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Introduction Vestibular schwannoma (VS) is a benign intracranial tumor in which the underlying genetics is largely uncertain, apart from mutations in the tumor suppressor gene NF2. Alternative tumorigenic mechanisms have been proposed, including a recurrent in-frame fusion transcript of the HTRA1 and SH3PXD2A genes. The gene product of the SH3PXD2A-HTRA1 fusion has been shown to promote proliferation, invasion and resistance to cell death in vitro and tumor growth in vivo. The aim of this study was to replicate the findings and to investigate the frequency of this fusion gene in another cohort of vestibular schwannoma patients. Methods The SH3PXD2A-HTRA1 transcript was synthesized in vitro using PCR and used as a positive control to assess the sensitivity of a real-time PCR assay. This real-time PCR assay was used to search for the presence of the fusion transcript in 121 Norwegian sporadic VS patients. Results The real-time PCR assay showed a high sensitivity and was able to detect as low as ~ 5 copies of the fusion transcript. Out of the 121 investigated tumors, only 1 harbored the SH3PXD2A-HTRA1 fusion. Conclusion Even though the SH3PXD2A-HTRA1 fusion has been shown to be a driver of tumorigenesis, our results suggest that it is a rare event in our VS patients. Further investigation is warranted in order to elucidate whether our results represent an extreme, and if the fusion is present also in other neoplasms.

Background The most common cause of primary adrenal failure (Addison’s disease) in the Western world is autoimmunity characterized by autoantibodies against the steroidogenic enzyme 21-hydroxylase (CYP21A2, 21OH). Detection of 21OH-autoantibodies is currently used for aetiological diagnosis, but how levels of 21OH-autoantibodies vary over time is not known. Setting Samples from the national Norwegian Addison’s Registry and Biobank established in 1996 (n = 711). Multi-parameter modelling of the course of 21OH-autoantibody indices over time. Results 21OH-autoantibody positivity is remarkably stable, and >90% of the patients are still positive 30 years after diagnosis. Even though the antibody levels decline with disease duration, it is only rarely that this downturn reaches negativity. 21OH-autoantibody indices are affected by age at diagnosis, sex, type of Addison’s disease (isolated vs autoimmune polyendocrine syndrome type I or II) and HLA genotype. Conclusion 21OH-autoantibodies are reliable and robust markers for autoimmune Addison’s disease, linked to HLA risk genotype. However, a negative test in patients with long disease duration does not exclude autoimmune aetiology.

Background Glioblastoma (GBM) is an aggressive malignant brain tumor where median survival is approximately 15 months after best available multimodal treatment. Recurrence is inevitable, largely due to O6 methylguanine DNA methyltransferase (MGMT) that renders the tumors resistant to temozolomide (TMZ). We hypothesized that pretreatment with bortezomib (BTZ) 48 hours prior to TMZ to deplete MGMT levels would be safe and tolerated by patients with recurrent GBM harboring unmethylated MGMT promoter. The secondary objective was to investigate whether 26S proteasome blockade may enhance differentiation of cytotoxic immune subsets to impact treatment responses measured by radiological criteria and clinical outcomes. Methods Ten patients received intravenous BTZ 1.3 mg/m2 on days 1, 4, and 7 during each 4th weekly TMZ‐chemotherapy starting on day 3 and escalated from 150 mg/m2 per oral 5 days/wk via 175 to 200 mg/m2 in cycles 1, 2, and 3, respectively. Adverse events and quality of life were evaluated by CTCAE and EQ‐5D‐5L questionnaire, and immunological biomarkers evaluated by flow cytometry and Luminex enzyme‐linked immunosorbent assay. Results Sequential BTZ + TMZ therapy was safe and well tolerated. Pain and performance of daily activities had greatest impact on patients' self‐reported quality of life and were inversely correlated with Karnofsky performance status. Patients segregated a priori into three groups, where group 1 displayed stable clinical symptoms and/or slower magnetic resonance imaging radiological progression, expanded CD4+ effector T‐cells that attenuated cytotoxic T‐lymphocyte associated protein‐4 and PD‐1 expression and secreted interferon γ and tumor necrosis factor α in situ and ex vivo upon stimulation with PMA/ionomycin. In contrast, rapidly progressing group 2 patients exhibited tolerised T‐cell phenotypes characterized by fourfold to sixfold higher interleukin 4 (IL‐4) and IL‐10 Th‐2 cytokines after BTZ + TMZ treatment, where group 3 patients exhibited intermediate clinical/radiological responses. Conclusion Sequential BTZ + TMZ treatment is safe and promotes Th1‐driven immunological responses in selected patients with improved clinical outcomes (Clinicaltrial.gov (NCT03643549))., Schematic of trial schedule. A, Timeline showing BORTEM‐17 treatment regimen. Bortezomib administered intravenous at days 1, 4, and 7 (48 hours pretreatment to deplete MGMT protein) before target TMZ 200 mg/m2 dose for 5 days (from and including days 3‐7), repeated in six cycles. In n = 3 patients per each dose 150 vs 175 vs 200 mg/m2 TMZ in dose pathfinding, safety evaluation. Clinical chemistry for renal, hepatic, and bone marrow monitoring for toxicity based on CTCAE v. 4.03. MRI tumor monitoring radiological response assessment based on RANO criteria. Rationale for sequential treatment schedule based on preclinical data. B, sequential administration in BORTEM‐17 clinical trial vs (C) previous studies where BTZ on days 1, 4, 8, and 11 was given concomitantly with TMZ from day 1 to 5, when MGMT levels were high. Dashed boxes mark days when TMZ doses might be more effective, (B) all five doses vs (C) three doses every month. BTZ, bortezomib; CBC Diff, complete blood count with differential test; CMP, comprehensive metabolic panel; KPS, Karnofsky performance score; LFT, liver function test; MGMT, O6‐methyl guanine DNA methyltransferase; MRI, magnetic resonance imaging; NANO, neurologic assessment in neuro‐oncology; QoL, quality of life; TMZ, temozolomide.

