Clues for early detection of autoimmune Addison's disease - myths and realities.

BACKGROUND: Early detection of autoimmune Addison's disease (AAD) is important as delay in diagnosis may result in a life-threatening adrenal crisis and death. The classical clinical picture of untreated AAD is well-described, but methodical investigations are scarce. OBJECTIVE: Perform a retrospective audit of patient records with the aim of identifying biochemical markers for early diagnosis of AAD. MATERIAL AND METHODS: A multicentre retrospective study including 272 patients diagnosed with AAD at hospitals in Norway and Sweden during 1978-2016. Scrutiny of medical records provided patient data and laboratory values. RESULTS: Low sodium occurred in 207 of 247 (84%), but only one-third had elevated potassium. Other common nonendocrine tests were largely normal. TSH was elevated in 79 of 153 patients, and hypoglycaemia was found in 10%. Thirty-three per cent were diagnosed subsequent to adrenal crisis, in whom electrolyte disturbances were significantly more pronounced (P < 0.001). Serum cortisol was consistently decreased (median 62 nmol L-1 [1-668]) and significantly lower in individuals with adrenal crisis (38 nmol L-1 [2-442]) than in those without (81 nmol L-1 [1-668], P < 0.001). CONCLUSION: The most consistent biochemical finding of untreated AAD was low sodium independent of the degree of glucocorticoid deficiency. Half of the patients had elevated TSH levels. Only a minority presented with marked hyperkalaemia or other nonhormonal abnormalities. Thus, unexplained low sodium and/or elevated TSH should prompt consideration of an undiagnosed AAD, and on clinical suspicion bring about assay of cortisol and ACTH. Presence of 21-hydroxylase autoantibodies confirms autoimmune aetiology. Anticipating additional abnormalities in routine blood tests may delay diagnosis.

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.

Consensus statement on the diagnosis, treatment and follow-up of patients with primary adrenal insufficiency.

Primary adrenal insufficiency (PAI), or Addison's disease, is a rare, potentially deadly, but treatable disease. Most cases of PAI are caused by autoimmune destruction of the adrenal cortex. Consequently, patients with PAI are at higher risk of developing other autoimmune diseases. The diagnosis of PAI is often delayed by many months, and most patients present with symptoms of acute adrenal insufficiency. Because PAI is rare, even medical specialists in this therapeutic area rarely manage more than a few patients. Currently, the procedures for diagnosis, treatment and follow-up of this rare disease vary greatly within Europe. The common autoimmune form of PAI is characterized by the presence of 21-hydroxylase autoantibodies; other causes should be sought if no autoantibodies are detected. Acute adrenal crisis is a life-threatening condition that requires immediate treatment. Standard replacement therapy consists of multiple daily doses of hydrocortisone or cortisone acetate combined with fludrocortisone. Annual follow-up by an endocrinologist is recommended with the focus on optimization of replacement therapy and detection of new autoimmune diseases. Patient education to enable self-adjustment of dosages of replacement therapy and crisis prevention is particularly important in this disease. The authors of this document have collaborated within an EU project (Euadrenal) to study the pathogenesis, describe the natural course and improve the treatment for Addison's disease. Based on a synthesis of this research, the available literature, and the views and experiences of the consortium's investigators and key experts, we now attempt to provide a European Expert Consensus Statement for diagnosis, treatment and follow-up.

Risk of hip fracture in Addison's disease: a population-based cohort study.

OBJECTIVES: The results of studies of bone mineral density in Addison's disease (AD) are inconsistent. There are no published data on hip fracture risk in patients with AD. In this study, we compare hip fracture risk in adults with and without AD. DESIGN: A population-based cohort study. METHODS: Through the Swedish National Patient Register and the Total Population Register, we identified 3219 patients without prior hip fracture who were diagnosed with AD at the age of ≥30 years during the period 1964-2006 and 31 557 age- and sex-matched controls. Time to hip fracture was measured. RESULTS: We observed 221 hip fractures (6.9%) in patients with AD and 846 (2.7%) in the controls. Patients with AD had a higher risk of hip fracture [hazard ratio (HR) = 1.8; 95% confidence interval (CI), 1.6-2.1; P < 0.001]. This risk increase was independent of sex and age at or calendar period of diagnosis. Risk estimates did not change with adjustment for type 1 diabetes, autoimmune thyroid disease, rheumatoid arthritis or coeliac disease. Women diagnosed with AD ≤50 years old had the highest risk of hip fracture (HR = 2.7; 95 % CI, 1.6-4.5). We found a positive association between hip fracture and undiagnosed AD [odds ratio (OR) = 2.4; 95 % CI, 2.1-3.0] with the highest risk estimates in the last year before AD diagnosis (OR = 2.8; 95 % CI, 1.8-4.2). CONCLUSION: Both clinically undiagnosed and diagnosed AD was associated with hip fractures, with the highest relative risk seen in women diagnosed with AD ≤50 years of age.

TSGA10 - A target for autoantibodies in autoimmune polyendocrine syndrome type 1 and systemic lupus erythematosus.

