17. Immunologic endocrine disorders

Innate Immunity in Autoimmune Thyroid Disease during Pregnancy

Autoimmune thyroid disease (AITD) is the most common organ-specific autoimmune disorder clinically presented as Hashimoto thyroiditis (HT) and Graves' disease (GD). The pathogenesis of AITD is caused by an inappropriate immune response related to genetic, non-genetic, and environmental factors. Pregnancy is one of the factors that have a great influence on the function of the thyroid gland because of the increased metabolic demand and the effects of hormones related to pregnancy. During pregnancy, an adaptation of the maternal immune system occurs, especially of the innate immune system engaged in maintaining adaptive immunity in the tolerant state, preventing the rejection of the fetus. Pregnancy-related hormonal changes (estrogen, progesterone, hCG) may modulate the activity of innate immune cells, potentially worsening the course of AITD during pregnancy. This especially applies to NK cells, which are associated with exacerbation of HD and GD. On the other hand, previous thyroid disorders can affect fertility and cause adverse outcomes of pregnancy, such as placental abruption, spontaneous abortion, and premature delivery. Additionally, it can cause fetal growth retardation and may contribute to impaired neuropsychological development of the fetus. Therefore, maintaining the thyroid equilibrium in women of reproductive age and in pregnant women is of the highest importance.

Unveiling the Link: A Comprehensive Narrative Review of the Relationship Between Type 1 Diabetes Mellitus and Celiac Disease

Type 1 diabetes mellitus (T1DM) is an autoimmune condition with a genetic predisposition. It has underlying autoimmune destruction of the pancreatic cells that produce insulin. It is often accompanied by other autoimmune conditions. This article focuses on celiac disease (CD), also an autoimmune disease. It is caused by gluten exposure. Both these conditions have genetic predisposing factors. Apart from the genetic background, aberrant small intestine immune response, inflammation, and different grades of enteropathy present in T1DM and CD are the same. With a mean frequency of 8%, the CD frequency of T1DM ranges from 3 to 16%. All T1DM patients should undergo serological testing for CD using antibodies to tissue transglutaminase at the time of T1DM onset. Individuals with T1DM and those accompanied by CD must follow a diet with no gluten. To outline the steps that can avert the development of these disorders and reduce the morbidity of the affected people, a complete understanding of the intricate pathophysiology of T1DM and its connection to CD has been undertaken in this review. The use of resources, such as PubMed and Google Scholar, has made this possible.

The importance of biomarker development for monitoring type 1 diabetes progression rate and therapeutic responsiveness

Type 1 diabetes (T1D) is an autoimmune condition of children and adults in which immune cells target insulin-producing pancreatic β-cells for destruction. This results in a chronic inability to regulate blood glucose levels. The natural history of T1D is well-characterized in childhood. Evidence of two or more autoantibodies to the islet antigens insulin, GAD, IA-2 or ZnT8 in early childhood is associated with high risk of developing T1D in the future. Prediction of risk is less clear in adults and, overall, the factors controlling the progression rate from multiple islet autoantibody positivity to onset of symptoms are not fully understood. An anti-CD3 antibody, teplizumab, was recently shown to delay clinical progression to T1D in high-risk individuals including adults and older children. This represents an important proof of concept for those at risk of future T1D. Given their role in risk assessment, islet autoantibodies might appear to be the most obvious biomarkers to monitor efficacy. However, monitoring islet autoantibodies in clinical trials has shown only limited effects, although antibodies to the most recently identified autoantigen, tetraspanin-7, have not yet been studied in this context. Measurements of beta cell function remain fundamental to assessing efficacy and different models have been proposed, but improved biomarkers are required for both progression studies before onset of diabetes and in therapeutic monitoring. In this mini-review, we consider some established and emerging predictive and prognostic biomarkers, including markers of pancreatic function that could be integrated with metabolic markers to generate improved strategies to measure outcomes of therapeutic intervention.

Nanotechnology in Immunotherapy for Type 1 Diabetes: Promising Innovations and Future Advances

Diabetes is a chronic condition which affects the glucose metabolism in the body. In lieu of any clinical “cure,” the condition is managed through the administration of pharmacological aids, insulin supplements, diet restrictions, exercise, and the like. The conventional clinical prescriptions are limited by their life-long dependency and diminished potency, which in turn hinder the patient’s recovery. This necessitated an alteration in approach and has instigated several investigations into other strategies. As Type 1 diabetes (T1D) is known to be an autoimmune disorder, targeting the immune system in activation and/or suppression has shown promise in reducing beta cell loss and improving insulin levels in response to hyperglycemia. Another strategy currently being explored is the use of nanoparticles in the delivery of immunomodulators, insulin, or engineered vaccines to endogenous immune cells. Nanoparticle-assisted targeting of immune cells holds substantial potential for enhanced patient care within T1D clinical settings. Herein, we summarize the knowledge of etiology, clinical scenarios, and the current state of nanoparticle-based immunotherapeutic approaches for Type 1 diabetes. We also discuss the feasibility of translating this approach to clinical practice.