Autoantibodies against type I interferons (IFN) alpha (α) and omega (ω), and interleukins (IL) 17 and 22 are a hallmark of autoimmune polyendocrine syndrome type 1 (APS-1), caused by mutations in the autoimmune regulator (AIRE) gene. Such antibodies are also seen in a number of monogenic immunodeficiencies.To determine whether screening for cytokine autoantibodies (anti-IFN-ω and anti-IL22) can be used to identify patients with monogenic immune disorders.A novel ELISA assay was employed to measure IL22 autoantibodies in 675 patients with autoimmune primary adrenal insufficiency (PAI) and a radio immune assay (RIA) was used to measure autoantibodies against IFN-ω in 1778 patients with a variety of endocrine diseases, mostly of autoimmune aetiology. Positive cases were sequenced for all coding exons of the AIRE gene. If no AIRE mutations were found, we applied next generation sequencing (NGS) to search for mutations in immune related genes.We identified 29 patients with autoantibodies against IFN-ω and/or IL22. Of these, four new APS-1 cases with disease-causing variants in AIRE were found. In addition, we identified two patients with pathogenic heterozygous variants in CTLA4 and NFKB2, respectively. Nine rare variants in other immune genes were identified in six patients, although further studies are needed to determine their disease-causing potential.Screening of cytokine autoantibodies can efficiently identify patients with previously unknown monogenic and possible oligogenic causes of autoimmune and immune deficiency diseases. This information is crucial for providing personalised treatment and follow-up of patients and their relatives.

The autoimmune regulator (AIRE) is essential for the establishment of central tolerance and prevention of autoimmunity. Interestingly, different AIRE mutations cause autoimmunity in either recessive or dominant-negative manners. Using engineered mouse models, we establish that some monoallelic mutants, including C311Y and C446G, cause breakdown of central tolerance. By using RNAseq, ATACseq, ChIPseq, and protein analyses, we dissect the underlying mechanisms for their dominancy. Specifically, we show that recessive mutations result in a lack of AIRE protein expression, while the dominant mutations in both PHD domains augment the expression of dysfunctional AIRE with altered capacity to bind chromatin and induce gene expression. Finally, we demonstrate that enhanced AIRE expression is partially due to increased chromatin accessibility of the AIRE proximal enhancer, which serves as a docking site for AIRE binding. Therefore, our data not only elucidate why some AIRE mutations are recessive while others dominant, but also identify an autoregulatory mechanism by which AIRE negatively modulates its own expression.

KARS1 encodes a lysyl-transfer RNA synthetase (LysRS) that links lysine to its cognate tRNA. Two different KARS1 isoforms exert functional effects in cytosol and mitochondria. Bi-allelic pathogenic variants in KARS1 have been associated to sensorineural hearing and visual loss, neuropathy, seizures, and leukodystrophy. We report the clinical, biochemical and neuroradiological features of nine individuals with KARS1-related disorder carrying 12 different variants with nine of them being novel. The consequences of these variants on the cytosol and/or mitochondrial LysRS were functionally validated in yeast mutants. Most cases presented with severe neurological features including congenital and progressive microcephaly, seizures, developmental delay/intellectual disability, and cerebral atrophy. Oculo-motor dysfunction and immuno-hematological problems were present in six and three cases, respectively. A yeast growth defect of variable severity was detected for most variants on both cytosolic and mitochondrial isoforms. The detrimental effects of two variants on yeast growth were partially rescued by lysine supplementation. Congenital progressive microcephaly, oculo-motor dysfunction and immuno-hematological problems are emerging phenotypes in KARS1-related disorders. The data in yeast emphasize the role of both mitochondrial and cytosolic isoforms in the pathogenesis of KARS1-related disorder and supports the therapeutic potential of lysine supplementation at least in a subset of patients. This article is protected by copyright. All rights reserved.

