Infections and autoimmune thyroid diseases: Parallel detection of antibodies against pathogens with proteomic technology

Impact of Experimental Congenital Toxoplasmosis on the Thyroid Gland: Histopathological and Immunobiochemical Indices Assessment

PURPOSE

The thyroid gland is one of the most vital endocrine organs. It is responsible for the synthesis and secretion of hormones principally triiodothyronine (T3) and thyroxine (T4). These hormones play a significant role in the functions and the metabolism of the body. The thyroid gland could be affected by several infections, among them Toxoplasma gondii. Congenital toxoplasmosis took place when the parasite reached the developing fetus and infected any nucleated cells within it. This study assessed the effect of experimental congenital toxoplasmosis on the thyroid gland structure and function.

METHODS

We used 34 Wistar rats and allocated them into two groups: normal control group (17 rats) and congenital toxoplasmosis group (17 rats). After euthanasia, the brain and the thyroid gland was assessed through histopathological examination. Thyroid functions examination was performed through measuring the serum levels of T3, thyroxine T4, and thyroid stimulating hormone (TSH). Moreover, serum levels of thyroid antibodies [thyroid-peroxidase antibody (TPO-Ab) and anti-thyroglobulin (TG-Ab)] were examined.

RESULTS

The examination of thyroid tissues of the congenital toxoplasmosis group showed decreased or absent colloid secretion. About 47.1% of follicles showed degeneration with different grades. Parafollicular cells hyperplasia were observed in 23.6% of specimens. The serum concentrations of T3, T4, and TSH were significantly higher in congenital toxoplasmosis group than the control group. The congenital toxoplasmosis group had lower serum concentrations of TPO-Abs than the control group.

CONCLUSION

These results indicated that congenital Toxoplasma infection could result in a central hyperthyroidism state with alteration of thyroid gland structure in offspring.

Seroprevalence of Toxoplasma gondii infection among patients of a tertiary hospital in Guangzhou, Guangdong province, PR China

PURPOSE

This study aimed to explore the prevalence of Toxoplasma gondii (T. gondii) among patients in Guangzhou city, South China, and to identify susceptible patient populations and analyze the causes of infection differences.

METHODS

From May 2020 to May 2022, a total of 637 sera were collected from patients, and 205 sera were collected from health participants as health control. All sera were examined by colloidal gold kits to detect the positivity of antibodies against T. gondii. And the positivity of antibodies in sera was confirmed with ARCHITECT i2000SR system.

RESULTS

The prevalence of T. gondii infection in patients was 7.06% (45/637), which was lower than the prevalence in health participants 4.88% (10/205). Among patients, 34 (5.34%) were positive only for IgG, 10 (1.57%) were only for IgM, and 1 (0.16%) was positive for both IgG and IgM. There was a significant difference in prevalence between male and female patients, but not among different age groups or diseases groups. The prevalence of T. gondii infection in diseases groups varied. The prevalence was relatively high in patients with the disorders of thyroid gland and the malignant neoplasms of digestive organs, which suggests that caution should be taken to avoid T. gondii infection in these patients. Surprisingly, the prevalence was quite low in diffuse Large B-cell Lymphoma (DLBC) patients. This may be due to the overexpression of TNF-α in tumor tissues of DLBC patients and the higher protein level of TNF-α in sera of DLBC patients.

CONCLUSION

This study provides a systematic exploration of the prevalence of T. gondii infection in patients in a tertiary hospital. Our data contributes to a better understanding of the epidemic investigation of T. gondii among patients in South China, which can help the prevention and treatment of the disease caused by T. gondii infection.

Molecular Mechanisms in Autoimmune Thyroid Disease

The most common cause of acquired thyroid dysfunction is autoimmune thyroid disease, which is an organ-specific autoimmune disease with two presentation phenotypes: hyperthyroidism (Graves-Basedow disease) and hypothyroidism (Hashimoto's thyroiditis). Hashimoto's thyroiditis is distinguished by the presence of autoantibodies against thyroid peroxidase and thyroglobulin. Meanwhile, autoantibodies against the TSH receptor have been found in Graves-Basedow disease. Numerous susceptibility genes, as well as epigenetic and environmental factors, contribute to the pathogenesis of both diseases. This review summarizes the most common genetic, epigenetic, and environmental mechanisms involved in autoimmune thyroid disease.

Role of Jumonji domain-containing protein D3 and its inhibitor GSK-J4 in Hashimoto's thyroiditis

Hashimoto's thyroiditis (HT) is an autoimmune illness caused by a combination of genetic, epigenetic, and environmental factors. The pathogenesis of HT is not fully elucidated, especially in epigenetics. The epigenetic regulator Jumonji domain-containing protein D3 (JMJD3) has been extensively investigated in immunological disorders. This study has been performed to explore the roles and potential mechanisms of JMJD3 in HT. Thyroid samples from patients and healthy subjects were collected. We first analyzed the expression of JMJD3 and chemokines in the thyroid gland using real-time PCR and immunohistochemistry. In vitro, the apoptosis effect of the JMJD3-specific inhibitor GSK-J4 on the thyroid epithelial cell line Nthy-ori 3-1 was evaluated using FITC Annexin V Detection kit. Reverse transcription-polymerase chain reaction and Western blotting were applied to examine the inhibitory effect of GSK-J4 on the inflammation of thyrocytes. In the thyroid tissue of HT patients, JMJD3 messenger RNA and protein levels were substantially greater than in controls (P < 0.05). Chemokines C-X-C motif chemokine ligand 10 (CXCL10) and C-C motif chemokine ligand 2 (CCL2) were elevated in HT patients, and thyroid cells with stimulation of tumor necrosis factor α (TNF-α). GSK-J4 could suppress TNF-α-induced synthesis of chemokines CXCL10 and CCL2 and prohibit thyrocyte apoptosis. Our results shed light on the potential role of JMJD3 in HT and indicate that JMJD3 may become a novel therapeutic target in HT treatment and prevention.

Pancreatic Pathological Changes in Murine Toxoplasmosis and Possible Association with Diabetes Mellitus

BACKGROUND

Previous studies have reported involvement of Toxoplasma gondii (T. gondii) infections in the pathogenesis of some autoimmune diseases, such as polymyositis, rheumatoid arthritis, autoimmune thyroiditis, and Crohn's disease. However, data on the association between T. gondii infections and Type 1 diabetes mellitus (T1DM) are still controversial. Therefore, in the present study, we aimed to investigate the pancreatic pathological changes in mouse models with acute and chronic toxoplasmosis and their association with T1DM.

MATERIALS AND METHODS

Three groups (10 mice each) of male Swiss Albino mice were used. One group of mice was left uninfected, whereas the second and third groups were infected with the acute virulent T. gondii RH strain and the chronic less virulent Me49 T. gondii strain, respectively. T. gondii-induced pancreatic pathological changes were evaluated by histopathological examination of pancreatic tissues. Moreover, the expression of insulin, levels of caspase-3, and the pancreatic infiltration of CD8⁺ T cells were evaluated using immunohistochemical staining.

RESULTS

Pancreatic tissues of T. gondii-infected animals showed significant pathological alterations and variable degrees of insulitis. Mice with acute toxoplasmosis exhibited marked enlargement and reduced numbers of islets of Langerhans. However, mice with chronic toxoplasmosis showed considerable reduction in size and number of islets of Langerhans. Moreover, insulin staining revealed significant reduction in β cell numbers, whereas caspase-3 staining showed induced apoptosis in islets of Langerhans of acute toxoplasmosis and chronic toxoplasmosis mice compared to uninfected mice. We detected infiltration of CD8⁺ T cells only in islets of Langerhans of mice with chronic toxoplasmosis.