Clinical Implications of the Coexistence of Anemia and Diabetes Mellitus in the Elderly Population

Diabetes mellitus (DM) and also anemia are common in the elderly and have a negative impact on the clinical outcomes of patients. The coexistence of anemia and DM seems to be insufficiently recognized; therefore, the aim of our study is to analyze the incidence and clinical consequences of this coexistence, including mortality, in the population of people aged ≥60. A retrospective study was conducted on 981 primary care clinic patients aged ≥60 during 2013-2014. The prevalence of coexistence of DM and anemia (defined in accordance with WHO) and data on the incidence of comorbidities, hospitalization, medical procedures, and all-cause mortality were analyzed. In the study population, 25% had DM, while 5.4% had both DM and anemia. Peripheral artery disease (PAD) was found in 48 patients (4.89%) of the entire study population, more often in men (p < 0.001). Diabetic patients with anemia compared to nonanemic diabetics had more comorbidities (median 4 (4, 5) vs. 3 (2-4); p < 0.001)-PAD more often (p = 0.004), more hospitalization (median 2 (0-11) vs. 0 (0-11); p < 0.001), and more frequent medical procedures (e.g., percutaneous coronary intervention (p < 0.001), coronary artery bypass surgery (p = 0.027), arteriography (p < 0.001), and bypass surgery or endovascular treatments of lower limb ischemia (p < 0.001)). The cumulative survival of patients with both DM and anemia vs. nonanemic diabetics at 36 months was 86.4% vs. 99.3% (p < 0.001). A multivariate logistic regression model showed anemia to be a significant risk factor for death in diabetic patients (p = 0.013). Patients with both DM and anemia have more comorbidities than nonanemic diabetic patients; they are more often hospitalized, require medical procedures more frequently, and are at a higher risk of death. Effective treatment of anemia in patients with DM is advisable and may well improve the prognosis of patients.

Autoimmune polyglandular diseases

Autoimmune polyglandular diseases (APD) are defined as the presence of two autoimmune -induced endocrine failures. With respect to the significant morbidity and potential mortality of APD, the diagnostic objective is to detect APD at an early stage, with the advantage of less frequent complications, effective therapy and better prognosis. This requires that patients at risk be regularly screened for subclinical endocrinopathies prior to clinical manifestation. Regarding the time interval between manifestation of first and further endocrinopathies, regular and long-term follow-up is warranted. Quality of life and psychosocial status are poor in APD patients and involved relatives. Familial clustering is high in patients with APD. Considering the high incidence of one or more endocrinopathies in first-degree relatives of patients with APD, family members should be regularly screened since they may also develop autoimmune endocrinopathies. Multidisciplinary management of these multiplex families in specialized centers is warranted.

Celiac disease and endocrine autoimmunity - the genetic link

Celiac disease is a small intestinal inflammatory disease with autoimmune features that is triggered and maintained by the ingestion of the storage proteins (gluten) of wheat, barley and rye. The prevalence of celiac disease is increased in patients with monoglandular and/or polyglandular autoimmunity and their relatives. Between 10 and 30% of patients with celiac disease are thyroid and/or type 1 diabetes antibody positive, while around 5 to 7% of patients with autoimmune thyroid disease and/or type 1 diabetes are IgA anti-tissue transglutaminase antibody positive. The close relationship between celiac disease and endocrine autoimmunity is largely explained by sharing a common genetic background. The HLA antigens DQ2 (DQA1*0501-DQB1*0201) and/or DQ8 (DQA1*0301-DQB1*0302), that are tightly linked to DR3 and DR4, respectively, are the major common genetic predisposition. Moreover, functional single nucleotide polymorphisms of various genes that are involved in immune regulation have been identified as "overlap" susceptibility genes for both celiac disease and monoglandular or polyglandular autoimmunity. While plausible, it remains to be established how far a gluten free diet may prevent or ameliorate glandular autoimmunity. In conclusion, all patients with celiac disease should be screened for type 1 diabetes and/or autoimmune thyroid disease. Conversely, patients with the above autoimmune endocrine disorders should be also screened for celiac disease.

A type 1 diabetes genetic risk score can discriminate monogenic autoimmunity with diabetes from early-onset clustering of polygenic autoimmunity with diabetes

AIMS/HYPOTHESIS

Identifying individuals suitable for monogenic autoimmunity testing and gene discovery studies is challenging: early-onset type 1 diabetes mellitus can cluster with additional autoimmune diseases due to shared polygenic risk and islet- and other organ-specific autoantibodies are present in both monogenic and polygenic aetiologies. We aimed to assess whether a type 1 diabetes genetic risk score (GRS) could identify monogenic autoimmune diabetes and be useful to prioritise individuals for gene discovery studies.