Background No reliable biomarkers exist to guide glucocorticoid (GC) replacement treatment in autoimmune Addison’s disease (AAD), leading to overtreatment with alarming and persistent side effects or undertreatment, which could be fatal. Objective To explore changes in gene expression following different GC replacement doses as a means of identifying candidate transcriptional biomarkers to guide GC replacement in AAD. Methods Step 1: Global microarray expression analysis on RNA from whole blood before and after intravenous infusion of 100 mg hydrocortisone (HC) in 10 patients with AAD. In 3 of the most highly upregulated genes, we performed real-time PCR (rt-PCR) to compare gene expression levels before and 3, 4, and 6 hours after the HC infusion. Step 2: Rt-PCR to compare expression levels of 93 GC-regulated genes in normal versus very low morning cortisol levels in 27 patients with AAD. Results Step 1: Two hours after infusion of 100 mg HC, there was a marked increase in FKBP5, MMP9, and DSIPI expression levels. MMP9 and DSIPI expression levels correlated with serum cortisol. Step 2: Expression levels of CEBPB, DDIT4, FKBP5, DSIPI, and VDR were increased and levels of ADARB1, ARIDB5, and POU2F1 decreased in normal versus very low morning cortisol. Normal serum cortisol levels positively correlated with DSIPI, DDIT4, and FKBP5 expression. Conclusions We introduce gene expression as a novel approach to guide GC replacement in AAD. We suggest that gene expression of DSIPI, DDIT4, and FKBP5 are particularly promising candidate biomarkers of GC replacement, followed by MMP9, CEBPB, VDR, ADARB1, ARID5B, and POU2F1.

Introduction/Aims The long-term humoral immune response after a natural giardiasis infection is not well understood. The aim of this study was to evaluate longitudinal serum IgA and IgG/M responses towards conserved regions of two Giardia variant-specific surface proteins (VSP) and whether these responses differ between Giardia assemblages and durations of infection. Methods We recruited thirty Giardia-positive patients, mainly returning travellers, and eighteen healthy adults presumed to be Giardia unexposed. Blood samples were collected before treatment, and at 6 weeks, 6 months and 12 months after the infection cleared. We used a multiplex bead-based flow cytometry immunoassay to measure Giardia specific IgA and IgG/M responses targeting two recombinant antigens from G. lamblia VSP proteins 3 and 5 (VSP3 and VSP5). Results Serum levels of anti-VSP5 and anti-VSP3 IgA decreased rapidly to low levels after treatment but continued to be substantially higher than that of presumed unexposed controls even after 6 and 12 months. The IgG/M response decreased more gradually but remained significantly higher than presumed unexposed controls at all time points, except for anti-VSP3 at 12 months. There were no significant difference in responses for infections with assemblage A and assemblage B Giardia lamblia. Chronic infections (>8 weeks) were associated with a significantly lower anti-VSP5 IgG/M response. Conclusion This study describes the kinetics of the humoral immune response against two Giardia VSP proteins over one year, and the considerable cross reactivity between the two human infective Giardia assemblages. Persons with chronic Giardia infection seem to have lower levels of VSP antibodies.

Autoimmunity against the adrenal cortex is the leading cause of Addison's disease in industrialized countries, with prevalence estimates ranging from 93-220 per million in Europe. The immune-mediated attack on adrenocortical cells cripples their ability to synthesize vital steroid hormones and necessitates life-long hormone replacement therapy. The autoimmune disease etiology is multifactorial involving variants in immune genes and environmental factors. Recently, we have come to appreciate that the adrenocortical cell itself is an active player in the autoimmune process. Here we summarize the complex interplay between the immune system and the adrenal cortex and highlight unanswered questions and gaps in our current understanding of the disease.

Autoimmune Addison’s disease is the predominant cause of primary adrenal failure, and is highly heritable. The genetic background has remained poorly understood due to the low prevalence and complex inheritance of the disease. We performed a genome-wide association study, which identified nine independent risk loci (P < 5 × 10–8). In addition to novel and previous risk loci involved in lymphocyte functionality, we further associated autoimmune Addison’s disease with two independent protein-coding alterations in the gene Autoimmune Regulator (AIRE). The most striking is the amino-acid substitution p.R471C (rs74203920, OR = 3.4 (2.7–4.3), P = 9.0 × 10–25), which introduces an additional cysteine residue in the zinc-finger motif of the PHD2 domain of AIRE. This unbiased elucidation of the genetic contribution to development of autoimmune Addison’s disease points to the importance of central immunological tolerance, and explains 35–41 percent of heritability.

Autoimmune Addison's disease (AAD) is a classic organ-specific autoimmune disease characterized by an immune-mediated attack on the adrenal cortex. As most autoimmune diseases, AAD is believed to be caused by a combination of genetic and environmental factors, and probably interactions between the two. Persistent viral infections have been suggested to play a triggering role, by invoking inflammation and autoimmune destruction. The inability of clearing infections can be due to aberrations in innate immunity, including mutations in genes involved in the recognition of conserved microbial patterns. In a whole exome sequencing study of anonymized AAD patients, we discovered several rare variants predicted to be damaging in the gene encoding Toll-like receptor 3 (TLR3). TLR3 recognizes double stranded RNAs, and is therefore a major factor in antiviral defense. We here report the occurrence and functional characterization of five rare missense variants in TLR3 of patients with AAD. Most of these variants occurred together with a common TLR3 variant that has been associated with a wide range of immunopathologies. The biological implications of these variants on TLR3 function were evaluated in a cell-based assay, revealing a partial loss-of-function effect of three of the rare variants. In addition, rare mutations in other members of the TLR3-interferon (IFN) signaling pathway were detected in the AAD patients. Together, these findings indicate a potential role for TLR3 and downstream signaling proteins in the pathogenesis in a subset of AAD patients., Highlights • Viral infections might play a triggering role in autoimmune Addison's disease, by invoking inflammation in the adrenals. • Rare variants in innate immune genes may influence the anti-viral immune response. • We have identified rare and damaging variants in the genes TLR3, IRF3, IKBKE and TICAM1 in patients with autoimmune Addison's disease. • Functional characterization of the TLR3 variants revealed a partial loss-of-function effect in three out of five variants. • PBMCs from patients carrying damaging TLR3 variants showed decreased production of IL28A/IFNλ2 in response to dsRNA.

