Determination of 21-hydroxylase autoantibodies: inter-laboratory concordance in the Euradrenal International Serum Exchange Program

The multiple faces of autoimmune Addison's disease in children

Primary adrenal insufficiency (PAI) is a rare medical condition, characterized by a deficiency in adrenal hormones. Although rare, PAI is a life-threatening disease requiring prompt recognition and treatment. However, symptoms of PAI are often non-specific and diagnosis can be challenging, causing frequent diagnostic delays. In adults, autoimmunity is the most common cause of PAI in industrialized countries, whereas in children, the most frequent etiology is represented by congenital defects of steroidogenesis and, in particular, by congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. A few recent case series from different countries have reported that autoimmunity is the second most common etiology of PAI in the pediatric age group. However, data on autoimmune PAI in children are still scant and the exact epidemiology, clinical manifestations, and long-term outcomes of this condition have yet to be defined. The scope of this review is to summarize the current knowledge on the etiology, presentation, and treatment of autoimmune PAI in childhood and to increase physicians' awareness of the signs that should raise an early suspicion of this condition.

Improving diagnostic precision in primary ovarian insufficiency using comprehensive genetic and autoantibody testing

STUDY QUESTION

Is it possible to find the cause of primary ovarian insufficiency (POI) in more women by extensive screening?

SUMMARY ANSWER

Adding next generation sequencing techniques including a POI-associated gene panel, extended whole exome sequencing data, as well as specific autoantibody assays to the recommended diagnostic investigations increased the determination of a potential etiological diagnosis of POI from 11% to 41%.

WHAT IS KNOWN ALREADY

POI affects ∼1% of women. Clinical presentations and pathogenic mechanisms are heterogeneous and include genetic, autoimmune, and environmental factors, but the underlying etiology remains unknown in the majority of cases.

STUDY DESIGN, SIZE, DURATION

Prospective cross-sectional study of 100 women with newly diagnosed POI of unknown cause consecutively referred to Haukeland University Hospital, Bergen, Norway, January 2019 to December 2021.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In addition to standard recommended diagnostic investigations including screening for chromosomal anomalies and premutations in the fragile X mental retardation 1 gene (FMR1) we used whole exome sequencing, including targeted analysis of 103 ovarian-related genes, and assays of autoantibodies against steroid cell antigens.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified chromosomal aberrations in 8%, FMR1 premutations in 3%, genetic variants related to POI in 16%, and autoimmune POI in 3%. Furthermore in 11% we identified POI associated genetic Variants of unknown signifcance (VUS). A homozygous pathogenic variant in the ZSWIM7 gene (NM_001042697.2) was found in two women, corroborating this as a novel cause of monogenic POI. No associations between phenotypes and genotypes were found.

LIMITATIONS, REASONS FOR CAUTION

Use of candidate genetic and autoimmune markers limit the possibility to discover new markers. To further investigate the genetic variants, family studies would have been useful. We found a relatively high proportion of genetic variants in women from Africa and lack of genetic diversity in the genomic databases can impact diagnostic accuracy.

WIDER IMPLICATIONS OF THE FINDINGS

Since no specific clinical or biochemical markers predicted the underlying cause of POI discussion of which tests should be part of diagnostic screening in clinical practice remains open. New technology has altered the availability and effectiveness of genetic testing, and cost-effectiveness analyses are required to aid sustainable diagnostics.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by grants and fellowships from Stiftelsen Kristian Gerhard Jebsen, the Novonordisk Foundation, the Norwegian Research Council, University of Bergen, and the Regional Health Authorities of Western Norway. The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

NCT04082169.

