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

Immunoregulation and male reproductive function: Impacts and mechanistic insights into inflammation

This paper investigates the complex relationship between the immune system and male reproductive processes, emphasizing how chronic inflammation can adversely affect male reproductive health. The immune system plays a dual role; it protects and regulates reproductive organs and spermatogenesis while maintaining reproductive health through immune privilege in the testes and the activities of various immune cells and cytokines. However, when chronic inflammation persists or intensifies, it can disrupt this balance, leading to immune attacks on reproductive tissues and resulting in infertility.This study provides a detailed analysis of how chronic inflammation can impair sperm production, sperm quality, and the secretion of gonadal hormones both directly and indirectly. It also delves into the critical roles of testicular immune privilege, various immune cells, and cytokines in sustaining reproductive health and examines the impacts of infections, autoimmune diseases, and environmental factors on male fertility.

Emerging role of gut microbiota in autoimmune diseases

Accumulating studies have indicated that the gut microbiota plays a pivotal role in the onset of autoimmune diseases by engaging in complex interactions with the host. This review aims to provide a comprehensive overview of the existing literatures concerning the relationship between the gut microbiota and autoimmune diseases, shedding light on the complex interplay between the gut microbiota, the host and the immune system. Furthermore, we aim to summarize the impacts and potential mechanisms that underlie the interactions between the gut microbiota and the host in autoimmune diseases, primarily focusing on systemic lupus erythematosus, rheumatoid arthritis, Sjögren's syndrome, type 1 diabetes mellitus, ulcerative colitis and psoriasis. The present review will emphasize the clinical significance and potential applications of interventions based on the gut microbiota as innovative adjunctive therapies for autoimmune diseases.

Single cell characterization of blood and expanded regulatory T cells in autoimmune polyendocrine syndrome type 1

Immune tolerance fails in autoimmune polyendocrine syndrome type 1 (APS-1) because of AIRE mutations. We have used single cell transcriptomics to characterize regulatory T cells (Tregs) sorted directly from blood and from in vitro expanded Tregs in APS-1 patients compared to healthy controls. We revealed only CD52 and LTB (down) and TXNIP (up) as consistently differentially expressed genes in the datasets. There were furthermore no large differences of the TCR-repertoire of expanded Tregs between the cohorts, but unique patients showed a more restricted use of specific clonotypes. We also found that in vitro expanded Tregs from APS-1 patients had similar suppressive capacity as controls in co-culture assays, despite expanding faster and having more exhausted cells. Our results suggest that APS-1 patients do not have intrinsic defects in their Treg functionality, and that their Tregs can be expanded ex vivo for potential therapeutic applications.

Regulatory T cells in autoimmune primary adrenal insufficiency

Primary adrenal insufficiency (PAI) is most often caused by an autoimmune destruction of the adrenal cortex resulting in failure to produce cortisol and aldosterone. The aetiology is thought to be a combination of genetic and environmental risk factors, leading to breakdown of immunological tolerance. Regulatory T cells (Tregs) are deficient in many autoimmune disorders, but it is not known whether they contribute to development of PAI. We aimed to investigate the frequency and function of naive and expanded Tregs in patients with PAI and polyendocrine syndromes compared to age- and gender-matched healthy controls. Flow cytometry was used to assess the frequency and characterize functional markers of blood Tregs in PAI (N = 15). Expanded Treg suppressive abilities were assessed with a flow cytometry based suppression assay (N = 20), while bulk RNA-sequencing was used to examine transcriptomic differences (N = 16) and oxygen consumption rate was measured by a Seahorse cell metabolic assay (N = 11). Our results showed that Treg frequency and suppressive capacity were similar between patients and controls. An increased expression of killer-cell leptin-like receptors and mitochondrial genes was revealed in PAI patients, but their expanded Tregs did not display signs of mitochondrial dysfunction. Our findings do not support a clear role for Tregs in the contribution of PAI development.

Major immunophenotypic abnormalities in patients with primary adrenal insufficiency of different etiology

Introduction

Patients with primary adrenal insufficiency (PAI) suffer from increased risk of infection, adrenal crises and have a higher mortality rate. Such dismal outcomes have been inferred to immune cell dysregulation because of unphysiological cortisol replacement. As the immune landscape of patients with different types of PAI has not been systematically explored, we set out to immunophenotype PAI patients with different causes of glucocorticoid (GC) deficiency.

Methods

This cross-sectional single center study includes 28 patients with congenital adrenal hyperplasia (CAH), 27 after bilateral adrenalectomy due to Cushing's syndrome (BADx), 21 with Addison's disease (AD) and 52 healthy controls. All patients with PAI were on a stable GC replacement regimen with a median dose of 25 mg hydrocortisone per day. Peripheral blood mononuclear cells were isolated from heparinized blood samples. Immune cell subsets were analyzed using multicolor flow cytometry after four-hour stimulation with phorbol myristate acetate and ionomycin. Natural killer (NK-) cell cytotoxicity and clock gene expression were investigated.

Results

The percentage of T helper cell subsets was downregulated in AD patients (Th1 p = 0.0024, Th2 p = 0.0157, Th17 p < 0.0001) compared to controls. Cytotoxic T cell subsets were reduced in AD (Tc1 p = 0.0075, Tc2 p = 0.0154) and CAH patients (Tc1 p = 0.0055, Tc2 p = 0.0012) compared to controls. NKCC was reduced in all subsets of PAI patients, with smallest changes in CAH. Degranulation marker CD107a expression was upregulated in BADx and AD, not in CAH patients compared to controls (BADx p < 0.0001; AD p = 0.0002). In contrast to NK cell activating receptors, NK cell inhibiting receptor CD94 was upregulated in BADx and AD, but not in CAH patients (p < 0.0001). Although modulation in clock gene expression could be confirmed in our patient subgroups, major interindividual-intergroup dissimilarities were not detected.

Discussion

In patients with different etiologies of PAI, distinct differences in T and NK cell-phenotypes became apparent despite the use of same GC preparation and dose. Our results highlight unsuspected differences in immune cell composition and function in PAI patients of different causes and suggest disease-specific alterations that might necessitate disease-specific treatment.

PDCD5 as a Potential Biomarker for Improved Prediction of the Incidence and Remission for Patients with Rheumatoid Arthritis

INTRODUCTION

Rheumatoid arthritis (RA) often involves an altered T-cell subpopulation, higher levels of inflammatory cytokines, and auto-antibodies. This study investigated whether PDCD5 could be a biomarker to predict the incidence and remission of RA so as to guide the therapeutic management of clinical RA.

METHODS

One hundred fifty-two patients (41 being in both active status and stable remission status) who were newly diagnosed with RA and 38 healthy controls were enrolled. Basic clinical data were collected before using blood samples remaining in the clinic after routine complete blood count. The ability of PDCD5 and important indicators to predict the remission of RA was estimated based on receiver operating characteristic curve (ROC) analysis.

RESULTS

PDCD5 expression was found to be significantly increased in RA patients in active status in comparison with healthy controls or those in stable remission status. Compared with anti-CCP, ESR and DAS28 score, PDCD5 was of better predictive value with an AUC of 0.846 (95% CI 0.780-0.912) for RA remission. The incidence risk of RA increased with higher levels of PDCD5 (OR = 1.73, 95% CI = 1.45-1.98, P = 0.005) in multiple logistic regression analysis, with the risk increasing by 2.94-times for high-risk group in comparison with low-risk group (OR = 2.94, 95% CI = 2.35-4.62, P < 0.001). The association between PDCD5 and RA remission showed a similar result. For correlation analysis, significant associations were eventually found between PDCD5 and indicated genes (FOXP3, TNF-α, IL-17A, IFN-γ and IL-6) as well as several important clinical parameters including IgG, RF, CRP, ESR, anti-CCP and DAS28 score.

