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Background: The rare monogenic syndrome Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED) leads to multisystemic autoimmunity with possible lung involvement. Autoimmune pneumonitis is a rare manifestation, with bronchiectasis being the most frequent radiologic pattern, and may lead to fatal outcome. The Sardinian population in Italy has a high incidence of APECED, although no case of lung manifestation has been reported yet in this cohort. This is the case of a Sardinian APECED patient referred to a bronchiectasis clinic. Our aim is to raise awareness and screen these patients earlier for pulmonary involvement and to initiate multidisciplinary treatment for better outcome., Case Presentation: A 49-year-old female native of Sardinia from consanguineous parents was diagnosed with APECED in childhood and was referred to our bronchiectasis clinic in March 2023. In addition to typical APECED features, she reported recurrent respiratory infections since childhood, chronic purulent sputum and a hospitalization for pneumonia. She came to our attention with a recent isolation of P. aeruginosa on sputum culture and diffuse cylindrical and varicoid bronchiectasis on her first CT scan. She underwent aetiologic screening for bronchiectasis with no evidence of another cause of disease. Lung treatment was optimized according to bronchiectasis guidelines, and during follow-up the patient developed methicillin-resistant Staphylococcus aureus (MRSA) infection and M. intracellulare pulmonary disease. The patient was offered P. aeruginosa eradication treatment with intravenous antibiotics and initiation of antimycobacterial therapy., Conclusion: This is the first documented lung involvement case of APECED in a Sardinian patient, and the first patient reported to enter a bronchiectasis program. The patient was prescribed lung imaging late in time when bronchiectasis complications were already present. Our case report highlights the need for early pulmonary screening and multidisciplinary management in patients with APECED., (© 2024. The Author(s).)

Autoimmune adrenal insufficiency (AAI) is a rare disease. This research evaluates three patients with AAI, including autoimmune polyglandular syndrome (APS) type 2. Two patients had APS or AAI during childhood, and one had a history of endocrine autoimmune disease, indicating a possible hereditary basis of the condition. Trio-based exome sequencing and high-resolution HLA typing were employed to analyze patients and their parents. Benign or likely benign variants of the AIRE gene were identified in all participants of the study. These variants, coupled with clinical data and the results of antibody studies to type I interferons, helped to exclude APS-1. Patients with APS-2, in contrast to patient with AAI, inherited distinct variants of unknown significance in the CLEC16A gene, which is associated with autoimmune diseases, including AAI. Various risk alleles in other genes associated with autoimmunity were identified in all patients. HLA typing of class II loci revealed alleles related to APS. Nevertheless, the frequencies of the haplotypes identified are substantial in the healthy Russian population. Immunological tests can detect antibody carriers and assess the risk of autoimmune disease development. In the future, to identify genetic predictors of autoimmune endocrinopathies, it is recommended to analyze the whole genome of patients and their relatives, examining clinically relevant variants in non-coding regions., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Buianova et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Autoimmune polyglandular syndrome (APS) comprises a complex association of autoimmune pathological conditions. APS Type 1 originates from loss-of-function mutations in the autoimmune regulator ( AIRE ) gene. APS2, APS3 and APS4 are linked to specific HLA alleles within the major histocompatibility complex, with single-nucleotide polymorphisms (SNPs) in non-HLA genes also contributing to disease. In general, variability in the AIRE locus and the presence of heterozygous loss-of-function mutations can impact self-antigen presentation in the thymus. In this study, whole-exome sequencing (WES) was performed on a sixteen-year-old female APS3A/B patient to investigate the genetic basis of her complex phenotype. The analysis identified two variants (p.Arg111Trp and p.Thr101Ile) of the hepatitis A virus cell receptor 2 gene (HAVCR2 ) encoding for the TIM-3 (T cell immunoglobulin and mucin domain 3) protein. These variants were predicted, through in silico analysis, to impact protein structure and stability, potentially influencing the patient's autoimmune phenotype. While confocal microscopy analysis revealed no alteration in TIM-3 fluorescence intensity between the PBMCs isolated from the patient and those of a healthy donor, RT-qPCR showed reduced TIM-3 expression in the patient's unfractionated PBMCs. A screening conducted on a cohort of thirty APS patients indicated that the p.Thr101Ile and p.Arg111Trp mutations were unique to the proband. This study opens the pathway for the search of TIM-3 variants possibly linked to complex autoimmune phenotypes, highlighting the potential of novel variant discovery in contributing to APS classification and diagnosis.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a life-threatening monogenic autoimmune disorder primarily caused by biallelic deleterious variants in the autoimmune regulator ( AIRE ) gene. We prospectively evaluated 104 patients with clinically diagnosed APECED syndrome and identified 17 patients (16%) from 14 kindreds lacking biallelic AIRE variants in exons or flanking intronic regions; 15 had Puerto Rican ancestry. Through whole-genome sequencing, we identified a deep intronic AIRE variant (c.1504-818 G>A) cosegregating with the disease in all 17 patients. We developed a culture system of AIRE -expressing primary patient monocyte-derived dendritic cells and demonstrated that c.1504-818 G>A creates a cryptic splice site and activates inclusion of a 109-base pair frame-shifting pseudoexon. We also found low-level AIRE expression in patient-derived lymphoblastoid cell lines (LCLs) and confirmed pseudoexon inclusion in independent extrathymic AIRE -expressing cell lines. Through protein modeling and transcriptomic analyses of AIRE -transfected human embryonic kidney 293 and thymic epithelial cell 4D6 cells, we showed that this variant alters the carboxyl terminus of the AIRE protein, abrogating its function. Last, we developed an antisense oligonucleotide (ASO) that reversed pseudoexon inclusion and restored the normal AIRE transcript sequence in LCLs. Thus, our findings revealed c.1504-818 G>A as a founder APECED-causing AIRE variant in the Puerto Rican population and uncovered pseudoexon inclusion as an ASO-reversible genetic mechanism underlying APECED.

