Interleukin-1beta -511T>C genetic variant contributes to recurrent pregnancy loss risk and peripheral natural killer cell proportion

Genomic regions associated with Holstein heifer times bred to artificial insemination and embryo transfer services

This study aimed to identify loci (p < 1 × 10-5) and gene sets (normalized enrichment score (NES) ≥ 3.0) associated with the number of times a heifer is bred to attain a successful pregnancy (TBRD) for Holstein heifers bred by artificial insemination (AI, n = 2754) or that were embryo transfer (ET, n = 1566) recipients. Eight loci were associated (p < 1 × 10-5) with TBRD in AI bred heifers and four loci were associated with TBRD in ET recipients. The gene set enrichment analysis with SNP data identified one gene set enriched (NES ≥ 3.0) with TBRD in AI bred heifers and two gene sets that were enriched with TBRD in ET recipients. The estimated pseudo-heritability for times bred to AI was 0.063 and 0.043 for ET. The identification of loci associated with embryonic loss aids in the selection of Holstein heifers with higher reproductive efficiencies that are AI bred or that are ET recipients.

Association between cytokine polymorphisms and recurrent pregnancy loss: A review of current evidence

Cytokines are a type of protein that play an important role in the immune response and can also affect many physiological processes in the body. Cytokine polymorphisms refer to genetic variations or mutations that occur within the genes that code for cytokines, which may affect the level of cytokine production and function. Some cytokine polymorphisms have been associated with an increased risk of developing certain diseases, while others may be protective or have no significant effect on health. In recent years, the role of cytokine polymorphisms in the development of recurrent pregnancy loss (RPL) has been studied. RPL or miscarriage is defined as the occurrence of two or more consecutive pregnancy losses before the 20th week of gestation. There are diverse causes leading to RPL, including genetic, anatomical, hormonal, and immunological factors. With regard to cytokine polymorphisms, a few of them have been found to be associated with an increased risk of RPL, for instance, variations in the genes that code for interleukin-6, tumor necrosis factor-alpha, and interleukin-10. The exact mechanisms by which cytokine polymorphisms affect the risk of recurrent miscarriage are still being studied, and further research is essential to fully understand this complex condition. This brief review aims to summarize the recent literature on the association between cytokine polymorphisms and RPL.

TLR signaling pathway and the effects of main immune cells and epigenetics factors on the diagnosis and treatment of infertility and sterility

Recurrent pregnancy loss (RPL), often known as spontaneous miscarriages occurring two or more times in a row, is a reproductive disease that affects certain couples. The cause of RPL is unknown in many cases, leading to difficulties in therapy and increased psychological suffering in couples. Toll-like receptors (TLR) have been identified as crucial regulators of inflammation in various human tissues. The occurrence of inflammation during parturition indicates that Toll-like receptor activity in tissues related to pregnancy may play a crucial role in the onset and continuation of normal function, as well as in various pregnancy complications like infection-related preterm. TLRs or their signaling molecules may serve as effective therapeutic targets for inhibiting premature activity. At the maternal-fetal interface, TLRs are found in both immune and non-immune cells, such as trophoblasts and decidual cells. TLR expression patterns are influenced by the phases of pregnancy. In this way, translational combinations like epigenetics, have indicated their impact on the TLRs.Importantly, abnormal DNA methylation patterns and histone alterations have an impressive performance in decreasing fertility by influencing gene expression and required molecular and cellular activities which are vital for a normal pregnancy and embryonic process. TLRs, play a central duty in the innate immune system and can regulate epigenetic elements by many different signaling pathways. The potential roles of TLRs in cells, epigenetics factors their ability to identify and react to infections, and their place in the innate immune system will all be covered in this narrative review essay.

Influence of Interleukin Polymorphisms on the Risk of Recurrent Pregnancy Loss: A Systematic Review and Meta-analysis

Background

Interleukin (IL) genes are essential for regulating the immune and inflammatory processes. Epidemiological studies suggest that polymorphisms in IL genes are associated with a higher risk of recurrent pregnancy loss (RPL).