CONCLUSIONS

This study suggested that increased PDCD5 expression was significantly linked to the incidence and remission of RA. PDCD5 may be used as a novel biomarker for the prediction of RA incidence and remission, especially due to its potential involvement in the development of the condition.

Boosting regulatory T cell function for the treatment of autoimmune diseases – That’s only half the battle!

Regulatory T cells (Treg) represent a subset of specialized T cells that are essential for the regulation of immune responses and maintenance of peripheral tolerance. Once activated, Treg exert powerful immunosuppressive properties, for example by inhibiting T cell-mediated immune responses against self-antigens, thereby protecting our body from autoimmunity. Autoimmune diseases such as multiple sclerosis, rheumatoid arthritis or systemic lupus erythematosus, exhibit an immunological imbalance mainly characterized by a reduced frequency and impaired function of Treg. In addition, there has been increasing evidence that – besides Treg dysfunction – immunoregulatory mechanisms fail to control autoreactive T cells due to a reduced responsiveness of T effector cells (Teff) for the suppressive properties of Treg, a process termed Treg resistance. In order to efficiently treat autoimmune diseases and thus fully induce immunological tolerance, a combined therapy aimed at both enhancing Treg function and restoring Teff responsiveness could most likely be beneficial. This review provides an overview of immunomodulating drugs that are currently used to treat various autoimmune diseases in the clinic and have been shown to increase Treg frequency as well as Teff sensitivity to Treg-mediated suppression. Furthermore, we discuss strategies on how to boost Treg activity and function, and their potential use in the treatment of autoimmunity. Finally, we present a humanized mouse model for the preclinical testing of Treg-activating substances in vivo.

Prevalence of Autoimmune Disease in Patients with Eosinophilic Esophagitis: A Cross-sectional Study of Three Hospitals in Japan

Objective Recent studies have found higher rates of autoimmune diseases, such as celiac disease, Crohn's disease, and ulcerative colitis, in patients with eosinophilic esophagitis (EoE) than in the general population. This study investigated the concomitant rate of autoimmune disease among Japanese patients with EoE and evaluated the clinicopathological characteristics of EoE patients with autoimmune disease. Methods The medical records of patients diagnosed with EoE between April 1, 2016, and June 30, 2020, were reviewed. We analyzed the concomitant rate of autoimmune diseases in patients with EoE and compared the clinical and histological differences between patients with and without autoimmune disease. Results Sixty-four patients with EoE were enrolled. Of them, 1 had ulcerative colitis (1.6%), 1 had autoimmune polyendocrine syndrome type 2 (1.6%), and 6 had endometriosis (28.5% of women, 44.4% of reproductive-aged women). No significant differences in the clinical course or histological findings were found between EoE patients with and without autoimmune diseases. No complications, including stenosis, were seen in EoE with autoimmune disease, and most patients with EoE and autoimmune diseases were responsive to proton pump inhibitors (PPIs). Conclusion In this study, 8 out of 64 patients with EoE had an autoimmune-related disease, including ulcerative colitis (n=1, 1.6%), autoimmune polyendocrine syndrome type 2 (n=1, 1.6%), or endometriosis (n=6, 44.4% of women of reproductive age), which is higher than that previously reported in the general population. Further investigations are required to clarify the relationship between EoE and autoimmune diseases.

Polymorphism in BACH2 gene is a marker of polyglandular autoimmunity

PURPOSE

Genetically predisposed individuals may develop several autoimmune diseases-autoimmune polyendocrine syndromes (APS). APS types 2-4, are complex disorders, which combine various organ-specific autoimmune conditions. Recent reports support the considerable role of the BACH2 gene in immune cell differentiation and shifting the T-cell balance towards regulatory T-cells. BACH2 polymorphisms are associated with autoimmune disorders, including Addison's disease (AD), Graves' disease (GD), and probably type 1 diabetes (T1D). Our study was aimed to investigate the BACH2 variant, rs3757247, in endocrine autoimmunity in the Polish population.

METHODS

The analysis comprised 346 individuals with APS, 387 with T1D only, and 568 controls. Genotyping was performed using TaqMan chemistry.

RESULTS

APS type 2 was found in 219 individuals, type 3 in 102, and type 4 in 25 subjects. Overall, AD was diagnosed in 244 subjects, Hashimoto's thyroiditis-in 238, T1D-in 127, GD-in 58, vitiligo and chronic gastritis each in 40 patients, celiac disease-in 28, premature menopause in 18, and alopecia in 4 patients. Minor T allele at rs3757247 was found in 56.4% APS vs. 44.1% control alleles (OR 1.59; 95%CI: 1.30-1.95, p < 0.0001). The distribution of genotypes revealed excess TT homozygotes in the APS cohort (33.2 vs. 20.1% in controls, p < 0.0001). The frequencies of rs3757247 alleles and genotypes in T1D patients did not present significant differences vs. controls (p-values > 0.05).

CONCLUSIONS

These results provide evidence of the association between BACH2 polymorphism and polyglandular autoimmunity. Since carriers of rs3757247 display increased risk for additional autoimmune conditions, this variant could identify individuals prone to develop APS.

Made to Measure: Patient-Tailored Treatment of Multiple Sclerosis Using Cell-Based Therapies

Currently, there is still no cure for multiple sclerosis (MS), which is an autoimmune and neurodegenerative disease of the central nervous system. Treatment options predominantly consist of drugs that affect adaptive immunity and lead to a reduction of the inflammatory disease activity. A broad range of possible cell-based therapeutic options are being explored in the treatment of autoimmune diseases, including MS. This review aims to provide an overview of recent and future advances in the development of cell-based treatment options for the induction of tolerance in MS. Here, we will focus on haematopoietic stem cells, mesenchymal stromal cells, regulatory T cells and dendritic cells. We will also focus on less familiar cell types that are used in cell therapy, including B cells, natural killer cells and peripheral blood mononuclear cells. We will address key issues regarding the depicted therapies and highlight the major challenges that lie ahead to successfully reverse autoimmune diseases, such as MS, while minimising the side effects. Although cell-based therapies are well known and used in the treatment of several cancers, cell-based treatment options hold promise for the future treatment of autoimmune diseases in general, and MS in particular.

Hygiene hypothesis and autoimmune diseases: A narrative review of clinical evidences and mechanisms

Since the start of the "modern era", characterized by the increase in urbanization, a progressive attention to hygiene and autoimmune conditions has considerably grown. Although these diseases are often multifactorial, it was demonstrated that environment factors such as pollution, diet and lifestyles may play a crucial role together with genetic signature. Our research, based on the newest and most significant literature of this topic, highlights that the progressive depletion of microbes and parasites due to increased socioeconomic improvement, may lead to a derangement of immunoregulatory mechanisms. Moreover, special attention was given to the complex interplay between microbial agents, as gut microbiome, diet and vitamin D supplementation with the aim of identifying promising future therapeutic options. In conclusion, autoimmunity cannot be limited to hygiene-hypothesis, but from the point of view of precision medicine, this theory represents a fundamental element together with the study of genomics, the microbiome and proteomics, in order to understand the complex functioning of the immune system.

