Antibodies against hair follicles are associated with alopecia totalis in autoimmune polyendocrine syndrome type I

Cutaneous Manifestations in Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED): A Comprehensive Review

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), or polyglandular autoimmune syndrome type 1 (PAS-1/APS-1), is a rare autosomal recessive disorder linked to mutations in the autoimmune regulator (AIRE) gene. This review provides a detailed analysis of cutaneous manifestations in APECED, focusing on chronic mucocutaneous candidiasis (CMC), alopecia areata (AA), and vitiligo. The classic triad of hypoparathyroidism, adrenal insufficiency, and CMC serves as a diagnostic cornerstone. However, the varied clinical spectrum of APECED, particularly its cutaneous presentations, poses a diagnostic challenge. CMC, often an early sign, varies in prevalence across populations, including Finnish (100%), Irish (100%), Saudi Arabian (80%), Italian (60-74.7%), North American (51-86%), and Croatian (57.1%) populations. Similarly, AA prevalence varies in different populations. Vitiligo also exhibits variable prevalence across regions. The review synthesizes the current knowledge arising from a narrative analysis of 14 significant human studies published in English up to October 2023. Moreover, this paper underscores the importance of early detection and monitoring, emphasizing cutaneous manifestations as key diagnostic indicators. Ongoing research and clinical vigilance are crucial for unraveling the complexities of this rare autoimmune syndrome and enhancing patient care.

Autoantigen Discovery in the Hair Loss Disorder, Alopecia Areata: Implication of Post-Translational Modifications

Alopecia areata (AA) is a chronic, multifactorial, polygenic, and heterogeneous disorder affecting growing hair follicles in susceptible individuals, which results in a non-scarring and reversible hair loss with a highly unpredictable course. Despite very considerable research effort, the nature of the precipitating factor(s) responsible for initiating AA in any given hair follicle remains unclear, due largely to significant gaps in our knowledge of the precise sequence of the etiopathogenic events in this dermatosis. However, disease-related changes in the immune-competence of the lower growing hair follicle, together with an active immune response (humoral and cellular) to hair follicle-associated antigens, are key associated phenomena. Confirmation of the hair follicle antigen(s) implicated in AA disease onset has remained stubbornly elusive. While it may be considered somewhat philosophical by some, it is also unclear whether immune-mediated hair loss in AA results from a) an ectopic (i.e., in an abnormal location) immune response to native (unmodified) self-antigens expressed by the healthy hair follicle, b) a normal immune response against modified self-antigens (or neoantigens), or c) a normal immune response against self-antigens (modified/non-modified) that were not previously visible to the immune system (because they were conformationally-hidden or sequestered) but become exposed and presentable in an MHC-I/-II molecule-restricted manner. While some candidate hair follicle antigen target(s) in AA are beginning to emerge, with a potential role for trichohyalin, it is not yet clear whether this represents the initial and immunodominant antigenic focus in AA or is simply one of an expanding repertoire of exposed hair follicle tissue damage-associated antigens that are secondary to the disease. Confirmation of autoantigen identity is essential for our understanding of AA etiopathogenesis, and consequently for developing a more informed therapeutic strategy. Major strides have been made in autoantigen discovery in other autoimmune conditions. In particular, some of these conditions may provide insights into how post-translational modifications (e.g., citrullination, deamidation, etc.) of hair follicle-restricted proteins may increase their antigenicity and so help drive the anti-hair follicle immune attack in AA.

Whole exome sequencing in Alopecia Areata identifies rare variants in KRT82

Alopecia areata is a complex genetic disease that results in hair loss due to the autoimmune-mediated attack of the hair follicle. We previously defined a role for both rare and common variants in our earlier GWAS and linkage studies. Here, we identify rare variants contributing to Alopecia Areata using a whole exome sequencing and gene-level burden analyses approach on 849 Alopecia Areata patients compared to 15,640 controls. KRT82 is identified as an Alopecia Areata risk gene with rare damaging variants in 51 heterozygous Alopecia Areata individuals (6.01%), achieving genome-wide significance (p = 2.18E−07). KRT82 encodes a hair-specific type II keratin that is exclusively expressed in the hair shaft cuticle during anagen phase, and its expression is decreased in Alopecia Areata patient skin and hair follicles. Finally, we find that cases with an identified damaging KRT82 variant and reduced KRT82 expression have elevated perifollicular CD8 infiltrates. In this work, we utilize whole exome sequencing to successfully identify a significant Alopecia Areata disease-relevant gene, KRT82, and reveal a proposed mechanism for rare variant predisposition leading to disrupted hair shaft integrity.

