Autoimmune Polyendocrine Syndrome Type 1 Patients Research Articles

Neurological Diseases and Prevalence of Antineuronal Antibodies in Patients with Autoimmune Polyendocrine Syndrome Type 1 – A National Cohort Study

Autoimmune polyendocrine syndrome type 1 (APS-1) is a rare monogenic disease caused by mutations in the autoimmune regulator gene. Although the disease-associated autoantibodies mostly target endocrine organs, autoantibodies from patients with APS-1 bind also to rat brain structures. The patients often have GAD65-antibodies, that can cause autoimmune encephalitis. However, neurological manifestations of APS-1 have not been systematically explored. We conducted a retrospective chart review on 44 Finnish patients with APS-1 (median age 38 years, 61% females) and collected all their neurological diagnoses. To assess the prevalence of serum antineuronal antibodies in APS-1, serum samples of 24 patients (median age 36 years, 63% females) were analyzed using a fixed cell-based assay. Of the 44 APS-1 patients, 10 (23%) had also received a diagnosis of a neurological disease. Of these neurological comorbidities, migraine (n = 7; 16%), central nervous system infections (n = 3; 7%), and epilepsy (n = 2; 5%) were the most prevalent. Other diagnoses recorded for single patients were axonal sensorimotor polyneuropathy, essential tremor, idiopathic intracranial hypertension, ischemic stroke, and trigeminal neuralgia. Serum antineuronal antibodies were detected in 42% of patients tested (10/24, 50% females, median age 42 years), GAD65 antibodies being the most common finding. Antibodies against glycine and aquaporin 4 were found in low titers. In four patients, relatively high titers of GAD65 antibodies without coexisting type 1 diabetes were found, but none presented with GAD65-encephalitis. Our study suggests an association between APS-1 and neurological disorders, the mechanisms of which are to be further investigated.

Ruxolitinib Rescues Multiorgan Clinical Autoimmunity in Patients with APS-1

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.

A novel AIRE mutation leads to autoimmune polyendocrine syndrome type-1.

Autoimmune polyendocrine syndrome type-1 (APS-1) is a rare inherited monogenic autoimmune disease characterized by the presence of at least two of three following major clinical features: chronic mucocutaneous candidiasis, hypoparathyroidism, and adrenal insufficiency. Mutations in autoimmune regulator (AIRE) gene have been found to contribute to APS-1. In the present study, we reported a 36-years-old male APS-1 patient who presented with hypoparathyroidism and Addison’s disease. The proband underwent complete clinical examinations and mutation screening was performed by Sanger sequencing on AIRE gene. A novel homozygous mutation in exon 9 of the AIRE gene (c.1024C>T) was identified. Based on sequencing findings, HEK293T cell-based assays were conducted to analyze the subcellular localization and mutant transcript processing. Our results revealed that p.Q342X mutant localized in nuclear speckles and exerted a dominant-negative effect on wildtype AIRE function. We reported the c.1024C>T mutation of AIRE gene for the first time, which enriched the AIRE mutation database and contributed to further understanding of APS-1.

Candidiasis in patients with APS-1: low IL-17, high IFN-γ, or both?

Chronic mucocutaneous candidiasis (CMC) is one of the earliest and most frequent clinical manifestations of autosomal recessive autoimmune polyendocrine syndrome type 1 (APS-1), a monogenic inborn error of immunity caused by deleterious variants of the autoimmune regulator (AIRE) gene. APS-1 patients suffer from various autoimmune diseases, due to the defective thymic deletion of autoreactive T cells, and the development of a large range of autoantibodies (auto-Abs) against various tissue antigens, and some cytokines. The mechanisms underlying CMC remained elusive for many years, until the description in 2010 of high serum titers of neutralizing auto-Abs against IL-17A, IL-17F, and/or IL-22, which are present in almost all APS-1 patients. Excessively high mucosal concentrations of IFN-γ were recently proposed as an alternative mechanism for CMC in APS-1.