Autoimmune polyendocrine syndrome type 1 (APS1) is a rare monogenic autoimmune disorder caused by mutations in the autoimmune regulator (AIRE) gene. High-titre autoantibodies are a characteristic feature of APS1 and are often associated with particular disease manifestations. Pituitary deficits are reported in approximately 7% of APS1 patients, with immunoreactivity to pituitary tissue frequently described. Using APS1 patient serum to immunoscreen a pituitary cDNA expression library, testis specific, 10 (TSGA10) was isolated. Immunoreactivity against TSGA10 was detected in 5/99 (5.05%) patients with APS1, but also in 5/135 (3.70%) systemic lupus erythematosus (SLE) patients and 1/188 (0.53%) healthy controls. TSGA10 autoantibodies were not detected in the serum from patients with any other autoimmune disease. Autoantibodies against TSGA10 were detectable from a young age in 4/5 positive APS1 patients with autoantibody titres remaining relatively constant over time. Furthermore, real-time PCR confirmed TSGA10 mRNA to be most abundantly expressed in the testis and also showed moderate and low expression levels throughout the entire body. TSGA10 should be considered as an autoantigen in a subset of APS1 patients and also in a minority of SLE patients. No recognizable clinical phenotype could be found to correlate with positive autoantibody reactivity.

Lymphocytic hypophysitis: report of two biopsy-proven cases and one suspected case with pituitary autoantibodies.

Lymphocytic hypophysitis (LyH) is a rare inflammatory disease, considered to be autoimmune. LyH has mainly been reported in females and in relation to pregnancy or the post-partum period. We describe a 73-yr-old woman and a 63-yr-old male who were evaluated at our clinic because of pituitary hormone deficits. Both patients had pituitary masses suggestive of a pituitary adenoma on magnetic resonance imaging (MRI). Transsphenoidal pituitary surgery was performed and histopathological examinations revealed LyH in both cases. Clinical, laboratory, radiological and the histopathological findings in these two patients are discussed in detail. In addition, we report on a 79-yr-old man with partial hypopituitarism and empty sella. Screening of a human pituitary cDNA library with his serum revealed autoantibodies against secretogranin II. This is a protein commonly present in human gonadotrophs, thyreotrophs and corticotrophs. Since the patient selectively showed the corresponding pituitary insufficiencies, we speculate on an autoimmune background. Further studies may ascertain the importance of secretogranin II autoantibodies as markers for LyH.

Autoantibodies against pituitary proteins in patients with adrenocorticotropin-deficiency.

BACKGROUND: An autoimmune cause of adrenocorticotropin (ACTH)-deficiency is presented, as it is known to be a characteristic feature of lymphocytic hypophysitis, a disease of the pituitary gland considered to be autoimmune. MATERIALS AND METHODS: The aim of this study was twofold: (1) to evaluate the occurrence of pituitary autoantibodies and (2) to correlate it to clinical and immunological features in a large group of patients with ACTH-deficiency of possible autoimmune aetiology. Sixty-five patients with ACTH-deficiency and 57 healthy subjects participated in the study. Pituitary autoantibodies were measured by an immunoblotting assay with human pituitary cytosol as antigen. RESULTS: Autoantibodies to a novel 36-kDa pituitary autoantigen were seen in sera from 18.5% (12/65) patients and only 3.5% (2/57) of control subjects (P = 0.0214). When taking only those subjects with strong immunoreactivity into account, the significance was lost; P = 0.3642. Immunoreactivity to a 49-kDa pituitary autoantigen was observed in 21.5% (14/65) of ACTH-deficient patients compared with 8.8% (5/57) of control subjects (P = 0.0910). This 49-kDa pituitary autoantigen has recently been identified as neurone-specific enolase and a candidate marker for neuroendocrine autoimmunity. Clinical parameters in patients with positive versus those with negative pituitary immunoreactivity did not differ. However, autoantibodies to thyroglobulin were positively correlated to immunoreactivity against the 36-kDa pituitary autoantigen (P = 0.014). CONCLUSIONS: Our findings of pituitary autoantibodies in patients' sera support the theory that an autoimmune destruction of corticotrophs may be the underlying cause of hormonal deficit in some patients with ACTH-deficiency.

No evidence for autoimmunity as a major cause of the empty sella syndrome.

OBJECTIVE: The cause of empty sella syndrome (ESS) remains largely unknown. We measured eleven organ-specific autoantibodies in serum in order to evaluate possible autoimmune components in ESS. PATIENTS: Thirty patients with ESS and 50 healthy blood donors participated in the study. MEASUREMENTS: Detection of pituitary autoantibodies was performed by immunoblotting with human pituitary cytosol as antigen. Thyroid peroxidase (TPO) and TSH receptor (TRAK) autoantibodies were analysed by radioimmunoassay. The remaining eight autoantibodies were detected by in vitro transcription and translation of the autoantigens and immunoprecipitation. RESULTS: The majority of the ESS patients (18/30) exhibited no immunoreactivity at all. None of the remaining 12 ESS patients reacted against more than one autoantigen. No immunoreactivity was found more frequently among ESS patients than healthy blood donors. Pituitary autoantibodies were not correlated to the ESS patients' pituitary function or sellar size, although the results indicated a tendency of increased autoimmunity in patients with hypopituitarism and normal sella size respectively. CONCLUSION: Detection of autoantibodies is a valuable tool in the diagnostic work-up of autoimmune diseases. By analysing a large number of organ-specific autoantibodies we found no evidence of ESS being associated with any specific autoimmune disease. The pathogenesis of ESS is believed to be heterogeneous and our findings suggest autoimmune components to be of minor importance. In some selective cases, ESS in combination with hypopituitarism may be the result of an autoimmune disease in the pituitary gland but this needs further investigation.