CONCLUSIONS

Acute and chronic toxoplasmosis mice displayed marked pancreatic pathological changes with reduced numbers of islets of Langerhans and insulin-producing-β cells. Since damage of β cells of islets of Langerhans is associated with the development of T1DM, our findings may support a link between T. gondii infections and the development of T1DM.

Changes in histone H3 lysine 4 trimethylation in Hashimoto's thyroiditis

INTRODUCTION

The precise pathogenesis of Hashimoto's thyroiditis (HT) is yet to be fully elucidated. The role of epigenetics in the pathogenesis of HT has scarcely been addressed. Tri-methylated histone H3 lysine 4 (H3K4me3) is generally regarded as a marker of gene activation. The aim of this study was to explore genome-wide H3K4me3 patterns and global protein levels in primary thyrocytes and thyroids from HT patients.

MATERIAL AND METHODS

Chromatin immunoprecipitation sequencing (ChIP-seq) was used to analyze genome-wide H3K4me3 patterns in primary cultured thyrocytes from three HT females and three age-matched female control subjects. Western blotting was used to analyze global H3K4me3 levels in thyrocytes and thyroid tissues. Gene expression was determined using RT-PCR. Mixed-lineage leukemia 1 (MLL1) protein levels were measured by western blotting and immunohistochemistry.

RESULTS

Nine genes - TG, CXCL8, CCL2, CXCL10, FASLG, ICAM1, ITGA4, IL18 and TRAIL - showed increased H3K4me3 enrichment in promoter regions around the transcriptional start sites, and gene expression of ICAM1, CCL2 and CXCL8 was consistently increased (p < 0.05). KEGG pathway analysis suggested that differential peak-related genes were markedly associated with autoimmune thyroid disease< 0.05).

CONCLUSIONS

This first investigation of genome-wide H3K4me3 distribution in thyroid follicular cells suggested that genes associated with autoimmune thyroiditis showed differential H3K4me3 enrichment, which was partly related to gene expression. Global H3K4me3 changes and increased MLL1 expression were found in thyroid tissues from HT patients.

Associations of Yersinia Enterocolitica Infection with Autoimmune Thyroid Diseases: A Systematic Review and Meta-Analysis

INTRODUCTION

Yersinia enterocolitica infection is reportedly associated with the development of autoimmune thyroid diseases (AITD). However, evidence that such infection can lead to AITD is controversial. Thus, this study was aimed to investigate the associations of Y. enterocolitica infection with AITD.

METHODS

A meta-analysis was performed using PubMed, Web of Science, Embase and Cochrane library to identify relevant studies. The odds ratios (OR) and associated 95% confidence intervals [CI] were obtained. Data were analyzed by STATA 13.0 (Stata Corporation, College Station, TX, USA).

RESULTS

Of 215 articles identified, 8 studies with a total of 1490 participants met the criteria and were included in the meta-analysis. There was a significant association between Y. enterocolitica positivity and AITD (OR: 4.31 [CI 95%: 1.81-10.07], P-value: 0.00). According to the subgroup analysis, Y. enterocolitica infection statistically increased the risk of Graves' disease (GD) (OR: 6.12, [CI 95%: 3.71-10.10], P-value: 0.00). Likewise, the pooled OR of association between Y. enterocolitica positivity and hashimoto's thyroiditis (HT) was 2.84 (CI 95%: 0.71-11.25, P-value: 0.1).

CONCLUSION

The current studies suggest that Y. enterocolitica may be associated with the development of AITD. Further study is needed to explore the underlying mechanisms.

A Cumulative Effect of Food and Viruses to Trigger Celiac Disease (CD): A Commentary on the Recent Literature

Celiac disease (CD) is a type of inflammatory chronic disease caused by nutrients such as gliadin that induce a TC (T cell)-mediated response in a partially known genetical background in an environment predisposed to inflammation, including viruses and food. Various experimental and clinical observations suggest that multiple agents such as viruses and bacteria have some common, inflammatory pathways predisposing individuals to chronic inflammatory diseases including celiac disease (CD). More recently, a Western diet and lifestyle have been linked to tissue inflammation and increase in chronic inflammatory diseases. In CD, the gliadin protein itself has been shown to be able to induce inflammation. A cooperation between viruses and gliadin is present in vitro and in vivo with common mechanisms to induce inflammation. Nutrients could have also a protective effect on CD, and in fact the anti-inflammatory Mediterranean diet has a protective effect on the development of CD in children. The possible impact of these observations on clinical practice is discussed.

Comparative assessment of gut microbial composition and function in patients with Graves' disease and Graves' orbitopathy

BACKGROUND

A previous study indicated that gut microbiota changed notably in Graves' orbitopathy (GO) patients as compared to controls. However, the characteristics of intestinal bacteria in Graves' disease (GD) and GO are unclear.

OBJECTIVE

The present study aimed to identify specific intestinal bacteria of GD and GO, respectively.

METHODS

The gut microbial communities of the fecal samples of 30 GD patients without GO, 33 GO subjects, and 32 healthy subjects were analyzed and compared by 16S rRNA gene sequencing.

RESULTS

At the phylum level, the proportion of Deinococcus-Thermus and Chloroflexi was decreased significantly in GO patients as compared to GD. At the genus level, the proportion of Subdoligranulum and Bilophila was increased while that of Blautia, Anaerostipes, Dorea, Butyricicoccus, Romboutsia, Fusicatenibacter, unidentified_ Lachnospiraceae, unidentified_Clostridiales, Collineslla, Intestinibacter, and Phascolarctobacterium was decreased in the GO group as compared to the GD group. Random forest analysis was used for the identification of specific intestinal microbiota, and Deinococcus-Thermus, Cyanobacteria and Chloroflexi were ranked in the top ten according to their contributions to sample classification. Moreover, compared to the control, there were multiple gut bacterial enrichment metabolic pathways in GO and GD patients, including nucleotide metabolism, enzyme family, and energy metabolism. Compared to GO, the only enrichment metabolic pathway found in GD was the viral protein family.

CONCLUSIONS

This study highlighted the significant differences in the intestinal microbiota and predictive functions of GD with GO, thereby providing new insights into the role of the gut bacteria that might contribute to the development of GO in GD patients.

Coronavirus Disease 2019 and the Thyroid - Progress and Perspectives

SARS-CoV-2 infection (COVID-19) is currently a tremendous global health problem. COVID-19 causes considerable damage to a wide range of vital organs most prominently the respiratory system. Recently, clinical evidence for thyroidal insults during and after COVID-19 has been accumulated. As of today, almost all non-neoplastic thyroid diseases, i.e., Graves' disease, Hashimoto's thyroiditis, subacute, painless and postpartum thyroiditis, have been reported as a complication of COVID-19, and causality by the virus has been strongly implicated in all of them. Similar thyroid problems have been reported in the past with the SARS-CoV outbreak in 2002. In this review, we briefly look back at the reported evidence of alteration in thyroid functionality and thyroid diseases associated with SARS-CoV and then proceed to examine the issue with COVID-19 in detail, which is then followed by an in-depth discussion regarding a pathogenetic link between Coronavirus infection and thyroid disease.