Objective

This study aimed to examine the association between RPL risk and IL gene polymorphisms.

Materials and Methods

A comprehensive search of the literature was conducted using PubMed, Google Scholar and Embase to identify relevant studies published until May 30, 2024. A total of 58 studies involving 13,696 participants (both RPL cases and controls) were included. Pooled odds ratios and 95% confidence intervals were calculated using fixed- or random-effects models, as appropriate, with ReviewManager version 5.4, Cochrane RoB Tool 2 and G*Power 3.1 software.

Results

The meta-analysis revealed significant correlations between RPL risk and genetic variations in IL-1β (-511T > C), IL-6 (-174 G > C) and IL-10 (-1082 A > G and-592 C > A), with statistical significance set at P < 0.05. Ethnic subgroup analysis showed that IL-1β (-511T > C) and IL-10 (-592 C > A) variations were strongly associated with RPL risk in Asian populations.

Interpretation

Our research suggests that genetic variations in IL-1β (-511T > C), IL-6 (-174 G > C) and IL-10 (-1082 A > G and-592 C > A) are associated with susceptibility to RPL.

Limitation

Our meta-analysis concentrated exclusively on single-factor studies and did not consider potential confounding variables such as age, environmental influences and lifestyle, which could affect susceptibility to RPL. In addition, the lack of individual raw data prevented us from investigating gene-environment and gene-gene interactions or the influence of other polymorphisms and cytokines in our analysis.

Protocol Registration

http://www.osf.io/qhbva.

The Progress of Research on Genetic Factors of Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) is both mental and physical health problem affecting about 1-5% of women of childbearing age. The etiology of RPL is complex, involving chromosomal abnormalities, autoimmune diseases, metabolic disorders, and endometrial dysfunction. The causes of abortion are still unknown in more than 50% of these cases. With the development of science and technology, an increasing number of scholars focus on this field and find that genetic factors may play an essential role in unexplained RPL, such as embolism-related genes, immune factor-related genes, and chromosomal numeric, and structural variation. This review summarizes the genetic factors associated with RPL, including genetic mutations and genetic polymorphisms, chromosomal variants, and chromosomal polymorphisms. Many related genetic factors have been found to be demographically and geographically relevant, some of which can be used for risk prediction or screening for the etiology of RPL. However, it is difficult to predict and prevent RPL due to uncertain pathogenesis and highly variable clinical presentation. Therefore, the genetic factors of RPL still need plentiful research to obtain a more accurate understanding of its pathogenesis and to provide more detection means for the screening and prevention of RPL.

The Update Immune-Regulatory Role of Pro- and Anti-Inflammatory Cytokines in Recurrent Pregnancy Losses

Recurrent pregnancy losses (RPL) is a common reproductive disorder with various underlying etiologies. In recent years, rapid progress has been made in exploring the immunological mechanisms for RPL. A propensity toward Th2 over Th1 and regulatory T (Treg) over Th17 immune responses may be advantageous for reproductive success. In women with RPL and animals prone to abortion, an inordinate expression of cytokines associated with implantation and early embryo development is present in the endometrium or decidua secreted from immune and non-immune cells. Hence, an adverse cytokine milieu at the maternal-fetal interface assaults immunological tolerance, leading to fetal rejection. Similar to T cells, NK cells can be categorized based on the characteristics of cytokines they secrete. Decidual NK (dNK) cells of RPL patients exhibited an increased NK1/NK2 ratio (IFN-γ/IL-4 producing NK cell ratios), leading to pro-inflammatory cytokine milieu and increased NK cell cytotoxicity. Genetic polymorphism may be the underlying etiologies for Th1 and Th17 propensity since it alters cytokine production. In addition, various hormones participate in cytokine regulations, including progesterone and estrogen, controlling cytokine balance in favor of the Th2 type. Consequently, the intricate regulation of cytokines and hormones may prevent the RPL of immune etiologies. Local or systemic administration of cytokines or their antagonists might help maintain adequate cytokine milieu, favoring Th2 over Th1 response or Treg over Th17 immune response in women with RPL. Herein, we provided an updated comprehensive review regarding the immune-regulatory role of pro- and anti-inflammatory cytokines in RPL. Understanding the roles of cytokines involved in RPL might significantly advance the early diagnosis, monitoring, and treatment of RPL.