Purpose of Review: The purpose of the review is to describe the most recent advancement in understanding of the pivotal role of autoimmune regulator ( AIRE ) gene expression in central and peripheral tolerance, and the implications of its impairment in the genetic and pathogenesis of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) manifestations with insight into possible treatment options., Recent Findings: AIRE gene expression has an important role of central and peripheral tolerance. Different AIRE gene mutations cause APECED, whereas polymorphisms and some variants may be implicated in development of other more frequently autoimmune diseases. Impaired negative T cell selection, reduction of T regulatory function, altered germinal center response, activated B cells and production of autoantibodies explain the development of autoimmunity in APECED. Recent data suggest that an excessive interferon-γ response may be the primer driver of the associated organ damage. Therefore, Janus kinase (JAK)-inhibitors may be promising therapies for treatment of broad spectrum of manifestations., Summary: AIRE has a pivotal role in immune tolerance. Disruption of this delicate equilibrium results in complex immune perturbation, ranging from severe autoimmunity, like APECED, to more common organ-specific disorders. Therefore, a deeper understanding of the correlation between AIRE function and clinical phenotype is warranted given the potential translational implication in clinical practice., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Autoimmune polyendocrine syndrome type 1 (APS-1) is a life-threatening, autosomal recessive syndrome caused by autoimmune regulator (AIRE) deficiency. In APS-1, self-reactive T cells escape thymic negative selection, infiltrate organs, and drive autoimmune injury. The effector mechanisms governing T-cell-mediated damage in APS-1 remain poorly understood., Methods: We examined whether APS-1 could be classified as a disease mediated by interferon-γ. We first assessed patients with APS-1 who were participating in a prospective natural history study and evaluated mRNA and protein expression in blood and tissues. We then examined the pathogenic role of interferon-γ using Aire -/- Ifng -/- mice and Aire -/- mice treated with the Janus kinase (JAK) inhibitor ruxolitinib. On the basis of our findings, we used ruxolitinib to treat five patients with APS-1 and assessed clinical, immunologic, histologic, transcriptional, and autoantibody responses., Results: Patients with APS-1 had enhanced interferon-γ responses in blood and in all examined autoimmunity-affected tissues. Aire -/- mice had selectively increased interferon-γ production by T cells and enhanced interferon-γ, phosphorylated signal transducer and activator of transcription 1 (pSTAT1), and CXCL9 signals in multiple organs. Ifng ablation or ruxolitinib-induced JAK-STAT blockade in Aire -/- mice normalized interferon-γ responses and averted T-cell infiltration and damage in organs. Ruxolitinib treatment of five patients with APS-1 led to decreased levels of T-cell-derived interferon-γ, normalized interferon-γ and CXCL9 levels, and remission of alopecia, oral candidiasis, nail dystrophy, gastritis, enteritis, arthritis, Sjögren's-like syndrome, urticaria, and thyroiditis. No serious adverse effects from ruxolitinib were identified in these patients., Conclusions: Our findings indicate that APS-1, which is caused by AIRE deficiency, is characterized by excessive, multiorgan interferon-γ-mediated responses. JAK inhibition with ruxolitinib in five patients showed promising results. (Funded by the National Institute of Allergy and Infectious Diseases and others.)., (Copyright © 2024 Massachusetts Medical Society.)

Background: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED, also called APS-1) is an inborn error of immunity with clear signs of B-cell autoimmunity such as neutralizing anti-IFN antibodies. In APECED, mutations in the AIRE gene impair thymic negative selection of T cells. The resulting T-cell alterations may then cause dysregulation of B-cell responses. However, no analysis of interactions of T and B cells in the germinal centers (GCs) in patients' secondary lymphatic tissues has been reported., Objective: This study examined the relationship between B cells and follicular T helper cells (TfH) in peripheral blood and lymph node (LN) GCs in patients with APECED., Methods: Immunophenotyping of peripheral blood B cells and TfH was performed for 24 patients with APECED. Highly multiplexed fluorescent immunohistochemical staining was performed on 7 LN biopsy samples from the patients to study spatial interactions of lymphocytes in the GCs at the single-cell level., Results: The patients' peripheral B-cell phenotype revealed skewing toward a mature B-cell phenotype with marked loss of transitional and naive B cells. The frequency of circulating TfH cells was diminished in the patients, while in the LNs the TfH population was expanded. In LNs the overall frequency of Treg cells and interactions of Treg cells with nonfollicular T cells were reduced, suggesting that aberrant Treg cell function might fail to restrain TfH differentiation., Conclusions: GC reactions are disrupted in APECED as a result of defective T-cell control., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

In the past 2 decades, a significant number of studies have been published describing the molecular and clinical aspects of immune dysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome. These studies have refined our knowledge of this rare yet prototypic genetic autoimmune disease, advancing the diagnosis, broadening the clinical spectrum, and improving our understanding of the underlying immunologic mechanisms. Despite these advances, Forkhead box P3 mutations have devastating consequences, and treating patients with IPEX syndrome remains a challenge, even with safer strategies for hematopoietic stem cell transplantation and gene therapy becoming a promising reality. The aim of this review was to highlight novel features of the disease to further advance awareness and improve the diagnosis and treatment of patients with IPEX syndrome., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

FOXP3 gene is a key transcription factor driving immune tolerance and its deficiency causes immune dysregulation, polyendocrinopathy, enteropathy X-linked syndrome (IPEX), a prototypic primary immune regulatory disorder (PIRD) with defective regulatory T (Treg) cells. Although life-threatening, the increased awareness and early diagnosis have contributed to improved control of the disease. IPEX currently comprises a broad spectrum of clinical autoimmune manifestations from severe early onset organ involvement to moderate, recurrent manifestations. This review focuses on the mechanistic advancements that, since the IPEX discovery in early 2000, have informed the role of the human FOXP3+ Treg cells in controlling peripheral tolerance and shaping the overall immune landscape of IPEX patients and carrier mothers, contributing to defining new treatments., (© 2023 The Authors. Immunological Reviews published by John Wiley & Sons Ltd.)

The immune regulator gene AIRE plays an essential role in the establishment of immune tolerance and the prevention of autoimmunity. This transcription factor plays a critical role in promoting self-tolerance in the thymus by regulating the expression of a large number of self-antigens that share the common feature of being tissue-restricted in their expression pattern in the periphery. Dysfunction of AIRE in humans causes a rare disease, autoimmune polyglandular syndrome type 1 (APS1), characterized by an autoimmune response against peripheral tissues, particularly endocrine tissues. Although a few dominant mutations have been described, the inactivation of AIRE is usually caused by recessive mutations. Recent data suggests that alterations in AIRE function contribute not only to APS1 but also to more common forms of autoimmune disease. Here, we present a previously unreported missense mutation (NM_000383.2:c.260 T > C) in exon 2 of the AIRE gene, predicted to cause the substitution (p.(Leu87Pro)) in the CARD domain of the AIRE protein. When inherited in conjunction with another dysfunctional AIRE allele, this mutation was associated with immune dysregulation in a pediatric patient. The presence of hypergammaglobulinemia, malabsorption syndrome, ectodermal dysplasia, mucocutaneous candidiasis, vitiligo, and hypothyroidism as well as the presence of multiple autoantibodies allowed us to confirm an APS1 diagnosis., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Chronic keratoconjunctivitis is a rare presentation of autoimmune polyglandular syndrome type 1 (APS-1) during the first year of life. Herein, We report a case of a 10-month-old baby girl with chronic bilateral keratoconjunctivitis, corneal scarring and neovascularization that was treated initially with topical immunosuppressants., Methods: Detailed ophthalmological assessment followed by molecular testing using whole exome sequencing., Results: In addition to the severe chronic bilateral keratoconjunctivitis, corneal scarring and neovascularization, patient weight was found to be low than 10th percentile. Further genetic testing revealed autoimmune regulator (AIRE) gene variant that was only reported once in the literature confirming the diagnosis of APS-1. Further workup detected hypoparathyroidism that was treated with calcium supplementation., Conclusion: Our case represents the importance of multidisciplinary services and highlights the role of genetic testing in diagnosing such syndromic cases. We reviewed previous reports and found that available treatment for ocular involvement is usually nonsatisfactory; however, early detection and referral by ophthalmologists could result in treating previously undetected endocrine disorders that can be life threatening if left untreated.