Common variants have been discovered to be associated with Alopecia Areata; however, rare variants have been less well studied. Here, the authors use whole-exome sequencing to identify associated rare variants in the hair keratin gene KRT82. Further, they find that individuals with Alopecia Areata have reduced expression of KRT82 in the skin and hair follicle.

Alopecia and the metabolic syndrome

Hair loss is a common condition that affects most people at some point in their lives. It can exist as an isolated problem or with other diseases and conditions. Androgenetic alopecia (AGA) and its association with the metabolic syndrome (MetS) have received increasing interest since 1972, when the first link between cardiovascular risk factors and hair loss was raised. We have reviewed studies concerning the relationship between alopecia and MetS. Many studies have investigated the relationship among AGA and MetS and its individual components, particularly in men, where a disproportionately large number of these studies supports this association. AGA has also been associated with other metabolic-related conditions, including coronary artery disease, polycystic ovary syndrome, and Cushing syndrome, as well as several nutritional deficiencies, all of which have led to many clinicians advocating for the screening of MetS and cardiovascular risk factors in patients who present with AGA.

Mechanisms of tolerance and potential therapeutic interventions in Alopecia Areata

This review aims to address the mechanisms of compromised immune tolerance contributing to the development and maintenance of Alopecia Areata (AA). Our goal is to also highlight future treatment opportunities and therapeutics that will safely and efficiently restore hair growth and maintain patients in remission. AA is a presumptive autoimmune disorder that coincides and genetically clusters to several other autoimmune diseases. In this review, we pay attention to the learnings from the mechanistic research and drug development in these other autoimmune conditions. Interestingly, most of these diseases have been linked to compromised central and peripheral tolerance, and increased intestinal inflammation with enhanced gut permeability. Break of tolerance and priming of the autoreactive T-cells to attack antigenic epitopes in the hair follicle most likely requires several steps which include escape from negative selection and compromised peripheral tolerance. Local skin-related changes are also of importance due to the patchy manifestation of the skin areas with loss of hair, particularly in the early disease. Here, we discuss the defective mechanisms of tolerance, both central and peripheral, and hypothesize that the disease is driven by areas of tolerance break, and that these could be targeted for successful therapeutic interventions.

The immune response to melanoma is limited by thymic selection of self-antigens

The expression of melanoma-associated antigens (MAA) being limited to normal melanocytes and melanomas, MAAs are ideal targets for immunotherapy and melanoma vaccines. As MAAs are derived from self, immune responses to these may be limited by thymic tolerance. The extent to which self-tolerance prevents efficient immune responses to MAAs remains unknown. The autoimmune regulator (AIRE) controls the expression of tissue-specific self-antigens in thymic epithelial cells (TECs). The level of antigens expressed in the TECs determines the fate of auto-reactive thymocytes. Deficiency in AIRE leads in both humans (APECED patients) and mice to enlarged autoreactive immune repertoires. Here we show increased IgG levels to melanoma cells in APECED patients correlating with autoimmune skin features. Similarly, the enlarged T cell repertoire in AIRE^−/− mice enables them to mount anti-MAA and anti-melanoma responses as shown by increased anti-melanoma antibodies, and enhanced CD4⁺ and MAA-specific CD8⁺ T cell responses after melanoma challenge. We show that thymic expression of gp100 is under the control of AIRE, leading to increased gp100-specific CD8⁺ T cell frequencies in AIRE^−/− mice. TRP-2 (tyrosinase-related protein), on the other hand, is absent from TECs and consequently TRP-2 specific CD8⁺ T cells were found in both AIRE^−/− and AIRE^+/+ mice. This study emphasizes the importance of investigating thymic expression of self-antigens prior to their inclusion in vaccination and immunotherapy strategies.

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.