Objective: Deciding the optimal doses of glucocorticoid (GC) replacement treatment in autoimmune Addison’s disease (AAD) is impeded by the lack of reliable biomarkers. This frequently results in over-treatment, with alarming and persistent side-effects, or under-replacement, which could be fatal. There is a need to think new in the quest for robust biomarkers to optimize GC replacement in AAD at an individual level. Aim: We aimed to identify genes that are consistently up- or down-regulated in patients with AAD in response to different GC replacement doses. This information can be used to establish novel biomarkers to guide GC treatment in AAD. Methods: Step 1: Global microarray expression analysis on RNA from whole blood before and after intravenous infusion of 100 mg hydrocortisone (HC) in 10 patients with AAD. To verify the results, we performed real-time PCR to compare gene expression levels of three of the highly differentially expressed genes (FKBP5, MMP9, and DSIPI) to compare gene expression levels before and two, four, and six hours after the HC infusion. Step 2: Rt-PCR to compare expression levels of 93 GC-regulated genes in normal versus very low morning cortisol levels in 27 patients with AAD. Results: Step 1: Two hours after infusion of 100 mg HC, there was a marked increase in FKBP5, MMP9, and DSIPI expression levels. MMP9 and DSIPI expression levels correlated with serum cortisol. Step 2: Expression levels of CEBPB, DDIT4, FKBP5, DSIPI, and VDR were increased and ADARB1, ARIDB5, and POU2F1 decreased in normal versus very low morning cortisol. Normal serum cortisol levels positively correlated with DSIPI, DDIT4, and FKBP5 expression. Conclusions: We introduce gene expression as a novel approach to guide GC replacement in AAD. We suggest that gene expression of DSIPI, DDIT4, and FKBP5 are particularly promising candidate biomarkers of GC replacement, followed by MMP9, CEBPB, VDR, ADARB1, ARID5B, and POU2F1.

Summary Autoimmune Addison’s disease (AAD), or primary adrenocortical insufficiency, is a classical organ-specific autoimmune disease with 160 years of history. AAD is remarkably homogeneous with one major dominant self-antigen, the cytochrome P450 21-hydroxylase enzyme, which is targeted by both autoantibodies and autoreactive T cells. Like most autoimmune diseases, AAD is thought to be caused by an unfortunate combination of genetic and environmental factors. While the number of genetic associations with AAD is increasing, almost nothing is known about environmental factors. A major environmental factor commonly proposed for autoimmune diseases, based partly on experimental and clinical data and partly on shared pathways between anti-viral immunity and autoimmunity, is viral infections. However, there are few reports associating viral infections to AAD, and it has proved difficult to establish which immunological processes that could link any viral infection with the initiation or progression of AAD. In this review, we will summarize the current knowledge on the underlying mechanisms of AAD and take a closer look on the potential involvement of viruses.

Autoimmune Addison's Disease (AAD) is an endocrine and immunological disease of uncertain pathogenesis resulting from the immune system's destruction of the hormone producing cells of the adrenal cortex. The underlying molecular mechanisms are largely unknown, but it is commonly accepted that a combination of genetic susceptibility and environmental impact is critical. In the present study, we identified multiple hypomethylated gene promoter regions in patients with isolated AAD using DNA isolated from CD4+ T cells. The identified differentially methylated regions were distributed evenly across the 10.5-kb-promoter regions covered by the array, and a substantial number localized to promoters of genes involved in immune regulation and autoimmunity. This study reveals a hypomethylated status in CD4+ T cells from AAD patients and indicates differential methylation of promoters of key genes involved in immune responses. publishedVersion

In about 95% of cases, congenital adrenal hyperplasia (CAH) is caused by mutations in CYP21A2 gene encoding steroid 21-hydroxylase (21OH). Recently, we have reported four novel CYP21A2 variants in the Norwegian population of patients with CAH, of which p.L388R and p.E140K were associated with salt wasting (SW), p.P45L with simple virilising (SV) and p.V211M+p.V281L with SV to non-classical (NC) phenotypes. We aimed to characterise the novel variants functionally utilising a newly designed in vitro assay of 21OH enzyme activity and structural simulations and compare the results with clinical phenotypes. CYP21A2 mutations and variants were expressed in vitro. Enzyme activity was assayed by assessing the conversion of 17-hydroxyprogesterone to 11-deoxycortisol by liquid chromatography tandem mass spectroscopy. PyMOL 1.3 was used for structural simulations, and PolyPhen2 and PROVEAN for predicting the severity of the mutants. The CYP21A2 mutants, p.L388R and p.E140K, exhibited 1.1 and 11.3% of wt 21OH enzyme activity, respectively, in vitro. We could not detect any functional deficiency of the p.P45L variant in vitro; although prediction tools suggest p.P45L to be pathogenic. p.V211M displayed enzyme activity equivalent to the wt in vitro, which was supported by in silico analyses. We found good correlations between phenotype and the in vitro enzyme activities of the SW mutants, but not for the SV p.P45L variant. p.V211M might have a synergistic effect together with p.V281L, explaining a phenotype between SV and NC CAH.