Differential Microbial Pattern Description in Subjects with Autoimmune-Based Thyroid Diseases: A Pilot Study

The interaction between genetic susceptibility, epigenetic, endogenous, and environmental factors play a key role in the initiation and progression of autoimmune thyroid diseases (AITDs). Studies have shown that gut microbiota alterations take part in the development of autoimmune diseases. We have investigated the possible relationship between gut microbiota composition and the most frequent AITDs. A total of nine Hashimoto's thyroiditis (HT), nine Graves-Basedow's disease (GD), and 11 otherwise healthy donors (HDs) were evaluated. 16S rRNA pyrosequencing and bioinformatics analysis by Quantitative Insights into Microbial Ecology and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) were used to analyze the gut microbiota. Beta diversity analysis showed that gut microbiota from our groups was different. We observed an increase in bacterial richness in HT and a lower evenness in GD in comparison to the HDs. GD showed a significant increase of Fusobacteriaceae, Fusobacterium and Sutterella compared to HDs and the core microbiome features showed that Prevotellaceae and Prevotella characterized this group. Victivallaceae was increased in HT and was part of their core microbiome. Streptococcaceae, Streptococcus and Rikenellaceae were greater in HT compared to GD. Core microbiome features of HT were represented by Streptococcus, Alistipes, Anaerostipes, Dorea and Haemophilus. Faecalibacterium decreased in both AITDs compared to HDs. PICRUSt analysis demonstrated enrichment in the xenobiotics degradation, metabolism, and the metabolism of cofactors and vitamins in GD patients compared to HDs. Moreover, correlation studies showed that some bacteria were widely correlated with autoimmunity parameters. A prediction model evaluated a possible relationship between predominant concrete bacteria such as an unclassified genus of Ruminococcaceae, Sutterella and Faecalibacterium in AITDs. AITD patients present altered gut microbiota compared to HDs. These alterations could be related to the immune system development in AITD patients and the loss of tolerance to self-antigens.

Cross-Reactivity between Chemical Antibodies Formed to Serum Proteins and Thyroid Axis Target Sites

In some instances, when chemicals bind to proteins, they have the potential to induce a conformational change in the macromolecule that may misfold in such a way that makes it similar to the various target sites or act as a neoantigen without conformational change. Cross-reactivity then can occur if epitopes of the protein share surface topology to similar binding sites. Alteration of peptides that share topological equivalence with alternating side chains can lead to the formation of binding surfaces that may mimic the antigenic structure of a variant peptide or protein. We investigated how antibodies made against thyroid target sites may bind to various chemical–albumin compounds where binding of the chemical has induced human serum albumin (HSA) misfolding. We found that specific monoclonal or polyclonal antibodies developed against thyroid-stimulating hormone (TSH) receptor, 5′-deiodinase, thyroid peroxidase, thyroglobulin, thyroxine-binding globulin (TBG), thyroxine (T4), and triiodothyronine (T3) bound to various chemical HSA compounds. Our study identified a new mechanism through which chemicals bound to circulating serum proteins lead to structural protein misfolding that creates neoantigens, resulting in the development of antibodies that bind to key target proteins of the thyroid axis through protein misfolding. For demonstration of specificity of thyroid antibody binding to various haptenic chemicals bound to HSA, both serial dilution and inhibition studies were performed and proportioned to the dilution. A significant decline in these reactions was observed. This laboratory analysis of immune reactivity between thyroid target sites and chemicals bound to HSA antibodies identifies a new mechanism by which chemicals can disrupt thyroid function.

The effects of toxoplasmosis on sex ratio at birth

Toxoplasmosis affects about one third of human population worldwide. It has a wide range of effects on the health, immunity, behaviour, and both prenatal and postnatal outcomes of infected hosts, including humans. Among these effects, stage of infection-specific shifts in secondary sex ratio were described about ten years ago both in humans and in artificially infected mice. In both women and female mice, in the early stage of infection the probability of giving birth of sons significantly increases, up to 260 sons to every 100 daughters. In the late stages of infection, the probability of giving birth to sons markedly decreases to as low as 78 to every 100 daughters. An ecological correlation study shows that the effect of latent toxoplasmosis on human population biology and demography can be large. In fact, the effect of prevalence of toxoplasmosis on a nationwide sex ratio was the third strongest effect from the effects of 15 factors included in the analysis. It has been suggested that toxoplasmosis-associated concentration of steroid hormones or glucose may be the proximal cause in the sex ratio shift. A more parsimonious explanation of the upward secondary sex ratio shift is found in a lower stringency of quality control of embryos, whose side-effect is increased survival rate of the more immunogenic male embryos in immunosuppressed infected females. The most parsimonious explanation of the downward secondary sex ratio shift relies on the Trivers-Willard hypothesis, which predicts an adaptive shift to more daughters in females with impaired health or lower socioeconomic status.

Association between Toxoplasma gondii infection and thyroid dysfunction: a case-control seroprevalence study

Background

The association between Toxoplasma gondii infection and thyroid disease has been poorly studied. Therefore, we sought to determine the association between T. gondii seropositivity and thyroid dysfunction.

Methods

We performed an age- and gender-matched case-control study of 176 patients suffering from hypothyroidism (n = 161) or hyperthyroidism (n = 15) and 528 control subjects without these diseases in a public hospital in Durango City, Mexico. Anti-Toxoplasma IgG antibodies were determined in sera from cases and controls using a commercially available enzyme-linked immunoassay.

Results

Anti-T. gondii IgG antibodies were found in 11 (6.3%) of 176 patients suffering from thyroid dysfunction and in 48 (9.1%) of 528 control subjects (OR = 0.66; 95% CI: 0.33–1.31; P = 0.23). Stratification by two groups of age (50 years and younger, and 51 year and older) showed that the youngest group of patients with thyroid dysfunction had a significantly lower seroprevalence of T. gondii infection than its age- and gender-matched control group (1/83: 1.2% vs 23/257: 8.6%; OR = 0.12; 95% CI: 0.01–0.93; P = 0.01). This stratification also showed that the youngest group of patients with hypothyroidism had a significantly lower seroprevalence of T. gondii infection than its age- and gender matched control group (0/75: 0% vs 21/233: 9.0%; P = 0.003).

Conclusions

Our results suggest that thyroid dysfunction is not associated with seropositivity to T. gondii in general; however, in young (50 years or less) patients, a negative association between infection and thyroid dysfunction and hypothyroidism was found. Further research to confirm this negative association is needed.

Celiac disease: should we care about microbes?

The prevalence of celiac disease (CeD) has increased in the last decades, suggesting a role for environmental factors in addition to gluten. Several cohort studies have shown that different gastrointestinal infections increase CeD risk. However, the mechanisms by which microbes participate in CeD have remained elusive. Recently, with the use of animal models, both viral and bacterial opportunistic pathogens were shown to induce immune activation relevant for CeD. The hypothesis that viral and/or bacterial infections can contribute to immune activation and breakdown of tolerance toward gluten in genetically susceptible individuals is therefore reinforced. Here, we discuss the evidence regarding the role of microbes in promoting CeD and the specific pathways triggered by microbes that could participate in CeD pathogenesis. Understanding these pathways will allow us to develop optimal microbiota-modulating strategies to help prevent CeD.