One of the difficulties in studying the pathogenesis of autoimmune diseases is that the disease is multifactorial involving sex, age, MHC, environment, and some genetic factors. Because deficiency of Aire, a transcriptional regulator, is an autoimmune disease caused by a single gene abnormality, Aire is an ideal research target for approaching the enigma of autoimmunity, e.g., the mechanisms underlying Aire deficiency can be studied using genetically modified animals. Nevertheless, the exact mechanisms of the breakdown of self-tolerance due to Aire's dysfunction have not yet been fully clarified. This is due, at least in part, to the lack of information on the exact target genes controlled by Aire. State-of-the-art research infrastructures such as single-cell analysis are now in place to elucidate the essential function of Aire. The knowledge gained through the study of Aire-mediated tolerance should help our understanding of the pathogenesis of autoimmune disease in general., (© 2024. The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.)

Autoimmune-polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a monogenic inborn error of autoimmunity that is caused by damaging germline variants in the AIRE gene and clinically manifests with multiple autoimmune diseases in patients. Studies on the function of the AIRE gene, discovered in 1997, have contributed to fundamental aspects of human immunology as they have been important in understanding the basic mechanism of immune balance between self and non-self. This chapter looks back to the discovery of the AIRE gene, reviews its main properties, and discusses the key findings of its function in the thymus. However, more recent autoantibody profilings in APECED patients have highlighted a gap in our knowledge of the disease pathology and point to the need to revisit the current paradigm of AIRE function. The chapter reviews these new findings in APECED patients, which potentially trigger new thoughts on the mechanism of immune tolerance., (© 2024. The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.)

Background: Autoimmunity can be the first or predominant manifestation in patients with primary immunodeficiency disorder, also known as inborn errors of immunity (IEI). This study aims to evaluate the immune status of pediatric patients with polyautoimmunity to identify those with underlying immune defects., Methods: In this cross-sectional study, pediatric patients with polyautoimmunity including at least one confirmed autoimmune endocrine disease were enrolled. Demographic and clinical data were collected using a questionnaire based on medical records and direct family interviews. For each patient, a basic immunologic evaluation was performed. The clinical diagnosis was established according to the criteria of the European Society for Immunodeficiencies (ESID). Based on the presence or absence of a history of severe and/or recurrent infections, patients were divided into two groups for comparison., Results: Thirty-nine patients, 18 males (46.2%) and 21 females (53.8%), were included. Fourteen patients (35.9%) had consanguineous parents. Fifteen patients (38.5%) had a history of severe and/or recurrent infections. The median (interquartile range: IQR) age of our patients at the time of evaluation was 11.1 (9-16) years. The median (IQR) age at the onset of infections and autoimmunities were 3 (1-10.8) and 5 (2.6-8) years, respectively. The most common infectious complications reported were pneumonia and candidiasis, each in 12.8% of the patients. The most prevalent autoimmune disorders were type 1 diabetes (74.3%) and autoimmune thyroiditis (58.9%). IEI was diagnosed in six patients (15.38%), five of which were from the group with severe or recurrent infections: three with selective IgA deficiency, two with common variable immunodeficiency (CVID), and one with immune dysregulation, polyendocrinopathy, enteropathy, Xlinked (IPEX), but without a history of infections., Conclusion: The occurrence of early onset polyautoimmunity in association with severe and/or recurrent infections or in patients with a positive family history should be a warning sign for physicians to initiate an evaluation for possible immunodeficiency disorders to prevent complications through early treatment., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Studies of the monogenic autoimmune disease immunodysregulation polyendocrinopathy enteropathy X-linked syndrome (IPEX) have elucidated the essential function of the transcription factor FOXP3 and thymic-derived regulatory T cells (T regs ) in controlling peripheral tolerance. However, the presence and the source of autoreactive T cells in IPEX remain undetermined. Here, we investigated how FOXP3 deficiency affects the T cell receptor (TCR) repertoire and T reg stability in vivo and compared T cell abnormalities in patients with IPEX with those in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED). To study T regs independently of their phenotype and to analyze T cell autoreactivity, we combined T reg -specific demethylation region analyses, single-cell multiomic profiling, and bulk TCR sequencing. We found that patients with IPEX, unlike patients with APECED, have expanded autoreactive T cells originating from both autoreactive effector T cells (T effs ) and T regs . In addition, a fraction of the expanded T regs from patients with IPEX lost their phenotypic and functional markers, including CD25 and FOXP3. Functional experiments with CRISPR-Cas9-mediated FOXP3 knockout T regs and T regs from patients with IPEX indicated that the patients' T regs gain a T H 2-skewed T eff -like function, which is consistent with immune dysregulation observed in these patients. Analyses of FOXP3 mutation-carrier mothers and a patient with IPEX after hematopoietic stem cell transplantation indicated that T regs expressing nonmutated FOXP3 prevent the accumulation of autoreactive T effs and unstable T regs . These findings could be directly used for diagnostic and prognostic purposes and for monitoring the effects of immunomodulatory treatments.

Autoimmune polyendocrine syndrome type-1 (APS-1) is caused by mono- or biallelic loss-of-function variants of the autoimmune regulator gene AIRE underlying early-onset multiorgan autoimmunity and the production of neutralizing autoantibodies against cytokines, accounting for mucosal candidiasis and viral diseases. Medical intervention is essential to prevent or attenuate autoimmune manifestations. Ruxolitinib is a JAK inhibitor approved for use in several autoimmune conditions. It is also used off-label to treat autoimmune manifestations of a growing range of inborn errors of immunity. We treated three APS-1 patients with ruxolitinib and followed them for at least 30 months. Tolerance was excellent, with no medical or biological adverse events. All three patients had remarkably positive responses to ruxolitinib for alopecia, nail dystrophy, keratitis, mucosal candidiasis, steroid-dependent autoimmune hepatitis, exocrine pancreatic insufficiency, renal potassium wasting, hypoparathyroidism, and diabetes insipidus. JAK inhibitors were therefore considered an effective treatment in three patients with APS-1. Our observations suggest that JAK/STAT pathways are involved in the pathogenesis of APS-1 autoimmune manifestations. They also suggest that JAK inhibitors should be tested in a broader range of APS-1 patients., (© 2023. The Author(s).)

Purpose: Autoimmune polyglandular syndrome Type 1 (APS-1) is a rare autosomal recessive disorder caused by defects in the autoimmune regulator (AIRE) gene. Patients are generally diagnosed at ages between five and fifteen years when they exhibit three or more manifestations, most typically mucocutaneous candidiasis, autoimmune Addison's disease, and hypoparathyroidism. Our study aims to report the first case of a Chinese APS-1 patient, presented with LCA as the initial and essential clinical feature of this rare syndrome., Methods: Detailed medical and family history were recorded for the patient. Also, the comprehensive ophthalmological examinations were conducted. Whole exome sequencing (WES) was applied to screen pathogenic variants. Sanger sequencing validation and segregation analysis were further performed for confirmation., Results: A 3-year-old boy with severely impaired vision and initially referred as LCA. However, with a detailed history review, oral candidiasis, dental enamel hypoplasia, and nail candida infection were revealed. Moreover, genetic analysis revealed the homozygous c.769C>T (p.R257X) in AIRE gene (NM_000383.3) as the causative variant., Conclusion: We presented one case diagnosed with APS-1 based on clinical characteristics and genetic analysis. Our study demonstrated that LCA could serve as a warning sign for APS-1 and a potential trigger of early screening, which might prevent life-threatening complications., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Autoimmune polyglandular syndromes (APS) are a heterogeneous group of clinical conditions characterized by functional impairment of multiple endocrine glands due to loss of central or peripheral immune tolerance. These syndromes are also often accompanied by autoimmune damage to non-endocrine organs. Taking into account the wide range of components and variants of the disease, APS is usually divided into a rare juvenile type (APS 1) and a more common adult type (APS 2-4). APS type 1 is caused by a monogenic mutation, while APS types 2-4 have a polygenic mode of inheritance. One subtype of adult APS (APS 3D) is characterized by a combination of autoimmune thyroid disease and autoimmune rheumatic disease. This review considers the available literature data on combinations that meet the above criteria. Many studies have noted a significantly higher prevalence of rheumatic diseases in patients with autoimmune thyroid disease compared with the control group. Also, as in a number of rheumatic diseases, a more frequent occurrence of autoimmune thyroiditis, primary hypothyroidism and Graves' disease was noted.