Autoimmune primary adrenal insufficiency -current diagnostic approaches and future perspectives

The adrenal glands are small endocrine glands located on top of each kidney, producing hormones regulating important functions in our body like metabolism and stress. There are several underlying causes for adrenal insufficiency, where an autoimmune attack by the immune system is the most common cause. A number of genes are known to confer early onset adrenal disease in monogenic inheritance patterns, usually genetic encoding enzymes of adrenal steroidogenesis. Autoimmune primary adrenal insufficiency is usually a polygenic disease where our information recently has increased due to genome association studies. In this review, we go through the physiology of the adrenals before explaining the different reasons for adrenal insufficiency with a particular focus on autoimmune primary adrenal insufficiency. We will give a clinical overview including diagnosis and current treatment, before giving an overview of the genetic causes including monogenetic reasons for adrenal insufficiency and the polygenic background and inheritance pattern in autoimmune adrenal insufficiency. We will then look at the autoimmune mechanisms underlying autoimmune adrenal insufficiency and how autoantibodies are important for diagnosis. We end with a discussion on how to move the field forward emphasizing on the clinical workup, early identification, and potential targeted treatment of autoimmune PAI.

Autoantibodies involved in primary and secondary adrenal insufficiency following treatment with immune checkpoint inhibitors

Primary and secondary adrenal insufficiency (AI) are commonly known immune-related adverse events following treatment with immune checkpoint inhibitors (ICIs), and are clinically relevant due to their morbidity and potential mortality. For this reason, upfront identification of patients susceptible for ICI-induced AI could be a step in improving patient's safety. Multiple studies have focused on the identification of novel biomarkers for ICI-induced AI, including autoantibodies, which may be involved in ICI-induced AI as a result of the T-cell-mediated activation of autoreactive B cells. This review highlights the currently described autoantibodies that may be involved in either primary [e.g. anti-21-hydroxylase, anti-17α-hydroxylase, anti-P450scc, anti-aromatic L-amino acid decarboxylase (AADC), anti-interferon (IFN)α and anti-IFNΩ] or secondary AI [e.g. anti-guanine nucleotide-binding protein G(olf) subunit alpha (GNAL), anti-integral membrane protein 2B (ITM2B), anti-zinc finger CCHC-type containing 8 (ZCCHC8), anti-pro-opiomelanocortin (POMC), anti-TPIT (corticotroph-specific transcription factor), anti-pituitary-specific transcriptional factor-1 (PIT-1) and others], and discusses the current evidence concerning their role as biomarker for ICI-induced AI. Standardized autoantibody measurements in patients (to be) treated with ICIs would be a clinically accessible and patient-friendly screening method to identify the patients at risk, and could change the management of ICI-induced AI.

Mistaken Identity: The Role of Autoantibodies in Endocrine Disease

BACKGROUND

Autoimmune endocrine diseases can be thought of as a case of mistaken identity. The immune system mistakenly attacks one's own cells, as if they were foreign, which typically results in endocrine gland hypofunction and inadequate hormone production. Type 1 diabetes mellitus and autoimmune thyroid disorders (Hashimoto and Graves diseases) are the most common autoimmune endocrine disorders, while conditions such as Addison disease are encountered less frequently. Autoantibody production can precede clinical presentation, and their measurement may aid verification of an autoimmune process and guide appropriate treatment modalities.

CONTENT

In this review, we discuss type 1 diabetes mellitus, autoimmune thyroid disorders, and Addison disease, emphasizing their associated autoantibodies and methods for clinical detection. We will also discuss efforts to standardize measurement of autoantibodies.

CONCLUSIONS

Autoimmune endocrine disease progression may take months to years and detection of associated autoantibodies may precede clinical onset of disease. Although detection of autoantibodies is not necessary for diagnosis, they may be useful to verify an autoimmune process.

The natural history of 21-hydroxylase autoantibodies in autoimmune Addison's disease

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.

