An immunological and genetic study of patients with gestational diabetes mellitus

Autoimmune Disease in Women: Endocrine Transition and Risk Across the Lifespan

Women have a higher incidence and prevalence of autoimmune diseases than men, and 85% or more patients of multiple autoimmune diseases are female. Women undergo sweeping endocrinological changes at least twice during their lifetime, puberty and menopause, with many women undergoing an additional transition: pregnancy, which may or may not be accompanied by breastfeeding. These endocrinological transitions exert significant effects on the immune system due to interactions between the hormonal milieu, innate, and adaptive immune systems as well as pro- and anti-inflammatory cytokines, and thereby modulate the susceptibility of women to autoimmune diseases. Conversely, pre-existing autoimmune diseases themselves impact endocrine transitions. Concentration-dependent effects of estrogen on the immune system; the role of progesterone, androgens, leptin, oxytocin, and prolactin; and the interplay between Th1 and Th2 immune responses together maintain a delicate balance between host defense, immunological tolerance and autoimmunity. In this review, multiple autoimmune diseases have been analyzed in the context of each of the three endocrinological transitions in women. We provide evidence from human epidemiological data and animal studies that endocrine transitions exert profound impact on the development of autoimmune diseases in women through complex mechanisms. Greater understanding of endocrine transitions and their role in autoimmune diseases could aid in prediction, prevention, and cures of these debilitating diseases in women.

Impaired Treg and NK cells profile in overweight women with gestational diabetes mellitus

PROBLEM

Maternal obesity is frequently associated with gestational diabetes mellitus (GDM), and immunological mechanisms seem to be involved in the physiopathology of these conditions. The aim of this study was to characterize the profile of immune cells in peripheral blood of overweight women with GDM.

METHOD OF STUDY

This case-control study included 27 glucose-tolerant (controls) and 31 GDM overweight pregnant women. Flow cytometry was used to assess the number of regulatory T cells (Treg) and natural killer (NK) cells in the peripheral blood. In addition, the expression of IL-10, TGF-B, and TNF-A in Treg and expression of IFN-G, TNF-A, granzyme, and perforin in NK cells were analyzed.

RESULTS

GDM patients had significantly lower frequency of TCD4⁺ CD25^bright and TCD4⁺ CD25⁺ FOXP3^high cells, higher production of TNF-A by Treg cells and higher percentage of NKCD16⁺ 56^dim cells than the controls.

CONCLUSION

The association between obesity and GDM is a condition where it is observed impaired Treg and NK cells profile, findings that seem to be related with the development of IR and inflammation.

The relationships between HLA class II alleles and antigens with gestational diabetes mellitus: A meta-analysis

Gestational diabetes mellitus (GDM) is defined as glucose intolerance with onset or first recognition during pregnancy. It is associated with an increased risk of pregnancy complications. Susceptibility to GDM is partly determined by genetics and linked with type 1 diabetes-associated high risk HLA class II genes. However, the evidence for this relationship is still highly controversial. In this study, we assessed the relationship between HLA class II variants and GDM. We performed meta-analysis on all of literatures available in PubMed, Embase, Web of Science and China National Knowledge Infrastructure databases. The odds ratio and 95% confidence interval of each variant were estimated. All statistical analyses were conducted using the Comprehensive Meta Analysis 2.2.064 software. At the allelic analysis, DQB1*02, DQB1*0203, DQB1*0402, DQB1*0602, DRB1*03, DRB1*0301 and DRB1*1302 reached a nominal level of significance, and only DQB1*02, DQB1*0602 and DRB1*1302 were statistically significant after Bonferroni correction. At the serological analysis, none of DQ2, DQ6, DR13 and DR17 was statistically significant following Bonferroni correction although they reached a nominal level of significance. In sum, our meta-analysis demonstrated that there were the associations between HLA class II variants and GDM but more studies are required to elucidate how these variants contribute to GDM susceptibility.

Expression of Natural Cytotoxicity Receptors on and Intracellular Cytokine Production by NK Cells in Women with Gestational Diabetes Mellitus

PROBLEM

To determine the role of peripheral blood NK (pNK) cells in putative etiology of gestational diabetes, the expression of surface markers on pNK cells and the percentage of cytokine-producing pNK cells in women at 12 weeks of pregnancy with gestational diabetes mellitus (GDM) were studied.

METHOD OF STUDY

Multicolor flow cytometry was used to analyze the expression of NK cell surface receptors (CD16, NKp46, and NKp30) and intracellular cytokines (IFN-γ, TNF-α, TGF-β, and VEGF) in pNK cells (CD56(dim) and CD56(bright) ) at 12 weeks of pregnancy with GDM (n = 7) and non-GDM (n = 28).