Autoimmune polyendocrine syndrome type 1 (APS-1) is caused by mutations in the autoimmune regulator (AIRE) gene. Most patients present with severe chronic mucocutaneous candidiasis and organ-specific autoimmunity from early childhood, but the clinical picture is highly variable. AIRE is crucial for negative selection of T cells, and scrutiny of different patient mutations has previously highlighted many of its molecular mechanisms. In patients with a milder adult-onset phenotype sharing a mutation in the canonical donor splice site of intron 7 (c.879+1G>A), both the predicted altered splicing pattern with loss of exon 7 (AireEx7-/-) and normal full-length AIRE mRNA were found, indicating leaky rather than abolished mRNA splicing. Analysis of a corresponding mouse model demonstrated that the AireEx7-/- mutant had dramatically impaired transcriptional capacity of tissue-specific antigens in medullary thymic epithelial cells but still retained some ability to induce gene expression compared with the complete loss-of-function AireC313X-/- mutant. Our data illustrate an association between AIRE activity and the severity of autoimmune disease, with implications for more common autoimmune diseases associated with AIRE variants, such as primary adrenal insufficiency, pernicious anemia, type 1 diabetes, and rheumatoid arthritis.

Homozygous mutations in the autoimmune regulator (AIRE) gene that cripple thymic negative selection of autoreactive T cells result in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). However, how AIRE regulates the T-cell response against foreign pathogens is not well understood. Here, we observed comparable primary CD8 + T cells but a markedly reduced memory T-cell population and protective function in Aire -/- mice compared with wild-type after infection with a strain of recombinant Listeria monocytogenes. In adoptive transfer models, exogenous congenic CD8 + T cells transferred into Aire -/- mice also showed a reduction in the memory T-cell population, indicating an important role for extrathymic Aire-expressing cells in shaping or sustaining memory T cells. Moreover, using a bone marrow chimeric model, we found that Aire expressed in radioresistant cells plays an important role in maintaining the memory phenotype. These results provide important insights into the role of extrathymic Aire in the T-cell response to infection., (© 2023 Federation of European Biochemical Societies.)

In the last 20 years, discoveries about the autoimmune regulator (AIRE) protein and its critical role in immune tolerance have provided fundamental insights into understanding the molecular basis of autoimmunity. This review provides a comprehensive overview of the effect of AIRE on immunological tolerance and the characteristics of autoimmune diseases in Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED), which is caused by biallelic AIRE mutations. A better understanding of the immunological mechanisms of AIRE deficiency may enlighten immune tolerance mechanisms and new diagnostic and treatment strategies for autoimmune diseases. Considering that not all clinical features of APECED are present in a given follow-up period, the diagnosis is not easy in a patient at the first visit. Longer follow-up and a multidisciplinary approach are essential for diagnosis. It is challenging to prevent endocrine and other organ damage compared with other diseases associated with multiple autoimmunities, such as FOXP3, LRBA, and CTLA4 deficiencies. Unfortunately, no curative therapy like haematopoietic stem cell transplantation or specific immunomodulation is present that is successful in the treatment., (© 2023 The Scandinavian Foundation for Immunology.)

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is a multisystemic rare genetic disorder characterised by abnormalities of the immune system. We report the ocular features of APECED in two siblings of an Indian family, out of four who are still living. The ocular features of this disorder primarily included madarosis, refractive error, heterochromia, corneal opacity and peripheral retinal pigment epithelium degeneration. There is marked phenotypical heterogeneity in this disorder. We found differences even between monozygotic twins. While one of the twins did not have any ocular issues, the other one did. The child with corneal involvement was the most symptomatic; however, it did not lead to visual impairment. On genetic workup, homozygous p.M1V mutation was found in exon 1 of AIRE gene that has not been studied in Indian subjects with APECED. To the best of our knowledge, there is no report in literature describing ocular features of APECED in an Indian family with distinctive genetic involvement., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome is a rare monogenic disease determined by biallelic mutations in AIRE gene, which encodes a transcription factor essential for central immune tolerance. Classic diagnosis is determined by the presence of two of the main APECED clinical diseases: chronic mucocutaneous candidiasis, chronic hypoparathyroidism, and Addison's disease. Non-endocrine autoimmunity, involving the liver, intestine, eyes, and kidneys, is generally reported in a minority of European patients, while American APECED patients have a higher tendency of developing organ-specific non-endocrine manifestations early in life. This observation led to the revision of the diagnostic criteria to permit earlier diagnosis based on the appearance of one classic triad symptom or one non-classical manifestation at a young age in the presence of IFNωAbs or AIRE mutations (Ferre-Lionakis criteria)., Patients and Methods: We analyzed the clinical, genetic, and autoantibody (Ab) profiles in a series of 14 pediatric Italian APECED patients with gastrointestinal manifestations (seven male and seven female patients). Ten patients presented hepatitis (APECED-associated hepatitis (APAH)), while seven were affected by constipation, diarrhea, and malabsorption. Four patients had developed APAH before classic triad symptoms., Results: Based on the age of appearance of non-endocrine manifestations including APAH and gastro-enteropathy, the Ferre-Lionakis criteria would have allowed an expedited diagnosis in 11/14 patients. Abs to tryptophan hydroxylase (TPHAb) and hepatic aromatic l-amino acid decarboxylase (AADC) were significantly associated with APECED patients of the present series. Abs to cP4501A2 were detectable in the serum of 4/8 patients with APAH, and Abs to cP4502A6 were detectable in 3/8 patients. AADC Abs tested positive in 5/7 patients, which is indicative of gastrointestinal dysfunction in APECED and TPHAb in 5/7 patients with gastrointestinal dysfunction. IFNAb was significantly associated with the syndrome., Conclusion: Although Ferre-Lionakis expanded criteria applied to the American cohorts of APECED patients would require validation in independent large cohorts of European patients, the results of this study emphasize the importance to evaluate the presence and the age of appearance of APAH and autoimmune enteropathy even in European cohorts for an earlier APECED diagnosis. An earlier APECED diagnosis would also allow the prevention of episodes of life-threatening hypocalcemic seizures and adrenal crisis, which are the main manifestations of undiagnosed APECED., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Paldino, Faienza, Cappa, Pietrobattista, Capalbo, Valenzise, Lampasona, Cudini, Carbone, Pagliarosi, Maggiore, Salerno, Betterle and Fierabracci.)