Fertility and pregnancy in women with primary adrenal insufficiency

Primary adrenal insufficiency (PAI) occurs in ~1/5000-1/7000 individuals and is in most cases caused by autoimmune Addison's disease (AAD). Around 10-20% of women with AAD develop premature ovarian insufficiency (POI) before the age of 40 years. 21-Hydroxylase autoantibodies (21OHAb) are the best single immune marker to classify AAD among PAI patients and autoimmune POI in hypergonadotropic hypogonadic women. In AAD, detection of steroid-cell autoantibodies (StCA) predicts future development of POI. AAD-related autoimmune POI is characterized by a selective destruction of theca cells with preservation of primary follicles and granulosa cells of secondary and tertiary follicles. Women with AAD show reduced fertility and parity. Patients with well-managed disease are generally expected to have uneventful pregnancies with favorable outcome, but increased risk of maternal and neonatal complications has been reported. Hence, AAD pregnant women must be carefully monitored by skilled staff which is familiar with the disorder and specific attention must be given to the substitutive therapy.

Autoimmune Addison's disease

Primary adrenal insufficiency (PAI) occurs in 1/5000-1/7000 individuals in the general population. Autoimmune Addison's disease (AAD) is the major cause of PAI and is a major component of autoimmune polyendocrine syndrome type 1 (APS1) and type 2 (APS2). Presence of 21-hydroxylase autoantibodies (21OHAb) identifies subjects with ongoing clinical or pre-clinical adrenal autoimmunity. AAD requires life-long substitutive therapy with two-three daily doses of hydrocortisone (HC) (15-25 mg/day) or one daily dose of dual-release HC and with fludrocortisone (0.5-2.0 mg/day). The lowest possible HC dose must be identified according to clinical and biochemical parameters to minimize long-term complications that include osteoporosis and cardiovascular and metabolic alterations. Women with AAD have lower fertility and parity as compared to age-matched healthy controls. Patients must be educated to double-triple HC dose in the case of fever or infections and to switch to parenteral HC in the case of vomiting, diarrhoea or acute hypotension.

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

BACKGROUND

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

PURPOSE

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

CONCLUSIONS

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

Coexistence of Congenital Adrenal Hyperplasia and Autoimmune Addison's Disease

Background: Underlying causes of adrenal insufficiency include congenital adrenal hyperplasia (CAH) and autoimmune adrenocortical destruction leading to autoimmune Addison's disease (AAD). Here, we report a patient with a homozygous stop-gain mutation in 3β-hydroxysteroid dehydrogenase type 2 (3βHSD2), in addition to impaired steroidogenesis due to AAD. Case Report: Whole exome sequencing revealed an extremely rare homozygous nonsense mutation in exon 2 of the HSD3B2 gene, leading to a premature stop codon (NM_000198.3: c.15C>A, p.Cys5Ter) in a patient with AAD and premature ovarian insufficiency. Scrutiny of old medical records revealed that the patient was initially diagnosed with CAH with hyperandrogenism and severe salt-wasting shortly after birth. However, the current steroid profile show complete adrenal insufficiency including low production of pregnenolone, dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEA-S), without signs of overtreatment with steroids. Conclusion: To the best of our knowledge, this is the first description of autoimmune adrenalitis in a patient with 3βHSD2 deficiency and suggests a possible association between AAD and inborn errors of the steroidogenesis.

A Wide Spectrum of Autoimmune Manifestations and Other Symptoms Suggesting Immune Dysregulation in Patients With Cartilage-Hair Hypoplasia

Background: Mutations in RMRP, encoding a non-coding RNA molecule, underlie cartilage-hair hypoplasia (CHH), a syndromic immunodeficiency with multiple pathogenetic mechanisms and variable phenotype. Allergy and asthma have been reported in the CHH population and some patients suffer from autoimmune (AI) diseases.

Objective: We explored AI and allergic manifestations in a large cohort of Finnish patients with CHH and correlated clinical features with laboratory parameters and autoantibodies.

Methods: We collected clinical and laboratory data from patient interviews and hospital records. Serum samples were tested for a range of autoantibodies including celiac, anti-cytokine, and anti-21-hydroxylase antibodies. Nasal cytology samples were analyzed with microscopy.