Mouse thymic epithelial cell lines expressing "Aire" and peripheral tissue-specific antigens reproduce in vitro negative selection of T cells

In the human thymus, AIRE (autoimmune regulator) gene is expressed in a very limited type of medullary thymic epithelial cells (mTECs) and no cognate cell lines are available, hence the molecular analysis of AIRE gene function has been difficult. To improve this situation, we attempted to isolate Aire-expressing cells and established three cell lines (Aire⁺TEC1, Aire⁺TEC2, Aire⁺DC) from the abnormally enlarged thymus, which was developed in the transgenic mice expressing SV40 T-antigen driven by the mouse Aire gene promoter. When these Aire⁺ cell lines were co-cultured with fresh thymocytes, they adhered to the majority of thymocytes and induced apoptosis as if negative selection of T-cells in the thymus is occurring in vitro. Further analysis revealed that these Aire⁺ cell lines are derived from mTECs and exhibit characteristic natures of "antigen presenting cells" including several distinct abilities: to express a variety of peripheral tissue-specific antigens, to produce immunoproteasome and immunological synapse, and to express some of TNFSFs (tumor necrosis factor super families). Thus, the newly established Aire⁺ cell lines will be invaluable for the further detailed analysis of AIRE gene function in the central tolerance of immunity and autoimmune disease.

Topical immunotherapy with diphenylcyclopropenone of patients with alopecia areata--a large retrospective study on 142 patients with a self-controlled design

BACKGROUND

Although diphenylcyclopropenone (DCP) is frequently used for the treatment of alopecia areata (AA), large studies with more than 100 patients are still scarce.

OBJECTIVE

To determine the efficacy of DCP immunotherapy in a large cohort of patients with AA who had been treated in our institute from January 2000 to December 2006.

METHODS

A total of 142 patients with AA undergoing topical DCP therapy in a self-controlled design were evaluated retrospectively.

RESULTS

Seven patients (4.9%) were anergic to DCP. Two of 135 patients (1.5%) discontinued DCP therapy because of adverse effects. Fifty-one patients (37.8%) had a complete response (CR: >90% re-growth of hair), 20 patients (14.8%) exhibited a partial response (PR: >50-90% re-growth), 26 patients (19.3%) experienced a minimal response (MR: 10-50% re-growth) and 38 patients (28.1%) had no response after DCP therapy (NR: <10% re-growth). Bivariate logistic analysis revealed that severity of hair loss at the beginning of DCP (P=0.001) is the only significant prognostic factor for therapeutic outcome. Twenty-three patients (45.1%) with CR had relapses upon discontinuation of the treatment or even during prolonged DCP therapy.

CONCLUSION

Topical immunotherapy with DCP of patients with AA is rather effective and mostly well tolerated. The extent of hair loss before therapy is the main predictor for the therapeutic success of DCP. However, DCP therapy is associated with a high degree of relapse of which patients should be well informed.

Serum Interleukin-4 and Total Immunoglobulin E in Nonatopic Alopecia Areata Patients and HLA-DRB1 Typing

Background. Interleukin-4 (IL-4), a Th₂ cytokine, can stimulate immunoglobulin E (IgE) transcription. No previous studies evaluated the genetic mechanisms in nonatopic AA patients with elevated serum IgE. Objective. To compare serum IL-4 and total IgE levels between Egyptian nonatopic AA patients and healthy subjects and to investigate a possible relation to HLA-DRB1 alleles. Results. Serum IL-4 and total IgE were measured by ELISA in 40 controls and 54 nonatopic AA patients. Patients' HLA-DRB1 typing by sequence specific oligonucleotide probe technique was compared to normal Egyptian population. We found significantly elevated serum IL-4 and total IgE in AA patients (particularly alopecia universalis, AU, and chronic patients) (P < .01). HLA-DRB1*11 is a general susceptibility/chronicity allele. DRB1*13 is a protective allele. DRB1*01 and DRB1*07 are linked to chronicity. Localized AA showed decreased DRB1*03 and DRB1*07. Extensive forms showed increased DRB1*08 and decreased DRB1*04. Elevated IL4 and IgE were observed in patients with DRB1*07 and DRB1*11 not DRB1*04. Conclusion. Serum IL-4 and IgE are elevated in nonatopic AA patients, particularly AU and chronic disease. Relevant susceptibility, chronicity, and severity HLADRB1 alleles may have a role in determining type, magnitude, and duration of immune response in AA favouring increased IL4 and IgE.