The role of viral infections in the development of autoimmune diseases

The exact aetiology of most autoimmune diseases remains unknown, nonetheless, several factors contributing to the induction or exacerbation of autoimmune reactions have been suggested. These include the genetic profile and lifestyle of the affected individual in addition to environmental triggers such as bacterial, parasitic, fungal and viral infections. Infections caused by viruses usually trigger a potent immune response that is necessary for the containment of the infection; however, in some cases, a failure in the regulation of this immune response may lead to harmful immune reactions directed against the host's antigens. The autoimmune attack can be carried out by different arms and components of the immune system and through different possible mechanisms including molecular mimicry, bystander activation, and epitope spreading among others. In this review, we examine the data available for the involvement of viral infections in triggering or exacerbating autoimmune diseases in addition to discussing the mechanisms by which these viral infections and the immune pathways they trigger possibly contribute to the development of autoimmunity.

Inter-Pathogen Peptide Sharing and the Original Antigenic Sin: Solving a Paradox

Aims:

To analyse the peptide commonality among viral, bacterial, and protozoan pathogens, and the immunopathologic consequences in the human host.

Methods:

HPV16, HCMV,C. diphtheriae, B. pertussis, C. tetani, T. gondii,andT. cruziwere analysed for common amino acid sequences that are additionally shared with the human host. The pentapeptide, a minimal immune determinant in humoral and cellular immune recognition, was used as a measurement unit of the peptide similarity level. Molecular modeling was applied to compare the amino acid contexts containing common minimal determinants.

Results:

Twenty-nine pentapeptides were found to occur, even hundreds of times, throughout the analyzed pathogen proteomes as well as in the human proteome. Such vast peptide commonalities together with molecular modeling data support the possibility that a pre-existing immune response to a first pathogen can be boosted by a successive exposure to a second different pathogen,i.e., the primary response to a pathogen can be transformed into a secondary response to a previously encountered different pathogen. Two possible consequences emerge. Firstly, no responses might be elicited against the pathogen lastly encountered either by infection or active immunization, but reactions could occur only with the early sensitizing pathogen, which is no more present in the organism. Secondly, the immune response boosted by the pathogen lastly encountered will find a way out by cross-reacting with human proteins.

Conclusion:

This study might explain the “original antigenic sin” phenomenon described seven decades ago [Francis T. Jr. Ann Intern Med 1953;39:203], thus providing explanations for vaccine failures and offering possible clues for designing successful vaccines.

Immunological Reactivity Using Monoclonal and Polyclonal Antibodies of Autoimmune Thyroid Target Sites with Dietary Proteins

Many hypothyroid and autoimmune thyroid patients experience reactions with specific foods. Additionally, food interactions may play a role in a subset of individuals who have difficulty finding a suitable thyroid hormone dosage. Our study was designed to investigate the potential role of dietary protein immune reactivity with thyroid hormones and thyroid axis target sites. We identified immune reactivity between dietary proteins and target sites on the thyroid axis that includes thyroid hormones, thyroid receptors, enzymes, and transport proteins. We also measured immune reactivity of either target specific monoclonal or polyclonal antibodies for thyroid-stimulating hormone (TSH) receptor, 5′deiodinase, thyroid peroxidase, thyroglobulin, thyroxine-binding globulin, thyroxine, and triiodothyronine against 204 purified dietary proteins commonly consumed in cooked and raw forms. Dietary protein determinants included unmodified (raw) and modified (cooked and roasted) foods, herbs, spices, food gums, brewed beverages, and additives. There were no dietary protein immune reactions with TSH receptor, thyroid peroxidase, and thyroxine-binding globulin. However, specific antigen-antibody immune reactivity was identified with several purified food proteins with triiodothyronine, thyroxine, thyroglobulin, and 5′deiodinase. Laboratory analysis of immunological cross-reactivity between thyroid target sites and dietary proteins is the initial step necessary in determining whether dietary proteins may play a potential immunoreactive role in autoimmune thyroid disease.

Molecular mimicry and autoimmune thyroid disease

Hypothesized 40 years ago, molecular mimicry has been thereafter demonstrated as an extremely common mechanism by which microbes elude immune response and modulate biosynthetic/metabolic pathways of the host. In genetically predisposed persons and under particular conditions, molecular mimicry between microbial and human antigens can turn a defensive immune response into autoimmunity. Such triggering role and its pathogenetic importance have been investigated and demonstrated for many autoimmune diseases. However, this is not the case for autoimmune thyroid disease, which appears relatively neglected by this field of research. Here we review the available literature on the possible role of molecular mimicry as a trigger of autoimmune thyroid disease. Additionally, we present the results of in silico search for amino acid sequence homologies between some microbial proteins and thyroid autoantigens, and the potential pathogenetic relevance of such homologies. Relevance stems from the overlap with known autoepitopes and the occurrence of specific HLA-DR binding motifs. Bioinformatics data published by our group support and explain the triggering role of Borrelia, Yersinia, Clostridium botulinum, Rickettsia prowazekii and Helicobacter pylori. Our new data suggest the potential pathogenic importance of Toxoplasma gondii, some Bifidobacteria and Lactobacilli, Candida albicans, Treponema pallidum and hepatitis C virus in autoimmune thyroid disease, indicating specific molecular targets for future research. Additionally, the consistency between in silico prediction of cross-reactivity and experimental results shows the reliability and usefulness of bioinformatics tools to precisely identify candidate molecules for in vitro and/or in vivo experiments, or at least narrow down their number.

A possible link between the Epstein-Barr virus infection and autoimmune thyroid disorders

The Epstein-Barr virus (EBV), also known as human herpesvirus 4, is a member of the Herpesviridae virus family. EBV infection can cause infectious mononucleosis (IM) in the lytic phase of EBV's life cycle. Past EBV infection is associated with lymphomas, and may also result in certain allergic and autoimmune diseases. Although potential mechanisms of autoimmune diseases have not been clearly elucidated, both genetic and environmental factors, such as infectious agents, are considered to be responsible for their development. In addition, EBV modifies the host immune response. The worldwide prevalence of autoimmune diseases shows how common this pathogen is. Normally, the virus stays in the body and remains dormant throughout life. However, this is not always the case, and a serious EBV-related illness may develop later in life. This explains the chronic course of autoimmune diseases that is often accompanied by exacerbations of symptoms. Based on the present studies, EBV infection can cause autoimmune diseases, such as systemic lupus erythematosus (SLE), multiple sclerosis (MS), rheumatoid arthritis (RA), Sjögren's syndrome, and autoimmune hepatitis. The EBV has also been reported in patients with autoimmune thyroid disorders. Although EBV is not the only agent responsible for the development of autoimmune thyroid diseases, it can be considered a contributory factor.

Association of active human herpesvirus-6 (HHV-6) infection with autoimmune thyroid gland diseases

OBJECTIVES

Viral infections frequently have been cited as important environmental factors implicated in the onset of autoimmune thyroiditis (AIT). The aim of this study was to determine the involvement of HHV-6 infection in the development of autoimmune thyroiditis.

METHODS

This study included 45 patients (42 female and 3 male; median age 47.00 IQR 38.50-57.00) with histologically, laboratory, and clinically confirmed autoimmune thyroiditis, as well as 30 autopsied subjects (26 female and 4 male; median age 58.50, IQR 51.50-67.00) without thyroid pathologies and 30 healthy blood donors (25 female and 5 male; median age 33.50, IQR 27.75-44.25) as controls. Results were obtained by applying molecular virology and immunohistochemistry techniques.

