Expression of HLA-DR by anagen hair follicles in alopecia areata

Alopecia in Multiple Sclerosis Patients Treated with Disease Modifying Therapies

BACKGROUND

There is currently limited literature addressing the reporting of alopecia in multiple sclerosis (MS) patients treated with disease-modifying therapies (DMTs). Anecdotal reports of hair thinning from patients on various DMTs prompted further investigation of a large database.

OBJECTIVE

To analyze total reports, source of reporting, age distribution, and sex distribution of alopecia associated with DMTs.

METHODS

FDA Adverse Event Reporting System (FAERS) public dashboard and OpenFDA database were analyzed for alopecia reports between January 1, 2009, and June 30, 2020, attributed to usage in MS of FDA approved DMTs. The main outcomes included total reports for each drug, age, sex distribution, and reporting source. OpenFDA data was used for statistical analyses including reporting odds ratios (ROR) and information components.

RESULTS

8759 alopecia reports were identified among 44 114 adverse events in skin and subcutaneous tissue disorders (19.9%). 3701 (42.3%) with teriflunomide, 1675 (19.1%) with dimethyl fumarate, 985 (11.2%) with natalizumab, 926 (10.6%) with fingolimod, 659 (7.5%) with interferon beta-1a, 257 (2.9%) with glatiramer acetate, 243 (2.8%) with ocrelizumab, 124 (1.4%) with interferon beta-1b, 117 (1.3%) with alemtuzumab, 36 (.4%) with siponimod, 24 (.3%) with cladribine, and 12 (.1%) with rituximab. Reports were mostly made by patients (78.3%) and highest in fifth and sixth decades of life. OpenFDA analyses showed increased ROR (ROR 95% confidence interval) of alopecia in females with teriflunomide (18.00, 17.12-18.93), alemtuzumab (1.43, 1.16-1.76), dimethyl fumarate (1.26, 1.18-1.34), and ocrelizumab (1.28, 1.11-1.49). Increased ROR in males was associated with teriflunomide (24.65, 20.72-29.31).

CONCLUSION

We identified many reports of alopecia for DMTs in addition to teriflunomide. Within the limitations of the database, increased RORs of alopecia were observed for females treated with alemtuzumab, dimethyl fumarate, and ocrelizumab. The source of reporting was largely driven by female patients. Possible alopecia, even if transient, should be considered during patient education when starting DMTs.

A "hair-raising" history of alopecia areata

A 3500-year-old papyrus from ancient Egypt provides a list of treatments for many diseases including "bite hair loss," most likely alopecia areata (AA). The treatment of AA remained largely unchanged for over 1500 years. In 30 CE, Celsus described AA presenting as scalp alopecia in spots or the "windings of a snake" and suggested treatment with caustic compounds and scarification. The first "modern" description of AA came in 1813, though treatment still largely employed caustic agents. From the mid-19th century onwards, various hypotheses of AA development were put forward including infectious microbes (1843), nerve defects (1858), physical trauma and psychological stress (1881), focal inflammation (1891), diseased teeth (1902), toxins (1912) and endocrine disorders (1913). The 1950s brought new treatment developments with the first use of corticosteroid compounds (1952), and the first suggestion that AA was an autoimmune disease (1958). Research progressively shifted towards identifying hair follicle-specific autoantibodies (1995). The potential role of lymphocytes in AA was made implicit with immunohistological studies (1980s). However, studies confirming their functional role were not published until the development of rodent models (1990s). Genetic studies, particularly genome-wide association studies, have now come to the forefront and open up a new era of AA investigation (2000s). Today, AA research is actively focused on genetics, the microbiome, dietary modulators, the role of atopy, immune cell types in AA pathogenesis, primary antigenic targets, mechanisms by which immune cells influence hair growth, and of course the development of new treatments based on these discoveries.

Epigallocatechin-3 Gallate Inhibits STAT-1/JAK2/IRF-1/HLA-DR/HLA-B and Reduces CD8 MKG2D Lymphocytes of Alopecia Areata Patients

BACKGROUND

Alopecia areata (AA) is associated with Interferon- γ (IFN-γ) mediated T-lymphocyte dysfunction and increased circulating Interleukine-17 (IL-17) levels. Epigallocatechin-3-gallate (EGCG) specifically inhibits IFN-γ pathways and unlike Janus Kinase 1 and 2 (JAK1/JAK2) inhibitors (tofacitinib, ruxolitinib), EGCG is safer, more cost-effective, and is a topically active agent. Our objective is to test the mode of action of EGCG in vitro and ex vivo using HaCat, Jurkat cell lines, and peripheral blood mononuclear cells (PBMCs) of AA patients and healthy controls (HCs), respectively.