Screening for associated autoimmune disorders in Polish patients with Addison's disease

Autoimmune Addison's disease (AAD) is the main reason of primary adrenal failure. More than a half of patients display additional autoimmune conditions, which represent a considerable clinical concern. This study aimed to investigate the prevalence of concomitant autoimmune disorders in 85 Polish AAD patients (61 females, 24 males). Mean age at AAD onset was 34.6 ± 12.6 years, significantly earlier in males (P < 0.001). Sixty-nine patients presented positive serum antibodies to 21-hydroxylase and shorter AAD duration than those with negative results (P = 0.027). Seventy-three subjects suffered from coexisting autoimmune disorders. Serum autoantibodies against thyreoperoxidase, thyroglobulin, TSH receptor, glutamic acid decarboxylase, insulin, tyrosine phosphatase-like protein IA2, parietal cell H(+)/K(+)-ATPase, intrinsic factor and tissue transglutaminase were detectable in 71.8, 41.2, 4.7, 21.0, 4.9, 2.5, 49.4, 12.0 and 3.5% of patients, respectively. Antinuclear antibodies were found in 12.5%. Thyroid autoimmunity was most common (46 subjects with lymphocytic thyroiditis, 19 with Graves' disease), followed by atrophic gastritis (29.4%), pernicious anaemia (11.8%), hypergonadotropic hypogonadism (8.2%), vitiligo (8.2%), type 1 diabetes (7.1%), celiac disease (3.5%) and alopecia (2.4%). Gender differences were observed only for thyroid autoimmunity. Current study confirms particular tendency of AAD patients to develop other autoimmune disorders. Active search for concomitant conditions is warranted to prevent serious complications.

Quantification of antineural antibodies in autoimmune neurological disorders

More than 50 different neurological pathologies have a confirmed or suspected autoimmune etiology affecting an estimated number of 75 million people worldwide. Autoantibodies are a useful diagnostic marker for most autoimmune diseases even though their pathological role is not evident, and several tests for their detection are commercially available. However, for autoimmune diseases involving the nervous system, lack of clear information on the identity of antineural antibody targets and the presence of many rare diseases have hampered the development of specific diagnostic assays. This review focuses on the actual knowledge on confirmed and suspected autoimmune diseases that target the CNS and the diagnostic relevance of corresponding antineural autoantibodies.

The autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome

The autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome is characterized by the presence of chronic mucocutaneous candidiasis, adrenal insufficiency, and hypoparathyroidism. Almost all patients have skin or nail findings early in the course of the disease. Therefore, the dermatologist is in the unique position of being able to identify patients with this syndrome early in its course and to facilitate careful monitoring of potentially lethal complications.

Alopecia areata

Alopecia areata (AA) is a nonscarring, autoimmune, inflammatory, hair loss on the scalp, and/or body. Etiology and pathogenesis are still unknown. The most common site affected is the scalp. Histopathology is characterized by an increased number of the catagen and telogen follicles, the presence of inflammatory lymphocytic infiltrate in the peribulbar region ("swarm of bees"). Corticosteroids are the most popular drugs for the treatment of this disease. Etiologic and pathogenic mechanisms, as well as other current treatments available will be discussed in this article.

Evaluation of the profile of alopecia areata and the prevalence of thyroid function test abnormalities and serum autoantibodies in Iranian patients

BACKGROUND

The study aimed at evaluating the prevalence of thyroid function abnormalities in patients with alopecia areata (AA) and its association with other autoimmune diseases and various autoimmune antibodies.

METHOD

We retrospectively analyzed medical records of 123 patients with AA. The main site of involvement, pattern, and extent of alopecia as well as presence of the similar disease in first-degree family members and serologic status of patients were recorded.

RESULTS

Participating in the study were 57 males and 66 females (6 to 59 years old). In the majority of patients (69.9%) the disease was manifested in the first two decades of life. Patients with family members having alopecia were recorded in 24.4%. Thyroid function abnormalities were found in 8.9% of patients. Positive autoimmune antibodies were associated with AA in 51.4% of patients with no significant association between the severity and duration of disease and presence of these antibodies.

