Innate and adaptive immunity in patients with autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy

Autoimmune polyendocrine syndrome type 1: case report and review of literature

Autoimmune polyendocrine syndrome type 1 (APECED) is a rare autosomal recessive disorder characterized by autoimmune multiorgan attack. The disease is caused by mutations in the autoimmune regulator gene (AIRE), resulting in defective AIRE protein, which is essential for selftolerance. Clinical manifestations are widely variable. Although the classic triad is composed by mucocutaneous candidiasis, hypoparathyroidism and adrenal failure, many other components may develop. Treatment is based on supplementation of the various deficiencies, and patients require regular follow-up throughout their lifespan. This article describes the case of a patient with the disease, and reviews literature data on the epidemiology, clinical course, immunogenetic aspects, diagnosis and treatment of the syndrome.

Autoimmune regulator regulates autophagy in THP-1 human monocytes

The autoimmune regulator (AIRE) is a crucial factor for the induction of central tolerance, and mutations in this gene lead to abnormal immune responses. However, the role of AIRE in autophagy in immune cells, especially in monocytes, is obscure. In the present study, we found that overexpression of AIRE in THP-1 human monocytes resulted in increased endogenous light chain 3 (LC3)-II level and elevated LC3 positive vesicles. Moreover, an autophagy inhibitor or knockdown of AIRE by small interference RNA attenuated these effects. In contrast, the expression of p62/SQSTM1 remained unchanged in THP-1 cells after the corresponding treatment. Our findings indicate that AIRE plays a role in the regulation of autophagy in THP-1 human monocytes.

Flow cytometry study of blood cell subtypes reflects autoimmune and inflammatory processes in autoimmune polyendocrine syndrome type I

Autoimmune polyendocrine syndrome type I (APS I) is a recessive disorder caused by mutations in the autoimmune regulator (AIRE) gene. AIRE is expressed in medullary epithelial cells where it activates transcription of organ-specific proteins in thymus, thereby regulating autoimmunity. Patients with APS I have, in addition to autoimmune manifestations in endocrine organs, also often ectodermal dystrophies and chronic mucocutaneous candidiasis. The aim of this study was to characterize immune cell subpopulations in patients with APS I and their close relatives. Extensive blood mononuclear cell immunophenotyping was carried out on 19 patients with APS I, 18 first grade relatives and corresponding sex- and age-matched healthy controls using flow cytometry. We found a significant relative reduction in T helper cells coexpressing CCR6 and CXCR3 in patients with APS I compared to controls (mean = 4.10% versus 5.94% respectively, P = 0.035). The pools of CD16(+) monocytes and regulatory T cells (Tregs) were also lower in patients compared with healthy individuals (mean = 15.75% versus 26.78%, P = 0.028 and mean = 4.12% versus 6.73%, P = 0.029, respectively). This is the first report describing reduced numbers of CCR6(+)CXCR3(+) T helper cells and CD16(+) monocytes in patients with APS I We further confirm previous findings of reduced numbers of Tregs in these patients.

Aire

Mutations in the transcriptional regulator, Aire, cause APECED, a polyglandular autoimmune disease with monogenic transmission. Animal models of APECED have revealed that Aire plays an important role in T cell tolerance induction in the thymus, mainly by promoting ectopic expression of a large repertoire of transcripts encoding proteins normally restricted to differentiated organs residing in the periphery. The absence of Aire results in impaired clonal deletion of self-reactive thymocytes, which escape into the periphery and attack a variety of organs. In addition, Aire is a proapoptotic factor, expressed at the final maturation stage of thymic medullary epithelial cells, a function that may promote cross-presentation of the antigens encoded by Aire-induced transcripts in these cells. Transcriptional regulation by Aire is unusual in being very broad, context-dependent, probabilistic, and noisy. Structure/function analyses and identification of its interaction partners suggest that Aire may impact transcription at several levels, including nucleosome displacement during elongation and transcript splicing or other aspects of maturation.