METHODS

distribution of T helper cells (Th1, Th17), and cytotoxic cells (CD8) in PBMCs isolated from 30 AA patients and 30 HCs was investigated by flowcytomterty. In vitro treatment of HaCat and Jurkat cells with 40 μm EGCG for 48 h was performed to measure the level of phosphorylation of signal transducer and activator of transcription protein STAT1, and replicated in ex vivo model using PBMCs of AA patients.

RESULTS

Interestingly, 40 μm EGCG is capable of completely inhibiting phosphorylation of STAT1 after 48 h in HaCat and Jurkat cells and ex vivo in PBMCs of AA patients. Based on QPCR data, the action of EGCG on p-STAT1 seems to be mediated via downregulation of the expression of JAK2 but not JAK1 leading to the inhibition of human leukocyte antigens (HLA-DR and HLA-B) expression probably via IRF-1. On the other hand, AA patients have significantly increased levels of Th1, Th17, and CD8 cells and the production of IFN-γ and IL-17 by PBMCs in AA patients was significantly higher compared to HC; p = 0.008 and p = 0.006, respectively. Total numbers of CD8+ cells were not significantly different between treated and untreated samples. However, CD8+ cells with positive Natural killer group 2 member D (NKG2D) transmembrane receptor (CD8+ NKG2D+ subset) was significantly reduced when PBMCs were treated with 20 μm EGCG for 48 h.

CONCLUSION

These results suggest that EGCG has a synergistic action that inhibits expression of HLA-DR and HLA-B molecules via the IFN-γ pathway to maintain immune privilege in HF; also it reduces CD8+ NKG2D+ subset.

Alopecia areata: a review of disease pathogenesis

BACKGROUND

Alopecia areata is a disorder that results in nonscarring hair loss. The psychological impact can be significant, leading to feelings of depression and social isolation. Objectives In this article, we seek to review the pathophysiological mechanisms proposed in recent years in a narrative fashion.

METHODS

We searched MEDLINE and Scopus for articles related to alopecia areata, with a particular emphasis on its pathogenesis.

RESULTS

The main theory of alopecia areata pathogenesis is that it is an autoimmune phenomenon resulting from a disruption in hair follicle immune privilege. What causes this breakdown is an issue of debate. Some believe that a stressed hair follicle environment triggers antigen presentation, while others blame a dysregulation in the central immune system entangling the follicles. Evidence for the latter theory is provided by animal studies, as well investigations around the AIRE gene. Different immune-cell lines including plasmacytoid dendritic cells, natural killer cells and T cells, along with key molecules such as interferon-γ, interleukin-15, MICA and NKG2D, have been identified as contributing to the autoimmune process.

CONCLUSIONS

Alopecia areata remains incurable, although it has been studied for years. Available treatment options at best are beneficial for milder cases, and the rate of relapse is high. Understanding the exact mechanisms of hair loss in alopecia areata is therefore of utmost importance to help identify potential therapeutic targets.

HLA-DRB1 polymorphisms and alopecia areata disease risk: A systematic review and meta-analysis

BACKGROUND

Published studies have reported conflicting and heterogeneous results regarding the association between human leukocyte antigen (HLA)-DRB1 polymorphisms and alopecia areata (AA). This study aimed to review and quantitatively analyze the association between HLA-DRB1 polymorphisms and AA.

METHODS

In this study, all relevant publications were searched through December 2016. Odds ratios (ORs) and confidence intervals (CIs) for comparisons between case and control groups were calculated. Stata 14.0 software was used to perform statistical analysis. This research does not require formal ethical approval because the data used in this analysis do not involve personal information and thus do not affect privacy.