RESULTS

The presence of persistent HHV-6 infection in AIT patients was significantly higher (p 0.0058) than in the control group (44/45 (98%) vs. 23/30 (77%), respectively). Also, a significantly higher frequency of HHV-6 activation marker (U79/80 mRNA) was found in patients' thyroid gland tissue samples with AIT in comparison with the control group (18/44 (41%) vs. 1/17 (6%), respectively; p 0.0118). The median HHV-6 load was found to be higher in patients with active viral infection than in patients without it (2147, IQR 971-4188 vs. 551, IQR 145-1589 copies/1×10⁶ cells; p 0.003). The presence of HHV-6 antigen expression was demonstrated in intrafollicular cellular clusters and immunohistochemistry indicated thyrocytes in the follicle wall.

CONCLUSIONS

These findings provide evidence of strong HHV-6 infection association with AIT development.

Effects of latent toxoplasmosis on autoimmune thyroid diseases in pregnancy

BACKGROUND

Toxoplasmosis, one of the most common zoonotic diseases worldwide, can induce various hormonal and behavioural alterations in infected hosts, and its most common form, latent toxoplasmosis, influences the course of pregnancy. Autoimmune thyroid diseases (AITD) belong to the well-defined risk factors for adverse pregnancy outcomes. The aim of this study was to investigate whether there is a link between latent toxoplasmosis and maternal AITD in pregnancy.

METHODS

Cross-sectional study in 1248 consecutive pregnant women in the 9-12th gestational weeks. Serum thyroid-stimulating hormone (TSH), thyroperoxidase antibodies (TPOAb), and free thyroxine (FT4) were assessed by chemiluminescence; the Toxoplasma status was detected by the complement fixation test (CFT) and anti-Toxoplasma IgG enzyme-linked immunosorbent assay (ELISA).

RESULTS

Overall, 22.5% of the women were positive for latent toxoplasmosis and 14.7% were screened positive for AITD. Women with latent toxoplasmosis had more often highly elevated TPOAb than the Toxoplasma-negative ones (p = 0.004), and latent toxoplasmosis was associated with decrease in serum TSH levels (p = 0.049). Moreover, we found a positive correlation between FT4 and the index of positivity for anti-Toxoplasma IgG antibodies (p = 0.033), which was even stronger in the TPOAb-positive Toxoplasma-positive women, (p = 0.014), as well as a positive correlation between FT4 and log2 CFT (p = 0.009).

CONCLUSIONS

Latent toxoplasmosis was associated with a mild increase in thyroid hormone production in pregnancy. The observed Toxoplasma-associated changes in the parameters of AITD are mild and do not seem to be clinically relevant; however, they could provide new clues to the complex pathogenesis of autoimmune thyroid diseases.

Current state of diagnostic technologies in the autoimmunology laboratory

The methods for detecting and measuring autoantibodies have evolved markedly in recent years, encompassing three generations of analytical technologies. Many different immunoassay methods have been developed and used for research and laboratory practice purposes, from the early conventional (or monoplex) analytical methods able to detect single autoantibodies to the more recent multiplex platforms that can quantify tens of molecules. Although it has been in use for over 50 years, indirect immunofluorescence remains the standard method for research on many types of autoantibodies, due to its characteristics of diagnostic sensitivity and also to recent technological innovations which permit it a greater level of automation and standardization. The recent multiplex immunometric methods, with varying levels of automation, present characteristics of higher diagnostic accuracy, but are not yet widely diffused in autoimmunology laboratories due to the limited number of autoantibodies that are detectable, and due to the high cost of reagents and systems. Technological advancement in autoimmunology continues to evolve rapidly, and in the coming years new proteomic techniques will be able to radically change the approach to diagnostics and possibly also clinical treatment of autoimmune diseases. The scope of this review is to update the state of the art of technologies and methods for the measurement of autoantibodies, with special reference to innovations in indirect immunofluorescence and in multiple proteomic methods.

Toxoplasmosis--a global threat. Correlation of latent toxoplasmosis with specific disease burden in a set of 88 countries

BACKGROUND

Toxoplasmosis is becoming a global health hazard as it infects 30-50% of the world human population. Clinically, the life-long presence of the parasite in tissues of a majority of infected individuals is usually considered asymptomatic. However, a number of studies show that this 'asymptomatic infection' may also lead to development of other human pathologies.

AIMS OF THE STUDY

The purpose of the study was to collect available geoepidemiological data on seroprevalence of toxoplasmosis and search for its relationship with mortality and disability rates in different countries.

METHODS AND FINDINGS

Prevalence data published between 1995-2008 for women in child-bearing age were collected for 88 countries (29 European). The association between prevalence of toxoplasmosis and specific disease burden estimated with age-standardized Disability Adjusted Life Year (DALY) or with mortality, was calculated using General Linear Method with Gross Domestic Product per capita (GDP), geolatitude and humidity as covariates, and also using nonparametric partial Kendall correlation test with GDP as a covariate. The prevalence of toxoplasmosis correlated with specific disease burden in particular countries explaining 23% of variability in disease burden in Europe. The analyses revealed that for example, DALY of 23 of 128 analyzed diseases and disease categories on the WHO list showed correlations (18 positive, 5 negative) with prevalence of toxoplasmosis and another 12 diseases showed positive trends (p<0.1). For several obtained significant correlations between the seroprevalence of toxoplasmosis and specific diseases/clinical entities, possible pathophysiological, biochemical and molecular explanations are presented.

CONCLUSIONS

The seroprevalence of toxoplasmosis correlated with various disease burden. Statistical associations does not necessarily mean causality. The precautionary principle suggests however that possible role of toxoplasmosis as a triggering factor responsible for development of several clinical entities deserves much more attention and financial support both in everyday medical practice and future clinical research.

Tracing environmental markers of autoimmunity: introducing the infectome

We recently introduced the concept of the infectome as a means of studying all infectious factors which contribute to the development of autoimmune disease. It forms the infectious part of the exposome, which collates all environmental factors contributing to the development of disease and studies the sum total of burden which leads to the loss of adaptive mechanisms in the body. These studies complement genome-wide association studies, which establish the genetic predisposition to disease. The infectome is a component which spans the whole life and may begin at the earliest stages right up to the time when the first symptoms manifest, and may thus contribute to the understanding of the pathogenesis of autoimmunity at the prodromal/asymptomatic stages. We provide practical examples and research tools as to how we can investigate disease-specific infectomes, using laboratory approaches employed from projects studying the “immunome” and “microbiome”. It is envisioned that an understanding of the infectome and the environmental factors that affect it will allow for earlier patient-specific intervention by clinicians, through the possible treatment of infectious agents as well as other compounding factors, and hence slowing or preventing disease development.

Toxoplasma gondii: bystander or cofactor in rheumatoid arthritis

Parasitic infections may induce variable immunomodulatory effects and control of autoimmune disease. Toxoplasma gondii (T. gondii) is a ubiquitous intracellular protozoan that was recently associated with autoimmunity. This study was undertaken to investigate the seroprevalence and clinical correlation of anti-T. gondii antibodies in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). We evaluated sera from European patients with RA (n = 125) and SLE (n = 164) for the prevalence of anti-T. gondii IgG antibodies (ATXAb), as well as other common infections such as Cytomegalovirus, Epstein-Barr, and Rubella virus. The rates of seropositivity were determined utilizing the LIAISON chemiluminescent immunoassays (DiaSorin, Italy). Our results showed a higher seroprevalence of ATXAb in RA patients, as compared with SLE patients [63 vs. 36 %, respectively (p = 0.01)]. The rates of seropositivity of IgG against other infectious agents were comparable between RA and SLE patients. ATXAb-seropositivity was associated with older age of RA patients, although it did not correlate with RA disease activity and other manifestations of the disease. In conclusion, our data suggest a possible link between exposure to T. gondii infection and RA.