B Cells and Autoantibodies in AIRE Deficiency.

Autoimmune polyendocrine syndrome type 1 (APS-1) is a rare but severe monogenetic autoimmune endocrine disease caused by failure of the Autoimmune Regulator (AIRE). AIRE regulates the negative selection of T cells in the thymus, and the main pathogenic mechanisms are believed to be T cell-mediated, but little is known about the role of B cells. Here, we give an overview of the role of B cells in thymic and peripheral tolerance in APS-1 patients and different AIRE-deficient mouse models. We also look closely into which autoantibodies have been described for this disorder, and their implications. Based on what is known about B cell therapy in other autoimmune disorders, we outline the potential of B cell therapies in APS-1 and highlight the unresolved research questions to be answered.

Patients with autoimmune polyendocrine syndrome type 1 have an increased susceptibility to severe herpesvirus infections

Almost all patients with autoimmune polyendocrine syndrome type 1 (APS-1) have neutralizing antibodies against type 1 interferons (IFN), important mediators of antiviral defense. Recently, neutralizing anti-IFN antibodies were shown to be a risk factor of severe COVID-19. Here we show in a cohort of 44 patients with APS-1 that higher titers of neutralizing anti-IFNα4 antibodies are associated with a higher and earlier incidence of VZV reactivation (herpes zoster). The patients also present with uncommonly severe clinical sequelae of herpetic infections. APS-1 patients had decreased humoral immune responses to varicella zoster virus, but cellular responses were comparable to healthy controls. These results suggest that blocking the type I interferon pathway in patients with APS-1 patients leads to a clinically significant immune deficiency, and susceptibility to herpesviruses should be taken into account when treating patients with APS-1.

Preexisting autoantibodies to type I IFNs underlie critical COVID-19 pneumonia in patients with APS-1.

Patients with biallelic loss-of-function variants of AIRE suffer from autoimmune polyendocrine syndrome type-1 (APS-1) and produce a broad range of autoantibodies (auto-Abs), including circulating auto-Abs neutralizing most type I interferons (IFNs). These auto-Abs were recently reported to account for at least 10% of cases of life-threatening COVID-19 pneumonia in the general population. We report 22 APS-1 patients from 21 kindreds in seven countries, aged between 8 and 48 yr and infected with SARS-CoV-2 since February 2020. The 21 patients tested had auto-Abs neutralizing IFN-α subtypes and/or IFN-ω; one had anti-IFN-β and another anti-IFN-ε, but none had anti-IFN-κ. Strikingly, 19 patients (86%) were hospitalized for COVID-19 pneumonia, including 15 (68%) admitted to an intensive care unit, 11 (50%) who required mechanical ventilation, and four (18%) who died. Ambulatory disease in three patients (14%) was possibly accounted for by prior or early specific interventions. Preexisting auto-Abs neutralizing type I IFNs in APS-1 patients confer a very high risk of life-threatening COVID-19 pneumonia at any age.

The autoimmune targets in IPEX are dominated by gut epithelial proteins

The autoimmune targets in IPEX are dominated by gut epithelial proteins

Calcium-Sensing Receptor Autoantibodies in Patients with Autoimmune Polyendocrine Syndrome Type 1: Epitopes, Specificity, Functional Affinity, IgG Subclass, and Effects on Receptor Activity.

