[Atypical clinical presentation of autoimmune polyglandular syndrome type 4]

Autoimmune polyglandular syndromes (APS) are rarely diagnosed conditions characterised by the combination of two or more autoimmune endocrinopathies and nonendocrine autoimmunopathies. They comprise a wide spectrum of autoimmune disorders, differing in the immunologic features of their pathogenesis. Based on their clinical manifestation, APS are divided into four different types. Primary hypoparathyroidism is characteristic for APS type 1, the major disease components of which are adrenal insufficiency, hypoparathyroidism, and candidiasis. However, the literature is sparse regarding the presence of hypoparathyroidism in the remaining types of APS. In our article, we present a case of a young female with primary hypoparathyroidism and a family history of autoimmune disorders who after several years developed type 1 diabetes. She also had anti-transglutaminase and anti-parietal cell antibodies. This constellation of two endocrine disorders and non-endocrine abnormalities led to the diagnosis of APS type 4. We show in details diagnostic and treatment strategies undertaken in our patient and their impact on the course of APS.

Large granular lymphocyte leukemia with pure red cell aplasia associated with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy: an unfortuitous association?

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a recessively inherited monogenic disease caused by a mutation in the autoimmune regulator (AIRE) gene. AIRE plays a major role in central (thymic) immune tolerance. In the absence of AIRE, autoimmunity develops that is especially targeted at endocrine tissues. T-cell large granular lymphocyte (T-LGL) leukemia is a monoclonal lymphoproliferative disease characterized by persistent and indolent lymphocytosis. Autoimmune manifestations, such as rheumatoid arthritis or autoimmune cytopenia, are also common. We report the case of a patient with APECED, who presented with pure red cell aplasia associated with T-LGL leukemia. The association of T-LGL leukemia and APECED is very rare and may not be fortuitous. The immunological mechanisms of this association are discussed.

Renal failure associated with APECED and terminal 4q deletion: evidence of autoimmune nephropathy

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disorder caused by mutations in the autoimmune regulator gene (AIRE). Terminal 4q deletion is also a rare cytogenetic abnormality that causes a variable syndrome of dysmorphic features, mental retardation, growth retardation, and heart and limb defects. We report a 12-year-old Saudi boy with mucocutaneous candidiasis, hypoparathyroidism, and adrenocortical failure consistent with APECED. In addition, he has dysmorphic facial features, growth retardation, and severe global developmental delay. Patient had late development of chronic renal failure. The blastogenesis revealed depressed lymphocytes' response to Candida albicans at 38% when compared to control. Chromosome analysis of the patient revealed 46,XY,del(4)(q33). FISH using a 4p/4q subtelomere DNA probe assay confirmed the deletion of qter subtelomere on chromosome 4. Parental chromosomes were normal. The deleted array was further defined using array CGH. AIRE full gene sequencing revealed a homozygous mutation namely 845_846insC. Renal biopsy revealed chronic interstitial nephritis with advanced fibrosis. In addition, there was mesangial deposition of C3, C1q, and IgM. This is, to the best of our knowledge, the first paper showing evidence of autoimmune nephropathy by renal immunofluorescence in a patient with APECED and terminal 4q deletion.

Impaired T(H)17 responses in patients with chronic mucocutaneous candidiasis with and without autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy

BACKGROUND

Accumulating evidence implicates T(H)17 cytokines in protection against Candida species infections, but the clinical relevance is not clear. Chronic mucocutaneous candidiasis (CMC) is a heterogeneous syndrome with the unifying feature of selective susceptibility to chronic candidiasis. Different subgroups with distinct clinical features are recognized, including autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), CMC with hypothyroidism, and isolated CMC. Understanding immune defects in patients with CMC will define cellular and molecular mechanisms crucial for protection against Candida species in human subjects.

OBJECTIVES

We sought to determine whether impaired T(H)17 responses underlie susceptibility to Candida species infections and whether the same defect is present in different CMC subgroups.

METHODS

We assessed T(H)17 responses of PBMCs to Candida and non-Candida species stimuli by measuring IL-17, IL-22, IL-21, IL-6, IL-23, and IFN-γ cytokine production using cytokine arrays and intracellular cytokine-producing cell numbers and proliferation with flow cytometry. PBMCs from healthy subjects and unaffected family members served as controls.