Isolation and structural identification of glycopolymers of Bifidobacterium bifidum BIM B-733D as putative players in pathogenesis of autoimmune thyroid diseases

Bifidobacterium bifidum 791 (commercially available as B. bifidum BIM B-733D) cell-surface biopolymers (BPs) interact selectively with human serum thyroid peroxidase (TPO) and thyroglobulin (Tg) autoantibodies (anti TPO and anti Tg, respectively). BPanti-TPO and BPanti-Tg were isolated from the soluble fraction of B. bifidum BIM B-733D by affinity chromatography with anti-TPO or anti-Tg, respectively. Homogeneity of affinity eluates (AEanti-TPO and AEanti-Tg) was tested by size exclusion chromatography. For each AE, the elution profiles generated on the basis of absorbance at 280 nm do not conform to ELISA data for functional activity characteristic of BPs. Moreover, high functional activity was detected in chromatographic fractions that had significantly different molecular weights and no absorbance at 280 nm, which suggests a non-protein (carbohydrate) nature of BPanti-TPO and BPanti-Tg. The semi-preparative size exclusion chromatography of AEanti-TPO and AEanti-Tg with detection by refractometer gave 5,000-7,000 Da fractions containing substances that interact selectively with either anti TPO (BPanti-TPO) or anti-Tg (BPanti-Tg) according to ELISA data. Analysis by two-dimensional NMR spectroscopy including a 1H, 13C-heteronuclear single-quantum coherence experiment indicated that both substances are linear α-1,6-glucans. For the first time, an immunological similarity (molecular mimicry) of glycopolymers of B. bifidum BIM B-733D and human thyroid proteins, TPO and Tg, was shown. On the whole, our data point to a possible role of bifidobacteria in the pathogenesis of autoimmune thyroid diseases (ATD). The main requirements for triggering/acceleration or prevention/abrogation of ATD by bifidobacteria through molecular mimicry mechanism are hypothesised to be (1) genetic predisposition to ATD and (2) intestinal epithelium penetration by α-1,6-glucan.

Chemokine (C-X-C motif) ligand (CXCL)10 in autoimmune diseases

(C-X-C motif) ligand (CXCL)10 (CXCL10) belongs to the ELR(-) CXC subfamily chemokine. CXCL10 exerts its function through binding to chemokine (C-X-C motif) receptor 3 (CXCR3), a seven trans-membrane receptor coupled to G proteins. CXCL10 and its receptor, CXCR3, appear to contribute to the pathogenesis of many autoimmune diseases, organ specific (such as type 1 diabetes, autoimmune thyroiditis, Graves' disease and ophthalmopathy), or systemic (such as rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, mixed cryoglobulinemia, Sjögren syndrome, or systemic sclerosis). The secretion of CXCL10 by cluster of differentiation (CD)4+, CD8+, natural killer (NK) and NK-T cells is dependent on interferon (IFN)-γ, which is itself mediated by the interleukin-12 cytokine family. Under the influence of IFN-γ, CXCL10 is secreted by several cell types including endothelial cells, fibroblasts, keratinocytes, thyrocytes, preadipocytes, etc. Determination of high level of CXCL10 in peripheral fluids is therefore a marker of host immune response, especially T helper (Th)1 orientated T-cells. In tissues, recruited Th1 lymphocytes may be responsible for enhanced IFN-γ and tumor necrosis factor-α production, which in turn stimulates CXCL10 secretion from a variety of cells, therefore creating an amplification feedback loop, and perpetuating the autoimmune process. Further studies are needed to investigate interactions between chemokines and cytokines in the pathogenesis of autoimmune diseases and to evaluate whether CXCL10 is a novel therapeutic target in various autoimmune diseases.

Protein arrays as tool for studies at the host-pathogen interface

Pathogens and parasites encode a wide spectrum of multifunctional proteins interacting to and modifying proteins in host cells. However, the current lack of a reliable method to unveil the protein-protein interactions (PPI) at the host-pathogen interface is retarding our understanding of many important pathogenic processes. Thus, the identification of proteins involved in host-pathogen interactions is important for the elucidation of virulence determinants, mechanisms of infection, host susceptibility and/or disease resistance. In this sense, proteomic technologies have experienced major improvements in recent years and protein arrays are a powerful and modern method for studying PPI in a high-throughput format. This review focuses on these techniques analyzing the state-of-the-art of proteomic technologies and their possibilities to diagnose and explore host-pathogen interactions. Major technical advancements, applications and protocol concerns are presented, so readers can appreciate the immense progress achieved and the current technical options available for studying the host-pathogen interface. Finally, future uses of this kind of array-based proteomic tools in the fight against infectious and parasitic diseases are discussed.

Rapidly growing thyroid mass in an immunocompromised young male adult

We describe a 20-year-old man diagnosed with a myelodysplastic syndrome (MDS), admitted to our hospital due to pancytopenia and fever of undetermined origin after myelosuppression with chemotherapy. Disseminated aspergillosis (DIA) was suspected when he developed skin and lung involvement. A rapidly growing mass was detected on the left neck area, during hospitalization. A thyroid ultrasound reported a 3.7 × 2.5 × 2.9 cm oval heterogeneous structure, suggestive of an abscess versus a hematoma. Fine needle aspiration of the thyroid revealed invasion of aspergillosis. Fungal thyroiditis is a rare occurrence. Thyroid fungal infection is difficult to diagnose; for this reason it is rarely diagnosed antemortem. To our knowledge, this is the 10th case reported in the literature in an adult where the diagnosis of fungal invasion to the thyroid was able to be corroborated antemortem by fine needle aspiration biopsy.

Infectome: a platform to trace infectious triggers of autoimmunity

The "exposome" is a term recently used to describe all environmental factors, both exogenous and endogenous, which we are exposed to in a lifetime. It represents an important tool in the study of autoimmunity, complementing classical immunological research tools and cutting-edge genome wide association studies (GWAS). Recently, environmental wide association studies (EWAS) investigated the effect of environment in the development of diseases. Environmental triggers are largely subdivided into infectious and non-infectious agents. In this review, we introduce the concept of the "infectome", which is the part of the exposome referring to the collection of an individual's exposures to infectious agents. The infectome directly relates to geoepidemiological, serological and molecular evidence of the co-occurrence of several infectious agents associated with autoimmune diseases that may provide hints for the triggering factors responsible for the pathogenesis of autoimmunity. We discuss the implications that the investigation of the infectome may have for the understanding of microbial/host interactions in autoimmune diseases with long, pre-clinical phases. It may also contribute to the concept of the human body as a superorganism where the microbiome is part of the whole organism, as can be seen with mitochondria which existed as microbes prior to becoming organelles in eukaryotic cells of multicellular organisms over time. A similar argument can now be made in regard to normal intestinal flora, living in symbiosis within the host. We also provide practical examples as to how we can characterise and measure the totality of a disease-specific infectome, based on the experimental approaches employed from the "immunome" and "microbiome" projects.