A major manifestation of autoimmune polyendocrine syndrome type 1 (APS1) is hypoparathyroidism, which is suggested to result from aberrant immune responses against the parathyroid glands. The calcium-sensing receptor (CaSR), which plays a pivotal role in maintaining calcium homeostasis by sensing blood calcium levels and regulating release of parathyroid hormone (PTH), is an autoantibody target in APS1. In this study, the aim was to characterize the binding sites, specificity, functional affinity, IgG subclass, and functional effects of CaSR autoantibodies using phage-display technology, ELISA, and bioassays. The results indicated that CaSR autoantibody binding sites were at aa 41-69, 114-126, 171-195, and 260-340 in the extracellular domain of the receptor. Autoantibodies against CaSR epitopes 41-69, 171-195, and 260-340 were exclusively of the IgG1 subclass. Autoantibody responses against CaSR epitope 114-126 were predominantly of the IgG1 with a minority of the IgG3 subclass. Only autoantibodies recognizing CaSR epitopes 114-126 and 171-195 affected receptor activity; inositol-phosphate accumulation was increased significantly in HEK293-CaSR cells, and PTH secretion from PTH-C1 cells was reduced significantly when either were incubated with purified Ab and Ca2+ compared with Ca2+ alone. In conclusion, although the majority of APS1 patients do not have CaSR-stimulating autoantibodies, the hypoparathyroid state in a small minority of patients is the result of functional suppression of the parathyroid glands.

The heterogeneity of autoimmune polyendocrine syndrome type 1: Clinical features, new mutations and cytokine autoantibodies in a Brazilian cohort from tertiary care centers

Autoimmune polyendocrine syndrome type 1 (APS1) is characterized by multiorgan autoimmunity. We aim at characterizing a multi-center Brazilian cohort of APS1 patients by clinical evaluation, searching mutation in the AIRE gene, measuring serum autoantibodies, and investigating correlations between findings. We recruited patients based on the clinical criteria and tested them for AIRE mutations, antibodies against interferon type I and interleukins 17A, 17F and 22. We identified 12 unrelated families (13 patients) with typical signs of APS1 in the proband, and the screening of relatives recognized an asymptomatic child. Candidiasis was present in all cases, and 19 other manifestations were observed. All patients carried one of 10 different mutations in AIRE, being 3 new ones, and were positive for anti-interferon type I serum antibody. Anti-interleukin-17A levels inversely correlated with the number of manifestations in each patient. This negative correlation may suggest a protective effect of anti-interleukin-17A with a potential therapeutic application.

Oral microbiota in autoimmune polyendocrine syndrome type 1

ABSTRACT Background: Autoimmune polyendocrine syndrome type-1 (APS-1) is a rare, childhood onset disease caused by mutations in the Autoimmune Regulator gene. The phenotypic expression is highly variable and includes disease manifestations in the oral cavity, including mucocutaneous candidiasis. Increasing evidence suggests a potential role of the skin, oral and gut microbiotas in the pathogenesis of autoimmunity. To date, no information exists regarding the oral microbiota in APS-1. Objective: To assess the bacterial microbiota of whole saliva in APS-1 patients by using high throughput sequencing. Design: Whole unstimulated saliva was collected from 10 APS-1 patients and 17 healthy controls and examined by high throughput sequencing of the hypervariable region V1-V2 of 16S rRNA using the 454 GS Junior system. Metastats (http://cbcb.umd.edu/software/metastats) was used to analyse the pyrosequencing reads. Results: A reduction in the total number of bacterial genera and species was detected in APS-1 compared to healthy controls. The proportion of the major phyla Firmicutes was higher (60% vs 41%, p = 0.002) and Bacteroidetes lower (15% vs 28%, p = 0.007) in APS-1 compared to healthy controls. On the genus level, Streptococcus and Gemella were prevalent in APS-1. Conclusion: Our findings indicate a significantly altered oral microbiota in APS-1.

Clonal Analysis of Regulatory T Cell Defect in Patients with Autoimmune Polyendocrine Syndrome Type 1 Suggests Intrathymic Impairment.