Autoimmune polyendocrine syndrome type-1 (APS1) is characterized by autoimmune manifestations affecting different organs from early childhood on. Immunological abnormalities, the resulting endocrinopathies, and their treatments may compromise bone health. For the first time in APS1, we analyzed transiliac bone biopsy samples by bone histomorphometry and quantitative backscattered electron imaging in three adult patients (female P1, 38 years; male P2, 47 years; male P3, 25 years). All had biallelic mutations in the autoimmune regulator gene and in addition to endocrinopathies, also significant bone fragility. Histomorphometry showed bone volume in the lower normal range for P1 (BV/TV, - 0.98 SD) and P3 (- 1.34 SD), mainly due to reduced trabecular thickness (TbTh, - 3.63 and - 2.87 SD). In P1, osteoid surface was low (OS/BS, - 0.96 SD); active osteoblasts and double labeling were seen only on cortical bone. P3 showed a largely increased bone turnover rate (BFR/BV, + 4.53 SD) and increased mineralization lag time (Mlt, + 3.40 SD). Increased osteoid surface (OS/BS, + 2.03 and + 4.71 SD for P2 and P3) together with a large proportion of lowly mineralized bone area (Trab CaLow, + 2.22 and + 9.81 SD for P2 and P3) and focal mineralization defects were consistent with abnormal mineralization. In all patients, the density and area of osteocyte lacunae in cortical and trabecular bone were similar to healthy adults. The bone tissue characteristics were variable and included decreased trabecular thickness, increased amount of osteoid, and abnormal mineralization which are likely to contribute to bone fragility in patients with APS1., (© 2023. The Author(s).)

Autoimmune polyendocrine syndrome type I (APS-1) is caused by mutations in the autoimmune regulator (AIRE) gene and characterised clinically by multiple autoimmune manifestations and serologically by autoantibodies against tissue proteins and cytokines. We here hypothesised that lack of AIRE expression in thymus affects blood immune cells and performed whole-blood microarray analysis (N = 16 APS-I patients vs 16 controls), qPCR verification, and bioinformatic deconvolution of cell subsets. We identified B cell responses as being downregulated in APS-1 patients, which was confirmed by qPCR; these results call for further studies on B cells in this disorder. The type I interferon (IFN-I) pathway was also downregulated in APS-1, and the presence of IFN antibodies is the likely reason for this mild overall downregulation of the IFN-I genes in most APS-1 patients., (© 2023 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Purpose: Biallelic loss-of-function mutations of AIRE cause the autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome. However, single nucleotide mutations may cause a milder phenotype. In this paper, we describe an unusual and mild phenotype in a mother and her two children (son and daughter) who carry a rare heterozygous mutation of AIRE., Methods and Results: The son presented with alopecia and subclinical hypothyroidism due to Hashimoto's Thyroiditis (HT); the daughter had alopecia, vaginal mycosis, stomach pains and subclinical hypothyroidism due to HT; and the mother had alopecia, vaginal mycosis and stomach pains. Organ- and non-organ-specific autoantibodies were evaluated as well as antibodies against interleukin-17A, -17F, -22 (IL-Abs) and interferon -α and -ω (IFN-Abs). The organ- and non-organ-specific autoantibodies screening was negative in the son, while the daughter was positive for liver-kidney microsomal antibodies (LKMAbs) and the mother was positive for glutamic acid decarboxylase antibodies (GADAbs). Daughter and mother were also positive for IFN-Abs. Analysis of the AIRE gene identified a rare heterozygous R203X mutation in all three family members., Conclusions: We describe for a first time a family with heterozygous R203X AIRE mutation causing an APECED-like condition, as confirmed by presence of IFN-Abs. The unusual mild phenotype should be reassuring for the patients and assist in their clinical management., (© 2022. The Author(s), under exclusive licence to Italian Society of Endocrinology (SIE).)

Immune dysregulation, polyendocrinopathy, enteropathy, and X-linked, known as IPEX syndrome, is a rare heterogeneous condition. Zhu-Tokita-Takenouchi-Kim Syndrome (ZTTK) is an autosomal dominant condition arising from a mutation in the SON gene, which is involved in mRNA splicing. A case showing interactions of mutations in these two genes is described in which both conditions become non-typical., (© 2022. The Author(s), under exclusive licence to Institute of Plant Genetics Polish Academy of Sciences.)

Problem: Autoimmune polyendocrinopathy-candidiasis- ectodermal dystrophy (APECED) pathology due to autoimmune regulator (AIRE) gene mutations leads to loss of central tolerance triggering immune attack, a factor causing infertility. One of the targets of autoimmune attack is ovary and its repercussion results in polycystic ovarian syndrome (PCOS). Although reduced Tregs have been reported in PCOS, a lacunae exists on the status of AIRE gene expression and its role in treg insufficiency via HIF1A-FOXP3 axis in PCOS., Method of Study: This is a case-control cohort study recruiting 40 normal and 40 PCOS volunteers for peripheral blood sample collection and PCOS diagnoses were based on Rotterdam Consensus criteria. AIRE and HIF1A expression status was analysed by qRT PCR and western blot. FACS analyses was conducted on AIRE silenced peripheral blood mononuclear cells (PBMCs) after Treg induction., Results: Our results indicate a reduced AIRE (fold change log2 (RQ) = -2.6, P < .01) and increased HIF1A (fold change log2 (RQ) = 3.6, P < .02) in PBMCs of PCOS subjects compared to age-matched controls. Western blot of AIRE and HIF1A corroborates with qRT PCR data. Our CHIP data demonstrate AIRE mediated HIF1A promoter regulation. Silencing of AIRE in PBMCs contributes to the upregulation of HIF1A transcripts by two-fold (P < .0015) and downregulation in FOXP3 expression by three-fold (P < .0017). FACS analyses revealed that silencing of AIRE reduces Tcell to Treg conversion., Conclusions: Our consolidated results derive a new connection among AIRE-HIF1A-FOXP3 with AIRE reduction enabling increased HIF1A resulting in reduced FOXP3 in PBMCs of PCOS patients leading to Treg insufficiency., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Multiple endocrine neoplasia type 2A (MEN2A) is caused by germline pathogenic variants in the RET proto-oncogene and is characterized by medullary thyroid cancer (MTC), pheochromocytoma, and hyperparathyroidism. Autoimmune polyendocrine syndromes (APS) are defined as multiple endocrine gland insufficiency associated with loss of immune tolerance. APS type 2 (APS-2) consists of at least two of the following diseases: type 1 diabetes mellitus (T1DM), autoimmune thyroid disease, and Addison's disease. We describe the clinical, molecular, and biochemical findings of MEN2A, APS-2, and Kabuki syndrome (KS) in a 16-year-old male. Whole exome sequencing was performed to identify the genetic cause of the pheochromocytoma and syndromic features including facial dysmorphism, developmental delay, and epilepsy. RET pathogenic variant and KMT2D pathogenic variant were identified, and he was diagnosed with MEN2A and KS. This is the first case of association between MEN2 and APS in adolescence and the second proven case in humans. In addition, this is the first report of MEN2 and APS in KS.