Results: The study cohort included 104 patients with genetically confirmed CHH; their median age was 39.2 years (range 0.6–73.6). Clinical autoimmunity was common (11/104, 10.6%) and included conditions previously undescribed in subjects with CHH (narcolepsy, psoriasis, idiopathic thrombocytopenic purpura, and multifocal motor axonal neuropathy). Patients with autoimmunity more often had recurrent pneumonia, sepsis, high immunoglobulin (Ig) E and/or undetectable IgA levels. The mortality rates were higher in subjects with AI diseases (χ(2)2 = 14.056, p = 0.0002). Several patients demonstrated serum autoantibody positivity without compatible symptoms. We confirmed the high prevalence of asthma (23%) and allergic rhinoconjunctivitis (39%). Gastrointestinal complaints, mostly persistent diarrhea, were also frequently reported (32/104, 31%). Despite the history of allergic rhinitis, no eosinophils were observed in nasal cytology in five tested patients.

Conclusions: AI diseases are common in Finnish patients with CHH and are associated with higher mortality, recurrent pneumonia, sepsis, high IgE and/or undetectable IgA levels. Serum positivity for some autoantibodies was not associated with clinical autoimmunity. The high prevalence of persistent diarrhea, asthma, and symptoms of inflammation of nasal mucosa may indicate common pathways of immune dysregulation.

Common genetic variation in the autoimmune regulator (AIRE) locus is associated with autoimmune Addison's disease in Sweden

Autoimmune Addison's disease (AAD) is the predominating cause of primary adrenal failure. Despite its high heritability, the rarity of disease has long made candidate-gene studies the only feasible methodology for genetic studies. Here we conducted a comprehensive reinvestigation of suggested AAD risk loci and more than 1800 candidate genes with associated regulatory elements in 479 patients with AAD and 2394 controls. Our analysis enabled us to replicate many risk variants, but several other previously suggested risk variants failed confirmation. By exploring the full set of 1800 candidate genes, we further identified common variation in the autoimmune regulator (AIRE) as a novel risk locus associated to sporadic AAD in our study. Our findings not only confirm that multiple loci are associated with disease risk, but also show to what extent the multiple risk loci jointly associate to AAD. In total, risk loci discovered to date only explain about 7% of variance in liability to AAD in our study population.

Cytokine Autoantibody Screening in the Swedish Addison Registry Identifies Patients With Undiagnosed APS1

CONTEXT

Autoimmune polyendocrine syndrome type 1 (APS1) is a monogenic disorder that features autoimmune Addison disease as a major component. Although APS1 accounts for only a small fraction of all patients with Addison disease, early identification of these individuals is vital to prevent the potentially lethal complications of APS1.

OBJECTIVE

To determine whether available serological and genetic markers are valuable screening tools for the identification of APS1 among patients diagnosed with Addison disease.

DESIGN

We systematically screened 677 patients with Addison disease enrolled in the Swedish Addison Registry for autoantibodies against interleukin-22 and interferon-α4. Autoantibody-positive patients were investigated for clinical manifestations of APS1, additional APS1-specific autoantibodies, and DNA sequence and copy number variations of AIRE.

RESULTS

In total, 17 patients (2.5%) displayed autoantibodies against interleukin-22 and/or interferon-α4, of which nine were known APS1 cases. Four patients previously undiagnosed with APS1 fulfilled clinical, genetic, and serological criteria. Hence, we identified four patients with undiagnosed APS1 with this screening procedure.

CONCLUSION

We propose that patients with Addison disease should be routinely screened for cytokine autoantibodies. Clinical or serological support for APS1 should warrant DNA sequencing and copy number analysis of AIRE to enable early diagnosis and prevention of lethal complications.

A new ELISA for autoantibodies to steroid 21-hydroxylase

Background:

A new ELISA for autoantibodies to steroid 21-hydroxylase (21-OH Ab) is described.

Methods:

In the assay test sample autoantibodies form a bridge between 21-OH coated onto the plate well and liquid phase 21-OH-biotin. Bound 21-OH-biotin is detected by the addition of streptavidin peroxidase and colorogenic peroxidase substrate.