METHODS

We studied 79 individuals with diabetes and at least one additional autoimmune disease diagnosed before the age of 5 years. We screened all participants for the seven genes known to cause monogenic autoimmunity that can include diabetes (AIRE, IL2RA, FOXP3, LRBA, STAT1, STAT3, STAT5B). We genotyped the top ten risk alleles for type 1 diabetes, including HLA and non-HLA loci, to generate a type 1 diabetes GRS.

RESULTS

Of the 79 individuals studied, 37 (47%) had mutations in the monogenic autoimmunity genes. The type 1 diabetes GRS was lower in these individuals than in those without mutations in these genes (median 9th vs 49th centile of type 1 diabetes controls, p < 0.0001). Age of diabetes diagnosis and type 1 diabetes GRS combined to be highly discriminatory of monogenic autoimmunity (receiver operating characteristic AUC: 0.88). Most individuals without a mutation in a known gene had a high type 1 diabetes GRS, suggesting that they have polygenic clustering of type 1 diabetes and additional autoimmunity and should not be included in gene discovery studies.

CONCLUSIONS/INTERPRETATION

We have shown that the type 1 diabetes GRS can identify individuals likely to have monogenic autoimmunity, helping both diagnostic testing and novel monogenic autoimmunity gene discovery. Individuals with monogenic autoimmunity have a different clinical course to those with polygenic type 1 diabetes and can respond well to therapies targeting the underlying genetic defect.

Plasmacytoid dendritic cells in patients with autoimmune thyroid disease

BACKGROUND

Patients with autoimmune thyroid diseases (AITD) show defects in immunoregulatory mechanisms. Herein we assessed the expression of different regulatory receptors in circulating and thyroid dendritic cells (DCs).

DESIGN

Peripheral blood samples from 49 patients with Hashimoto's thyroiditis, 35 with Graves' disease, and 34 healthy subjects were studied. Clinical parameters included grades of goiter and ophthalmopathy, thyroid function, and antibody tests. Thyroid tissue samples from 10 AITD patients were also analyzed. Levels of DCs and their expression of different regulatory molecules (IDO, ILT2, ILT3, PSGL-1, PD-L1) were studied. In vitro interferon-α response by plasmacytoid DCs (pDCs) and tryptophan (Trp) metabolites were determined.

RESULTS

Significant low levels of pDCs, but not conventional DCs, were detected in the peripheral blood from AITD patients, mainly in those with severe disease. Furthermore, a diminished expression of ILT3, PSGL-1, and CD69 by peripheral blood pDCs from AITD patients was observed. An increased number of pDCs was found in thyroid tissue, showing a diminished expression of ILT3 and PSGL-1. A lower proportion of IDO+ pDCs, a significant increase in Trp levels, a decrease in the kyneruine/Trp ratio, and an increased in vitro interferon-α response were present in AITD patients. Finally, a significant correlation was found between the in vitro synthesis of IL-10 by stimulated T cells and expression of IDO by pDCs.

CONCLUSIONS

The diminished number of pDCs in the peripheral blood from AITD patients as well as their abnormal phenotype could contribute significantly to the pathogenesis.

From markers to molecular mechanisms: type 1 diabetes in the post-GWAS era

By the year 2000, a draft of the human genome sequence was completed. Millions of single-nucleotide polymorphisms (SNPs) had been deposited into public databases, and high throughput technologies were under development for SNP genotyping. At that time, it was predicted that large case control association studies would provide far better resolution and power than genome-wide linkage studies. Type 1 diabetes was one of the first phenotypes to be examined by genome-wide association studies (GWAS), and to date over 50 genomic regions have been associated with the disease. In general, the great majority of these loci individually contribute a relatively small degree of risk, and most loci lie outside of coding sequences. The identification of molecular mechanisms from these genomic data therefore remains a significant challenge. Here, we summarize genetic candidate, linkage, and association studies of type 1 diabetes and discuss a potential strategy to identify mechanisms of disease from genomic data.

Cationic nanomicelles for delivery of plasmids encoding interleukin-4 and interleukin-10 for prevention of autoimmune diabetes in mice

PURPOSE

To evaluate the in vivo transfection efficiency of N-acyl derivatives of low-molecular weight chitosan (LMWC) to deliver pVIVO2-mIL4-mIL10 plasmid encoding interleukin-4 (IL-4) and interleukin-10 (IL-10) in multiple, low-dose streptozotocin induced diabetic mouse model.