Summary Autoimmune Addison's disease (AAD) is caused by selective destruction of the hormone-producing cells of the adrenal cortex. As yet, little is known about the potential role played by environmental factors in this process. Type I and/or type III interferons (IFNs) are signature responses to virus infections, and have also been implicated in the pathogenesis of autoimmune endocrine disorders such as type 1 diabetes and autoimmune thyroiditis. Transient development of AAD and exacerbation of established or subclinical disease, as well as the induction of autoantibodies associated with AAD, have been reported following therapeutic administration of type I IFNs. We therefore hypothesize that exposure to such IFNs could render the adrenal cortex susceptible to autoimmune attack in genetically predisposed individuals. In this study, we investigated possible immunopathological effects of type I and type III IFNs on adrenocortical cells in relation to AAD. Both types I and III IFNs exerted significant cytotoxicity on NCI-H295R adrenocortical carcinoma cells and potentiated IFN-γ- and polyinosine-polycytidylic acid [poly (I : C)]-induced chemokine secretion. Furthermore, we observed increased expression of human leucocyte antigen (HLA) class I molecules and up-regulation of 21-hydroxylase, the primary antigenic target in AAD. We propose that these combined effects could serve to initiate or aggravate an ongoing autoimmune response against the adrenal cortex in AAD.

Addison's disease is a prototypic organ-specific autoimmune disease affecting the adrenal cortex. The CXC chemokine ligand 10 (CXCL10) is expressed early in viral infections, and is produced by primary adrenocortical cells stimulated by certain cytokines. CXCL10 is also elevated in the serum of Addison's disease patients. We therefore investigated if the viral RNA substitute polyinosine-polycytidylic acid (poly (I:C)) could influence the cytokine induced production of CXCL10 by adrenocortical cells. We found that poly (I:C) could induce CXCL10 in NCI-H295R adrenocortical carcinoma cells, either alone or synergistically along with cytokines interferon-γ and tumor necrosis factor-α. This effect was found to be mediated by toll-like receptor 3 and both nuclear factor κB (NFκB) and signal transducer and activator of transcription-1 (STAT1), but not type I interferons, seemed to be involved. We propose that the combination of environmental and endogenous factors presented here, could contribute to the multifactorial pathogenesis of autoimmune Addison's disease.

Context: Autoimmune polyendocrine syndrome type 1 (APS1) is a childhood-onset monogenic disease defined by the presence of two of the three major components: hypoparathyroidism, primary adrenocortical insufficiency, and chronic mucocutaneous candidiasis (CMC). Information on longitudinal follow-up of APS1 is sparse. Objective: To describe the phenotypes of APS1 and correlate the clinical features with autoantibody profiles and autoimmune regulator (AIRE) mutations during extended follow-up (1996–2016). Patients: All known Norwegian patients with APS1. Results: Fifty-two patients from 34 families were identified. The majority presented with one of the major disease components during childhood. Enamel hypoplasia, hypoparathyroidism, and CMC were the most frequent components. With age, most patients presented three to five disease manifestations, although some had milder phenotypes diagnosed in adulthood. Fifteen of the patients died during follow-up (median age at death, 34 years) or were deceased siblings with a high probability of undisclosed APS1. All except three had interferon-ω) autoantibodies, and all had organ-specific autoantibodies. The most common AIRE mutation was c.967_979del13, found in homozygosity in 15 patients. A mild phenotype was associated with the splice mutation c.879+1G>A. Primary adrenocortical insufficiency and type 1 diabetes were associated with protective human leucocyte antigen genotypes. Conclusions: Multiple presumable autoimmune manifestations, in particular hypoparathyroidism, CMC, and enamel hypoplasia, should prompt further diagnostic workup using autoantibody analyses (eg, interferon-ω) and AIRE sequencing to reveal APS1, even in adults. Treatment is complicated, and mortality is high. Structured follow-up should be performed in a specialized center., Extended follow-up (1996–2016) of 52 Norwegian APS-1 patients describing clinical manifestations, natural course including mortality, autoantibody profiles and Autoimmune Regulator (AIRE) mutations.

Autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy (APECED) is a monogenic autoimmune disease caused by mutations in the AIRE gene. Although mainly an endocrine disease, a substantial fraction of patients have gastrointestinal manifestations. In this study, we have examined the role of anticommensal responses and their regulation. APECED patients had increased levels of Abs against Saccharomyces cerevisiae (p < 0.0001) and against several species of commensal gut bacteria, but not against species predominantly associated with other locations. The anticommensal Ab levels did not correlate with gastrointestinal autoantibodies, neutralizing anti–IL-17 or –IL-22 Abs, or gastrointestinal symptoms, although scarcity of the available clinical data suggests that further study is required. However, the anti–S. cerevisiae Ab levels showed a significant inverse correlation with FOXP3 expression levels in regulatory T cells (Treg), previously shown to be dysfunctional in APECED. The correlation was strongest in the activated CD45RO+ population (ρ = −0.706; p < 0.01). APECED patients also had decreased numbers of FOXP3+ cells in gut biopsies. These results show that APECED patients develop early and sustained responses to gut microbial Ags in a pattern reminiscent of Crohn’s disease. This abnormal immune recognition of gut commensals is linked to a systemic Treg defect, which is also reflected as a local decrease of gut-associated Treg. To our knowledge, these data are the first to show dysregulated responses to non-self commensal Ags in APECED and indicate that AIRE contributes to the regulation of gut homeostasis, at least indirectly. The data also raise the possibility of persistent microbial stimulation as a contributing factor in the pathogenesis of APECED.

In primary adrenocortical failure (Addison's disease) caused by autoimmunity, autoantibodies to the steroidogenic cytochrome P450 enzyme 21-hydroxylase (21OH) are detected in the majority of patients. It is currently uncertain whether the autoantibodies themselves participate in the pathogenesis, or if they merely reflect an on-going T cell mediated response. The identification of T cells reactive with 21OH, if any, has been hampered by the lack of a high-quality antigen. In the current study recombinant human 21OH has been expressed in Spodoptera frugiperda insect cells using a baculovirus expression system. Recombinant enzymatically active 21OH was purified to apparent homogeneity by immobilized metal ion affinity chromatography. The purified enzyme was highly immunogenic in immunized SJL/J mice, and immune responses to 21OH-derived peptides assayed as T cell proliferation and interferon gamma production could be invoked after priming with the recombinant protein. Furthermore, purified 21OH was recognized by sera from patients with autoimmune Addison's disease, and it could block the binding of radiolabeled in vitro translated 21OH in a sensitive fluid-phase radioimmunoassay. We conclude that the recombinant preparation of 21OH presented here is of sufficient purity and quality to be used for studies of cellular and humoral immunity in autoimmune Addison's disease.

Autoimmune Addison's disease is thought to result from T cell mediated autoimmunity. Autoantibodies against the steroidogenic cytochrome P450 enzyme 21-hydroxylase (21OH) are found in most patients, and 21OH is therefore a likely target for antigen-specific T cells.The aim was to study cellular immunity to 21OH and its associations with 21OH autoantibodies and human leukocyte antigen alleles in autoimmune Addison's disease.Peripheral blood mononuclear cells were collected from 33 patients with autoimmune Addison's disease and 21 controls. Cellular proliferation and production of cytokines in response to stimulation with 21OH or 21OH-derived peptides were tested.Cellular proliferation (P = 0.0009) and secretion of interferon-gamma (P0.0001) in response to 21OH was significantly higher in patients compared to healthy controls and associated with the presence of 21OH autoantibodies (P = 0.0052). Furthermore, the 21OH-specific production of interferon-gamma was enhanced in the presence of 21OH autoantibodies. This effect was partially inhibited by antibodies against the Fc receptor for IgG, CD32. Moreover, mature dendritic cells proved superior to the other antigen-presenting cells in invoking cellular responses to 21OH. An association between cellular immunity to 21OH and the high-risk HLA genotype for Addison's disease, DRB1*0301-DQ2/DRB1*0404-DQ8, was observed (P = 0.0089). Finally, a significant association between the DRB1*0404-DQ8 haplotype and cellular responses to a 21OH-derived peptide predicted to bind to DRB1*0404 was detected (P = 0.0055).Patients with autoimmune Addison's disease have circulating 21OH-specific T cells, with amino acids 342-361 of 21OH possibly constituting a disease-specific epitope presented by HLA-DRB1*0404.

SummaryThe autoimmune regulator (AIRE) gene is crucial for establishing central immunological tolerance and preventing autoimmunity. Mutations in AIRE cause a rare autosomal-recessive disease, autoimmune polyendocrine syndrome type 1 (APS-1), distinguished by multi-organ autoimmunity. We have identified multiple cases and families with mono-allelic mutations in the first plant homeodomain (PHD1) zinc finger of AIRE that followed dominant inheritance, typically characterized by later onset, milder phenotypes, and reduced penetrance compared to classical APS-1. These missense PHD1 mutations suppressed gene expression driven by wild-type AIRE in a dominant-negative manner, unlike CARD or truncated AIRE mutants that lacked such dominant capacity. Exome array analysis revealed that the PHD1 dominant mutants were found with relatively high frequency (>0.0008) in mixed populations. Our results provide insight into the molecular action of AIRE and demonstrate that disease-causing mutations in the AIRE locus are more common than previously appreciated and cause more variable autoimmune phenotypes.