A case of eosinophilic esophagitis with autoimmune polyendocrine syndrome type 2, including autoimmune gastritis

Both eosinophilic esophagitis (EoE) and autoimmune polyendocrine syndrome (APS) are relatively rare diseases in Japan. We herein report a case of EoE with APS in a 67-year-old Japanese man who presented with chest pain and dysphagia. On the basis of endoscopic findings and histological analysis, we diagnosed the patient with EoE along with autoimmune gastritis. Additional serological examinations revealed the presence of Hashimoto's thyroiditis and type 1 diabetes, which led to the final diagnosis of APS. His symptoms did not respond to treatment with a proton-pump inhibitor but improved with topical steroid therapy. This case of coexisting EoE and APS-2 is quite rare and has several implications for the pathogenesis of both conditions.

Regulating the regulators: Is introduction of an antigen-specific approach in regulatory T cells the next step to treat autoimmunity?

In autoimmunity, the important and fragile balance between immunity and tolerance is disturbed, resulting in abnormal immune responses to the body's own tissues and cells. CD4⁺CD25^hiFoxP3⁺ regulatory T cells (Tregs) induce peripheral tolerance in vivo by means of direct cell-cell contact and release of soluble factors, or indirectly through antigen-presenting cells (APC), thereby controlling auto-reactive effector T cells. Based on these unique capacities of Tregs, preclinical studies delivered proof-of-principle for the clinical use of Tregs for the treatment of autoimmune diseases. To date, the first clinical trials using ex vivo expanded polyclonal Tregs have been completed. These pioneering studies demonstrate the feasibility of generating large numbers of polyclonal Tregs in a good manufacturing practices (GMP)-compliant manner, and that infusion of Tregs is well tolerated by patients with no evidence of general immunosuppression. Nonetheless, only modest clinical results were observed, arguing that a more antigen-specific approach might be needed to foster a durable patient-specific clinical cell therapy without the risk for general immunosuppression. In this review, we discuss current knowledge, applications and future goals of adoptive immune-modulatory Treg therapy for the treatment of autoimmune disease and transplant rejection. We describe the key advances and prospects of the potential use of T cell receptor (TCR)- and chimeric antigen receptor (CAR)-engineered Tregs in future clinical applications. These approaches could deliver the long-awaited breakthrough in stopping undesired autoimmune responses and transplant rejections.

Development of Quantitative Methylation-Specific Droplet Digital PCR (ddMSP) for Assessment of Natural Tregs

Regulatory T cells (Tregs) suppress immune responses in vivo in an antigen-specific manner. Of clinical relevance, Tregs can be isolated and expanded in vitro while maintaining immunoregulatory function. Tregs are classified as CD4⁺CD25^highCD127^low FOXP3⁺ cells. Demethylation of the Treg-specific demethylation region (TSDR) of FOXP3 is found in natural Tregs (nTregs). We report a method for the characterization of the differential methylation pattern of the FOXP3 TSDR in patient-derived and expanded nTregs. Human TSDR sequences from nTregs (unmethylated sequence) and pancreatic (methylated sequence) cells were amplified and cloned into plasmids. A droplet digital TaqMan probe-based qPCR (ddPCR) assay using methylation-specific primers and probes was employed to quantify unmethylated and methylated sequences. The methylation-specific droplet digital PCR (ddMSP) assay was specific and selective for unmethylated DNA in mixtures with methylated DNA in the range of 5000 copies/μL to less than 1 copy/μL (R ² = 0.99) even in the presence of non-selective gDNAs. CD4⁺CD25^highCD127^lowFOXP3⁺ human nTregs, in the presence of Dynabeads or activators, were expanded for 21 days. There was a decrease in the unmethylated ratio of Tregs after expansion with essentially the same ratio at days 10, 14, and 17. However, the activator expanded group showed a significant decrease in unmethylated targets at day 21. The suppression activity of activator-expanded nTregs at day 21 was decreased compared to cells expanded with Dynabeads. These data suggest that the ddMSP can quantitatively monitor nTreg expansion in vitro. These data also indicate that the assay is sensitive and specific at differentiating nTregs from other cells and may be useful for rapid screening of nTregs in clinical protocols.

Case Report: Clinical and Immunological Features of a Chinese Cohort With Mycoplasma-Induced Rash and Mucositis

Dermatological disorders are the most common extrapulmonary complications of Mycoplasma pneumoniae, of which Mycoplasma-induced rash and mucositis (MIRM) has recently been proposed to be a separate diagnostic entity. MIRM could easily be misdiagnosed as atypical Stevens-Johnson syndrome by clinicians due to the unawareness of this rare disease. We retrospectively reviewed the inpatient database from Jan. 2016 to Dec. 2019 of the Children's Hospital of Fudan University. In total, five patients (mean age 5.5 years, three male) matched the diagnostic criteria of MIRM. All patients had scattered lesions and more than two sites of mucosal involvement. The serum IgA level of three patients was higher than normal. Two patients had a significant decrease in peripheral blood CD3+ T and CD4+ T cells that improved with recovery. The percentage of TCRαβ+ CD4-CD8-T cells of Patient five was higher than normal. All patients received treatments with antibiotics and corticosteroids, 3 patients received intravenous immunoglobulin. Among five patients, three patients complained of dyspigmentation, and two patients had an uneventful recovery. MIRM is a separate entity with predominant mucosal involvement and excellent prognosis that more often affects younger patients. Excessive inflammatory reactions may lead to immune disorders, including lymphopenia and a redistribution of CD4+ T cells. We recommend that pneumonia accompanied by mucocutaneous eruptions, especially in young patients, should raise clinical suspicion of MIRM.

Expansion and suppressive capacity of regulatory T cells isolated from patients across the leprosy spectrum: a pilot study

Knowledge of the role of Tregs in the immunopathogenesis of the different clinical outcomes within the leprosy spectrum remains limited due to the lack of studies directly assessing their suppression capacity. We thus tested a protocol to expand Tregs from the peripheral blood of patients across the leprosy spectrum and analyzed their suppressive capacity in autologous TCD4+ responses. Results of these pilot assays show that Tregs can be expanded and exert suppressive capacity, but also that their rate of expansion and suppressive capacity are influenced by the patient's clinical classification, suggesting that they possibly retain some in vivo characteristics.

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.

Epidemiology, pathogenesis, and diagnosis of Addison's disease in adults

BACKGROUND

Addison's disease (AD) is a rare disorder and among adult population in developed countries is most commonly caused by autoimmunity. In contrast, in children genetic causes are responsible for AD in the majority of patients.

PURPOSE

This review describes epidemiology, pathogenesis, genetics, natural history, clinical manifestations, immunological markers and diagnostic strategies in patients with AD. Standard care treatments including the management of patients during pregnancy and adrenal crises consistent with the recent consensus statement of the European Consortium and the Endocrine Society Clinical Practice Guideline are described. In addition, emerging therapies designed to improve the quality of life and new strategies to modify the natural history of autoimmune AD are discussed.

CONCLUSIONS

Progress in optimizing replacement therapy for patients with AD has allowed the patients to lead a normal life. However, continuous education of patients and health care professionals of ever-present danger of adrenal crisis is essential to save lives of patients with AD.