RESULTS

In patients with CMC with hypothyroidism, T(H)17 cells demonstrated decreased proliferation and IL-17 production in response to Candida species. In contrast, in patients with APECED, T(H)17 cell proliferation and IL-17 production were normal unless exposed to APECED plasma, which inhibited both functions in both APECED and normal PBMCs. Candida species-stimulated IL-22 production was impaired in all patients with CMC, whereas IL-6 and IL-23 responses were unaltered.

CONCLUSION

An impaired T(H)17 response to Candida species, although mediated by different mechanisms, was present in all CMC subgroups studied and might be a common factor predisposing to chronic candidiasis.

[Autoimmune polyendocrine syndrome type 2 associated with autoimmune hypophysitis and coeliac disease]

Autoimmune polyendocrine syndromes (APS) are organ-specific autoimmune disorders affecting multiple endocrine glands; these are gradually destroyed by action of autoantibodies. Similarly to other autoimmune diseases, the presence of certain genetic predisposition is an essential prerequisite to the disease development; polymorphism of the main histocompatible system (HLA in humans) appears to play the most important role. APS are categorized into four types, based on what combination of endocrine glands is affected. APS type 1, characterised by hypoparathyreosis, mucocutaneous candidiasis and Addison's disease, is frequently seen in childhood. For a more common APS type 2 to be diagnosed, Addison's disease together with autoimmune thyroiditis (Schmidt's syndrome) and/or together with diabetes mellitus type I (Carpenter's syndrome) must be present. The third type of autoimmune polyendocrine syndromes (APS type 3) involves the same disorder of endocrine glands as type 2 but usually without any defect of adrenal cortex. If the autoimmune endocrine gland disorder does not fulfil the criteria of APS 1-3, the disease may be categorized as autoimmune polyendocrine syndrome type 4. The authors present a case of 33 years old APS type 2 patient who, over 20 years, developed a wide range of autoimmune endocrinopathies, including endocrinopathies that are less common, such as adenohypophysitis, and are associated with other organ-specific diseases (coeliac disease). The case is presented to demonstrate the fact that APS represent a dynamic process and that it is always important to keep in mind that, over time, a patient may develop other autoimmune diseases. To conclude, the authors emphasise the recommendation to test patients with monoglandular endocrinopathy for the presence of any secondary endocrine disorders.

[A case of autoimmune polyglandular syndrome-related Parkinsonian syndrome that required differentiation from multiple system atrophy]

A 76-year-old woman experienced unsteadiness in walking in 1996. On the basis of clinical and imaging findings, the patient was diagnosed multiple system atrophy. During follow-up, her gait disturbance became aggravated leaving her unable to walk unaided. She was referred to our department in 2003. T2-weighted images on brain magnetic resonance imaging (MRI) revealed low signal intensity in both putamina and a linear high-signal-intensity area on their outsides. Single photon emission computed tomography (SPECT) disclosed a reduced blood flow in both corpora striata. These findings were consistent with the diagnosis of Parkinsonian-type multiple system atrophy. The patient had anti-glutamic acid decarboxylase (GAD) antibody-positive type 1 diabetes mellitus and a normal thyroid function, and was positive for antithyroid antibodies. She was not found to have anemia on blood tests, but was positive for intrinsic factor antibodies. Vitamin B12 was markedly reduced to below the detection limit. The findings suggested that the patient's condition was autoimmune polyglandular syndrome type 3. In 2004, treatment with intramuscular injection of vitamin B12 was initiated, after which the patient's gait disturbance was improved and she was able to walk unaided. In 2009, her unsteady gait returned and was again unable to walk unaided. Autoimmune encephalopathy was suspected, and thus high-dose intravenous immunoglobulin therapy was performed. Following treatment she was able to walk steadily. This case suggests the importance of detailed tests for autoantibodies, including endocrine autoantibodies, and the measurement of vitamin B12 and total homocysteine levels in view of the possibility of autoimmune polyglandular syndrome-related neurological disorders in diabetic patients with intractable neurological disorders that are difficult to diagnose.