Autoimmune Addison's disease (AAD) is a disorder caused by an immunological attack on the adrenal cortex. The interferon (IFN)-inducible chemokine CXCL10 is elevated in serum of AAD patients, suggesting a peripheral IFN signature. However, CXCL10 can also be induced in adrenocortical cells stimulated with IFNs, cytokines, or microbial components. We therefore investigated whether peripheral blood mononuclear cells (PBMCs) from AAD patients display an enhanced propensity to produce CXCL10 and the related chemokine CXCL9, after stimulation with type I or II IFNs or the IFN inducer poly (I:C). Although serum levels of CXCL10 and CXCL9 were significantly elevated in patients compared with controls, IFN stimulated patient PBMC produced significantly less CXCL10/CXCL9 than control PBMC. Low CXCL10 production was not significantly associated with medication, disease duration, or comorbidities, but the low production of poly (I:C)-induced CXCL10 among patients was associated with an AAD risk allele in the phosphatase nonreceptor type 22 (PTPN22) gene. PBMC levels of total STAT1 and -2, and IFN-induced phosphorylated STAT1 and -2, were not significantly different between patients and controls. We conclude that PBMC from patients with AAD are deficient in their response to IFNs, and that the adrenal cortex itself may be responsible for the increased serum levels of CXCL10. publishedVersion

The steroidogenic enzyme 21-hydroxylase (21OH) is the main autoantigen in autoimmune primary adrenal failure (Addison’s disease). Autoantibodies against 21OH are immunological markers of an ongoing autoimmune process but are not directly involved in the tissue destruction. Autoreactive T cells are thought to mediate tissue damage, but the T cell antigen(s) has not been identified. To find out whether 21OH contains important immunodominant epitopes for T cells, we first immunized BALB/c and SJL inbred mouse strains with recombinant 21OH and showed that lymph node cells proliferated effectively following in vitro stimulation with recombinant 21OH (stimulation indices (SI) 20–40). We further synthesized a series of peptides based on 21OH with amino acid sequences with propensity to bind to major histocompatibility complex class II molecules. Only a few peptides could trigger lymphocytes of 21OH-primed mice to proliferate. One of these, 21OH (342–361), stimulated effectively 21OH-primed lymph node cells of SJL mice (SI = 4–8) and also, although to a lesser extent, of BALB/c mice (SI = 2.5). When SJL mice were immunized with 21OH (342–361), the immunizing peptide as well as peptide 21OH (346–361) triggered a significant proliferative response (SI = 24). A peptide from another part of 21OH, namely 21OH (191–202), did not stimulate the 21OH (342–361)-primed cells. Moreover, stimulation of lymph node cells of mice immunized with 21OH (342–361) with 21OH resulted in a significant proliferative response. We conclude that 21OH (342–361) is an immunodominant determinant for T cells in SJL and probably BALB/c mice. 21OH (342–361) corresponds to the substrate binding site of the enzyme. The p342–361 region may be involved in the pathogenesis of autoimmune adrenal failure in humans.

Human cytomegalovirus (HCMV) antigens in glioblastoma (GBM) present opportunities for personalised immunotherapy. However, their presence in GBM tissue is still under debate, and evidence of their impact on functional immune responses and prognosis is sparse. Here, we investigated the presence of pp65 (UL83) and immediate early 1 (IE-1) HCMV antigens in a cohort of Norwegian GBM patients (n = 177), using qPCR, immunohistochemistry, and serology. HCMV status was then used to investigate whether viral antigens influenced immune cell phenotype, infiltration, activation and patient survival. Pp65 and IE-1 were detected by qPCR in 23% and 43% of GBM patients, respectively. Furthermore, there was increased seropositivity in GBM patients relative to donors (79% vs. 48%, respectively; Logistic regression, OR = 4.05, 95%CI [1.807-9.114], P = 0.001, also when adjusted for age (OR = 2.84, 95%CI [1.110-7.275], P = 0.029). Tissue IE-1-positivity correlated with increased CD3+CD8+ T-cell infiltration (P < 0.0001), where CD8+ effector memory T (TEM) cells accounted for the majority of CD8+T cells compared with peripheral blood of HCMV+ patients (P < 0.0001), and HCMV+ (P < 0.001) and HCMV− (P < 0.001) donors. HLA-A2/B8-restricted HCMV-specific CD8+ T cells were more frequent in blood and tumor of HCMV+ GBM patients compared with seronegative patients, and donors irrespective of their serostatus. In biopsies, the HCMV-specific CD8+ TEM cells highly expressed CTLA-4 and PD-1 immune checkpoint protein markers compared with populations in peripheral blood (P < 0.001 and P < 0.0001), which expressed 3-fold greater levels of CD28 (P < 0.001 and P < 0.0001). These peripheral blood T cells correspondingly secreted higher levels of IFNγ in response to pp65 and IE-1 peptide stimulation (P < 0.001). Thus, despite apparent increased immunogenicity of HCMV compared with tumor antigens, the T cells were tolerised, and HCMV status did not impact patient survival (Log Rank3.53 HR = 0.85 95%CI [0.564-1.290], P = 0.45). Enhancing immune functionality in the tumor microenvironment thus may improve patient outcome. publishedVersion