METHODS

N-acyl LMWC nanomicelles were characterized for size and charge. The pVIVO2-mIL4-mIL10/N-acyl LMWC polyplexes were injected intramuscularly in mice and compared for transfection efficiency with naked DNA and FuGENE® HD. Bicistronic pVIVO2-mIL4-mIL10 plasmid was compared with individual plasmids encoding IL-4 and IL-10 for efficacy. The levels of blood glucose and serum IL-4, IL-10, TNF-α and IFN-γ were monitored. The ability of plasmid administration to protect from insulitis and biocompatibility of N-acyl LMWC were studied.

RESULTS

The N-acyl LMWC led to significantly higher (p < 0.05) expression of IL-4 and IL-10 and reduced the levels of blood glucose, TNF-α and IFN-γ, especially in animals treated with pVIVO2-mIL4-mIL10 plasmid. The pancreas of pDNA/N-acyl LMWC polyplex treated animals exhibited protection from insulitis and the delivery systems were found to be biocompatible.

CONCLUSIONS

N-acyl derivatives of LMWC are efficient and biocompatible gene delivery vectors, and the administration of bicistronic pVIVO2-mIL4-mIL10 plasmid polyplexes can protect the pancreatic islets from insulitis, possibly due to the synergistic effect of IL-4 and IL-10 encoding plasmids.

Cellular immunity and immunopathology in autoimmune Addison's disease

Autoimmune adrenocortical failure, or Addison's disease, is a prototypical organ-specific autoimmune disorder. In common with related autoimmune endocrinopathies, Addison's disease is only manageable to a certain extent with replacement therapy being the only treatment option. Unfortunately, the available therapy does not restore the physiological hormone levels and biorhythm. The key to progress in treating and preventing autoimmune Addison's disease lies in improving our understanding of the predisposing factors, the mechanisms responsible for the progression of the disease, and the interactions between adrenal antigens and effector cells and molecules of the immune system. The aim of the present review is to summarize the current knowledge on the role of T cells and cellular immunity in the pathogenesis of autoimmune Addison's disease.

Estimation of genetic risk for Type 1 diabetes mellitus in newborns on dried blood spot

BACKGROUND

The main contribution to genetic susceptibility for Type 1 Diabetes Mellitus (T1DM) is conferred by the Human Leukocyte Antigens (HLA).

AIM

We evaluated the feasibility of large scale screening on Dried Blood Spot (DBS) to estimate the genetic risk for T1DM in newborns.

SUBJECTS AND METHODS

Peripheral blood DBS samples from 256 newborns, were genotyped for HLA DRB1 and DQB1 alleles identification by a commercially available assay based on a dissociation enhancer lanthanide fluorescence system available in many newborn screening laboratories. Results were compared with those obtained in two wide multicentric studies on cord blood (DIABFIN and PREVEFIN).

RESULTS

Genotyping on DBS revealed 6 subjects at high risk for T1DM, 99 at moderate risk for T1DM and the remaining at low risk for T1DM. We found 100% concordance between both techniques for HLA-DQB1 and DRB1 determination, confirming the feasibility of large scale screening on DBS.

CONCLUSIONS

DBSs represent a resource for future studies about new genetics markers. This assay for estimate the genetic risk of T1DM on DBS showed an excellent sensitivity, specificity and accuracy compared with conventional techniques. Moreover, this assay resulted less expensive, and it could be easily performed on material already collected for newborn screening programs.

Antidiabetic effects of scoparic acid D isolated from Scoparia dulcis in rats with streptozotocin-induced diabetes

We evaluated the antihyperglycaemic effect of scoparic acid D (SAD), a diterpenoid isolated from the ethanol extract of Scoparia dulcis in streptozotocin (STZ)-induced diabetic male Wistar rats. SAD was administered orally at a dose of 10, 20 and 40 mg kg(-1) bodyweight for 15 days. At the end of the experimental period, the SAD-treated STZ diabetic rats showed decreased levels of glucose as compared with diabetic control rats. The improvement in blood glucose levels of SAD-treated rats was associated with a significant increase in plasma insulin levels. SAD at a dose of 20 mg kg(-1) bodyweight exhibited a significant effect when compared with other doses. Further, the effect of SAD was tested on STZ-treated rat insulinoma cell lines (RINm5F cells) and isolated islets in vitro. SAD at a dose of 20 microg mL(-1) evoked two-fold stimulation of insulin secretion from isolated islets, indicating its insulin secretagogue activity. Further, SAD protected STZ-mediated cytotoxicity and nitric oxide (NO) production in RINm5F cells. The present study thus confirms the antihyperglycaemic effect of SAD and also demonstrated the consistently strong cytoprotective properties of SAD.