Characterization of proinsulin-specific regulatory T cells in type 1 diabetes at different ages of onset

BACKGROUND AND OBJECTIVES

Regulatory T cells (Tregs) play an important role in maintaining tolerance to self-antigens. Defects in the frequency and function of polyclonal Tregs have been reported in type 1 diabetes (T1D). However, characteristics of proinsulin (PI)-specific Tregs in human T1D have not yet been explored. Therefore, we aimed to characterize PI-specific Tregs in two distinct pathophysiological subtypes of T1D, juvenile-onset T1D (JOT1D) and adult-onset T1D (AOT1D), distinguished by the age of onset.

METHODS

Peripheral blood mononuclear cells of the recruited subjects were stimulated in vitro with PI-derived peptides. PI-specific Tregs were characterized by flow cytometry using the combination of markers CD25, CD137, FOXP3 and CD45RA.

RESULTS

Firstly, we observed similar frequencies of polyclonal Tregs in the T1D (n = 25) and healthy control (HC) (n = 20) subjects (P = 0.96), with a positive correlation between age and frequency of polyclonal Tregs (r = +0.35, P = 0.04). While the frequency of polyclonal Tregs was higher in AOT1D group (P = 0.02), both JOT1D (n = 14) and AOT1D groups (n = 11) had a comparable frequency of PI-specific Tregs in their peripheral blood. The frequency of PI-specific memory Tregs was significantly high in both the JOT1D (P = 0.02) and AOT1D (P = 0.009) groups compared to their respective HC groups (n = 10). Finally, we observed no significant difference in the expression of FOXP3 and IL-2 receptor in PI-specific Tregs in all the groups.

CONCLUSIONS

Unlike polyclonal Tregs, both T1D subtypes harbor comparable frequencies of PI-specific Tregs. Chronic antigen presentation results in a distinct memory-like phenotype of PI-specific Tregs in these subjects irrespective of the age of disease onset.

Old Friends, immunoregulation, and stress resilience

There is a considerable body of evidence indicating that chronic adverse experience, especially chronic psychosocial stress/trauma, represents a major risk factor for the development of many somatic and affective disorders, including inflammatory bowel disease (IBD) and posttraumatic stress disorder (PTSD). However, the mechanisms underlying the development of chronic stress-associated disorders are still in large part unknown, and current treatment and prevention strategies lack efficacy and reliability. A greater understanding of mechanisms involved in the development and persistence of chronic stress-induced disorders may lead to novel approaches to prevention and treatment of these disorders. In this review, we provide evidence indicating that increases in immune (re-)activity and inflammation, potentially promoted by a reduced exposure to immunoregulatory microorganisms ("Old Friends") in today's modern society, may be causal factors in mediating the vulnerability to development and persistence of stress-related pathologies. Moreover, we discuss strategies to increase immunoregulatory processes and attenuate inflammation, as for instance contact with immunoregulatory Old Friends, which appears to be a promising strategy to promote stress resilience and to prevent/treat chronic stress-related disorders.

The Footprints of Poly-Autoimmunity: Evidence for Common Biological Factors Involved in Multiple Sclerosis and Hashimoto's Thyroiditis

Autoimmune diseases are a diverse group of chronic disorders and affect a multitude of organs and systems. However, the existence of common pathophysiological mechanisms is hypothesized and reports of shared risk are emerging as well. In this regard, patients with multiple sclerosis (MS) have been shown to have an increased susceptibility to develop chronic autoimmune thyroid diseases, in particular Hashimoto's thyroiditis (HT), suggesting an autoimmune predisposition. However, studies comparing such different pathologies of autoimmune origin are still missing till date. In the present study, we sought to investigate mechanisms which may lead to the frequent coexistence of MS and HT by analyzing several factors related to the pathogenesis of MS and HT in patients affected by one or both diseases, as well as in healthy donors. In particular, we analyzed peripheral blood mononuclear cell gene-expression levels of common candidate genes such as TNFAIP3, NR4A family, BACH2, FOXP3, and PDCD5, in addition to the regulatory T cell (Treg) percentage and the 25-hydroxy vitamin D serum levels. Our findings support the plausibility of the existence of common deregulated mechanisms shared by MS and HT, such as BACH2/PDCD5-FOXP3 pathways and Tregs. Although the biological implications of these data need to be further investigated, we have highlighted the relevance of studies comparing different autoimmune pathologies for the understanding of the core concepts of autoimmunity.

High-dose vitamin D in Addison's disease regulates T-cells and monocytes: A pilot trial

OBJECTIVES

On the basis of the immunomodulatory actions of vitamin D (VD), we investigated the effects of high-dose VD therapy over a 3 mo period on the immune response in patients with Addison's disease (AD).

METHODS

This randomized, controlled, crossover trial included 13 patients with AD who received either cholecalciferol (4000 IU/d) for 3 mo followed by 3 mo placebo oil or the sequential alternative placebo followed by verum. Glucocorticoid replacement doses remained stable. The primary outcome measures were changes in 25-hydroxyvitamin D3 (25(OH)D₃) levels and immune cells including T helper cells (Th; CD3⁺CD4⁺), late-activated Th cells (CD3⁺CD4⁺HLA-DR⁺), regulatory T cells (CD3⁺CD4⁺CD25^brightCD127^dim/neg), cytotoxic T cells (Tc; CD3⁺CD8⁺), late-activated Tc cells (CD3⁺CD8⁺HLA-DR⁺), and monocytes. The explorative analysis included the correlation of changes with VD-related gene polymorphisms and 21-hydroxylase antibody titers.

RESULTS

Ten of 13 patients (77%) were VD deficient. Median 25(OH)D₃ concentrations increased significantly to 41.5 ng/ml (median changes: 19.95 ng/ml; P = 0.0005) after 3 mo of cholecalciferol treatment. Within the T-cells, only the late-activated Th (median changes: 1.6%; P = 0.02) and late-activated Tc cells (median changes: 4.05%; P = 0.03) decreased, whereas monocytes (median changes: 1.05%; P = 0.008) increased after VD therapy. T-cell changes were associated with two polymorphisms (CYP27B1-rs108770012 and VDR-rs10735810), but no changes in the 21-hydroxylase antibody titers were observed.

CONCLUSIONS

Three months of treatment with cholecalciferol achieved sufficient 25(OH)D₃ levels and can regulate late-activated T-cells and monocytes in patients with AD. Explorative analysis revealed potential genetic contributions. This pilot trial provides novel insights about immunomodulation in AD.

IL-17A-Producing Foxp3+ Regulatory T Cells and Human Diseases

CD4+Foxp3+ regulatory T (Treg) cells play major roles in immune homeostasis. While CD4+Foxp3+ Treg cells act to suppress other immune effector cells, there is growing evidence that they also produce pro-inflammatory cytokines, such as IL-17A, in inflammatory conditions. The pro-inflammatory cytokine milieu, toll-like receptor (TLR) signaling, and specific transcription factors are important for the production of IL-17A by CD4+Foxp3+ Treg cells. In particular, IL-17A-producing CD4+Foxp3+ Treg cells express RORγt, the T helper (Th) 17-specific transcription factor, in addition to Foxp3. IL-17A-producing CD4+Foxp3+ Treg cells are also involved in the pathogenesis of various diseases. Here we review the mechanisms underlying the induction of IL-17A-producing CD4+Foxp3+ Treg cells and the roles of these cells in human disease.