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is an early onset systemic autoimmune genetic disorder caused by mutation of the forkhead box protein 3 (FOXP3) gene. Enteropathy, endocrinopathy and skin manifestations are considered the classic triad of IPEX syndrome. However, patients with IPEX syndrome display a variety of phenotypes including life threatening multi-organ autoimmunity. Here, we present the case of two siblings with IPEX syndrome with the same hemizygous mutation, but with different types of symptomology at onset of the disease.

Background: Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare disorder of the immune regulatory system caused by forkhead box P3 ( FOXP3 ) mutations. Abnormal numbers or functions of regulatory T (Treg) cells account for the various autoimmune symptoms. We aimed to explore the molecular genetics and phenotypic spectra of patients with atypical IPEX syndrome in China., Methods: We analyzed the molecular, clinical and immune phenotype characteristics of five Chinese patients with FOXP3 mutations., Results: We summarized the molecular and phenotypic features of five patients with FOXP3 mutations, including two novel mutations. Four of the five patients displayed atypical phenotypes, and one developed immune-related peripheral neuropathy. Three of the five patients showed normal frequencies of Treg cells, but the proportions of subsets of Treg cells, CD4 + T cells and B cells were out of balance., Conclusions: Our report broadens the understanding of the clinical features of atypical IPEX syndrome. Our detailed analyses of the immunological characteristics of these patients enhance the understanding of the possible mechanisms underlying the clinical manifestations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Huang, Fang, Zeng, Chen, Yang, Sun, Dai, An, Tang, Dou, Zhao and Zhou.)

Autoimmune polyendocrine syndrome type 1 (APS-1) is an autosomal recessive hereditary pathology that develops with endocrine and non-endocrine manifestations in childhood. The classic triad of APS-1 includes chronic candidiasis of the skin and mucous membranes, adrenal insufficiency, and hypoparathyroidism. APS-1 is often accompanied by hypogonadism, type 1 diabetes, autoimmune thyroiditis, vitiligo, alopecia, asplenia, pneumonitis, gastritis, pernicious anemia, and intestinal dysfunction, nephritis, and hepatitis. The prevalence rate is highest in genetically isolated populations (up to 1:6500-1:9000). APS-1 occurs because of mutations in the autoimmune regulator (AIRE) gene, leading to a disrupted mechanism of normal antigen expression, the formation of abnormal clones of immune cells, and autoimmune damage to various organs. Analysis of the AIRE gene is the main diagnostic method for early detection of APS-1 and the choice of methods for its treatment. Timely genetic counseling makes it possible to identify the disease early, prescribe appropriate treatment and prevent serious complications. This paper analyzes scientific information characterizing clinical manifestations of autoimmune polyendocrine syndrome type 1 in association with its pathogenetic features, epidemiology, and current management., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Patients with loss of function in the gene encoding the master regulator of central tolerance AIRE suffer from a devastating disorder called autoimmune polyendocrine syndrome type 1 (APS-1), characterized by a spectrum of autoimmune diseases and severe mucocutaneous candidiasis. Although the key mechanisms underlying the development of autoimmunity in patients with APS-1 are well established, the underlying cause of the increased susceptibility to Candida albicans infection remains less understood. Here, we show that Aire + MHCII + type 3 innate lymphoid cells (ILC3s) could sense, internalize and present C. albicans and had a critical role in the induction of Candida-specific T helper 17 (T H 17) cell clones. Extrathymic Rorc-Cre-mediated deletion of Aire resulted in impaired generation of Candida-specific T H 17 cells and subsequent overgrowth of C. albicans in the mucosal tissues. Collectively, our observations identify a previously unrecognized regulatory mechanism for effective defense responses against fungal infections., (© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background: Autoimmune disease, including autoimmune thyroid disease, with uncharacteristic symptoms can be due to additional severe disease. We report a life-threatening debut of autoimmune polyglandular syndrome type II (APS II) defined as Addison's disease combined with autoimmune diabetes and/or thyroid disease., Patient Findings: A 33-year-old male with newly diagnosed hypothyroidism was referred to a tertiary center due to fatigue and 20-kg rapid weight loss. Malignancy was excluded. After a gastroscopy, he developed Addison's crisis; he was admitted to our hospital and stabilized. Final diagnoses included Hashimoto's thyroiditis, Addison's disease, vitiligo, and pernicious anemia. Whole genome sequencing found no genetic variants associated with component diseases. Human leukocyte antigen typing revealed DR3/DR4 and DQ8/DQ2 heterozygosity associated with APS II. A patient with Hashimoto's thyroiditis and weight loss presented with Addison's crisis and was diagnosed with APS II., Conclusions: Awareness of potential polyautoimmunity in clinical evaluation of patients with thyroid disease improves diagnosis and can be lifesaving., (© 2022. The Author(s).)

Objective: The autoimmune polyendocrine syndrome type 1 (APS-1) is an autosomal recessive disorder characterised by immune dysregulation and autoimmune endocrine gland destruction. APS-1 is caused by biallelic mutations affecting the autoimmune regulator (AIRE) gene on chromosome 21q22.3, which facilitates immunological self-tolerance. The objective was to investigate >300 probands with suspected APS-1 or isolated hypoparathyroidism for AIRE abnormalities., Methods: Probands were assessed by DNA sequence analysis. Novel variants were characterised using 3D modelling of the AIRE protein. Restriction enzyme and microsatellite analysis were used to investigate for uniparental isodisomy., Results: Biallelic AIRE mutations were identified in 35 probands with APS-1 and 5 probands with isolated hypoparathyroidism. These included a novel homozygous p.(His14Pro) mutation, predicted to disrupt the N-terminal caspase activation recruitment domain of the AIRE protein. Furthermore, an apparently homozygous AIRE mutation, p.Leu323fs, was identified in an APS-1 proband, who is the child of non-consanguineous asymptomatic parents. Microsatellite analysis revealed that the proband inherited two copies of the paternal mutant AIRE allele due to uniparental isodisomy. Hypoparathyroidism was the most common endocrine manifestation in AIRE mutation-positive probands and >45% of those harbouring AIRE mutations had at least two diseases out of the triad of candidiasis, hypoparathyroidism, and hypoadrenalism. In contrast, type 1 diabetes and hypothyroidism occurred more frequently in AIRE mutation-negative probands with suspected APS-1. Around 30% of AIRE mutation-negative probands with isolated hypoparathyroidism harboured mutations in other hypoparathyroid genes., Conclusions: This study of a large cohort referred for AIRE mutational analysis expands the spectrum of genetic abnormalities causing APS-1.

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare genetic disorder that typically presents in the first year of life with severe diarrhea, autoimmune endocrine disorder, and inflammatory dermatitis, most commonly an eczematous dermatitis. IPEX syndrome is caused by variants in the FOXP3 gene leading to dysregulation of T-regulatory (Treg) cells and an aberrant immune response. Here, we present a case of severe IPEX syndrome diagnosed following whole genome sequencing (WGS) in a 2-week-old boy with bloody mucoid diarrhea, failure to thrive, and a diffuse eczematous dermatitis. As multiple variants of interest were identified with WGS, this case highlights the importance of relating the clinical symptoms to the genetic results., (© 2022 Wiley Periodicals LLC.)