Frequency and function of circulating invariant NKT cells in autoimmune diabetes mellitus and thyroid diseases in Colombian patients

The frequency and functionality of peripheral blood invariant (iNKT) cells and their subsets, as well as other regulatory T-cell subsets, were evaluated in patients with type 1A diabetes mellitus (DM1), Hashimoto's disease, and Graves' disease. In addition to healthy individuals (HC), patients with type 2 diabetes mellitus (DM2) were included as controls because this disease has a different physiopathology. A similar frequency of total iNKT cells, as well as their subsets, existed among HC and the different study groups. Similar results were reported when we compared the frequency of CD4(+)/CD25(high) T cells, CD8(+)/CD28(negative) T cells, and gamma-delta T cells among HC and study groups, whereas patients with DM2 exhibited a higher frequency of CD8(+)/CD28(negative) T cells compared with HC and DM1. Also, patients with DM2 exhibited a lower frequency of CD4(negative) and CD4(+) iNKT cells expressing tumor necrosis factor-alpha (TNF-alpha) than HC. We did not observe significant differences in the frequency of iNKT cells expressing interleukin-4 or interferon-gamma among study groups and controls. Our findings support a normal frequency and function of peripheral blood iNKT cells in different endocrine autoimmune diseases, but an abnormal expression of TNF-alpha by circulating iNKT cells from patients with DM2.

The molecular genetics of type 1 diabetes: new genes and emerging mechanisms

Susceptibility to type 1 diabetes (T1D) is determined by complex interactions between several genetic loci and environmental factors. Alleles at the human leukocyte antigen (HLA) locus explain up to 50% of the familial clustering of T1D, and the remainder is contributed to by multiple loci, of which only four were known until recently. First-stage results of genome-wide association (GWA) studies performed with high-density genotyping arrays have already produced four novel loci and the promise that, with the completion of the second stage of the GWA studies, most of the genetic basis of T1D will be known. We will review what is known to date about the mechanisms of genetic susceptibility to T1D, with special emphasis on possible diagnostic and therapeutic applications of these recent genetic findings.

Spectrum of Autoantibodies in Tunisian Adult Type 1 Diabetes Mellitus

As an autoimmune disease, type 1 diabetes mellitus (T1DM) is characterized by the presence of several autoantibodies. The aim of this study was to examine a broad spectrum of antibodies in Tunisian adult T1DM and to compare their prevalence with a healthy control group. Two hundred sixty-one diabetics and 100 healthy blood donors were enrolled in this study. Indirect immunofluorescence was performed for the detection of islet cell, antiendomysial, antinuclear, antimitochondrial, antismooth muscle, antireticulin, and antikeratin antibodies. Enzyme-linked immunosorbent assay was used for measuring anticardiolipin, antigliadin, antitransglutaminase, and antithyroperoxidase antibodies. Latex agglutination was used for the detection of rheumatoid factors. As expected, islet cell antibodies were the most frequent (33.7%). Antigliadin, antithyroperoxidase, and antikeratin antibodies were relatively frequent (18%, 15.3%, and 10.3%, respectively) and were statistically more prevalent in diabetics than in controls. There was no correlation between diabetes duration and any autoantibody, except for islet cell antibodies that were more frequent at the onset of diabetes. Several autoantibodies nonspecific of diabetes are frequent in diabetic patients, which may be associated with or predictors of some autoimmune diseases, and can also reflect a special profile of autoimmunity in diabetics in comparison to healthy controls.

Type 1 diabetes: pathogenesis and prevention

Type 1 diabetes results from the autoimmune destruction of insulin-producing beta cells in the pancreas. Genetic and, as yet undefined, environmental factors act together to precipitate the disease. The excess mortality associated with the complications of type 1 diabetes and the increasing incidence of childhood type 1 diabetes emphasize the importance of therapeutic strategies to prevent this chronic disorder. Why is it considered that type 1 diabetes might be preventable? Different strands of diabetes research are coming together to suggest therapeutic targets. Islet cell autoantibody assays make it possible to accurately identify people at risk of future disease. In most cases, a long prodrome provides a window of opportunity to reverse the autoimmune process. Although no current "cure" exists, recent genetic data and preliminary trial results suggest T cells as a target for preventive strategies. Another potentially attainable target is induction of tolerance to the beta-cell proteins such as insulin that are inappropriately recognized. Other strategies involve beta-cell replacement, but currently there are insufficient donor cells available. This may be overcome as the processes controlling the differentiation of pancreatic and nonpancreatic progenitors as well as replication of existing islet beta cells are unravelled.

Anemia and the role of erythropoietin in diabetes

Anemia is more common in patients with diabetes than without diabetes, and the problem is magnified in patients with renal impairment. Diabetic patients with anemia may be at increased risk of adverse outcomes from diabetic retinopathy, nephropathy, neuropathy, and cardiovascular disease. The etiology of anemia in diabetes is multifactorial and includes inflammation, nutritional deficiencies, concomitant autoimmune diseases, drugs, and hormonal changes in addition to kidney disease. Anemia that is associated with erythropoietin deficiency may have prognostic significance for persons with nephropathy or heart failure. In early diabetic nephropathy, damage to the peritubular fibroblasts can occur and lead to erythropoietin deficiency and anemia prior to the loss of filtration. Correction of the anemia not only leads to less fatigue, greater exercise tolerance, and an improved quality of life but also to a reduction in mortality and hospital admissions for congestive heart failure (CHF). Data are accumulating that suggest that treatment of anemia will slow the progression of microvascular and macrovascular complications, including postural hypotension from autonomic neuropathy, retinopathy, and loss of renal function from diabetic nephropathy. Promptly diagnosing and treating anemia in patients with diabetes may result in an improved quality of life and decreased morbidity and mortality.