Predictive role of the immunostaining pattern of immunofluorescence and the titers of antipituitary antibodies at presentation for the occurrence of autoimmune hypopituitarism in patients with autoimmune polyendocrine syndromes over a five-year follow-up

CONTEXT

Antipituitary antibodies (APA) are frequently present in patients with autoimmune polyendocrine syndrome (APS).

DESIGN

The aim was to evaluate the predictive value of APA for the occurrence of hypopituitarism. A total of 149 APA-positive and 50 APA-negative patients with APS and normal pituitary function were longitudinally studied for 5 yr.

METHODS

APA, by indirect immunofluorescence, and anterior pituitary function were assessed yearly in all patients. The risk for developing autoimmune pituitary dysfunction was calculated using survival and multivariate analysis.

RESULTS

Hypopituitarism occurred in 28 of 149 (18.8%) APA-positive patients but in none of the 50 APA-negative patients. The immunostaining pattern in APA-positive patients involved either isolated pituitary cells [type 1 pattern; n=99 (66.4%)] or all pituitary cells [type 2 pattern; n=50 (33.6%)]. All patients developing pituitary dysfunction throughout the study span had a type 1 pattern. Kaplan-Meier curves for cumulative survival showed a significantly higher rate for developing hypopituitarism in relation to positive APA tests (P<0.005), pattern of immunostaining (P<0.0001), and APA titers (P<0.000001). Cox regression analysis in APA-positive patients with a type 1 pattern demonstrated a significantly (P<0.0001) higher risk for the onset of hypopituitarism in relation to increasing titers of APA.

CONCLUSIONS

APA measurement by immunofluorescence may help to predict the occurrence of hypopituitarism but only when considering the immunostaining pattern and their titers. Combined evaluation of these parameters allows identifying patients at higher risk for pituitary autoimmune dysfunction, thus requiring a strict pituitary surveillance to disclose a preclinical phase of hypopituitarism and possibly interrupt therapeutically the progression to clinically overt disease.

Autoantibodies against IL-17A, IL-17F, and IL-22 in patients with chronic mucocutaneous candidiasis and autoimmune polyendocrine syndrome type I

Most patients with autoimmune polyendocrine syndrome type I (APS-I) display chronic mucocutaneous candidiasis (CMC). We hypothesized that this CMC might result from autoimmunity to interleukin (IL)-17 cytokines. We found high titers of autoantibodies (auto-Abs) against IL-17A, IL-17F, and/or IL-22 in the sera of all 33 patients tested, as detected by multiplex particle-based flow cytometry. The auto-Abs against IL-17A, IL-17F, and IL-22 were specific in the five patients tested, as shown by Western blotting. The auto-Abs against IL-17A were neutralizing in the only patient tested, as shown by bioassays of IL-17A activity. None of the 37 healthy controls and none of the 103 patients with other autoimmune disorders tested had such auto-Abs. None of the patients with APS-I had auto-Abs against cytokines previously shown to cause other well-defined clinical syndromes in other patients (IL-6, interferon [IFN]-gamma, or granulocyte/macrophage colony-stimulating factor) or against other cytokines (IL-1beta, IL-10, IL-12, IL-18, IL-21, IL-23, IL-26, IFN-beta, tumor necrosis factor [alpha], or transforming growth factor beta). These findings suggest that auto-Abs against IL-17A, IL-17F, and IL-22 may cause CMC in patients with APS-I.

A case of type 1 diabetes onset and recurrence of Graves' disease during pegylated interferon-α plus ribavirin treatment for chronic hepatitis C

We report a case of type 1 diabetes onset and recurrence of Graves' disease during pegylated interferon (PEG-IFN)-alpha plus ribavirin treatment for chronic hepatitis C. The patient was a 55-year-old woman diagnosed with chronic hepatitis at age 46 years. She was treated for Graves' disease at 50 years of age. Because Graves' disease remitted, PEG-IFN-alpha plus ribavirin treatment was started for chronic hepatitis C. She was examined because of complaints of general fatigue, weight loss, and palpitations after 24 weeks of the treatment. She was diagnosed with a recurrence of Graves' disease, and methimazole treatment was started. However, she complained of malaise, thirst, polyuria, and loss of body weight. Her fasting blood glucose level was 292 mg/dL and HbA1c was 9.3%. Serum anti-GAD (glutamic acid decarboxylase) antibodies were 2.2 U/mL. She was diagnosed with type 1 diabetes with ketosis, and insulin treatment was started. Serum anti-GAD antibodies gradually increased to 15.1 U/mL. Graves' disease and type 1 diabetes are often complicated, and the coincidental occurrence of these 2 diseases is known as autoimmune polyglandular syndrome type III. However, only a few cases have shown that these diseases occur after IFN treatment.