RESULTS

Twelve articles were identified. For HLA-DRB1*04 and HLA-DRB1*16 polymorphisms, the OR (95% CIs) was 1.49 (1.24-1.78) and 1.61 (1.08-2.41), and P was <.01 and <.01, respectively. For HLA-DRB1*0301, HLA-DRB1*09, and HLA-DRB1*13 polymorphisms, the OR (95% CIs) was 0.42 (0.28-0.63), 0.74 (0.55-0.99), and 0.62 (0.40-0.98), and P was <.01, <.01, and <.01, respectively. Statistical evidence revealed no publication bias (P > .05).

CONCLUSION

The present meta-analysis suggested that HLA-DRB1*04 and HLA-DRB1*16 polymorphisms might be associated with increased AA risk, while HLA-DRB1*0301, HLA-DRB1*09, and HLA-DRB1*13 polymorphisms might decrease the AA risk. Studies with adequate methodological quality on gene-gene and gene-environment interactions are needed to validate the results in the future.

Subclinical sensitization with diphenylcyclopropenone is sufficient for the treatment of alopecia areata: Retrospective analysis of 159 cases

BACKGROUND

Contact immunotherapy with diphenylcyclopropenone (DPCP) is presently considered the treatment of choice for extensive alopecia areata. However, a major concern with contact immunotherapy is that it causes various adverse effects (AEs) that contribute to discontinuation of treatment.

OBJECTIVE

We investigated whether a modified DPCP treatment protocol can promote hair regrowth with fewer AEs.

METHODS

All patients were sensitized with 0.1% DPCP and began treatment with 0.01% DPCP. Thereafter, the DPCP concentration was slowly increased according to the treatment response and AEs. This was a retrospective review of DPCP treatment with modified protocols in 159 patients with alopecia areata.

RESULTS

Of the 159 patients, 46 (28.9%) showed a complete response and 59 (37.1%) showed a partial response. No patients had AEs after sensitization. During the treatment, only 3 patients (1.9%) showed severe AEs, and 55 showed moderate AEs; however, all were well controlled with antihistamines alone or antihistamines and medium-potency topical steroids. There was no association between treatment response and AEs.

LIMITATIONS

Sample size, subject composition, and the retrospective study design represent potential limitations.

CONCLUSION

A modified DPCP treatment protocol with subclinical sensitization could induce a favorable therapeutic response and result in fewer AEs.

Insignificant Correlation between Thyroid Hormone and Antithyroid Peroxidase Antibodies in Alopecia Areata Patients in Northern Rajasthan

Background

Alopecia areata (AA) is a common, recurrent form of nonscarring alopecia which often presents as circumscribed patches of spontaneous hair loss. The global prevalence of this disease varies from 0.1% to 0.2% in general population and 7-30 cases per 1000 dermatological patients. The etiology of AA still remains uncertain; however, genetic or environmental factor and autoimmunity are claimed responsible for it. Various autoimmune diseases, such as Hashimoto's thyroiditis, diabetes mellitus, vitiligo, and lupus erythematosus, have been reported in association with AA.

Aim

The index study was aimed at estimation of serum T3, T4, thyroid-stimulating hormone, and antithyroid peroxidase (TPO) antibodies.

Material and Methods

Similar age/sex-matched AA patients and controls (110 in each group). Enhanced chemiluminescence immunoassay for thyroid profile and anti-TPO antibody level estimation in veinous blood sample.

Observations

The mean/standard deviation (SD) of T3 was 3.30 ± 0.84 pg/ml in AA while 3.27 ± 0.67 pg/ml in controls (P = 0.302). Serum mean/SD of T4 level was1.23 ± 0.76 ng/dl in AA patients while 1.17 ± 0.34 ng/dl in controls (P = 0.522). The mean/SD of anti-TPO levels in AA patients was 21.52 ± 35.09 while 56.43 ± 140.72 in controls (P = 0.136).

Limitation

The limitation of this study was moderate number of AA patients and different genotype of study population.

Conclusion

Occurrence of thyroid dysfunction and evidence of anti-TPO antibodies in AA is rare event in this study population.