HLA genotyping supports a nonautoimmune etiology in patients diagnosed with diabetes under the age of 6 months

Children with permanent diabetes are usually assumed to have type 1 diabetes. It has recently been shown that there are genetic subgroups of diabetes that are often diagnosed during the neonatal period but may present later. A recent Italian study proposed that type 1 diabetes is rare before 6 months of age. We aimed to examine genetic susceptibility to type 1 diabetes in patients diagnosed with diabetes before the age of 2 years. We analyzed HLA class II genotypes, markers of autoimmune diabetes, in 187 children with permanent diabetes diagnosed at <2 years of age. Of the 79 subjects diagnosed at <6 months of age, 41% (95% CI 0.30-0.51) had type 1 diabetes-associated high-risk genotypes, a proportion similar to that in healthy population control subjects (44%, P=0.56). This group included 32 patients with mutations in the KCNJ11 gene, which encodes Kir6.2 (44% high-risk HLA class II genotypes), and 47 in whom the etiology of diabetes was unknown (38% high-risk HLA class II genotypes). Of 108 patients diagnosed between 6 and 24 months of age, 93% (0.86-0.99) had high-risk HLA class II genotypes compared with 44% of the population control subjects (P<0.0001). We conclude that infants diagnosed with diabetes before 6 months of age are unlikely to have autoimmune type 1 diabetes and are most likely to have a monogenic etiology.

Immunogenetics of Hashimoto's thyroiditis

Hashimoto's thyroiditis (HT) is an organ-specific T-cell mediated disease. It is a complex disease, with a strong genetic component. To date, significant progress has been made towards the identification and functional characterization of HT susceptibility genes. In this review, we will summarize the recent advances in our understanding of the genetic input to the pathogenesis of HT.

Paraneoplastic Neurologie Syndrome and Autoimmune Addison Disease in a Patient with Thymoma

A 48-year-old man with autoimmune Addison disease developed the following paraneoplastic neurologic syndromes (PNNS): limbic encephalitis, opsoclonus/myoclonus, and sensorimotor and autonomic neuropathies. An anterior mediastinal mass detected on a chest computed tomographic scan was found on resection to be a noninvasive lymphocytic thymoma. The PNNS went into remission 1 year after the thymectomy. This is the first case of thymoma associated with autoimmune Addison disease and PNNS to be described in the literature.

Exploring the idiotypes of insulin antibodies as markers for remission in Type 1 diabetes

AIMS

Complete or partial remission can occur in newly diagnosed Type 1 diabetes patients. We created idiotype-specific reagents to explore the idiotypes of insulin antibodies (IA) in a patient in remission, and to compare with a patient who was not.

METHODS

Phage display was used to create a library of phagotopes specific to insulin binding in four sera. Sera from a Type 1 diabetes subject deemed to have undergone remission were taken at diagnosis and again during remission. Sera from a non-remitter were taken at diagnosis and after 3 months on insulin. Phagotopes from the four sera were randomly selected and tested for insulin specificity in a radiobinding assay by using sera from remitters and non-remitters.

RESULTS

IA-binding phagotope selected from serum during remission displaced insulin binding in all nine IA(+) remitters and all 10 IA(+) non-remitters. IA-binding phagotope selected from the non-remission patient (3 months after insulin therapy) displaced insulin binding in 8/9 IA(+) remitters and 8/10 IA(+) non-remitters. The consensus peptide sequences adduced from the phages were identical for both these phagotopes. Phagotopes derived from insulin autoantibody-positive individuals at diagnosis were unable to displace insulin binding in the IA(+) sera 3 months later, whether in remission or not.

CONCLUSIONS

We have established the principle of using phage display in the investigation of insulin antibodies during remission in Type 1 diabetes. The immunological characteristics of IA 3 months after the introduction of insulin treatment were different from those at diagnosis of Type 1 diabetes (IAA). Using phage display technology, it was not possible to distinguish insulin antibodies according to remission status.