Understanding recurrent pregnancy loss: recent advances on its etiology, clinical diagnosis, and management

Recurrent pregnancy loss (RPL) has become an important reproductive health issue worldwide. RPL affects about 2%-3% of reproductive-aged women, and makes serious threats to women's physical and mental health. However, the etiology of approximately 50% of RPL cases remains unknown (unexplained RPL), which poses a big challenge for clinical management of these patients. RPL has been widely regarded as a complex disease where its etiology has been attributed to numerous factors. Heretofore, various risk factors for RPL have been identified, such as maternal ages, genetic factors, anatomical structural abnormalities, endocrine dysfunction, prethrombotic state, immunological factors, and infection. More importantly, development and applications of next generation sequencing technology have significantly expanded opportunities to discover chromosomal aberrations and single gene variants responsible for RPL, which provides new insight into its pathogenic mechanisms. Furthermore, based upon patients' diagnostic evaluation and etiologic diagnosis, specific therapeutic recommendations have been established. This review will highlight current understanding and recent advances on RPL, with a special focus on the immunological and genetic etiologies, clinical diagnosis and therapeutic management.

UHRF1 shapes both the trophoblast invasion and decidual macrophage differentiation in early pregnancy

Trophoblasts play critical roles in establishment and maintenance of a normal pregnancy. Their dysfunction in early pregnancy is closely related to pregnancy-related diseases, including recurrent pregnancy loss (RPL). Epigenetic modifications dynamically change during pregnancy; however, the role of the epigenetic modifier UHRF1 in trophoblast regulation remains unknown. This is the first study to show that UHRF1 expression was localized in the cytoplasm of cytotrophoblasts, syncytiotrophoblasts, and villi columns, and decreased in the villi of patients with RPL. The invasion and cell viability in a UHRF1 knockdown trophoblast cell line were significantly decreased. In addition, the mRNA expression profiles of Swan71 cells were partially altered by UHRF1 knockdown. The altered immune-related genes were screened out and the pro-inflammatory TH1-type chemokine/cytokines CXCL2 and IL-1β were identified as the most promising targets of UHRF1 in the trophoblasts, which were significantly increased in the UHRF1 knockdown Swan71 cells, villi, and serum from patients with RPL. The macrophages treated with the supernatants of UHRF1 knockdown Swan71 cells were polarized to the M1 phenotype and secreted high levels of pro-inflammatory cytokines, which might be driven by the activated MyD88/NF-κB signaling pathway and mediated by the increased expression of CXCR2 and IL-1R1 (CXCL2 and IL-1β receptors, respectively). In addition, the supernatants of UHRF1 knockdown Swan71 cells showed stronger chemotaxis to macrophages than those from the controls. Our findings highlight the previously unknown roles of UHRF1 as one of the key regulators on the trophoblasts and their cross-talk with local immune cells, and demonstrate a potential approach for RPL intervention.

Cumulative Evidence for Association of IL-10 -1082G > A Polymorphism with Susceptibility to Recurrent Pregnancy Loss: A Systematic Review and Meta-Analysis

The IL-10 -1082 G > A polymorphism has been reported to be associated with a risk of recurrent pregnancy loss (RPL) with inconsistent results. Thus, to clarify the effect of the polymorphism on the susceptibility to RPL, a meta-analysis was performed. Methods: A systematic literature search in PubMed, Web of Science, Scopus and SciELO was performed to identify the relevant studies published up to December 20, 2019, and related information was extracted. Results: A total of 17 case-control studies with 3,224 RPL cases and 3,295 controls were selected. Pooled data revealed that IL-10 -1082 G > A polymorphism was significantly associated with risk of RPL in the global population. Moreover, subgroup analysis indicated a significant association in Caucasians, but not in Asian or mixed populations. Conclusions: Our pooled data highlights that IL-10 -1082 G > A polymorphism is a risk factor for RPL susceptibility in the global population, especially in Caucasians.