RESULTS

CD56(bright) /CD16(-) NK and CD56(bright) /NKp46(+) NK cell percentage were significantly lower in GDM women than that in non-GDM women. IFN-γ- and TNF-α-producing CD56(+) cells, respectively, were significantly high, while TGF-β- and VEGF-producing CD56(+) cells and CD56(bright) cells, respectively, were significantly low in GDM women.

CONCLUSIONS

Women with GDM possibly have abnormal NK cell function for the expression of surface receptors and cytokine production.

Glycosylation failure extends to glycoproteins in gestational diabetes mellitus: evidence from reduced α2-6 sialylation and impaired immunomodulatory activities of pregnancy-related glycodelin-A

OBJECTIVE

Gestational diabetes mellitus (GDM) is a common metabolic disorder of pregnancy. Patients with GDM are at risk for high fetal mortality and gestational complications associated with reduced immune tolerance and abnormal carbohydrate metabolism. Glycodelin-A (GdA) is an abundant decidual glycoprotein with glycosylation-dependent immunomodulatory activities. We hypothesized that aberrant carbohydrate metabolism in GDM was associated with changes in glycosylation of GdA, leading to defective immunomodulatory activities.

RESEARCH DESIGN AND METHODS

GdA in the amniotic fluid from women with normal (NGdA) and GDM (DGdA) pregnancies was purified by affinity chromatography. Structural analysis of protein glycosylation was preformed by lectin-binding assay and mass spectrometry. Cytotoxicity, cell death, cytokine secretion, and GdA binding of the GdA-treated lymphocytes and natural killer (NK) cells were determined. The sialidase activity in the placental tissue from normal and GDM patients was measured.

RESULTS

GDM affected the glycosylation but not the protein core of GdA. Specifically, DGdA had a lower abundance of α2-6-sialylated and high-mannose glycans and a higher abundance of glycans with Sda (NeuAcα2-3[GalNAcβ1-4]Gal) epitopes compared with NGdA. DGdA had reduced immuosuppressive activities in terms of cytotoxicity on lymphocytes, inhibitory activities on interleukin (IL)-2 secretion by lymphocytes, stimulatory activities on IL-6 secretion by NK cells, and binding to these cells. Desialylation abolished the immunomodulation and binding of NGdA. Placental sialidase activity was increased in GDM patients, which may account for the reduced sialic acid content of DGdA.

CONCLUSIONS

Taken together, this study provides the first direct evidence for altered enzymatic glycosylation and impaired bioactivity of GdA in GDM patients.

Gestational diabetes: risk factors and recent advances in its genetics and treatment

The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study of over 23000 diabetes-free pregnancies has shown that at a population level an unequivocal linear relationship exists between maternal glucose concentrations around the beginning of the third trimester of pregnancy and the risk of their baby being born above the ninetieth centile for weight. With the rising incidence of gestational diabetes (GDM) across the developed world, largely paralleling the increased prevalence of obesity, there has been a sharp increase in the risk of pregnancy complications developing related to the birth of macrosomic babies. The associated additional long-term complications of GDM pregnancies means that in the future there is likely to be a large increase in the incidence of type 2 diabetes and associated conditions in both the mothers and their affected offspring. The present review seeks to highlight recent advances and remaining gaps in knowledge about GDM in terms of its genetics (where some of the recently discovered polymorphic risk factors for type 2 diabetes have also proved to be risk factors for GDM) and its treatment by diet, exercise and drugs.

Onset of autoimmune type 1 diabetes during pregnancy: Prevalence and outcomes

Although this has been recently challenged, gestational diabetes mellitus (gestational diabetes) is still defined as an "impairment of glucose tolerance with onset or first recognition during pregnancy". According to this definition, all pathophysiological conditions leading to beta cell deficiency may reveal as gestational diabetes, due to the physiological insulin resistance associated with pregnancy. In rare patients, gestational diabetes is associated with the presence of islet autoantibodies and with a high risk of progression to overt type 1 diabetes after delivery. This condition has often been compared to the Latent Autoimmune Diabetes in Adults. The frequency of islet autoantibodies in gestational diabetes has been assessed in many studies, but data about the clinical presentation of this subtype and about its prognosis are few. We review these studies and discuss the links of autoimmune gestational diabetes with type 1 diabetes mellitus.

Diabetes related autoimmunity in gestational diabetes mellitus: is it important?