Systemic Activation of NRF2 Alleviates Lethal Autoimmune Inflammation in Scurfy Mice

The transcription factor NRF2 (nuclear factor [erythroid-derived 2]-like 2) plays crucial roles in the defense mechanisms against oxidative stress and mediates anti-inflammatory actions under various pathological conditions. Recent studies showed that the dysfunction of regulatory T cells (Tregs) is directly linked to the initiation and progression of various autoimmune diseases. To determine the Treg-independent impact of NRF2 activation on autoimmune inflammation, we examined scurfy (Sf) mice, which are deficient in Tregs and succumb to severe multiorgan inflammation by 4 weeks of age. We found that systemic activation of NRF2 by Keap1 (Kelch-like ECH-associated protein 1) knockdown ameliorated tissue inflammation and lethality in Sf mice. Activated T cells and their cytokine production were accordingly decreased by Keap1 knockdown. In contrast, NRF2 activation through cell lineage-specific Keap1 disruption (i.e., in T cells, myeloid cells, and dendritic cells) achieved only partial or no improvement in the inflammatory status of Sf mice. Our results indicate that systemic activation of NRF2 suppresses effector T cell activities independently of Tregs and that NRF2 activation in multiple cell lineages appears to be required for sufficient anti-inflammatory effects. This study emphasizes the possible therapeutic application of NRF2 inducers in autoimmune diseases that are accompanied by Treg dysfunction.

IL-33 improves the suppressive potential of regulatory T cells in patients with type 1 diabetes

AIMS

The presented study was aimed to analyze the influence of IL-33 on regulatory T cells (Tregs) suppressive potential in patients with type 1 diabetes.

METHODS

We analyzed the ability of IL-33 treated Tregs to inhibit the production of IFN-γ by effector T lymphocytes in an in vitro co-culture. The study group consisted of 22 patients with type 1 diabetes and 12 age and sex-matched healthy individuals.

RESULTS

Our findings revealed that in vitro IL-33 treatment of Tregs derived from patients with type 1 diabetes resulted in quantitative as well as qualitative changes in this cell population, confirming immunoregulatory features of IL-33.

CONCLUSION

IL-33 could be considered as a potential therapeutic tool in adoptive therapies of type 1 diabetes.

Exacerbation of spontaneous autoimmune nephritis following regulatory T cell depletion in B cell lymphoma 2-interacting mediator knock-out mice

Regulatory T cells (Tregs ) have been recognized as central mediators for maintaining peripheral tolerance and limiting autoimmune diseases. The loss of Tregs or their function has been associated with exacerbation of autoimmune disease. However, the temporary loss of Tregs in the chronic spontaneous disease model has not been investigated. In this study, we evaluated the role of Tregs in a novel chronic spontaneous glomerulonephritis model of B cell lymphoma 2-interacting mediator (Bim) knock-out mice by transient depleting Tregs . Bim is a pro-apoptotic member of the B cell lymphoma 2 (Bcl-2) family. Bim knock-out (Bim-/- ) mice fail to delete autoreactive T cells in thymus, leading to chronic spontaneous autoimmune kidney disease. We found that Treg depletion in Bim-/- mice exacerbated the kidney injury with increased proteinuria, impaired kidney function, weight loss and greater histological injury compared with wild-type mice. There was a significant increase in interstitial infiltrate of inflammatory cells, antibody deposition and tubular damage. Furthermore, the serum levels of cytokines interleukin (IL)-2, IL-4, IL-6, IL-10, IL-17α, interferon (IFN)-γ and tumour necrosis factor (TNF)-α were increased significantly after Treg depletion in Bim-/- mice. This study demonstrates that transient depletion of Tregs leads to enhanced self-reactive T effector cell function followed by exacerbation of kidney disease in the chronic spontaneous kidney disease model of Bim-deficient mice.

Apportioning Blame: Autoreactive CD4+ and CD8+ T Cells in Type 1 Diabetes

Type 1 diabetes (T1D) is one of the most studied archetypal organ-specific autoimmune diseases. Although many clinical, epidemiological, and pathological characteristics have been described, there are still important issues which need to be resolved as these will have a major impact on the development of future antigen-specific immunotherapies. An important question relates to T lymphocytes in the development of the disease, in particular their role in the destruction of insulin-producing beta cells. Since the discovery that certain class II histocompatibility complex molecules (HLA) are linked to the development of T1D, much research has focused on CD4⁺ helper T lymphocytes; however, recent studies highlight class I HLA molecules as an independent risk factor; hence, research into the role played by CD8⁺ cytotoxic T lymphocytes has gained momentum. In this review, we summarize recent studies clarifying the role played by both sets of autoreactive T lymphocytes in T1D, discuss the targets recognized by these cells and their phenotype in T1D patients. Finally, we will examine the possible generation of regulatory CD8⁺ T lymphocytes upon different immuno-intervention strategies.

Decreased Circulating T Regulatory Cells in Egyptian Patients with Nonsegmental Vitiligo: Correlation with Disease Activity

Background. Vitiligo is an acquired depigmentary skin disorder resulting from autoimmune destruction of melanocytes. Regulatory T cells (Tregs), specifically CD4⁺CD25⁺ and Forkhead box P3⁺ (FoxP3⁺) Tregs, acquired notable attention because of their role in a variety of autoimmune pathologies. Dysregulation of Tregs may be one of the factors that can break tolerance to melanocyte self-antigens and contribute to vitiligo pathogenesis. Methods. In order to sustain the role of Tregs in pathogenesis and disease activity of vitiligo, surface markers for CD4⁺CD25⁺ and FoxP3⁺ peripheral Tregs were evaluated by flow cytometry in 80 Egyptian patients with nonsegmental vitiligo in addition to 60 healthy control subjects and correlated with clinical findings. Results. Vitiligo patients had significantly decreased numbers of both peripheral CD4⁺CD25⁺ and FoxP3⁺ T cells compared to control subjects (11.49%  ± 8.58% of CD4⁺ T cells versus 21.20%  ± 3.08%, and 1.09%  ± 0.96% versus 1.44%  ± 0.24%, resp., P < 0.05 for both). Peripheral numbers of CD4⁺CD25⁺ and FoxP3⁺ Tregs correlated negatively with VIDA score. Conclusion. Treg depletion with impaired immune downregulatory function might play a key role in the autoimmune conditions beyond nonsegmental vitiligo particularly in active cases. Effective Treg cell-based immunotherapies might be a future hope for patients with progressive vitiligo.

Expression of PD-1 Molecule on Regulatory T Lymphocytes in Patients with Insulin-Dependent Diabetes Mellitus

Type 1 diabetes is caused by autoreactive T cells that destroy pancreatic beta cells. Animal models suggested that a CD4⁺CD25⁺ population has a regulatory function capable of preventing activation and effector functions of autoreactive T cells. However, the role of CD4⁺CD25^high T cells in autoimmunity and their molecular mechanisms remain the subject of investigation. We therefore evaluated T regulatory cell frequencies and their PD-1 expression in the peripheral blood of long-standing diabetics under basal conditions and after CD3/CD28 stimulation. Under basal conditions, the percentages of T regulatory cells were significantly higher while that of T effector cells were significantly lower in patients than in controls. The ratio of regulatory to effector T cells was higher in patients than that in controls, suggesting that T regulatory cells were functional in patients. Percentages of total PD-1⁺, PD-1^low and PD-1^high expressing T regulatory cells did not change in patients and in controls. After stimulation, a defect in T regulatory cell proliferation was observed in diabetics and the percentages of total PD-1⁺, PD-1^low and PD-1^high expressing cells were lower in patients. Our data suggest a defective activation of T regulatory cells in long-standing diabetics due to a lower expression of PD-1 on their surface.