Relationship between common interleukin 1-beta gene polymorphisms and the risk of gestational disorders: An updated meta-analysis

Background: To quantitatively estimate the relationship between IL-1β -511C>T, -31T>C, and +3954C>T polymorphisms and risk of gestational disorders. Methods: In this meta-analysis, eligible publications were searched in Web of Knowledge, MEDLINE, PubMed, Scopus, and Google Scholar databases (updated April 2020), using appropriate or relevant keywords. Case-control population-based reports were included if provided with genotypic frequencies of both studied groups. Statistical analyses were performed using the MetaGenyo web tool software, where a P value less than 0.05 indicated a significant association. For the assessment of between-study variations, heterogeneity analysis was applied with the I² statistics. Results: A total of thirteen studies were included. We observed a significant association between IL-1β-31T>C polymorphism and reduced risk of gestational disorders under codominant CT vs. CC [OR= 0.74, CI (0.59-0.92)], and dominant CT+TT vs. CC [OR= 0.74, CI (0.60-0.91)] contrasted genetic models. The stratified analysis considering the disease type showed that the 511C>T variant, under the recessive CC vs. CT+TT model, enhanced the risk of preterm birth by 1.29 fold. Conclusion: Our results failed to support an association between two IL-1β polymorphisms, 511C>T and +3954C>T, with the overall risk of gestational disorders. In contrast, the 31T>C variant reduced the incidence of such diseases. Further studies are encouraged to get more precise estimates of effect sizes.

Interleukin-1 beta is significantly upregulated in the decidua of spontaneous and recurrent miscarriage placentas

BACKGROUND

Pregnancy is an extraordinarily complex immunological process. For successful pregnancy maintenance the maternal immune system must adapt to and tolerate the semi-allogenic fetus at the fetomaternal interface of the placenta. This balance is regulated by cytokines with a predominant T helper 2 (Th-2) system and a suppressed inflammatory T helper 1 (Th-1) response. This study investigates the role of the Th-1 pro-inflammatory cytokine Interleukin-1 beta (IL-1β) and its role in early pregnancy loss.

PATIENTS AND METHODS

In order to identify differences in IL- β levels a TaqMan® Human Cytokine Network Array, with placental tissue obtained from patients with healthy pregnancies (n = 15) and recurrent miscarriage (n = 15), was carried out. Protein expression of IL-1β in the decidua of healthy pregnancies (n = 15), spontaneous (n = 18) and recurrent miscarriages (n = 15), was investigated by immunohistochemistry. The identification of IL-1β expressing cells in the decidua was done with double-immunofluorescence.

RESULTS

Gene expression analysis identified a nearly 54-times higher expression of IL-1β in placental tissue of patients suffering from recurrent abortion. Immunohistochemistry confirmed a significant upregulation of IL-1β in the decidua of recurrent miscarriage specimens (p = 0.01) as well as in the decidua of women with spontaneous abortion (p = 0.001). Double-immunofluorescence identified decidual stoma cells as IL-1β expressing cells.

CONCLUSION

Significant upregulation of IL-1β may be associated with an imbalanced immune system and a procoagulant state that could be responsible for early pregnancy loss. These results provide new evidence of the complex interplay of IL-1β at the fetomaternal interface and its crucial role in miscarriage processes.