Alopecia areata

Alopecia areata is an autoimmune disorder characterized by transient, non-scarring hair loss and preservation of the hair follicle. Hair loss can take many forms ranging from loss in well-defined patches to diffuse or total hair loss, which can affect all hair-bearing sites. Patchy alopecia areata affecting the scalp is the most common type. Alopecia areata affects nearly 2% of the general population at some point during their lifetime. Skin biopsies of affected skin show a lymphocytic infiltrate in and around the bulb or the lower part of the hair follicle in the anagen (hair growth) phase. A breakdown of immune privilege of the hair follicle is thought to be an important driver of alopecia areata. Genetic studies in patients and mouse models have shown that alopecia areata is a complex, polygenic disease. Several genetic susceptibility loci were identified to be associated with signalling pathways that are important to hair follicle cycling and development. Alopecia areata is usually diagnosed based on clinical manifestations, but dermoscopy and histopathology can be helpful. Alopecia areata is difficult to manage medically, but recent advances in understanding the molecular mechanisms have revealed new treatments and the possibility of remission in the near future.

Histopathologic Findings in the Alopecia Associated with Vogt-Koyanagi-Harada Disease

Background:

Vogt-Koyanagi-Harada (VKH) disease is a rare autoimmune disease primarily involving pigmented structures. The commonly associated alopecia usually precedes leukodermic changes seen in the hair and skin.

Objective:

We present a 46-year-old oriental woman with VKH disease who developed diffuse alopecia followed by the regrowth of nonpigmented hairs. The biopsy specimens showed a peribulbar mononuclear infiltrate with increased telogen/catagemanagen follicles. The most prominent additional histologic finding was melanin pigment release from the matrix into the dermal papillae, fibrous tracks, and surrounding perifollicular sheaths. The peribulbar mononuclear cells showed diffuse immunohistochemical staining of approximately 80 to 90% of the cells for CD3, CD45RO. More than 50% of the mononuclear cells showed positive staining for CD4, whereas approximately 10 to 20% showed staining for TIA with TIA+ cells within the follicular epithelium.

Conclusion:

Although the histologic features seen in the alopecia associated with VKH are consistent with alopecia areata, the prominent pigment release does suggest that the prime target are the melanocytes and that keratinocytes may be secondarily involved.

Identification of Autoantigen Epitopes in Alopecia Areata

Alopecia areata (AA) is believed to be a cell-mediated autoimmune hair loss disease. Both CD4 and cytotoxic CD8 T cells (CTLs) are important for the onset and progression of AA. Hair follicle (HF) keratinocyte and/or melanocyte antigen epitopes are suspected potential targets of autoreactive CTLs, but the specific epitopes have not yet been identified. We investigated the potential for a panel of known epitopes, expressed by HF keratinocytes and melanocytes, to induce activation of CTL populations in peripheral blood mononuclear cells. Specific synthetic epitopes derived from HF antigens trichohyalin and tyrosinase-related protein-2 induced significantly higher frequencies of response in AA CTLs compared with healthy controls (IFN-gamma secretion). Apoptosis assays revealed conditioned media from AA peripheral blood mononuclear cells stimulated with trichohyalin peptides elevated the expression of apoptosis markers in primary HF keratinocytes. A cytokine array revealed higher expression of IL-13 and chemokine ligand 5 (CCL5, RANTES) from AA peripheral blood mononuclear cells stimulated with trichohyalin peptides compared with controls. The data indicate that AA affected subjects present with an increased frequency of CTLs responsive to epitopes originating from keratinocytes and melanocytes; the activated CTLs secreted soluble factors that induced apoptosis in HF keratinocytes. Potentially, CTL response to self-antigen epitopes, particularly trichohyalin epitopes, could be a prognostic marker for human AA.

What causes alopecia areata?

The pathobiology of alopecia areata (AA), one of the most frequent autoimmune diseases and a major unsolved clinical problem, has intrigued dermatologists, hair biologists and immunologists for decades. Simultaneously, both affected patients and the physicians who take care of them are increasingly frustrated that there is still no fully satisfactory treatment. Much of this frustration results from the fact that the pathobiology of AA remains unclear, and no single AA pathogenesis concept can claim to be universally accepted. In fact, some investigators still harbour doubts whether this even is an autoimmune disease, and the relative importance of CD8(+) T cells, CD4(+) T cells and NKGD2(+) NK or NKT cells and the exact role of genetic factors in AA pathogenesis remain bones of contention. Also, is AA one disease, a spectrum of distinct disease entities or only a response pattern of normal hair follicles to immunologically mediated damage? During the past decade, substantial progress has been made in basic AA-related research, in the development of new models for translationally relevant AA research and in the identification of new therapeutic agents and targets for future AA management. This calls for a re-evaluation and public debate of currently prevalent AA pathobiology concepts. The present Controversies feature takes on this challenge, hoping to attract more skin biologists, immunologists and professional autoimmunity experts to this biologically fascinating and clinically important model disease.

