of multiparous women and their partners from Brazil and Denmark. HLA-G distribution was significantly different in ASD children compared to both control groups (Brazilian p_c=1×10^-4; Danish p_c=1×10^-3). Since HLA-G distribution was similar in the two control groups, their data were pooled. Results indicated that HLA-G*01:01 was significantly less frequent (p_c=1×10^-4; OR:0.5, 95%CI: 0.3-0.7) whereas HLA-G*01:05N was significantly more frequent (p_c=2×10^-3; OR:7.3, 95%CI: 2.4-26.6) in ASD children compared to combined controls. Finally, no clear pattern emerged when HLA-G allelic distribution was analyzed in healthy sibs. Notably, HLA-G allelic distribution found in ASD mothers was similar to that observed in the control subgroup of women with recurrent miscarriages, whilst it was significantly different compared to women without miscarriages (p_c=6×10^-4 df=12). Since HLA-G*01:01 is associated with the elicitation of KIR-mediated tolerogenic responses and HLA-G*01:05N correlates with NK cells activation, results herein indicate that an immune activating milieu during pregnancy is more likely observed in association with the development of ASD, similarly to what occurs in women with recurrent miscarriages.