[Adrenocortical insufficiency and diabetes mellitus type 1]

Adrenocortical disorders represents an important problem in patients with type 1 diabetes mellitus and therefore many physicians are concerned with this issue. The causes of adrenocortical insufficiency include both autoimmunity and dysregulation related to insufficiently compensated diabetes. Early diagnosis of hypocorticism remains doubtful. Diagnostic approaches are not standardized or unified and especially their evaluation and interpretation are a matter of discussion. Treatment of proven hypocorticism, notably of the subclinical form in diabetic patients, remains questionable. Modes of substitution used presently cannot mimic fully diurnal rhythm of glucocorticoid secretion in spite of newly developed drug forms. The risk of glucocorticoid overdose persists, and insulinotherapy need to be adjusted permanently.

Type 1 diabetes and autoimmune polyglandular syndrome: a clinical review

Type 1 diabetes mellitus (T1DM) results from autoimmune destruction of insulin-producing beta cells and is characterised by the presence of insulitis and &and beta-cell autoantibodies. Up to one third of patients develop an autoimmune polyglandular syndrome. Fifteen to 30% of T1DM subjects have autoimmune thyroid disease (Hashimoto's or Graves' disease), 5 to 10% are diagnosed with autoimmune gastritis and/or pernicious anaemia (AIG /PA), 4 to 9% present with coeliac disease (CD), 0.5% have Addison's disease (AD), and 2 to 10% show vitiligo. These diseases are characterised by the presence of autoantibodies against thyroid peroxidase (for Hashimoto's thyroiditis), TSH receptor (for Graves' disease), parietal cell or intrinsic factor (for AIG /PA), tissue transglutaminase (for CD), and 21-hydroxylase (for AD). Early detection of antibodies and latent organ-specific dysfunction is advocated to alert physicians to take appropriate action in order to prevent full-blown disease. Hashimoto's hypothyroidism may cause weight gain, hyperlipidaemia, goitre, and may affect diabetes control, menses, and pregnancy outcome. In contrast, Graves' hyperthyroidism may induce weight loss, atrial fibrillation, heat intolerance, and ophthalmopathy. Autoimmune gastritis may manifest via iron deficiency or vitamin B12 deficiency anaemia with fatigue and painful neuropathy. Clinical features of coeliac disease include abdominal discomfort, growth abnormalities, infertility, low bone mineralisation, and iron deficiency anaemia. Adrenal insufficiency may cause vomiting, anorexia, hypoglycaemia, malaise, fatigue, muscular weakness, hyperkalaemia, hypotension, and generalised hyperpigmentation. Here we will review prevalence, pathogenetic factors, clinical features, and suggestions for screening, follow-up and treatment of patients with T1DM and/or autoimmune polyglandular syndrome.

The autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy or autoimmune polyglandular syndrome type 1

Autoimmune polyglandular syndromes are rare autoimmune endocrinopathies that are associated with nonendocrine autoimmunopathies. Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), also named autoimmune polyglandular syndrome type 1 (APS-1), is distinguished from autoimmune polyglandular syndrome 2 (APS-2). Major disease components of APECED are adrenal insufficiency, hypoparathyroidism, and candidiasis. The diagnosis is established by the presence of two out of the three components. Minor clinical features include autoimmune hepatitis, which occurs in up to 20% of APECED patients, and ranges from a mild to a fulminant course. The disease mostly affects juvenile patients from Sardegna, Italy, Finland, and Iran (Iranian Jews), but it also occurs in other ethnic groups. The AIRE gene responsible for APECED is expressed in cells involved in induction and maintenance of immune tolerance. Genetic alterations of the single gene are associated with APECED. Because a specific therapy is not currently available, treatment consists of hormone replacement and caring for clinical symptoms.