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

ObjectiveSteroid 21-hydroxylase, encoded by CYP21A2, is the major autoantigen in autoimmune Addison's disease (AAD). CYP21A2 is located in the region of the HLA complex on chromosome 6p21.3, which harbours several risk alleles for AAD. The objective was to investigate whether CYP21A2 gene variants confer risk of AAD independently of other risk alleles in the HLA loci.DesignDNA samples from 381 Norwegian patients with AAD and 340 healthy controls (HC) previously genotyped for the HLA-A, -B, -DRB1, and -DQB1 and MICA loci were used for genotyping of CYP21A2.MethodsGenotyping of CYP21A2 was carried out by direct sequencing. Linkage of CYP21A2 to the HLA loci was assessed using UNPHASED version 3.0.10 and PHASE version 2.1.ResultsHeterozygotes of the single-nucleotide polymorphisms (SNPs) rs397515394, rs6467, rs6474, rs76565726 and rs6473 were detected significantly more frequently in AAD patients compared with HC (PHLA–DRB1 haplotypes. rs6472C protected against AAD (odds ratio=0.15, 95% CI (0.08–0.30), P=3.8×10−10). This SNP was not in an LD with HLA loci (P=0.02), but did not increase protection when considering the effect of HLA–DRB1 alleles. Mutations causing congenital adrenal hyperplasia were found in heterozygosity in ConclusionGenetic variants of CYP21A2 associated to AAD are in LD with the main AAD risk locus HLA-DRB1, and CYP21A2 does not constitute an independent susceptibility locus.

An important characteristic of autoimmune polyendocrine syndrome type 1 (APS 1) is the existence of neutralizing autoantibodies (nAbs) against the type I interferons (IFN) -α2 and -ω at frequencies close to 100%. Type 1 IFN autoantibodies are detected by antiviral neutralizing assays (AVA), binding assays with radiolabelled antigens (RLBA), enzyme-linked immunosorbent assay (ELISA), or by reporter-based cell assays. We here present a simple and reliable version of the latter utilizing a commercially available cell line (HEK-Blue IFN-α/β). All 67 APS 1 patients were positive for IFN-ω nAbs, while 90% were positive for IFN-α2 nAbs, a 100% and 96% correlation with RLBA, respectively. All blood donors and non-APS 1 patients were negative. The dilution titer required to reduce the effect of IFN-ω nAbs correlated with the RLBA index. This cell-based autoantibody assay (CBAA) is easy to perform, suitable for high throughput, while providing high specificity and sensitivity.

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.

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

Patients with the autoimmune polyendocrine syndrome I (APS I) have high titers of neutralizing IgG autoantibodies against type I interferons (IFNs), in particular IFN-omega. Until now, the most specific assay has been the antiviral interferon neutralizing assay (AVINA), which has the drawbacks of requiring a cytolytic virus, being cumbersome and difficult to standardise. We have developed a fast and reliable immunoassay based on radiolabelled IFN-omega for quantifying anti-IFN-omega antibodies. Sera from 48 APS I patients were analysed together with those from 5 control groups. All sera from APS I patients were positive for anti-IFN-omega, while, except one serum, all sera from the controls were negative. This method has the advantage over bioassays that it is readily adapted to high throughput. It provides an alternative, sensitive and specific diagnostic test for APS I, and an ideal screening tool to precede mutational analyses of the AIRE gene in suspected APS I cases.

Autoimmune polyendocrine syndrome type I (APS I) is a rare hereditary condition considered a model disease for organ specific autoimmunity. A wide range of autoantibodies targeting antigens present in the affected organs have been identified. Autoantibodies against aromatic l-amino acid decarboxylase (AADC) are present in about 50% of APS I patients. In order to increase our understanding of autoantibody specificity in APS I, the aim of the present study was to localize target regions on AADC recognized by sera from APS I patients. Using several complementing strategies, we have shown that autoantibodies against AADC mainly recognize conformational epitopes. The major antigenic determinants were detected N-terminally to amino acid residue 237. Replacement of amino acids 227–230 (ERDK) with alanine residues reduced the reactivity towards AADC by >80% in all patient sera tested, suggesting that amino acids 227–230 are an important part of an immunodominant epitope.

Background Autoimmune Addison’s disease (AAD) is caused by multiple genetic and environmental factors. Variants of genes encoding immunologically important proteins such as the HLA molecules are strongly associated with AAD, but any environmental risk factors have yet to be defined. We hypothesized that primary or reactivating infections with cytomegalovirus (CMV) could represent an environmental risk factor in AAD, and that CMV specific CD8+ T cell responses may be dysregulated, possibly leading to a suboptimal control of CMV. In particular, the objective was to assess the HLA-B8 restricted CD8+ T cell response to CMV since this HLA class I variant is a genetic risk factor for AAD. Methods To examine the CD8+ T cell response in detail, we analyzed the HLA-A2 and HLA-B8 restricted responses in AAD patients and healthy controls seropositive for CMV antibodies using HLA multimer technology, IFN-γ ELISpot and a CD107a based degranulation assay. Results No differences between patients and controls were found in functions or frequencies of CMV-specific T cells, regardless if the analyses were performed ex vivo or after in vitro stimulation and expansion. However, individual patients showed signs of reactivating CMV infection correlating with poor CD8+ T cell responses to the virus, and a concomitant upregulation of interferon regulated genes in peripheral blood cells. Several recently diagnosed AAD patients also showed serological signs of ongoing primary CMV infection. Conclusions CMV infection does not appear to be a major environmental risk factor in AAD, but may represent a precipitating factor in individual patients. Electronic supplementary material The online version of this article (doi:10.1186/s12967-016-0822-z) contains supplementary material, which is available to authorized users.