Thyroid dysfunction after bone marrow transplantation for primary immunodeficiency without the use of total body irradiation in conditioning

Thyroid dysfunction, a common long-term complication following bone marrow transplantation (BMT), is frequently associated with total body irradiation (TBI) given in the pre-BMT conditioning protocol. We report our preliminary observation of the prevalence of thyroid dysfunction in children transplanted for primary immunodeficiency (PID) who were given cytoreductive conditioning with busulphan and cyclophosphamide, but without TBI. We evaluated thyroid-stimulating hormone (TSH) and free thyroxine (fT4) in 83 survivors transplanted between 1987 and 2002. We found nine children (10.8%) with clinical and/or biochemical thyroid dysfunction at 4 months to 4.5 years post-BMT of which three had positive antithyroid microsomal antibodies. Two patients were classified as primary and seven as compensated hypothyroidism (hyperthyrotropinaemia). Four patients with clinical features of hypothyroidism received replacement thyroxine, while five of the seven patients with compensated hypothyroidism remain off thyroxine because we suspect this may be a transient phenomenon. Abnormalities of thyroid function including severe primary hypothyroidism may occur post-BMT in children receiving chemotherapy conditioning without TBI. Thyroid function should be assessed regularly in this group of patients.

Berson, Yalow, and the JCI: the agony and the ecstasy

The isolation of insulin in 1921 by Banting, Best, Collip, and Macleod stands as one of the most dramatic stories in modern medical investigation. Only two years passed between the initial experiments in dogs to widespread human application to the awarding of the Nobel Prize in 1923. Insulin-related research has also served as a focus, at least in part, for the work of three other Nobel Prize recipients: determination of the chemical structure of insulin by Frederick Sanger in 1958; determination of the three-dimensional structures of insulin and vitamin B12 by Dorothy Hodgkin in 1964; and finally, the development of immunoassay by Solomon Berson and Rosalyn Yalow in 1959-1960, which led to a Nobel Prize for Yalow in 1977 (five years after the untimely death of Berson). The history of Yalow and Berson's discovery and its impact on the field is an illustration of the adage that every story has two sides.

Potential mechanisms of interferon-alpha induced autoimmunity

The type I interferons (IFN) are cytokines encoded by a multigene family comprising 13 closely related IFN-A genes, and a single IFN-B gene. These factors are rapidly induced upon viral infection, and have pleiotropic effects. Historically, the induction of a cell-autonomous state of antiviral resistance, the inhibition of cell growth, and the regulation of apoptosis were appreciated first. More recently, it became generally accepted that they can regulate immune effector functions. This latter feature led them to be reconsidered as signals linking innate and adaptive immunity, and potentially orchestrating autoimmunity associated with viral infection and IFN-alpha therapy. Common to almost all autoimmune diseases is their polygenic inheritance, incomplete penetrance, and evidence for the role of environmental factors, particularly viral infection. In addition, they are characterized by increased numbers of circulating autoreactive T- and B-cells. Endogenously produced or therapeutically applied IFN-alpha can tilt the usually tightly controlled balance towards activation of these autoreactive cells via a vast array of mechanisms. The genetic susceptibility factors determine which type of autoimmunity will develop. IFN-alpha induces numerous target genes in antigen presenting cells (APC), such that APC are stimulated and enhance humoral autoimmunity, promote isotype switching, and potently activate autoreactive T cells. Moreover, IFN-alpha can synergistically amplify T cell autoreactivity by directly promoting T cell activation and keeping activated T cells alive. In essence, type I IFNs may constitute one example of genes that have been conserved because they confer dominant disease resistance, but at the same time they can trigger autoimmunity in genetically susceptible individuals.

Defective suppressor function of human CD4+ CD25+ regulatory T cells in autoimmune polyglandular syndrome type II

In autoimmune polyglandular syndromes (APS), several organ-specific autoimmune diseases are clustered. Although APS type I is caused by loss of central tolerance, the etiology of APS type II (APS-II) is currently unknown. However, in several murine models, depletion of CD4⁺ CD25⁺ regulatory T cells (T_regs) causes a syndrome resembling human APS-II with multiple endocrinopathies. Therefore, we hypothesized that loss of active suppression in the periphery could be a hallmark of this syndrome. T_regs from peripheral blood of APS-II, control patients with single autoimmune endocrinopathies, and normal healthy donors showed no differences in quantity (except for patients with isolated autoimmune diseases), in functionally important surface markers, or in apoptosis induced by growth factor withdrawal. Strikingly, APS-II T_regs were defective in their suppressive capacity. The defect was persistent and not due to responder cell resistance. These data provide novel insights into the pathogenesis of APS-II and possibly human autoimmunity in general.

Is there a causative role for tetanus toxoid vaccination in the development of allergy-like symptoms and in the increasing prevalence of atopic diseases?