Altered insulin requirement in patients with type 1 diabetes and primary adrenal insufficiency receiving standard glucocorticoid replacement therapy

OBJECTIVE

Current glucocorticoid replacement regimens fail to fully mimic physiologic cortisol secretion in patients with primary adrenal insufficiency. This may lead to changes in insulin requirement in patients with primary adrenal insufficiency and type 1 diabetes. Therefore, we assessed insulin requirement in patients with autoimmune polyendocrine syndrome type 2 (APS-2).

DESIGN AND SUBJECTS

Ten females with primary adrenal insufficiency and type 1 diabetes (mean duration of type 1 diabetes 13+/-11 years and of primary adrenal insufficiency 11+/-9 years) were retrospectively assessed regarding insulin regimen and insulin dose adjustment. Data were compared with control patients matched for age, sex and duration of diabetes drawn from all patients with type 1 diabetes attending the diabetes outpatient clinics at the University Hospital Wuerzburg for a scheduled consultation.

RESULTS

Glycaemia was well controlled in both groups (mean HbA1c 6.99+/-0.81% in APS-2 patients versus 6.69+/-1.03% in control patients). The mean weight-adjusted daily dose of insulin was non-significantly higher in patients with APS-2 compared with control patients (0.69+/-0.35 IU/kg body weight versus 0.51+/-0.17 respectively). The mean insulin (IU)/carbohydrate-ratio for 10 g of carbohydrate in the morning was 1.9+/-1.0 and 1.4+/-0.5 respectively. However, the insulin/carbohydrate-ratios were significantly higher in the APS-2 patients both at noon (mean ratio 2.0+/-0.9 vs 1.1+/-0.5 in control patients) and in the evening (mean ratio 2.1+/-1.1 vs 1.3+/-0.5 respectively; P<0.05).

CONCLUSIONS

Glucocorticoid replacement therapy in patients with primary adrenal insufficiency and type 1 diabetes leads to significant changes in insulin requirement compared with patients with type 1 diabetes only.

[Association of CTLA-4 + 49A/G and CT60 gene polymorphism with type 1 diabetes and thyroid autoimmunity]

OBJECTIVE

To investigate the association of CTLA-4 + 49A/G and CT60 gene polymorphisms with type 1 diabetes (T1DM) and thyroid autoimmunity. Subjects Three hundred thirty-two T1DM patients and 476 controls were recruited in the study.

METHOD

The CTLA-4 + 49 A/G and CT60 polymorphisms of CTLA-4 gene were analyzed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method. Thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) were determined by radioimmunoassay. Glutamic acid decarboxylase antibody (GADA) and protein tyrosine phosphatase antibody (IA-2A) were measured by radioligand immunoassay.

RESULTS

(1) The CTLA-4 + 49 A/G polymorphism was significantly associated with T1DM complicated with thyroid autoimmunity (OR = 2.43, P < 0.01) and with T1DM alone (OR = 1.66, P < 0.05). (2) The CTLA-4 CT60 polymorphism was also significantly associated with T1DM complicated with thyroid autoimmunity (OR = 2.67, P < 0.01) and with T1DM alone (OR = 1.60, P = 0.02). (3) T1DM with thyroid autoimmunity was characterized by a significantly higher frequency of CTLA-4 CT60 GG genotype (77.8% vs 62.3%, P < 0.05) and GADA (77.8% vs 57.4%, P < 0.05) compared to the patients without thyroid antibodies.

CONCLUSION

CTLA-4 + 49 A/G and CT60 gene polymorphism confers genetic susceptibility to type 1 diabetes, particularly in patients with thyroid autoimmunity.

Clinical manifestations and management of patients with autoimmune polyendocrine syndrome type I

Autoimmune polyendocrine syndrome type I (APS-I) is a monogenic model disease of autoimmunity. Its hallmarks are chronic mucocutaneous candidosis, hypoparathyroidism and adrenal insufficiency, but many other autoimmune disease components occur less frequently. The first components usually appear in childhood, but may be delayed to adolescence or early adult life. There is enormous variation in presentation and phenotype, which makes the diagnosis difficult. Antibodies against interferon-omega and -alpha have recently been shown to be sensitive and relatively specific markers for APS-I, and mutational analysis of the autoimmune regulator gene gives the diagnosis in >95% of cases. The treatment and follow-up of patients is demanding and requires the collaboration of specialists of several fields. However, the literature is especially sparse regarding information on treatment and follow-up; hence, we present here a comprehensive overview on clinical characteristics, treatment and follow-up based on personal experience and published studies.