CONCLUSION

The incidence of positive auto-immune antibodies in Iranian patients is higher than previous reports. Concerning the female:male ratio, thyroid function tests and the prevalence of alopecia in first-degree relatives, our results are compatible with previous data obtained from different ethnic populations. Previous reports documented that a greater severity and longer duration of AA were seen in the early onset forms; however our result are relatively different which could be explained by differences in genetic factors.

Profiling of Alopecia Areata Autoantigens Based on Protein Microarray Technology

Protein biochips have a great potential in future parallel processing of complex samples as a research tool and in diagnostics. For the generation of protein biochips, highly automated technologies have been developed for cDNA expression library production, high throughput protein expression, large scale analysis of proteins, and protein microarray generation. Using this technology, we present here a strategy to identify potential autoantigens involved in the pathogenesis of alopecia areata, an often chronic disease leading to the rapid loss of scalp hair. Only little is known about the putative autoantigen(s) involved in this process. By combining protein microarray technology with the use of large cDNA expression libraries, we profiled the autoantibody repertoire of sera from alopecia areata patients against a human protein array consisting of 37,200 redundant, recombinant human proteins. The data sets obtained from incubations with patient sera were compared with control sera from clinically healthy persons and to background incubations with anti-human IgG antibodies. From these results, a smaller protein subset was generated and subjected to qualitative and quantitative validation on highly sensitive protein microarrays to identify novel alopecia areata-associated autoantigens. Eight autoantigens were identified by protein chip technology and were successfully confirmed by Western blot analysis. These autoantigens were arrayed on protein microarrays to generate a disease-associated protein chip. To confirm the specificity of the results obtained, sera from patients with psoriasis or hand and foot eczema as well as skin allergy were additionally examined on the disease-associated protein chip. By using alopecia areata as a model for an autoimmune disease, our investigations show that the protein microarray technology has potential for the identification and evaluation of autoantigens as well as in diagnosis such as to differentiate alopecia areata from other skin diseases.

Alopecia Areata: Autoimmunity—The Evidence Is Compelling

There is strong evidence indicating that alopecia areata is a tissue-specific, autoimmune disease. Hair loss is associated with a perifollicular lymphocytic infiltrate made up primarily of CD4+ cells, along with a CD8+ intrafollicular infiltrate. Evidence of immune activation includes expression of HLA-DR; HLA-A,B,C; and ICAM-1 on the follicular epithelium. It is likely that the follicular expression of HLA-DR and ICAM-1 is induced by interferon-gamma produced by T cells. Antibodies to follicular epithelium are often present, but their significance is not known. Lesional scalp from alopecia areata patients grafted onto nude mice regrows hair coincident with a loss of infiltrating lymphocytes from the graft. Hair loss can be transferred to human scalp explants on SCID mice by injection of lesional T cells. It is necessary to activate the T cells by culture with follicular autoantigens. Melanocyte-associated antigens are also capable of activating T cells to induce hair loss, suggesting that they are capable of functioning as autoantigens for alopecia areata. Parallel evidence in rodent models of spontaneous alopecia areata also strongly supports a role for T cells in the pathogenesis of this condition.

The transcription factors SOX9 and SOX10 are vitiligo autoantigens in autoimmune polyendocrine syndrome type I

Vitiligo is common in the hereditary disorder autoimmune polyendocrine syndrome type I (APS I). Patients with APS I are known to have high titer autoantibodies directed against various tissue-specific antigens. Using sera from APS I patients for immunoscreening of a cDNA library from human scalp, we identified the transcription factors SOX9 and SOX10 as novel autoantigens related to this syndrome. Immunoreactivity against SOX9 was found in 14 (15%) and against SOX10 in 20 (22%) of the 91 APS I sera studied. All patients reacting with SOX9 displayed reactivity against SOX10, suggesting shared epitopes. Among the 19 patients with vitiligo, 12 (63%) were positive for SOX10 (p < 0.0001). Furthermore, three of 93 sera from patients with vitiligo unrelated to APS I showed strong reactivity against SOX10, which may indicate a more general role of SOX10 as an autoantigen in vitiligo.