Results:

Of 100 samples from patients with autoimmune Addison’s disease, 86 (86%) were positive for 21-OH Ab ELISA whereas 84 (84%) were positive in an immunoprecipitation assay based on 125I-labeled 21-OH. Six (0.6%) of 928 healthy adult blood donors and 1 (2.0%) of 49 adult patients with type 1 diabetes mellitus (T1DM) were positive by ELISA. No samples from adult patients with Graves’ disease (GD; n=50), celiac disease (n=29), systemic lupus erythematosis (n=9) or rheumatoid arthritis (n=20) were positive by ELISA. However, 2/51 (3.9%) children with GD, 3/69 (4.3%) children with Hashimoto’s thyroiditis (HT) and 3/119 (2.5%) children with T1DM alone or associated with autoimmune thyroid disorders were ELISA positive.

Conclusions:

The new assay should be useful for screening patients known to be at increased risk of developing clinical autoimmune Addison’s disease, in particular children with HT, GD and/or T1DM.

Heritability of Addison's disease and prevalence of associated autoimmunity in a cohort of 112,100 Swedish twins

PURPOSE

The pathophysiology behind autoimmune Addison's disease (AAD) is poorly understood, and the relative influence of genetic and environmental factors remains unclear. In this study, we examined the heritability of AAD and explored disease-associated autoimmune comorbidity among Swedish twins.

METHODS

A population-based longitudinal cohort of 112,100 Swedish twins was used to calculate the heritability of AAD, and to explore co-occurrence of 10 organ-specific autoimmune disorders in twin pairs with AAD. Diagnoses were collected 1964-2012 through linkage to the Swedish National Patient Register. The Swedish Prescribed Drug Register was used for additional diagnostic precision. When available, biobank serum samples were used to ascertain the AAD diagnosis through identification of 21-hydroxylase autoantibodies.

RESULTS

We identified 29 twins with AAD. Five out of nine (5/9) monozygotic pairs and zero out of fifteen (0/15) dizygotic pairs were concordant for AAD. The probandwise concordance for monozygotic twins was 0.71 (95% CI 0.40-0.90) and the heritability 0.97 (95% CI 0.88-99). Autoimmune disease patterns of monozygotic twin pairs affected by AAD displayed a higher degree of similarity than those of dizygotic twins, with an incidence rate ratio of 15 (95% CI 1.8-116) on the number of shared autoimmune diagnoses within pairs.

CONCLUSIONS

The heritability of AAD appears to be very high, emphasizing the need for further research on the genetic etiology of the disease. Monozygotic twin concordance for multiple autoimmune manifestations suggests strong genetic influence on disease specificity in organ-specific autoimmunity.

Extended exome sequencing identifies BACH2 as a novel major risk locus for Addison's disease

BACKGROUND

Autoimmune disease is one of the leading causes of morbidity and mortality worldwide. In Addison's disease, the adrenal glands are targeted by destructive autoimmunity. Despite being the most common cause of primary adrenal failure, little is known about its aetiology.

METHODS

To understand the genetic background of Addison's disease, we utilized the extensively characterized patients of the Swedish Addison Registry. We developed an extended exome capture array comprising a selected set of 1853 genes and their potential regulatory elements, for the purpose of sequencing 479 patients with Addison's disease and 1394 controls.

RESULTS

We identified BACH2 (rs62408233-A, OR = 2.01 (1.71-2.37), P = 1.66 × 10^-15 , MAF 0.46/0.29 in cases/controls) as a novel gene associated with Addison's disease development. We also confirmed the previously known associations with the HLA complex.

CONCLUSION

Whilst BACH2 has been previously reported to associate with organ-specific autoimmune diseases co-inherited with Addison's disease, we have identified BACH2 as a major risk locus in Addison's disease, independent of concomitant autoimmune diseases. Our results may enable future research towards preventive disease treatment.