In vivo levels of IL-4, IL-10, TGF-β1 and IFN-γ mRNA of the peripheral blood mononuclear cells in patients with alopecia areata in comparison to those in patients with atopic dermatitis

Alopecia areata (AA) has been considered to be supported by an aberrant expression of IFN-gamma as a result of antigen dependent immune response. On the other hand, AA sometimes concurs with atopic diseases, although the mechanism of the concurrence is not clear. This study was designed to elucidate the immune status of AA and the similarity between AA and atopic dermatitis (AD) by analysis of in vivo levels of mRNA of Th1, Th2, and suppressive cytokines of peripheral blood mononuclear cells (PBMC). Using semiquantitative RT-PCR, the levels of cytokine mRNA were measured in freshly isolated PBMC of 47 patients with AA, 15 patients with AD, and 12 healthy controls (HC). The levels of IL-4, IFN-gamma, and TGF-beta1 mRNA were lower in patients with AA than those in HC. The levels of IL-10 mRNA in AA were comparable with those in HC. Decreased levels of IFN-gamma and TGF-beta1 were also shown in patients with AD. These results indicated a similarity (decreased levels of IFN-gamma and TGF-beta1) between AD and AA based on the cytokine profile. In addition, decreased levels of IL-4 mRNA in AA might also explain the experience that the severity of atopic disease coincident with AA is mild in the most of cases. Next, we compared the levels of these cytokine mRNA among the three subgroups of AA that were categorized based on the severity of the symptoms: mild, severe and totalis. Although there was no significant difference between any combinations of the subgroups, there was a tendency to increase the levels of IFN-gamma mRNA and to decrease the levels of IL-4 mRNA according to the severity of alopecia. However, the levels of IFN-gamma mRNA in any subgroups were less than those of HC. These results suggest that IFN-gamma is therefore involved in the pathogenesis of AA, although the information from PBMC is limited. In conclusion, AA might be induced by an aberrant expression of IFN-gamma in individuals whose PBMC produce low amounts of IFN-gamma and TGF-beta1. Further analysis is therefore required to investigate the phenotypes of the population in PBMC with or without reference to regulatory T cells.

[Alopecia areata in animal models--new insights into pathogenesis and treatment of a T cell-mediated autoimmune disorder]

Alopecia areata is a common disease, but for ethical reasons it seems difficult to perform large-scale studies to elucidate the pathogenesis and to develop new therapeutic approaches in man. It is therefore helpful to develop appropriate animal models. The Dundee experimental bald rat (DEBR) and the C3H/HeJ mouse are well-established animal models for alopecia areata and can be used for the study of genetic aspects, pathogenesis and therapy of the disease. In C3H/HeJ mice alopecia areata can be experimentally induced by grafting lesional skin from an affected mouse to a histocompatible recipient which offers the possibility to study the influence of various factors on the development of the disease. Studies on the C3H/HeJ mouse and the DEBR have corroborated the concept that alopecia areata is a T-cell mediated autoimmune disease and various steps and aspects of the pathogenesis have been elucidated. Based on this knowledge new therapeutic options may be developed such as inhibition of lymphocyte-homing by an anti-CD44v10 antibody, or inhibition of costimulation by monoclonal antibodies. Therapeutic studies in the C3H/HeJ mouse and the DEBR suggest that alopecia areata can be treated by topical tacrolimus but treatment in humans may only be successful after development of an improved vehicle that facilitates penetration of tacrolimus down to the hair bulb. Current investigations in mice are designed to elucidate the mechanisms how contact sensitizers act in the treatment of alopecia areata, and this will hopefully lead to the development of more specific approaches based on the beneficial effect of contact sensitizers.