Allergic diseases are a worldwide health problem. They mainly affect people living in developed countries where an increasing prevalence of allergy symptoms has been recorded in the last 20-30 years. The cause of this increase is still disputed, and, among others, the "hygiene hypothesis" supported the concept that relevant changes in lifestyle could have a relationship with the phenomenon. More recently the recorded parallel increase in autoimmune diseases has suggested to consider the "hygiene hypothesis" as a cause of a more general disregulation of the immune system leading to both allergy and to autoimmunity. Here are reported a series of observations, evidence, and data from the literature leading to a different hypothesis. The key points are: (1) the presence of two subsets of patients having allergy symptoms based on an IgE-mediated mechanism or not; (2) the positive results obtained with the autologous serum skin test in either cutaneous or respiratory affected subjects, mainly in children and adult females; (3) the presence of IgG autoantibodies against the alpha-chain of the high affinity IgE receptor (FcepsilonRIalpha) in non-IgE-mediated urticaria and even in respiratory subjects; (4) the cross-reactivity between epitopes of the tetanus toxoid molecule and the FcepsilonRIalpha detected by means of an alpha-chain affinity purified IgG fraction; (5) the positive skin reactivity obtained using IgG anti-tetanus toxoid preparations in allergic and non-allergic volunteers. The presence of IgG autoantibodies actively generated by the population-based vaccination with tetanus toxoid could induce both mediator release from activated mast cell and Th2 cytokine production early in life. There are epidemiological evidences that tetanus toxoid vaccination could be linked with an increased tendency to have allergy symptoms. The different epidemiological distribution of non-IgE-mediated symptoms, mainly affecting young infants would be in agreement with the present hypothesis. The prevalent mother-to-child relationship in terms of risk for allergy symptoms could be explained with the trans-placenta transfer of IgG. A similar transfer could also take place through the mother milk during breast feeding. It may thus be hypothesized that the increased prevalence of allergic diseases could be caused by the generalized tetanus toxoid immunization procedure, progressively extended to most of the countries worldwide in the last 30-40 years. Both the induction of non-IgE-mediated symptoms caused by the mast cell activation via the anti-FcepsilonRIalpha IgG and the long lasting Th2 inflammation of affected tissues would be the inducing mechanisms. This hypothesis would re-configure part of the allergic diseases as a Th2 phenotypic expression of an autoimmune disease.

Helicobacter pylori infection and gastric autoimmune diseases: is there a link?

BACKGROUND

Helicobacter pylori is thought to be involved in atrophic body gastritis. We explored the prevalence of H. pylori infection in asymptomatic subjects with gastric parietal cell antibodies, as well as in patients with pernicious anemia, to evaluate a possible role of H. pylori gastric infection in gastric autoimmunity.

PATIENTS AND METHODS

We studied 79 consecutive asymptomatic subjects with parietal cell antibodies, 24 patients with pernicious anemia, and 66 parietal cell antibody-negative controls. All patients underwent gastric biopsies for histology and detection of H. pylori. Red blood cell count and volume, serum levels of gastrin, pepsinogen I, iron, folic acid, vitamin B12, and circulating antibodies to H. pylori and to intrinsic factor were also determined.

RESULTS

We found an atrophic body gastritis in 14 of the 79 asymptomatic subjects with parietal cell antibodies (18%) and in 2 of the 66 controls (3%) (p =.01). Mean levels of gastrin were increased (p <.0001), while those of pepsinogen were reduced (p <.001) compared with controls. H. pylori was identified at the gastric level and/or circulating anti-H. pylori antibodies were detected in 46 parietal cell antibody-positive subjects (58%) compared with 26 controls (39%) (p =.03). In patients with pernicious anemia we found an atrophic body gastritis in 18 of 24 cases (75%) (p <.001 vs. controls). Mean levels of gastrin were markedly increased (p <.0001) and those of pepsinogen I decreased (p <.0001) relative to controls. Only five of these patients (21%) had evidence of H. pylori infection compared with 46 of the parietal cell antibody-positive subjects (58%) (p =.003) and 26 of the controls (39%). Considering all patients with gastric autoimmunity (i.e. with parietal cell antibodies and/or with pernicious anemia), H. pylori was found in 44 of 72 of those without atrophy (61%) but in 6 of 31 with gastric body atrophy (19%) (p <.001), indicating that H. pylori infection is greatly reduced when gastric acid secretion decreases.

CONCLUSIONS

The frequent detection of H. pylori infection in subjects with early gastric autoimmunity, indicated by the presence of parietal cell antibodies, suggests that H. pylori could have a crucial role in the induction and/or the maintenance of autoimmunity at the gastric level.

Genetics of type 1A (immune mediated) diabetes

Type 1A (immune mediated) diabetes is genetically heterogeneous with important examples for man and animal models with major mutations (autosomal recessive and X-linked recessive) identified as well as oligogenic/polygenic inheritance. For the most common forms of type 1A diabetes alleles of DQ and DR within the major histocompatibility complex are important determinants of disease and allow identification of high risk individuals at birth. Further understanding of both common and rare genetic determinants of type 1A diabetes will contribute to understanding the pathogenesis of diabetes and of autoimmunity.