Mutations in the autoimmune regulator gene disrupt thymic T cell development and negative selection, leading to the recessively inherited polyendocrine autoimmune disease autoimmune polyendocrine syndrome type 1 (APS-1). The patients also have a functional defect in the FOXP3+ regulatory T cell population, but its origin is unclear. Here, we have used T cell receptor sequencing to analyse the clonal relationship of major CD4+ T cell subsets in three patients and three healthy controls. The naive regulatory T cells showed little overlap with helper T cell subsets, supporting divergence in the thymus. The activated/memory regulatory T cell subset displayed more sharing with helper T cells, but was mainly recruited from the naive regulatory T cell population. These clonal patterns were very similar in both patients and controls. However, naive regulatory T cells isolated from the patients had a significantly longer T cell receptor complementarity-determining region 3 than any other population, suggesting failure of thymic selection. These data indicate that the peripheral differentiation of regulatory T cells in APS-1 patients is not different from that in healthy controls. Rather, the patients' naive regulatory T cells may have an intrinsic defect imprinted already in the thymus.

Altered Immune Activation and IL-23 Signaling in Response to Candida albicans in Autoimmune Polyendocrine Syndrome Type 1.

Autoimmune polyendocrine syndrome type 1 (APS-1) is a rare, childhood onset disease caused by mutations in the autoimmune regulator (AIRE) gene. Chronic mucocutaneous candidiasis (CMC) is one of the three major disease components and is, to date, mainly explained by the presence of neutralizing auto-antibodies against cytokines [interleukin (IL)-17A, IL-17F, and IL-22] from T helper 17 cells, which are critical for the protection against fungal infections. However, patients without current auto-antibodies also present CMC and we, therefore, hypothesized that other immune mechanisms contribute to CMC in APS-1. Whole blood was stimulated with Candida albicans (C. albicans) in a standardized assay, and immune activation was investigated by analyzing 46 secreted immune mediators. Then, peripheral blood mononuclear cells were stimulated with curdlan, a Dectin-1 agonist and IL-23 inducer, and the IL-23p19 response in monocytes was analyzed by flow cytometry. We found an altered immune response in APS-1 patients compared with healthy controls. Patients fail to increase the essential ILs, such as IL-2, IL-17A, IL-22, and IL-23, when stimulating whole blood with C. albicans. A significantly altered IL-23p19 response was detected in patients' monocytes upon stimulation with curdlan. APS-1 patients have an altered immune response to C. albicans including a dysregulation of IL-23p19 production in monocytes. This probably contributes to the selective susceptibility to CMC found in the majority of patients.

Identification of autoimmune polyendocrine syndrome type 1 in patients with isolated hypoparathyroidism.

The prevalence of autoimmune polyendocrine syndrome type 1 (APS1) among isolated hypoparathyroidism (HP) or primary adrenal insufficiency (PAI) is not well established. We studied the frequency of APS1 in patients with HP or PAI by measuring interferon-α (IFN-α) antibody levels, a highly sensitive and specific marker for APS1. In a single-centre cross-sectional study, 37 Indian patients with isolated HP and 40 patients with PAI were tested for IFN-α antibody using an indirect ELISA. In patients with elevated IFN-α antibody, the autoimmune regulator (AIRE) gene was bidirectionally sequenced. Three (8·1%) patients with isolated HP had elevated IFN-α antibody levels (range: 367-17382 units; positive titre >56 units). Homozygous or compound heterozygous AIRE mutations were detected in all three patients, including a novel mutation (p.T68P). All three APS1 patients had atypical features. The first patient, diagnosed at 7 years of age, died suddenly 5 months later. The second patient had late-onset HP (at the age of 34 years) and a solitary episode of transient mucocutaneous candidiasis 5 years later. The final patient developed HP at the age of 14 years and premature ovarian insufficiency 14 years later. Interleukin-22 antibodies, as well as most other organ-specific antibodies, were absent in the 3 APS1 patients. All patients with PAI were negative for IFN-α antibody. Eight percentage of patients with isolated HP had elevated IFN-α antibody levels and AIRE mutation-positive APS1. All APS1 patients had atypical clinical features. Testing for IFN-α antibody should be considered in patients with idiopathic HP.