Peripheral blood natural killer cell proportion and ovarian function in women with recurrent implantation failure

Current knowledge of the association between peripheral natural killer (NK) cell proportion and ovarian function in reproductive-age women is limited. We explored the association between NK cell proportion and ovarian function in women who underwent in-vitro fertilization (IVF) treatment. This was a retrospective cohort study using the data of 20-44-year-old women with recurrent implantation failure (RIF) who were tested for NK cell proportion and anti-Müllerian hormone (AMH). Indicators of ovarian function included AMH, observed-to-(age-appropriate) reference AMH ratio, high FSH, peak E₂ and total number of oocytes during the first IVF cycle following the test. We used different model specification controlling for women's age, and body mass index. Among a total of 936 women, majority showed lower AMH compared to age-appropriate level. Average NK cell proportion was 13.5 ± 5.7%. Number of oocytes showed positive association with NK cell (ß = 0.040, p = .025). In the subgroup with NK ≥ 18%, NK cell proportion was negatively associated with AMH (-0.106, p = .012), AMH ratio (-0.049, p = .014) and number of oocytes (-0.021, p < .001) while the associations with others remain close to null. High NK cell proportion may be harmful to ovarian reserve or function.

Association of IL-1β, IL-6, TNF-α, and TGFβ1 Gene Polymorphisms with Recurrent Spontaneous Abortion in Polycystic Ovary Syndrome

Recurrent spontaneous abortion (RSA) is a common pregnancy-associated complication of polycystic ovary syndrome (PCOS) which is an endocrine malfunction disease. Patients with PCOS may have several underlying contributing and interrelated factors, which have been reported in women with RSA. The incidence rate between PCOS and RSA remains uncertain. The aim of this study is to determine the possible association of IL-1β-511C/T, IL-6-174G/C, TNF-α-1031T/C, and TGFβ1-509T/C with RSA patients with or without PCOS. A total of 140 RSA patients, 70 of which were PCOS patients, and 140 healthy females with no history of RSA or PCOS were included in this study. PCR amplification, genotyping, and sequence analysis were employed to investigate the presence of the polymorphisms. The genotypic and allelic frequencies were calculated separately for each subject. Out of the four studied polymorphisms, the IL-1β-511C/T genotype in RSA without PCOS patients (12.7%) was significantly different compared with that in control subjects (p = 0.047). For IL-6-174C/G, there was a tendency towards more CC carriers among RSA with PCOS patients (10%) than in controls (3%). The GG genotype in RSA women with PCOS (60%) was significantly different compared with that in control subjects (p = 0.033), and the GC genotype in RSA with PCOS patients (30%) showed a marginal significant difference compared with that in control subjects (p = 0.050). Significant difference was identified in the allelic frequencies in RSA patients with PCOS compared to controls (p = 0.025). IL-6-174G/C and TNF-α-1031T/C polymorphisms are significantly associated with RSA patients in Saudi patients with PCOS, while the IL-1β-511C/T polymorphism is significantly associated with RSA patients without PCOS.

Study of the Association Between microRNA (miR-25T>C, miR-32C>A, miR-125C>T, and miR-222G>T) Polymorphisms and the Risk of Recurrent Pregnancy Loss in Korean Women

Recurrent pregnancy loss (RPL), which is defined as two pregnancy losses that occur before 20 weeks of gestation, is relatively common, occurring in approximately 1–5% of women. The underlying cause is often unclear, although numerous factors may contribute to RPL, including environmental and immunological factors, blood coagulation disorders, and genetics. In particular, single nucleotide variants have been associated with RPL, including those found in microRNAs (miRNAs). We investigated the association between four miRNA polymorphisms, miR-25T>C, miR-32C>A, miR-125aC>T, and miR-222G>T, and RPL in a cohort consisting of 361 RPL patients and 272 controls. Subjects were genotyped at miRNA loci by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, and genotype frequencies were calculated. We then performed allele and genotype combination analyses and measured the association between miRNA polymorphisms and clinical variables in both RPL patients and controls. We detected a statistically significant association between RPL and the miR-25T/miR-32C/miR-125aT/miR-222T allele combination (adjusted odds ratio (AOR), 4.361; 95% confidence interval (CI), 1.496–12.72; P = 0.003). Three-gene combinations, including miR-32C/miR-125aT/miR-222T (AOR, 3.085; 95% CI, 1.254–7.588; P = 0.010) and miR-25T/miR-125aT/miR-222T (AOR, 2.929; 95% CI, 1.183–7.257; P = 0.015), and the two-gene combination miR-125aT/miR-222T (AOR, 2.417; 95% CI, 1.084–5.386; P = 0.026) were also associated with RPL. Analysis of variance (ANOVA) revealed that platelet counts and blood urea nitrogen levels were significantly different in RPL patients expressing different miR-125aC>T and miR-25T>C genotypes, respectively (P < 0.05). In addition, creatinine levels were lower in RPL patients expressing the minor alleles miR-25T>C and miR-32C>A. We investigated miRNAs (miR-25, miR-32, miR-125a, miR-222) in RPL patients and healthy controls. Significantly different allele frequencies were detected by ANOVA. We suggest that miRNAs and clinical factors can impact RPL occurrence.