Can mesenchymal stem cells reverse chronic stress-induced impairment of lung healing following traumatic injury?

BACKGROUND

One week following unilateral lung contusion (LC), rat lungs demonstrate full histologic recovery. When animals undergo LC plus the addition of chronic restraint stress (CS), wound healing is significantly delayed. Mesenchymal stem cells (MSCs) are pluripotent cells capable of immunomodulation, which have been the focus of much research in wound healing and tissue regeneration. We hypothesize that the addition of MSCs will improve wound healing in the setting of CS.

METHODS

Male Sprague-Dawley rats (n = 6-7 per group) were subjected to LC/CS with or without the injection of MSCs. MSCs were given as a single intravenous dose of 5 × 10 cells in 1 mL Iscove's Modified Dulbecco's Medium at the time of LC. Rats were subjected to 2 hours of restraint stress on Days 1 to 6 following LC. Seven days following injury, rats were sacrificed, and the lungs were examined for histologic evidence of wound healing using a well-established histologic lung injury score (LIS) to grade injury. LIS examines inflammatory cells/high-power field (HPF) averaged over 30 fields, interstitial edema, pulmonary edema, and alveolar integrity, with scores ranging from 0 (normal) to 11 (highly damaged). Peripheral blood was analyzed by flow cytometry for the presence of T-regulatory (C4CD25FoxP3) cells. Data were analyzed by analysis of variance followed by Tukey's multiple comparison test, expressed as mean (SD).

RESULTS

As previously shown, 7 days following isolated LC, LIS has returned to 0.83 (0.41), with a subscore of zero for inflammatory cells/HPF. The addition of CS results in an LIS of 4.4 (2.2), with a subscore of 1.9 (0.7) for inflammatory cells/HPF. Addition of MSC to LC/CS decreased LIS to 1.7 (0.8), with a subscore of zero for inflammatory cells/HPF. Furthermore, treatment of animals undergoing LC/CS with MSCs increased the %T-regulatory cells by 70% in animals undergoing LC/CS alone (12.9% [2.4]% vs. 6.2% [1.3%]).

CONCLUSION

Stress-induced impairment of wound healing is reversed by the addition of MSCs given at the time of injury in this rat LC model. This improvement in lung healing is associated with a decrease in the number of inflammatory cells and an increase in the number of T-regulatory cells. Further study into the mechanisms by which MSCs hasten wound healing is warranted.

Interleukin-2 and subunit alpha of its soluble receptor in autoimmune Addison's disease--an association study and expression analysis

Autoimmune Addison's disease (AAD) results from T cell-mediated destruction of the adrenal cortex, commonly accompanied by autoantibodies to 21-hydroxylase (21OH). In order to gain insight into the obscure aetiology of this disease, we investigated the roles of the IL2 and IL2RA genes, encoding interleukin-2 and subunit alpha of its receptor (IL2Ra), respectively. The association of AAD with IL2 and IL2RA polymorphisms (rs6822844, rs2069762, rs3136534, rs11594656, rs3118470 and rs2104286) was tested in 223 patients and 672 healthy controls. Functional studies consisted of gene expression analysis in cultured PBMCs exposed to 21OH and evaluation of serum interleukin by ELISA assays. The frequency of the minor C allele of rs3136534 was significantly decreased in AAD subjects compared to controls (OR 0.71; 95%CI 0.561-0.887; p = 0.003). Only AAD cells responded to 21OH with an elevated IL2 and IL2RA mRNA synthesis (p = 0.004 and p = 0.009 versus controls, respectively), paralleled by increased supernatant levels of both cytokines (p = 0.031 and p = 0.001 versus controls). IL2 mRNA level in 21OH-stimulated AAD PBMCs correlated negatively with age (p = 0.036) and positively with serum antibodies to 21OH (p = 0.006). Carriers of the rs2104286 AA genotype demonstrated higher IL2RA mRNA (p = 0.022) and soluble IL2Ra secretion (p = 0.029) upon 21OH stimulation. Serum interleukin-2 in AAD subjects was significantly higher compared to controls (4.61 ± 4.3 versus 1.71 ± 3.2 pg/mL, p < 0.001), whereas sIL2Ra levels remained similar in both groups (p = 0.885). In conclusion, the study reveals an association between AAD and IL2 locus. It confirms specific 21OH-directed reactivity of the peripheral AAD lymphocytes, which display increased synthesis of interleukin-2 and sIL2Ra.

Circulating level of CD4+ CD25+ FOXP3+ T cells in patients with chronic urticaria

BACKGROUND

CD4+ CD25+ T-regulatory (Treg) cells play critical roles in maintaining peripheral tolerance and preventing autoimmunity. As characteristics of Treg cells have not been precisely investigated in chronic urticaria (CU) yet, this study was performed.

OBJECTIVE

To determine the frequencies of circulating CD4+ CD25+ FOXP3+ T cells and serum levels of interleukin (IL)-10, transforming growth factor (TGF)-β, and IL-17 in patients with chronic autoimmune urticaria and chronic idiopathic urticaria compared to healthy controls.

METHODS

Peripheral blood mononuclear cells (PBMCs) were obtained from patients with CU and healthy controls. The frequency of CD4+ CD25+ T cells in PBMCs and expression levels of FOXP3 were detected by flow cytometry. The serum levels of IL-10, TGF-β, and IL-17 were measured by enzyme-linked immunosorbent assay.

RESULTS

A significant decrease in the percentage of circulating CD4+ CD25+ FOXP3+ T cells was detected in patients with CU, compared to control subjects. However, no significant difference was detected on the serum levels of IL-10, TGF-β, and IL-17 between patients with CU and control subjects.

CONCLUSIONS

This study demonstrated that the frequency of Treg cells in PBMCs was decreased in patients with CU. Further studies are needed to clarify the exact role of Treg cells in the pathogenesis of CU and factors regulating their function.

Lymphocytic profiling in thyroid cancer provides clues for failure of tumor immunity

Thyroid cancers are usually surrounded by a significant number of immune-reactive cells. Tumor-associated lymphocytes as well as background lymphocytic thyroiditis are frequently mentioned in pathology reports of patients who have undergone surgery for thyroid cancer. The nature of this lymphocytic reaction is not well understood. The fact that cancer can survive in this adverse microenvironment is indicative of immune regulation. We characterized the lymphocytic infiltration that accompanies thyroid cancer and compared it with that present in thyroid autoimmunity. We found that double-negative (DN) T cells were significantly more abundant in thyroid cancer than in thyroid autoimmunity. Although FOXP3(+) regulatory T cells were also present, DN T cells were the dominant cell type, associated with thyroid cancer. Furthermore, upon stimulation, the DN T cells associated with cancer remained unchanged, while the few (<5%) DN T cells associated with thyroid autoimmunity increased in numbers (>20%). CD25 expression on DN T cells remained unchanged after stimulation, which indicates that the increase in the absolute number of DN T cells in thyroid autoimmunity was at the expense of inactivation of single-positive T cells. We concluded that in the setting of thyroid cancer, DN T cells appear to suppress tumor immunity. In contrast, in thyroid autoimmunity, DN T cells were barely present and only increased at the expense of inactivated, single-positive T cells upon induction. Together, these findings indicate that thyroid cancer-associated DN T cells might regulate proliferation and effector function of T cells and thereby contribute to tumor tolerance and active avoidance of tumor immunity.