Some GDM women show autoantibody positivity during and after pregnancy and pancreatic autoantibodies can appear for the first time in some patients after delivery. Autoantibody positivity is often accompanied by a high frequency of DR3 and DR4 alleles, which are classically related to the development of type 1 diabetes and, although not all studies agree on this point, by an immunological imbalance expressed by the behaviour of the lymphocyte subpopulation, which can be seen as diabetic anomalies overlapping with the immunological changes that occur during pregnancy. It is worth emphasizing that such patients may develop classical type 1 diabetes during and/or after their pregnancy or they may evolve, often some years after their pregnancy, into cases of latent autoimmune diabetes of adulthood (LADA). Autoimmune GDM accounts for a relatively small number of cases (about 10% of all GDM) but the risk of these women developing type 1 diabetes or LADA is very high, so these patients must be identified in order to prevent the severe maternal and fetal complications of type 1 diabetes developing in pregnancy, or its acute onset afterwards. Since women with autoimmune GDM must be considered at high risk of developing type 1 diabetes in any of its clinical forms, these women should be regarded as future candidates for the immunomodulatory strategies used in type 1 diabetes.

Thyroid function abnormalities and antithyroid antibody prevalence in pregnant women at high risk for gestational diabetes mellitus

Both gestational diabetes mellitus (GDM) and thyroid dysfunction in pregnancy compromise maternal and fetal health. The aim of the present study was to determine the prevalence of abnormal thyroid function and antithyroid antibodies during early pregnancy in a population at high risk for GDM. Serum free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) were measured in 301 pregnant women who underwent routine 'universal screening' for GDM. The antithyroid peroxidase antibody (antiTPOAb) was also quantified in 255 of these women. GDM was confirmed by a 75-g oral glucose tolerance test using World Health Organization criteria. No statistically significant difference was found between the 80 (26.6%) women with GDM and the 221 (73.4%) women without GDM for any of the thyroid function tests. In the cohort tested for antiTPOAb, the 51 (20.0%) women who were positive for antiTPOAb had higher mean TSH (1.57 +/- 2.49 mIU/l; p < 0.001) than the women negative for antiTPOAb. Seventeen (5.6%) women had low FT4 while 12 (4.0%) women had high TSH; 28 (9.3%) women had low serum TSH, among whom three (1.0%) also had high FT4. The significantly higher prevalence of hypothyroxinemia and antiTPOAb titers than generally reported warrants routine screening for thyroid abnormalities. This screening, which can be effectively and easily incorporated into screening practices already in place for GDM, would result in improved obstetric care.

Lymphocyte subsets and cytokines in women with gestational diabetes mellitus and their newborn

This study aimed to identify potential immunological markers for predicting type 1 diabetes in patients with gestational diabetes mellitus (GDM) and any immunological impairment in their newborn. In 62 GDM patients and 74 women with normal glucose tolerance (NGT), and their babies, we assessed total lymphocytes, T lymphocyte subsets CD3 and CD8 expressing T cell receptor (TCR) alpha/beta or gamma/delta, CD16 and CD19, pancreatic autoantibodies and cytokines (IL-5, IL-2, soluble receptor IL-2). At delivery, umbilical cord blood samples were taken for lymphocyte subpopulations and cytokine measurements. GDM mothers had higher levels of total lymphocytes, CD8 expressing TCR gamma/delta, and lower levels of CD3 expressing TCR alpha/beta than NGT controls. Insulin-treated GDM mothers had lower CD4 and CD4/CD8 ratios, and higher CD8 and IL-5 than diet-treated GDM or controls. Five women were positive for pancreatic autoantibodies, with lower CD4 (p<0.01) and CD4/CD8 ratios (p<0.05), and higher CD8 (p<0.03) and CD19 than GDM and control mothers negative for autoantibodies. GDM newborn had higher CD8 gamma/delta and lower CD16 than NGT babies. There were no significant differences in TNF-alpha concentrations in the cord blood obtained from the GDM and NGT newborn. In conclusion, GDM women and their newborn have lymphocyte subset impairments, which are more important in patients positive for autoantibodies and/or treated with insulin.

Lymphocyte sub-populations in gestational diabetes

PROBLEM

We hypothesize that the normal immunologic responses by the maternal immune system during pregnancy are not as well-regulated in gestational diabetes (GD) patients as in healthy pregnant women.

METHOD OF STUDY

Using two-color flow cytometry we evaluated frequencies of peripheral blood lymphocytes in 20 GD patients being treated with insulin; 43 GD patients treated with dietary therapy but no insulin; 44 women experiencing normal pregnancies; and 48 non-pregnant women.

RESULTS

When compared with healthy pregnant women, both GD cohorts showed higher percentages CD4(+)CD25(+) (P < 0.05), CD4(+)CD45RO(+) (P < 0.05) and CD4(+)CD29(+) (P < 0.01) but lower percentages of CD4(+)CD45RA(+) (P < 0.05). Higher percentages of the activated phenotypes CD8(+)CD25(+) and CD8(+)HLA-DR(+) cells in the diet-treated cohort and CD4(+)HLA-DR(+) cells in insulin-treated GB cohort, were observed compared with healthy pregnant subjects (P < 0.05).