Lab-on-a-chip: emerging analytical platforms for immune-mediated diseases

Miniaturization of analytical procedures has a significant impact on diagnostic testing since it provides several advantages such as: reduced sample and reagent consumption, shorter analysis time and less sample handling. Lab-on-a-chip (LoC), usually silicon, glass, or silicon-glass, or polymer disposable cartridges, which are produced using techniques inherited from the microelectronics industry, could perform and integrate the operations needed to carry out biochemical analysis through the mechanical realization of a dedicated instrument. Analytical devices based on miniaturized platforms like LoC may provide an important contribution to the diagnosis of high prevalence and rare diseases. In this paper we review some of the uses of Lab-on-a-chip in the clinical diagnostics of immune-mediated diseases and we provide an overview of how specific applications of these technologies could improve and simplify several complex diagnostic procedures.

Serum markers of infections in patients with primary biliary cirrhosis: evidence of infection burden

BACKGROUND

Currently not much is known regarding the environmental factors involved in primary biliary cirrhosis (PBC). It is even more unclear which factors may determine the subgroup (i.e., AMA status) of patients with PBC. We thus tested AMA+and AMA- PBC patients' sera for antibodies (Abs) against multiple infectious agents.

METHODS

Sera from 69 patients with PBC (49 AMA+and 20 AMA-) and 100 matched controls were screened for IgG-Abs against Toxoplasma gondii, Helicobacter pylori, Epstein-Barr virus (EBV), cytomegalovirus (CMV), hepatitis B, and hepatitis C utilizing the BioPlex 2200 and ELISA kits (Bio-Rad Laboratories, USA).

RESULTS

The prevalence of four anti-infectious agents Abs was significantly elevated among PBC patients when compared with controls, namely anti-T. gondii (ATxA; 71% vs. 40%, p<0.0001), EBV early antigen (EA; 44% vs. 12%, p<0.0001), H. pylori (54% vs. 31%, p<0.01), and CMV (90% vs. 75%, p<0.05) Abs, respectively. The co-occurrence of these four anti-infectious agents Abs was highly common in PBC, whereas this infection burden was rare in healthy subjects (20% vs. 3% respectively, p<0.0001). Furthermore, specific infections interactions possibly increasing PBC risk were noted as well. Seropositivity of ATxA was inversely associated with cirrhosis among PBC patients (p<0.05). Finally, no differences were observed between AMA- sera and their AMA+counterparts with regard to seroprevalence of any of the investigated infectious agents.

CONCLUSIONS

We note the association of ATxA and PBC, with the possibility of a milder disease manifestation. We also suggest that multiple exposures to infectious agents may contribute to PBC risk.

Prevalence of anti-Toxoplasma antibodies in patients with autoimmune diseases

The identification of etiological factors in the induction of autoimmunity has remained elusive despite an enormous effort at dissection of the molecular structure of the target antigens and effector mechanisms. One characteristic feature of autoantigens is their repetitive structure as well as their conservation and evolution. Toxoplasma (T.) gondii is a primitive protozoan. We hypothesized that patients with autoimmune disease would have broad reactions against Toxoplasma antigens based on autoantigen conservation. To address this issue, we assessed serologic evidence of reactivity to Toxoplasma gondii along with a large profile of autoantibodies in patients with various autoimmune diseases (AID). We included sera of 1514 patients with 11 different AID collected from referral centers in Europe and Latin America as well as from 437 geographically matched controls, for the prevalence of anti Toxoplasma antibodies (ATxA) IgG and IgM and serum autoantibodies utilizing the BioPlex 2200 system (Bio- Rad Laboratories, USA). Serum ATxA IgG were positive in 42% of patients with AID versus 29% of controls (p < 0.0001). Among Europeans, ATxA IgG were associated with anti-phospholipid syndrome (APS; p < 0.0001), cryoglobulinemia (p < 0.0001), ANCA-associated vasculitides (p < 0.01), autoimmune thyroid diseases (p < 0.0001), systemic sclerosis (SSc; p < 0.0001) and rheumatoid arthritis (RA; p < 0.0001). Of note, Latin American RA sera exhibited similar frequency of ATxA IgG as controls. ATxA IgM were more prevalent in European patients with APS (p < 0.01), SSc (p < 0.05) and inflammatory bowel disease (IBD, p < 0.05) than in controls. Further, in AID patients the presence of ATxA correlated with autoantibodies characteristic of APS (anti- cardiolipin, B2GPI, complex of cardiolipin- B2GPI, prothrombin, phosphatydilethanolamine), and of SSc (anti-centromere, Scl-70). Our findings suggest that T. gondii may contribute to the pathogenesis of AID. This interaction may depend on or explain observed geoepidemiological variance in AID.

Vitamin D and autoimmune thyroid diseases

The role of vitamin D as an immune modulator has been emphasized in recent years, and low levels of the hormone were observed in several autoimmune diseases including multiple sclerosis and systemic lupus erythematosus. Vitamin D mediates its effect though binding to vitamin D receptor (VDR), and activation of VDR-responsive genes. While VDR gene polymorphism was found to associate with autoimmune thyroid diseases (AITDs), few studies examined levels of vitamin D in these patients and those that did yielded conflicting results. We therefore undertook to evaluate the levels of vitamin D in patients with AITDs compared to patients with non-AITDs and healthy controls. Serum vitamin D (25-OH) levels were measured in 50 patients with AITDs, 42 patients with non-AITDs and 98 healthy subjects, utilizing the LIAISON chemiluminescence immunoassay (DiaSorin, Saluggia, Italy). Vitamin D deficiency was designated at levels lower than 10 ng/ml. Antithyroid antibodies, thyroid functions and demographic parameters were evaluated in all patients. The prevalence of vitamin D deficiency was significantly higher in patients with AITDs compared with healthy individuals (72% versus 30.6%; P<0.001), as well as in patients with Hashimoto's thyroiditis compared to patients with non-AITDs (79% versus 52%; P<0.05). Vitamin D deficiency also correlated to the presence of antithyroid antibodies (P=0.01) and abnormal thyroid function tests (P=0.059). Significantly low levels of vitamin D were documented in patients with AITDs that were related to the presence of anti thyroid antibodies and abnormal thyroid function tests, suggesting the involvement of vitamin D in the pathogenesis of AITDs and the advisability of supplementation.

Bioassays for TSH-receptor autoantibodies: an update

Immunoglobulins in patients with Graves' disease (GD) that modulate the thyroid stimulating hormone receptor (TSH-R) do so via stimulating cAMP dependent signals (TSI), blocking TSH or inhibition of TSH-receptor activation (TBI) or inducing apoptotic signals. These functional immunoglobulins represent powerful biomarkers of anti-self reactivity in the thyroid and systemic tissues that harbor TSH-R expressing target cells. TSI on thyrocytes induce hyperthyroidism, and TSI on TSH-R fibroblasts of orbital muscles, skin and heart provoke the release of cytokines and antigen-specific T-cell responses leading to systemic inflammation. Bioassays of anti-TSH-R autoantibodies provide decisive information on GD activity. This review examines the past and present bioassays in GD. The critical goal of cell-based anti-TSH-R autoantibody bioassays, to identify the pathogenic immunoglobulins in GD under robust and standardized conditions suitable for routine clinical laboratory practice, is discussed.