IL-1β and IL-10 gene polymorphisms in women with gestational diabetes

AIMS

Gestational diabetes (GDM) is carbohydrate intolerance occurring in pregnant women. In the GDM pathogenesis, the low-grade inflammation plays a significant role. Various inflammatory mediators are considered to be risk factors leading to GDM development including cytokines. Studies suggest that some cytokines such as: IL-1β and IL-10 play an important role in GDM pathogenesis. The aim of the study was to examine the associations between IL-1β rs16944, and IL-10 rs1800872 gene polymorphisms and GDM.

METHODS

This study included 204 pregnant women with GDM and 207 pregnant women with normal glucose tolerance. The diagnosis of GDM was based on a 75-g oral glucose tolerance test administered at 24-28 weeks' gestation. Among the pregnant women with GDM, 152 (75%) were treated with diet control alone throughout the pregnancy, whereas the remaining 52 (25%) were treated with diet control and insulin until delivery.

RESULTS

There were no statistically significant differences in the distribution of IL-1β rs16944 and IL-10 rs1800872 between GDM and healthy women. However among women treated with insulin, we observed the increased frequency of IL-1β rs16944 AA genotype carriers. Additionally, we observed increased daily insulin requirement in women with IL-1β rs16944 AA genotype. Moreover, women with IL-10 rs1800872 AA genotype had higher body mass and BMI before pregnancy as well as higher body mass and BMI increase during pregnancy.

CONCLUSIONS

The results of our study suggest the association between IL-1β rs16944 AA genotype and increased frequency of the need of insulin treatment as well as increased daily insulin requirement.

Polymorphisms in interleukin genes and their association with the risk of recurrent pregnancy loss

Interleukins play important roles in pregnancy. Altered expression and splicing of various interleukins have been linked to the pathophysiology of recurrent pregnancy loss. Polymorphisms in interleukin genes can affect the expression and/or splicing of their respective genes and thus influence the risk of recurrent pregnancy loss. In this work, we examined the association between the IL1B rs16944, IL1B rs1143634, IL6 rs1800795, IL6 rs1800796, IL10 rs1800896 and IL18 rs187238 polymorphisms and recurrent pregnancy loss risk in a Chinese population. Study subjects comprised 598 idiopathic recurrent pregnancy loss patients and 603 controls. The genotyping was accomplished by PCR-RFLP. Regression analysis was performed to evaluate the disease association. After adjustment by Bonferroni correction, only the IL1B rs16944 and IL6 rs1800796 polymorphisms were significantly associated with risk of recurrent pregnancy loss. The heterozygous TC genotype of IL1B rs16944 had an adjusted odds ratio (aOR) of 1.4209 (1.1302-1.8929) (P = 0.0019), while the homozygous CC genotype had an aOR of 1.7398 (1.2133-2.3203) (P = 0.0008). A significant association was also observed for the C allele [aOR = 1.3747 (1.1296-1.8972)] (P = 0.0003). For IL6 rs1800796, the heterozygous CG genotype, the homozygous GG genotype and the G allele had aORs of 0.7342 (0.4412-0.8423) (P = 0.0016), 0.5424 (0.1768-0.7865) (P = 0.0014) and 0.7009 (0.4511-0.8034) (P = 0.0007), respectively. In summary, the IL1B rs16944 and IL6 rs1800796 variants were associated with an increased and a decreased recurrent pregnancy loss risk, respectively.