CONCLUSIONS

Expanded populations of activated peripheral blood T cells are associated with GD, suggesting that normal maternal immunosuppression is less effective in GD-afflicted women.

Chromosomal anomalies among the offspring of women with gestational diabetes

A limited body of data over the past 35 years has suggested that autoimmunity may be responsible for some cases of aneuploidy. The role of diabetes mellitus in the etiology of chromosomal anomalies has been infrequently studied. This study was designed to compare the prevalence of chromosome abnormalities among the offspring of women with gestational diabetes and the offspring of women without it. The authors used data from 7,332 women who underwent amniocentesis in a prospective study of pregnancy outcome (1984-1988) and examined the prevalence of autosomal and sex chromosome defects associated with gestational diabetes. Among the offspring of 231 women with gestational diabetes, the crude prevalence of chromosomal defects was twice as high as that seen in the offspring of 7,101 women without gestational diabetes. These anomalies were predominantly numeric sex chromosome defects. After adjusting for potential confounding by maternal age, body mass index, education, and first-trimester exposures in multiple logistic regression analysis, the authors found that women with gestational diabetes were 7.7 times as likely (95% confidence interval: 2.8, 21.1) to have an infant with a numeric sex chromosome defect as those without gestational diabetes. These results support the theory that some women who develop gestational diabetes may have underlying biochemical changes that induce nondisjunction and the development of chromosomal defects.

Low frequency of autoantibodies to islet cell, glutamic acid decarboxylase, and second-islet antigen in patients with gestational diabetes mellitus: a follow-up study

The aim of the study was to determine the frequency of patients with gestational diabetes mellitus (GDM) who have serological markers typical of autoimmune type 1 DM. The specific pancreatic markers, ICAs, glutamic decarboxylase (GADAbs), and second islet antigen (IA2Abs), were measured in 70 women with GDM during the pregnancy and after delivery. ICAs were measured by indirect immunofluorescence and GADAbs and IA2Abs were determined by a radiobinding assay with recombinant antigens. On entering the study, 1 of 70 (1.4%) patients was positive for both ICAs (80 JDF-U) and GADAbs (167 U/mL), while another (1.4%) was positive for ICAs (40 JDF-U). None of the patients was positive for IA2Abs. During follow-up, positivity was maintained unchanged in the two positive patients. Four previously negative patients had seroconversion: one for both ICAs (20 JDF-U) and GADAbs (49.3 U/mL) and the other three for GADAbs (1.8, 1.4, and 15.3 U/mL, respectively). The IA2Abs remained negative in all patients. Overall, during the observation period 6 of 70 (8.6%) patients had or developed autoantibodies against endocrine pancreas. During follow-up 15 patients developed clinical DM (10 type 2, 5 type 1) and 7 demonstrated impaired glucose tolerance (IGT) after OGTT. No correlations were demonstrated between the immunological patterns and the evolution in DM. In patients with GDM, the frequency of pancreatic autoantibodies varies during the pregnancy and after delivery, but a small subgroup of patients bearing these markers is identifiable. GDM is a complex syndrome, constituted by different types of diabetes mellitus where the autoimmune form is very rare.

Type 1 diabetes islet autoantibody markers

The diagnosis of type 1 diabetes versus other forms of diabetes such as type 2 diabetes is paramount to guiding proper therapy. Several islet autoantibodies have been identified that serve to diagnose immune-mediated, type 1a diabetes in clinically ambiguous cases. These autoantibodies also serve to predict type 1 diabetes in nondiabetic individuals. The most useful islet autoantibodies include islet cell cytoplasmic autoantibodies, insulin autoantibodies, glutamic acid decarboxylase autoantibodies, and insulinoma-associated-2 autoantibodies. Once type 1 diabetes can be safely and reliably prevented, large-scale islet autoantibody screening programs of the general pediatric population may be warranted. It is controversial whether islet autoantibodies influence the course of type 1 diabetes following diagnosis.

Autoimmune gestational diabetes mellitus: a distinct clinical entity?

This review gives an update of the present knowledge on what is defined here as autoimmune gestational diabetes mellitus (GDM). Autoimmune phenomena associated with type 1 diabetes mellitus (DM) can be detected in a subgroup of women with GDM. Islet autoantibodies are present in sera from women with GDM with variable frequency. Distinct phenotypic and genotypic features may be recognised in this subset of women with GDM, which are representative of a distinct clinical entity. Furthermore, these women are at increased risk of developing type 1 DM after pregnancy. However, the eventual progression of the autoimmune destruction of beta-cells in these subjects may follow different time-course patterns thus leading to variable forms of presentation of autoimmune DM. As a high-risk group for type 1 diabetes, women with previous autoimmune GDM may be candidates for potential immune intervention strategies.