Selective depletion of regulatory T cell subsets by docetaxel treatment in patients with nonsmall cell lung cancer

Regulatory T (Treg) cells are potent suppressors that maintain immune homeostasis. Accumulation of Treg can inhibit effective immune responses in cancer patients, leading to tumor development and progression. Despite direct cytotoxicity, several chemotherapeutic drugs have been reported to deplete Treg cells for better prognosis for cancer patients. Treg cells are a heterogenous population with at least three different subsets, nonsuppressive, resting, and activated Treg cells. However, the characteristics of Treg cell subsets in lung cancer patients and how chemotherapy affects Treg cells remain elusive. In this study, we first analyzed Treg cell subsets in peripheral blood samples from 40 nonsmall cell lung cancer (NSCLC) patients and 20 healthy donors. Treg cells, specifically activated Treg cell subset, significantly increased in patients with NSCLC. Compared to nonsuppressive Treg cells, activated Treg cells expressed higher level of CD39 and predominantly produced inhibitory cytokines. In vitro assay showed that docetaxel reduced all three subsets of Treg cells. More importantly, we found docetaxel-based chemotherapy significantly decreased all three Treg subsets after 4 cycles of treatment in 17 NSCLC patients. Taken together, this study revealed dynamic changes of various Treg cell subsets in NSCLC patients before and after chemotherapy, providing activated Treg cells as a potential target for chemotherapy.

Neurologic complications of disorders of the adrenal glands

Disorders of the adrenal glands frequently have secondary neurological manifestations, while some diseases that involve the central nervous system are accompanied by adrenal gland dysfunction. Excessive corticosteroid secretions in primary or secondary Cushing's syndrome causes muscle weakness and behavioral disturbances, such as emotional lability and sometimes depression, while adrenal insufficiency may cause fatigue, weakness, and depression. Adrenoleukodystrophy and adrenoneuromyelopathy are X-linked recessive disorders of the metabolism of very long chain fatty acids that manifest with white matter abnormalities of the brain, myelopathy and/or neuropathy, as well as adrenal insufficiency. Other disorders of the adrenal glands include hyperaldosteroidism, which may cause weakness from hypokalemia. Dysfunction of the adrenal medulla causes excessive or deficient secretion of catecholamines, primarily causing cardiovascular symptoms. This chapter reviews the clinical manifestations and diagnostic aspects and treatment of the various disorders of the adrenal glands. Some of the congenital adrenal diseases are also discussed.

Regulatory T cells require renal antigen recognition through the TCR to protect against injury in nephritis

Regulatory T cells (Treg) are important for maintaining immune homeostasis. Adoptive transfer of Tregs is protective in renal disease models in both immunocompetent and immunodeficient mice. However the involvement of TCR recognition of renal antigens remains to be clarified. To address this question, we made use of Tregs from the DO11.10 mouse (a TCR transgenic (Tg) mouse), that recognise the non-murine antigen Ovalbumin (OVA) and therefore are not activated by renal antigens. DO11.10 Tregs were assessed functionally in vitro and demonstrated equivalent suppression to WT BALB/c Tregs. Adriamycin Nephropathy (AN) was induced in mice which had been transfused with CD4+CD25+Tregs isolated from DO11.10 or BALB/c mice. To eliminate the memory/activation state as a cause of differences in activity, the protective capacity of DO11.10 Tregs pre-activated with OVA in vivo was assessed. Transfer of WT BALB/c Tregs significantly attenuated the development of AN with less glomerulosclerosis, tubular atrophy and macrophage infiltration as compared to AN mice without Treg transfer. However, mice receiving either naïve or pre-activated DO11.10 Tregs were not protected from AN. The lack of protection by DO11.10 Tregs was not due to failure to traffic to the affected kidney. These results suggest that antigen recognition in the kidney is important for Treg protection against injury.

Natural regulatory T cells in isolated early responders compared with dual responders with allergic asthma

BACKGROUND

Natural regulatory T (Treg) cells are implicated in the regulation of the inflammatory response in patients with allergic asthma.

OBJECTIVES

We sought to determine changes in Treg cell numbers in the airways and peripheral blood of isolated early responder (IER) versus dual responder (DR) subjects with mild allergic asthma before and after allergen challenge.

METHODS

Induced sputum was collected from 22 subjects with allergic asthma (10 IERs and 12 DRs) and peripheral blood collected from 8 DRs with allergic asthma at 0, 7, and 24 hours after allergen challenge. Treg cells were identified by using fluorescently labeled antibodies to CD4 and forkhead box protein 3 and enumerated by using flow cytometry.

RESULTS

There was a significant increase in the percentage of sputum CD4(+) cells 24 hours after allergen challenge in both IERs and DRs. The percentage of sputum Treg cells significantly decreased 24 hours after challenge in DRs but not IERs. This change was significantly correlated with the magnitude of the late asthmatic response. There was also a significant increase in the absolute number of sputum CD4(+) cells and Treg cells at 24 hours in DRs only. The ratio of the number of Treg cells to CD4(+) cells at 24 hours was significantly smaller in DRs compared with that in IERs. None of the above changes were observed in peripheral blood.

CONCLUSIONS

DRs exhibit a diminished percentage of airway Treg cells after allergen challenge that is not observed in IERs and a significantly lower ratio of Treg cells to CD4(+) cells, which might contribute to the development of the late asthmatic response.

CD4⁺ CD45RA⁻ FoxP3high activated regulatory T cells are functionally impaired and related to residual insulin-secreting capacity in patients with type 1 diabetes

Accumulating lines of evidence have suggested that regulatory T cells (T(regs)) play a central role in T cell-mediated immune response and the development of type 1A and fulminant type 1 diabetes. CD4(+) forkhead box protein 3 (FoxP3)(+) T cells are composed of three phenotypically and functionally distinct subpopulations; CD45RA(+) FoxP3(low) resting T(regs) (r-T(regs)), CD45RA(-) FoxP3(high) activated T(regs) (a-T(regs)) and CD45RA(-) FoxP3(low) non-suppressive T cells (non-T(regs)). We aimed to clarify the frequency of these three subpopulations in CD4(+) FoxP3(+) T cells and the function of a-T(regs) with reference to subtypes of type 1 diabetes. We examined 20 patients with type 1A diabetes, 15 patients with fulminant type 1 diabetes, 20 patients with type 2 diabetes and 30 healthy control subjects. A flow cytometric analysis in the peripheral blood was performed for the frequency analysis. The suppressive function of a-T(regs) was assessed by their ability to suppress the proliferation of responder cells in a 1/2:1 co-culture. A flow cytometric analysis in the peripheral blood demonstrated that the frequency of a-T(regs) was significantly higher in type 1A diabetes, but not in fulminant type 1 diabetes, than the controls. Further, the proportion of a-T(regs) among CD4(+) FoxP3(+) T cells was significantly higher in patients with type 1A diabetes with detectable C-peptide but not in patients with type 1A diabetes without it and with fulminant type 1 diabetes. A proliferation suppression assay showed that a-T(regs) were functionally impaired both in fulminant type 1 diabetes and in type 1A diabetes. In conclusion, a-T(regs) were functionally impaired, related to residual insulin-secreting capacity and may be associated with the development of type 1 diabetes.