Genetic and epigenetic variations associated with idiopathic recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a reproductive disorder defined as two or more successive and spontaneous pregnancy losses (before 20 weeks of gestation), which affects approximately 1-2% of couples. At present, the causes of RPL remain unknown in a considerable number of cases, leading to complications in treatment and high levels of stress in couples. Idiopathic recurrent pregnancy loss (iRPL) has become one of the more complicated reproductive problems worldwide due to the lack of information about its etiology, which limits the counseling and treatment of patients. For that reason, iRPL requires further study of novel factors to provide scientific information for determining clinical prevention and targeted strategies. The aim of this study is to describe the most recent and promising progress in the identification of potential genetic and epigenetic risk factors for iRPL, expanding the genetic etiology of the disease.

Association between TNF, IL1B, IL6, IL10 and IFNG polymorphisms and recurrent miscarriage: a case control study

BACKGROUND

Approximately half of recurrent miscarriages have unexplained etiology. Recent evidences suggest that cytokines are important determinants in pregnancy maintenance and as such, cytokine gene polymorphisms, which can affect cytokine production and/or functionality, could play a role in the disorder. Thus, we aimed to investigate the association of selected cytokine gene polymorphisms with risk of recurrent miscarriage among Chinese.

METHODS

TNF -238G > A, TNF -308G > A, IL1B -511 T > C, IL1B 3954C > T, IL6 -174G > C, IL6 -634C > G, IL10 -1082A > G and IFNG 874A > T polymorphisms were genotyped on 775 women with idiopathic recurrent miscarriage and 805 healthy parous control women. Logistic regression analysis was performed to determine the odds ratios (ORs) of the association between the polymorphisms and recurrent miscarriage risk.

RESULTS

Among the eight polymorphisms studied, only the IL1B -511 T > C and IL6 -634C > G polymorphisms showed statistically significant associations with recurrent miscarriage risk. For the former, a significantly increased risk of recurrent miscarriage was observed for the mutant (CC) genotype (OR: 1.377; 95% CI: 1.039-1.824; P = 0.026). However, for the IL6 -634C > G polymorphism, a decreased recurrent miscarriage risk was observed for the heterozygous (CG) genotype (OR: 0.614; 95% CI: 0.493-0.765; P < 0.001) and the mutant (GG) genotype (OR: 0.414; 95% CI: 0.251-0.684; P = 0.001).

CONCLUSIONS

The IL1B -511 T > C polymorphism may serve as important risk factor for recurrent miscarriage while the IL6 -634C > G polymorphism may protect against the risk of recurrent miscarriage.

Association between Genetic Polymorphisms in Interleukin Genes and Recurrent Pregnancy Loss - A Systematic Review and Meta-Analysis

Interleukins are a group of immunomodulatory proteins that mediate a variety of immune reactions in the human body. To investigate the association between interleukin gene polymorphisms and recurrent pregnancy loss (RPL), we reviewed 21 studies from MEDLINE, EMBASE, OVID SP and PubMed to evaluate RPL-related interleukin gene polymorphisms. Meta-analysis was performed on 12 of the polymorphisms, and a review included the others. Our integrated results indicated that IL-1β (-511C/T) (P = 0.02, 95% CI 0.77[0.62,0.96]), IL-6 (-634C/G) (P<0.001, 95% CI 2.91[2.01,4.22]), IL-10 (-1082G/A, -819T/C) (P = 0.01, 95% CI 0.80[0.67,0.96]; P<0.01, 95% CI 0.66[0.49,0.89]), and IL-18 (-137G/C, -105G/A) (P<0.01, 95% CI 1.69[1.24,2.31]; P = <0.01, 95% CI 1.41[1.17,1.70]) consistently associated with RPL after meta-analysis. IL-17A rs2275913 and IL-17F rs763780, IL-21 rs2055979 and rs13143866, IL-1β (-31C/T), IL-6 (-2954G/C), and IL-10 (-536A/G) were reported only once as having a significant association with RPL. The potential mechanism underlying miscarriage and these polymorphisms and future research directions are also discussed.