Background: Autoimmune disorders are reported as presenting signs in patients with immunoglobulin A (IgA) deficiency. Herein, we aim to evaluate serum IgA among patients with autoimmune polyendocrinopathy., Methods: Patients with two or more autoimmune endocrinopathies were selected and the serum IgA levels were measured. Patients with an isolated low serum IgA (<7 mg/dL) after exclusion of other causes of hypogammaglobulinemia were considered as selective IgA deficiency (SIgAD), while partial IgA deficiency (PIgAD) was defined as IgA levels below lower limits of IgA normal range for age but higher than 7 mg/dL., Results: Fifty-three patients (19 [35.8%] male and 34 [64.2%] female) with autoimmune polyendocrinopathy enrolled in the study. Parental consanguinity and positive family history of autoimmunity were reported in 38.0% and 52.9% of patients, respectively. Overall, IgA deficiency was observed in 5 (9.4%) patients including PIgAD in 3 (5.7%) and SIgAD in 2 (3.8%) patients. Among IgA deficient patients, the first autoimmune disorder was developed at earlier ages ( p = .002), and the prevalence of infection ( p = .002), lymphoproliferation ( p = .021), and overlap between insulin-dependent diabetes mellitus and autoimmune thyroiditis ( p = .032) were significantly higher than patients with normal IgA. Also, the number of autoimmune comorbidities was closely correlated with the occurrence of IgA deficiency ( p = .008)., Conclusion: The prevalence of IgA deficiency in patients with autoimmune polyendocrinopathy is higher than that in the general population. In these patients, immunologic workup may lead to early diagnosis of inborn error of immunity, which can positively impact the evolution of complications and even management of the autoimmune disorders.

Targeted monoclonal antibody (mAb) therapies show great promise for the treatment of transplant rejection and autoimmune diseases by inducing more specific immunomodulatory effects than broadly immunosuppressive drugs routinely used. We recently described the therapeutic advantage of targeting CD45RC, expressed at high levels by conventional T (Tconv) cells (CD45RChi), their precursors, and terminally differentiated T (TEMRA) cells, but not by regulatory T cells (Tregs; CD45RClo/-). We demonstrated efficacy of anti-CD45RC mAb treatment in transplantation, but its potential has not been examined in autoimmune diseases. Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare genetic syndrome caused by loss-of-function mutations of autoimmune regulator (AIRE), a key central tolerance mediator, leading to abnormal autoreactive T cell responses and autoantibody production. Herein, we show that, in a rat model of APECED syndrome, anti-CD45RC mAb was effective for both prevention and treatment of autoimmune manifestations and inhibited autoantibody development. Anti-CD45RC mAb intervention depleted CD45RChi T cells, inhibited CD45RChi B cells, and restored the Treg/Tconv cell ratio and the altered Treg transcriptomic profile. In APECED patients, CD45RC was significantly increased in peripheral blood T cells, and lesioned organs from APECED patients were infiltrated by CD45RChi cells. Our observations highlight the potential role for CD45RChi cells in the pathogenesis of experimental and human APECED syndrome and the potential of anti-CD45RC antibody treatment.

APECED (Autoimmune-Polyendocrinopathy-Candidiasis-Ectodermal-Dystrophy) is a severe and incurable multiorgan autoimmune disease caused by mutations in the AIRE (autoimmune regulator) gene. Without functional AIRE, the development of central and peripheral immune tolerance is severely impaired allowing the accumulation of autoreactive immune cells in the periphery. This leads to multiple endocrine and non-endocrine autoimmune disorders and mucocutaneous candidiasis in APECED patients. Recent studies have suggested that AIRE also has novel functions in stem cells and contributes to the regulatory network of pluripotency. In preparation of therapeutic gene correction, we generated and assessed patient blood cell-derived iPSCs, potentially suitable for cell therapy in APECED. Here, we describe APECED-patient derived iPSCs's properties, expression of AIRE as well as classical stem cell markers by qPCR and immunocytochemistry. We further generated self-aggregated EBs of the iPSCs. We show that APECED patient-derived iPSCs and EBs do not have any major proliferative or apoptotic defects and that they express all the classical pluripotency markers similarly to healthy person iPSCs. The results suggest that the common AIRE R257X truncation mutation does not affect stem cell properties and that APECED iPSCs can be propagated in vitro and used for subsequent gene-correction. This first study on APECED patient-derived iPSCs validates their pluripotency and confirms their ability for differentiation and potential therapeutic use., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Karvonen, Krohn, Ranki and Hau.)

Competing Interests: The authors declare no conflicts of interest.

The core function of the immune response is to distinguish between self and foreign. The multiorgan human autoimmune disease, autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED/autoimmune polyendocrine syndrome type 1) is an example of what happens in the body when central immune tolerance goes astray. APECED revealed the existence and function of the autoimmune regulator gene, which has a central role in the development of tolerance. The discovery of autoimmune regulator was the start of a new period in immunology and in understanding the role of central and peripheral tolerance, also very relevant to many skin diseases as we highlight in this review., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

PTPN2 is an important protein tyrosine phosphatase (PTP) that plays a key role in cell signaling. Deletions or inactivating mutations of PTPN2 have been described in different pathologies and underline its critical role in hematopoiesis, autoimmunity, and inflammation. Surprisingly, despite the major pathophysiological implications of PTPN2, the structural analysis of this PTP and notably of its pathogenic mutants remains poorly documented. Contrary to other human PTP enzymes, to date, only one structure of PTPN2 (wild-type form) has been reported. Here, we report the first crystal structure of a pathogenic mutant of PTPN2 (Cys216Gly) that causes an autoimmune enteropathy. We show in particular that this mutant adopts a classical PTP fold. More importantly, albeit inactive, the mutant retains its ability to bind substrates and to adopt the characteristic catalytically competent closed form of PTP enzymes. This novel PTPN2 structure may serve as a new tool to better understand PTP structures and the structural impacts of pathogenic mutations. Moreover, the C216G PTPN2 structure could also be helpful to design specific ligands/inhibitors., (© 2021 The Protein Society.)

Immune cells infiltrate the peripheral nervous system (PNS) after injury and with autoimmunity, but their net effect is divergent. After injury, immune cells are reparative, while in inflammatory neuropathies (e.g., Guillain Barré Syndrome and chronic inflammatory demyelinating polyneuropathy), immune cells are proinflammatory and promote autoimmune demyelination. An understanding of immune cell phenotypes that distinguish these conditions may, therefore, reveal new therapeutic targets for switching immune cells from an inflammatory role to a reparative state. In an autoimmune regulator (Aire)-deficient mouse model of inflammatory neuropathy, we used single-cell RNA sequencing of sciatic nerves to discover a transcriptionally heterogeneous cellular landscape, including multiple myeloid, innate lymphoid, and lymphoid cell types. Analysis of cell-cell ligand-receptor interactions uncovered a macrophage-mediated tumor necrosis factor-α (TNF-α) signaling axis that is induced by interferon-γ and required for initiation of autoimmune demyelination. Developmental trajectory visualization suggested that TNF-α signaling is associated with metabolic reprogramming of macrophages and polarization of macrophages from a reparative state in injury to a pathogenic, inflammatory state in autoimmunity. Autocrine TNF-α signaling induced macrophage expression of multiple genes ( Clec4e , Marcksl1 , Cxcl1 , and Cxcl10 ) important in immune cell activation and recruitment. Genetic and antibody-based blockade of TNF-α/TNF-α signaling ameliorated clinical neuropathy, peripheral nerve infiltration, and demyelination, which provides preclinical evidence that the TNF-α axis may be effectively targeted to resolve inflammatory neuropathies., Competing Interests: The authors declare no competing interest., (Copyright © 2022 the Author(s). Published by PNAS.)