AIREing out autoimmunity

Autoimmunity Because of mutations in the AIRE gene, patients with autoimmune polyendocrine syndrome type 1 (APS1) suffer dysfunction in multiple endocrine glands and are often infertile. Female infertility can be explained by autoimmune ovarian failure, but the causes of male infertility are unclear. Now Landegren et al. report that the prostatic secretory molecule tranglutaminase 4 (TGM4) is a male-specific autoantigen in APS1 patients that could contribute to subfertility. Autoantibodies to TGM4 appeared in APS1 patients beginning at puberty, and similar antibodies lead to destructive prostatitis in AIRE -deficient mice. Together, these data may explain the infertility observed in male APS1 patients. Sci. Transl. Med. 7 , 292ra101 (2015).

Transglutaminase 4 as a prostate autoantigen in male subfertility

Autoimmune polyendocrine syndrome type 1 (APS1), a monogenic disorder caused by AIRE gene mutations, features multiple autoimmune disease components. Infertility is common in both males and females with APS1. Although female infertility can be explained by autoimmune ovarian failure, the mechanisms underlying male infertility have remained poorly understood. We performed a proteome-wide autoantibody screen in APS1 patient sera to assess the autoimmune response against the male reproductive organs. By screening human protein arrays with male and female patient sera and by selecting for gender-imbalanced autoantibody signals, we identified transglutaminase 4 (TGM4) as a male-specific autoantigen. Notably, TGM4 is a prostatic secretory molecule with critical role in male reproduction. TGM4 autoantibodies were detected in most of the adult male APS1 patients but were absent in all the young males. Consecutive serum samples further revealed that TGM4 autoantibodies first presented during pubertal age and subsequent to prostate maturation. We assessed the animal model for APS1, the Aire-deficient mouse, and found spontaneous development of TGM4 autoantibodies specifically in males. Aire-deficient mice failed to present TGM4 in the thymus, consistent with a defect in central tolerance for TGM4. In the mouse, we further link TGM4 immunity with a destructive prostatitis and compromised secretion of TGM4. Collectively, our findings in APS1 patients and Aire-deficient mice reveal prostate autoimmunity as a major manifestation of APS1 with potential role in male subfertility.

Autoantibodies targeting neurotransmitter biosynthetic enzymes in attention-deficit/hyperactivity disorder (ADHD)

Autoantibodies targeting neurotransmitter biosynthetic enzymes in attention-deficit/hyperactivity disorder (ADHD)

Tryptophan Hydroxylase Autoantibodies as Markers of a Distinct Autoimmune Gastrointestinal Component of Autoimmune Polyendocrine Syndrome Type 1

Autoantibodies to tryptophan hydroxylase (TPHAbs) directed against serotonin-producing enterochromaffin cells (EC) have been reported in autoimmune-polyendocrine-syndrome type 1 (APS-1) patients with gastrointestinal dysfunction (GID). Serotonin plays a critical role in enteric function and its peripheral blood levels reflect serotonin release from the gastrointestinal tract. We test the hypothesis that TPHAbs mark a distinct autoimmune component of APS-1 characterized by an autoimmune attack toward EC, which results in clinical GID. TPHAbs were measured in 64 APS-1 patients. Endoscopy with gastric (antrum/body) and duodenal biopsy was carried in 16 TPHAbs+ patients (8 with and 8 without GID) and in 2 TPHAbs- patients (without GID). Immunohistochemistry of biopsy specimens was carried out using antibodies to serotonin, chromogranin-A, CD3, CD4, CD8, and CD20. Serotonin serum levels were measured in TPHAbs+ and TPHAbs- patients who had endoscopy. Thirty-seven of 64 patients were TPHAbs+ (11/12 with GID and 26/52 without GID; P < .001). Gastric and duodenal biopsies in all 8 TPHAb+ patients with GID showed lymphocytic infiltration with increased CD3+CD8+ intraepithelial lymphocytes and absence of EC. Furthermore, mean serotonin serum levels were below the normal range in TPHAb+ patients with GID (P < .01). In 8 TPHAb+ patients without GID gastric and duodenal biopsies showed different grades of inflammatory infiltration and reduced number of EC. Mean serotonin serum levels were near the lower limit of the normal range. In all TPHAbs+ patients the biopsies showed a reduced number of chromogranin-A positive cells consistent with enteroendocrine cells depletion. TPHAbs- patients without GID showed normal gastrointestinal mucosa and serotonin serum levels. TPHAbs appear to be markers of a distinct autoimmune component of APS-1. Progressive involvement of the gastrointestinal EC leads to the transition from preclinical to clinical disease, characterized by GID and reduced serotonin serum levels.