Identification of outer membrane porin f protein of Yersinia enterocolitica recognized by antithyrotopin receptor antibodies in Graves' disease and determination of its epitope using mass spectrometry and bioinformatics tools

CONTEXT

In addition to genetic susceptibility, Yersinia enterocolitica (YE) infection played an important causative role in the pathogenesis of Graves' disease (GD) through molecular mimicry. However, the specific YE proteins and epitopes recognized by anti-TSH receptor (TSHR) autoantibodies (TRAb) have not been fully clarified, resulting in conflicting results from clinical research.

OBJECTIVE

Our aim was to explore the roles of YE in the pathogenesis of GD and identify the YE proteins and epitopes that are similar to the TSHR and are recognized by TRAb.

DESIGN

Assays of YE antibodies, TRAb, thyroglobulin antibodies, and thyroid microsomal antibodies as well as cross-absorption and two-way immunodiffusion were performed in patients with GD. Using mass spectrometry and the bioinformatics tools of protein structure modeling and epitope prediction, we identified the YE protein and its epitope, which was recognized by TRAb and was similar to TSHR.

RESULTS

Our study demonstrated for the first time that the YE protein outer membrane porin F protein (ompF) shared cross-immunogenicity with a leucine-rich domain of TSHR. The epitope recognized by antihuman TSHR antibody is located within the ompF region of amino acids 190-197, and the polyantibody against ompF protein showed TSAb activity.

CONCLUSIONS

Our results suggest that YE ompF is involved in the production of TRAb and the pathogenesis of GD through molecular mimicry. These findings are potentially important for understanding the role molecular mimicry plays in the disturbance of immune tolerance and the induction of autoimmunity to the TSHR.

Infectious aspects and the etiopathogenesis of rheumatoid arthritis

Infections are believed to contribute to the maturation of the immune system from the innate to the adaptive phases and therefore may take part in the induction of autoimmune conditions. In the current study, we present an extensive analysis conducted on sera samples of patients with rheumatoid arthritis in order to seek evidence of previous or coexisting infectious processes using the Bio-Rad BioPlex immunoassay analyzer. We detected higher rates of serological evidence of infections with Epstein-Barr virus and cytomegalovirus viruses. Our findings may indicate a role of these viruses in the pathogenesis of RA.

Interferon induced with helicase C domain 1 (IFIH1) and virus-induced autoimmunity: a review

In addition to genetic factors, environmental triggers, including viruses and other pathogens, are thought to play a major role in the development of autoimmune disease. Recent findings have shown that viral-induced autoimmunity is likely to be genetically determined. In large-scale genetic analyses, an association of interferon induced with helicase C domain 1 (IFIH1) gene variants encoding a viral RNA-sensing helicase with susceptibility to several autoimmune diseases was found. To date, the precise role of IFIH1 in pathogenic mechanisms of viral-induced autoimmunity has yet to be fully elucidated. However, recent reports suggest that IFIH1 may play a role in the etiology of type 1 diabetes. Rare IFIH1 alleles have been shown to be protective against diabetes, and their carriage correlates with lower production of this helicase and its functional disruption. In contrast, upregulation of IFIH1 expression by viruses is associated with more severe disease, and could exacerbate the autoimmune process in susceptible individuals.

Infectious antibodies in systemic lupus erythematosus patients

Infections can act as environmental triggers that induce or promote systemic lupus erythematosus (SLE) in genetically predisposed individuals. New technologies, developed recently, enable simultaneous assessment of multiple antibodies. Antibodies to specific infectious agents may shed light into the mechanisms of induction of SLE. The aim of this study was to investigate the prevalence of seropositivity and the titers of antibodies to bacterial, viral, and parasitic agents in SLE patients compared with non-autoimmune controls. Sera from 260 individuals (120 SLE patients and 140 controls) were tested by the BioPlex 2200 Multiplexed Immunoassay method (BioRad) for the prevalence and titers of antibodies to eight infectious agents (Epstein-Barr virus: early antigen IgG, nuclear antigen IgG, viral capsid antigen IgG and IgM, heterophile IgM; cytomegalovirus IgG and IgM; Toxoplasma gondii IgG and IgM; rubella IgG and IgM; Treponema pallidum TPr15G, TPr17G, TPr47G; herpes simplex virus type 1 and 2 IgG; hepatitis C virus and hepatitis B core antibodies. Cytomegalovirus IgM and Epstein-Barr virus early antigen IgG (but not other Epstein-Barr virus antigens) were significantly more prevalent in SLE patients than in controls. Conversely, positive titers of hepatitis B core and rubella IgG antibodies were less prevalent in the SLE patients than in controls. Other differences in titer positivity prevalence were not detected between patients and controls. The titers of the cytomegalovirus IgM, Toxoplasma IgG, Epstein-Barr virus early antigen, and viral capsid antigen IgG antibodies were significantly higher in SLE compared with controls. Our data suggest the importance of previous exposure to infectious agents in the induction and the prevention of SLE.

Graves' disease associated with infectious mononucleosis due to primary Epstein-Barr virus infection: report of 3 cases

Although the etiology of Graves' disease is still not clear, it is generally suggested that environmental factors such as infections contribute to the development of Graves' disease. We report here three cases of Graves' disease which presented simultaneously with infectious mononucleosis due to primary EBV infection. Acute EBV infection might play an important role in the onset of Graves' disease. These three women complained of a sore throat or neck pain, resembling subacute thyroiditis. In the case of thyrotoxicosis accompanied by sore throat or neck pain, Graves' disease must be distinguished from subacute thyroiditis.

Common infectious agents prevalence in antiphospholipid syndrome

Antiphospholipid syndrome is characterized by thrombosis and pregnancy loss. Infections are generally associated with autoimmune diseases, but in the setting of antiphospholipid syndrome this link has been suggested as having a pathogenic role. In this study, 98 patients with antiphospholipid syndrome were screened for antibodies directed to several infectious agents. The main finding in this study is the significantly higher prevalence of IgM antibodies to toxoplasma and rubella. This novel finding suggests that these infections might be associated with antiphospholipid syndrome. As autoimmune diseases and, in particular, antiphospholipid syndrome are associated with infections, mainly the catastrophic type of the syndrome, this finding implies that a current infection with these agents, i.e. toxoplasma and rubella, might either be related to the pathogenesis of antiphospholipid syndrome or alternatively to its manifestations. Lupus (2009) 18, 1149—1153.

Navigating the passage between Charybdis and Scylla: recognizing the achievements of Noel Rose

This special edition of the Journal of Autoimmunity is dedicated to celebrate the enormous contributions of Dr. Noel Rose, a physician-scientist, someone that can be readily anointed as a gifted scientist who laid down the foundation and fundamental concepts of human autoimmunity. Dr. Rose performed a series of landmark studies that extend back more than 50 years and whose work is the cornerstone of the commonly used term "from the bench to the bedside." The studies included not only characterization of a normal immune response but, more importantly, defining the nature of not only the antigen, but also the aberrant response that results in organ, tissue specific reactions and immunopathology. These pioneering studies contributed to the biochemical nature of antigens, dissection of the immune repertoire, the recognition of the importance of genetics and environment, and the distinctions between a normal and an autoimmune response. Hence, this volume has been coined "Navigating the Passage Between Charybdis and Scylla: Recognizing the Achievements of Noel Rose."