Sicilian family with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) and lethal lung disease in one of the affected brothers

INTRODUCTION

We report the clinical and immunological features of the autoimmune regulator gene (AIRE) in two Sicilian brothers with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). They were compound heterozygotes with R203X/R257X. Both had oral candidiasis since the first year of life and later developed hypoparathyroidism and Addison disease. The elder brother had experienced recurrent lower respiratory infections since 5 years of age and over the years developed severe obstructive lung disease with bronchiectasis, which led to death at 18 years of age. Both brothers had circulating autoantibodies against tryptophan hydroxylase and serotonin-producing cells were absent in the duodenal mucosa. This was associated with intestinal dysfunction in only the elder brother.

CONCLUSION

(1) In the first Sicilian family with APECED reported up to now we found a heterozygous mutation that had been previously reported only once. (2) In the older brother of this family we observed a severe and lethal lung disease; this case adds to a growing literature describing this association between APECED and respiratory illnesses. (3) Tryptophan hydroxylase antibodies might be hypothesized to be the marker of an autoimmune gastrointestinal illness possibly associated with APECED.

Epstein Barr virus induced lymphoma in a child with IPEX syndrome

IPEX syndrome (immune deficiency, polyendocrinopathy, enteropathy, X-linked) is a disorder or regulatory T cell (Treg) function which can result in early death due to infection or complications related to autoimmunity. Therapeutic options for these patients can include allogeneic stem cell transplantation (SCT) or the use of immunosuppressive regimens to control the manifestations of autoimmunity. We report a patient with IPEX syndrome who was managed with rapamycin and subsequently developed EBV induced lymphoma.

Primary immune deficiency disorders presenting as autoimmune diseases: IPEX and APECED

BACKGROUND

Several primary immune deficiency disorders are associated with autoimmunity and malignancy, suggesting a state of immune dysregulation. The concept of immune dysregulation as a direct cause of autoimmunity in primary immune deficiency disorders (PIDDs) has been strengthened by the recent discovery of distinct clinical entities linked to single-gene defects resulting in multiple autoimmune phenomena including immune dysregulation, polyendocrinopathy, enteropathy and X-linked (IPEX) syndrome, and autoimmune polyendocrinopathy, candidiasis and ectodermal dystrophy (APECED) syndrome.

CONCLUSION

Reviewing recent advances in our understanding of the small subgroup of PIDD patients with defined causes for autoimmunity may lead to the development of more effective treatment strategies for idiopathic human autoimmune diseases.

Autoimmune polyendocrine syndrome type 1 and NALP5, a parathyroid autoantigen

BACKGROUND

Autoimmune polyendocrine syndrome type 1 (APS-1) is a multiorgan autoimmune disorder caused by mutations in AIRE, the autoimmune regulator gene. Though recent studies concerning AIRE deficiency have begun to elucidate the molecular pathogenesis of organ-specific autoimmunity in patients with APS-1, the autoantigen responsible for hypoparathyroidism, a hallmark of APS-1 and its most common autoimmune endocrinopathy, has not yet been identified.

METHODS

We performed immunoscreening of a human parathyroid complementary DNA library, using serum samples from patients with APS-1 and hypoparathyroidism, to identify patients with reactivity to the NACHT leucine-rich-repeat protein 5 (NALP5). Subsequently, serum samples from 87 patients with APS-1 and 293 controls, including patients with other autoimmune disorders, were used to determine the frequency and specificity of autoantibodies against NALP5. In addition, the expression of NALP5 was investigated in various tissues.

RESULTS

NALP5-specific autoantibodies were detected in 49% of the patients with APS-1 and hypoparathyroidism but were absent in all patients with APS-1 but without hypoparathyroidism, in all patients with other autoimmune endocrine disorders, and in all healthy controls. NALP5 was predominantly expressed in the cytoplasm of parathyroid chief cells.

CONCLUSIONS

NALP5 appears to be a tissue-specific autoantigen involved in hypoparathyroidism in patients with APS-1. Autoantibodies against NALP5 appear to be highly specific and may be diagnostic for this prominent component of APS-1.