Autoantibodies against aromatic amino acid hydroxylases in patients with autoimmune polyendocrine syndrome type 1 target multiple antigenic determinants and reveal regulatory regions crucial for enzymatic activity

Patients with autoimmune polyendocrine syndrome type 1 (APS-1) frequently have autoantibodies directed against the aromatic amino acid hydroxylases tryptophan hydroxylase (TPH) and tyrosine hydroxylase (TH). We aimed to characterize these autoantibodies with regard to their antigenic determinants, their influence on enzymatic activity and their clinical associations. In particular, we wanted to compare autoantibodies against the two different isoforms of TPH, which display different tissue distribution. Using sera from 48 Scandinavian APS-1 patients we identified 36 patients (75%) with antibodies against one or more of these three enzymes. Antibodies against TPH1, but not TPH2, were associated with malabsorption in the whole Scandinavian cohort, while TH antibodies were associated with dental enamel hypoplasia in Norwegian patients. Subsequent experiments with selected patient sera indicated that while the C-terminal domain was the immunodominant part of TPH1, the epitopes of TPH2 and TH were mainly located in the N-terminal regulatory domains. We also identified a TPH1 specific epitope involved in antibody mediated inhibition of enzyme activity, a finding that provides new insight into the enzymatic mechanisms of the aromatic amino acid hydroxylases and knowledge about structural determinants of enzyme autoantigens. In conclusion, TPH1, TPH2 and TH all have unique antigenic properties in spite of their structural similarity.

Novel neuronal and endocrine autoantibody targets in autoimmune polyendocrine syndrome type 1

Context. Although pituitary autoantibodies have frequently been reported in Autoimmune Polyendocrine Syndrome type 1 (APS1), the autoimmune involvement of the hypothalamic-pituitary axis remains to be elucidated. Objective. Our aim was to identify in APS1 patients novel autoantibodies, especially against hypothalamic-pituitary targets, and to correlate their presence with clinical features. Patients. We analyzed 14 APS1 patients from Sardinia, compared to other diseases and healthy donors. Measure(s). We used immunohistochemistry, on tissues substrates from various neuroendocrine organs, to detect autoantibody targets. Immunoenzymatic assays, as well as absorption with specific antigens were used to reveal autoantibodies against growth hormone (GH), luteinizing hormone (LH) and somatocrinin (GHRH). Clinical evaluations included GH secretory and cardiovascular autonomic neuropathy tests. Results. Sera from 12/14 APS1 patients revealed autoantibodies reacting with the hypothalamic-pituitary axis, cerebellum, substantia nigra, and/or adrenal medulla, as well as with GH, LH and/or GHRH. Of APS1 patients, 5 showed GH deficiency, in association (4/5 cases) with autoantibodies to hypothalamic and/or pituitary targets. Hypogonadotrophic hypogonadism was revealed in one APS1 patient, together with autoantibodies against gonadotropes. Autonomic neuropathy was detected in 5 of 10 patients, associated with autoantibodies to adrenal medulla in 2 cases. Of 5 patients with autoantibodies to cerebellar neurons, 2 reported emotional or memory alterations. Conclusions. The majority of Sardinian APS1 patients developed autoantibodies to an assortment of neuroendocrine cells. Novel targets of clinical relevance may include pituitary hormones, uncharacterized pituitary targets, and adrenal medullary cells. An high prevalence of GH deficiency, and possibly of autonomic neuropathy, were also revealed.