Objective: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) is a rare autosomal recessive systemic autoimmune disease caused by mutations in the autoimmune regulator (AIRE) gene. Incidence of this genetic disorder is estimated at 1/90,000-200,000 worldwide and 1/6500-9000 in genetically isolated populations such as Iran. Here, we investigated AIRE gene mutations in eight independent Iranian non-Jewish families., Methods: We sequenced the coding regions of the AIRE gene and documented mutations which were further confirmed in respective parents., Results: In total, 11 cases from 8 independent families were recruited. Mucosal candidiasis, Addison's disease and hypoparathyroidism were the most common clinical manifestations in these patients. One novel homozygous splice acceptor mutation (c.308-1G>C), and one novel heterozygous stop-gain mutation (c.1496delC) combined with a known heterozygous c.232T>C missense mutation were found. Moreover, we observed previously described splice donor (c.1095+2T>A), frameshift (c.967-979del), stop-gain (c.415C>T), and missense (c.62C>T) mutations among the patients. All results were co-segregated in parents., Conclusion: Here, we reported two novel mutations in the AIRE gene leading to APECED. Our data could provide insight into the phenotypic and genotypic spectrum of APECED in the non-Jewish Iranian population. These findings, in addition to future functional assays, can elucidate disease-causing mechanisms related to the AIRE gene and assist in genetic counseling and diagnosis., (© 2022. The Author(s).)

Purpose: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is more prevalent in some founder populations, but relatively unexplored in Canada. This study aimed at investigating the French-Canadian patients through phenotypic and genotypic characterization., Method: Phenotype and demographic characterization were done for 12 affected individuals belonging to eight unrelated families. Samples from 11 cases were analyzed in a molecular clinical laboratory, and muscle biopsies were reviewed for two individuals with a limb-girdle muscle dystrophy., Results: The clinical phenotype was similar to that observed in European Caucasian populations but differed in the non-endocrine spectrum from the American-reported series of cases. Two cases exhibited a limb-girdle muscle dystrophy, and we found preliminary evidence of a mitochondrial dysfunction, since all three biopsies examined showed COX-deficient fibers in excess of what would be expected for age. Electron microscopy showed mitochondrial accumulation without abnormal cristea or inclusions. The c.1616C > T variant in the AIRE gene was responsible for 100% of APECED cases in the French-Canadian population of Saguenay-Lac-Saint-Jean in Quebec, Canada., Conclusions: We report the first series of French-Canadian cases affected with APECED. The Saguenay-Lac-Saint-Jean region was uncovered as a new founder population for this condition. Muscle biopsy findings expanded the range of previously described APECED-related myopathology. Long term follow-up of our genetically homogeneous French-Canadian cases may help determine if the c.1616C > T variant increases the risk of muscle involvement. A neonatal screening program is under consideration to prevent undesired life-threatening endocrine manifestations., (© 2021. Crown.)

Autoimmune polyendocrine syndrome (APS) is assumed to involve an immune system malfunction and entails several autoimmune diseases co-occurring in different tissues of the same patient; however, they are orphans of its accurate diagnosis, as its genetic basis and pathogenic mechanism are not understood. Our previous studies uncovered alterations in the ATPase H+/K+ Transporting Subunit Alpha (ATP4A) proton pump that triggered an internal cell acid-base imbalance, offering an autoimmune scenario for atrophic gastritis and gastric neuroendocrine tumors with secondary autoimmune pathologies. Here, we propose the genetic exploration of APS involving gastric disease to understand the underlying pathogenic mechanism of the polyautoimmune scenario. The whole exome sequencing (WES) study of five autoimmune thyrogastric families uncovered different pathogenic variants in SLC4A2, SLC26A7 and SLC26A9, which cotransport together with ATP4A. Exploratory in vitro studies suggested that the uncovered genes were involved in a pathogenic mechanism based on the alteration of the acid-base balance. Thus, we built a custom gene panel with 12 genes based on the suggested mechanism to evaluate a new series of 69 APS patients. In total, 64 filtered putatively damaging variants in the 12 genes of the panel were found in 54.17% of the studied patients and none of the healthy controls. Our studies reveal a constellation of solute carriers that co-express in the tissues affected with different autoimmune diseases, proposing a unique genetic origin for co-occurring pathologies. These results settle a new-fangled genetics-based mechanism for polyautoimmunity that explains not only gastric disease, but also thyrogastric pathology and disease co-occurrence in APS that are different from clinical incidental findings. This opens a new window leading to the prediction and diagnosis of co-occurring autoimmune diseases and clinical management of patients.

Background: Autoimmune Polyglandular Syndrome type 1 (APS-1) is a rare recessive inherited disease, caused by AutoImmune Regulator (AIRE) gene mutations and characterized by three major manifestations: chronic mucocutaneous candidiasis (CMC), chronic hypoparathyroidism (CH) and Addison's disease (AD)., Methods: Autoimmune conditions and associated autoantibodies (Abs) were analyzed in 158 Italian patients (103 females and 55 males; F/M 1.9/1) at the onset and during a follow-up of 23.7 ± 15.1 years. AIRE mutations were determined., Results: The prevalence of APS-1 was 2.6 cases/million (range 0.5-17 in different regions). At the onset 93% of patients presented with one or more components of the classical triad and 7% with other components. At the end of follow-up, 86.1% had CH, 77.2% AD, 74.7% CMC, 49.5% premature menopause, 29.7% autoimmune intestinal dysfunction, 27.8% autoimmune thyroid diseases, 25.9% autoimmune gastritis/pernicious anemia, 25.3% ectodermal dystrophy, 24% alopecia, 21.5% autoimmune hepatitis, 17% vitiligo, 13.3% cholelithiasis, 5.7% connective diseases, 4.4% asplenia, 2.5% celiac disease and 13.9% cancer. Overall, 991 diseases (6.3 diseases/patient) were found. Interferon-ω Abs (IFNωAbs) were positive in 91.1% of patients. Overall mortality was 14.6%. The AIRE mutation R139X was found in 21.3% of tested alleles, R257X in 11.8%, W78R in 11.4%, C322fsX372 in 8.8%, T16M in 6.2%, R203X in 4%, and A21V in 2.9%. Less frequent mutations were present in 12.9%, very rare in 9.6% while no mutations in 11% of the cases., Conclusions: In Italy, APS-1 is a rare disorder presenting with the three major manifestations and associated with different AIRE gene mutations. IFNωAbs are markers of APS-1 and other organ-specific autoantibodies are markers of clinical, subclinical or potential autoimmune conditions., (© 2021. The Author(s).)