Insights into type 1 diabetes from the autoimmune polyendocrine syndromes

PURPOSE OF REVIEW

Advances in human genetics and investigations in animal models of autoimmune disease have allowed insight into the basic mechanisms of immunologic tolerance. These advances allow us to understand the pathogenesis of type 1 diabetes and other autoimmune diseases as never before. Here, we discuss the tolerance mechanisms of the autoimmune polyendocrine syndromes and their relevance to type 1 diabetes.

RECENT FINDINGS

Defects in central tolerance with alteration of self-antigen expression levels in the thymus are a potent cause of autoimmunity. Peripheral tolerance defects that alter T-cell activation and signaling also play an important role in the pathogenesis of diabetes and other associated autoimmune disorders, with multiple modest defects working in concert to produce disease. Regulation of the immune response through the action of regulatory T cells is a potent mode of tolerance induction in autoimmunity that is important in type 1 diabetes.

SUMMARY

Rare syndromes of autoimmunity provide a valuable window into the breakdown of tolerance and identify multiple checkpoints that are critical for generation of autoimmunity. Understanding the application of these in type 1 diabetes will allow the development of future immunomodulatory therapies in the treatment and prevention of disease.

Genetic polymorphisms of FOXP3 in Italian patients with systemic sclerosis

A case control study to evaluate the possible influence of FOXP3 polymorphisms (rs3761548 and rs2280883) in the susceptibility of systemic sclerosis in an Italian Caucasian population. Subgroup analysis was also performed to test association between these SNPs and specific disease phenotypes. The study groups consisted of 467 individuals: 228 patients (194 with limited cutaneous form and 34 with diffuse cutaneous form of the disease) and 239 healthy control subjects. Genotyping was performed by high resolution melting analysis. Genotype distribution and allele frequency of the FOXP3 polymorphisms were analyzed statistically, using χ(2) or Fisher exact test. Single-marker analysis of allelic and genotype frequencies revealed that SNP rs3761548 was not associated with systemic sclerosis susceptibility. Analysis of genotype and allele distributions of the rs2280883 genetic variant was associated, only in female subjects with systemic sclerosis, its limited subtype, and anti-centromere autoantibodies. Although these findings require replication in a larger set and other populations, FOXP3 rs2280883 may represent a novel susceptibility locus for systemic sclerosis in female subjects.

T helper and regulatory T cell cytokine profile in active, stable and narrow band ultraviolet B treated generalized vitiligo

BACKGROUND

Vitiligo is a T cell mediated autoimmune depigmenting disease. Altered cytokine concentrations have been suggested in the pathogenesis of vitiligo.

METHODS

T helper and regulatory T cell cytokines (IL-2, IFN-γ, IL-10, IL-13, IL-17 and TGF-β) have been estimated by ELISA and their clinical correlation was determined. The study had 3 groups: group I with 80 vitiligo patients (60 active and 20 stable), group II with 25 narrow band ultraviolet B treated vitiligo and group III with 70 healthy controls.

RESULTS

Significant difference was found in the serum interleukin (IL)-10, IL-13, IL-17A and TGF-β1 concentrations among 3 groups (P<0.05). In group I, serum IL-2, IL-17A concentrations were significantly increased and TGF-β1 concentrations were decreased in active vitiligo compared to stable vitiligo (P<0.05). Concentrations of IL-2, IL-10 and IL-13 (rho=-0.307, rho=-0.407, rho=-0.351 and P<0.05; respectively) were negatively- and TGF-β1 concentrations were positively-correlated (rho=0.799, P=0.001) with disease duration. Interleukin-13 concentrations were negatively- and serum TGF-β1 concentrations were positively-correlated (rho=-0.326, rho=0.244 and P<0.05; respectively) with percentage of body surface area involvement.

CONCLUSIONS

Increased concentrations of serum IL-10, IL-13, and IL-17A and decreased concentrations of TGF-β1 suggested altered cell-mediated immunity that may facilitate the melanocyte cytotoxicity in vitiligo.

Impairment of regulatory T cells in myasthenia gravis: studies in an experimental model

Myasthenia gravis (MG) is an antibody mediated, T cell dependent autoimmune disease characterized by muscle fatigability in which autoantibodies directed to the acetylcholine receptor (AChR) impair neuromuscular transmission. The identification of CD4⁺CD25⁺Foxp3⁺Treg cells as important regulators of tolerance opened a major area of investigation raising the possibility that a dysfunction in the Treg compartment is involved in the etiology and pathogenesis of autoimmune diseases, including MG. In this paper we summarize shortly Treg abnormalities that were reported in MG patients and report on our studies of Treg in experimental autoimmune MG (EAMG). Hopefully these studies would pave the way towards the development of novel Treg-based treatment modalities that will restore self-tolerance in MG and other autoimmune diseases. In our previous studies in EAMG we have shown that Treg cells transferred from healthy rat donors to myasthenic rats suppress EAMG. However, Treg cells from sick animals do not have the same in vivo suppressive activity as those from healthy donors. The objective of the present study was to further characterize quantitative and qualitative alterations in Treg cells of rats with EAMG. We found that the frequency of CD4⁺CD25⁺Foxp3⁺Treg cells within the spleen and PBL was decreased in EAMG rats as compared to naïve and CFA-immunized healthy controls. Treg cells from myasthenic rats were less effective than Treg cells from controls in suppressing the proliferation of CD4⁺T effector cells in response to ConA and of B cells in response to LPS. Moreover, CD4⁺CD25⁺ cells from EAMG rats exhibited an elevated extent of apoptosis and expressed upregulated levels of FAS and of Th17-associated cytokines. Since EAMG is an induced disease, these quantitative and qualitative alterations in Treg cells do not reflect predisposing impairments and seem to be associated with the specific autoimmune response resulting from AChR immunization.

Regulatory T cell kinetics in the peripheral blood of patients with Crohn's disease

Estimates of T regulatory cell populations in the periphery of patients with Crohn's disease are confounded by disease activity and concomitant immunotherapeutic agents known to affect T cell proliferation and survival. We performed deuterium pulse/chase experiments in patients with quiescent Crohn's disease on no immunotherapy and healthy control subjects to estimate T regulatory cell kinetics. Quantification of deuterated DNA isolated from T cell subsets over 10 days was determined by mass spectrophotometry. We demonstrate enhanced proliferation within the T regulatory cell population from patients with Crohn's disease when compared to non-T regulatory cells and T regulatory cells from healthy control subjects. We speculate that T regulatory cells isolated from the periphery of patients with Crohn's disease experience persistent antigen stimulation resulting in excess proliferative rates.

Regulatory T-cells in chronic lymphocytic leukemia and autoimmune diseases

Regulatory T-cells (Tregs) constitute a small subset of cells that are actively involved in maintaining self-tolerance, in immune homeostasis and in antitumor immunity. They are thought to play a significant role in the progression of cancer and are generally increased in patient with chronic lymphocytic leukemia (CLL). Their number correlates with more aggressive disease status and is predictive of the time to treatment, as well. Moreover, it is now clear that dysregulation in Tregs cell frequency and/or function may result in a plethora of autoimmune diseases, including multiple sclerosis, type 1 diabetes mellitus, myasthenia gravis, systemic lupus erythematosus, autoimmune lymphoproliferative disorders, rheumatoid arthritis, and psoriasis. Efforts are made aiming to develop approaches to deplete Tregs or inhibit their function in cancer and autoimmune disorders, as well.