Alopecia areata susceptibility in rodent models

With our current view of alopecia areata as an autoimmune disease, it is probable that disease development in an individual is dependent on multiple genetic and environmental factors interacting in a complex system. Rodent models afford the opportunity to investigate alopecia areata development and to define the significance of the different factors involved. Recently, rodent model characterization has been conducted using flow cytometry, microarray analysis, and functional studies. From these a pattern of events in alopecia areata development has emerged. Although the preliminary activation events for the onset of alopecia areata remain unknown, the response of the immune system is characterized by antigen presentation and costimulation of lymphocytes in the lymph nodes and skin, a deficiency of CD4+/CD25+ regulatory cells, and an action of activated lymphocytes on hair follicles via Fas/FasL signaling and cytokines. Thus, onset of disease may require appropriate (or inappropriate) expression of stimulatory antigens within the hair follicle, the breakdown of the putative hair follicle immune privilege, the presentation of antigens to the immune system, a failure of immune system regulation, and the ability of the activated immune system to disrupt anagen-stage hair follicles. Once the sequence of events is initiated, it may become a self-perpetuating cycle, with epitope spreading leading to a wider range of targets in chronic alopecia areata. Rodent model studies have provided significant insight into alopecia areata, but much more remains to be explained about the mechanisms of disease development.

Expression of vascular endothelial growth factor, apoptosis inhibitors (survivin and p16) and CCL27 in alopecia areata before and after diphencyprone treatment: an immunohistochemical study

BACKGROUND

Alopecia areata (AA) is a relatively common inflammatory form of nonscarring hair loss of unknown pathogenesis, but possibly of autoimmune origin. Topical immunotherapy, using a potent contact allergen such as diphencyprone (DPC), is currently considered the most effective mode of treatment. However, the way in which DPC operates on hair follicles in AA still remains to be elucidated. Vascular endothelial growth factor (VEGF), essential for angiogenesis and vascular permeability, may be responsible for maintaining proper vasculature around hair follicles, and several studies provide evidence that apoptosis is a central element in the regulation of hair follicle and vascular regression. The cutaneous lymphocyte-associated antigen (CLA) and the skin-associated chemokine CCL27 highlight an important role for epithelial cells in controlling homeostatic lymphocyte trafficking.

OBJECTIVES

To determine the expression pattern of VEGF, factor (F)VIII, survivin, p16, CD4, CD8, CLA and CCL27 in alopecic skin before and after treatment with DPC. Methods Immunohistochemical staining methods were applied to skin biopsy specimens obtained from alopecic areas of 14 patients before and after DPC treatment and from five healthy subjects. Sections were incubated with monoclonal antibodies against VEGF, FVIII, survivin, p16, CCL27, CLA, CD4 and CD8, and their immunohistochemical expression was evaluated by light microscopy.

RESULTS

The intensity of VEGF staining in alopecic human hair follicles was significantly lower than in healthy scalp tissue. FVIII immunostaining showed a significantly reduced development of the microvasculature in AA in comparison with healthy scalp tissue. After DPC therapy, cells of alopecic hair follicles showed a significant increase of VEGF immunopositivity, and the number of capillary vessels expressing FVIII was markedly increased in comparison with untreated scalp tissue. The increase in microvessels was associated with strong survivin expression in endothelial cells after treatment. All alopecic specimens showed expression of p16 in the hair follicle outer root sheath (ORS), with a significant increase after therapy. After treatment we observed a significantly decreased number of CD4+ cells and an increase of CD8+ cells (CD4/CD8 ratio 0.85) in alopecic skin compared with untreated scalp tissue (CD4/CD8 ratio 3.45). Most of the T lymphocytes found in inflammatory skin lesions expressed CLA antigen and after therapy we observed a significantly higher CLA positivity in hair follicles (50% or more) in comparison with untreated alopecic scalp tissue. Alopecic patients showed a CCL27 immunopositivity significantly lower than in normal scalp tissue. After DPC therapy the labelling intensity for CCL27 showed a significant increase both in the ORS and in the inner root sheath; similarly, in the basal interfollicular keratinocytes we observed a moderate increase in CCL27 expression.

CONCLUSIONS

Topical immunotherapy exerts an important role in angiogenesis, upregulating VEGF in human hair follicle keratinocytes and upregulating survivin to preserve endothelial cell viability. Moreover, it considerably alters the peribulbar CD4/CD8 ratio, restoring a condition close to normal scalp skin. Our study could contribute to explaining some aspects of AA pathogenesis that are still unknown and aid understanding of how DPC could act in this complex disease.

Neurotrophins and their role in pathogenesis of alopecia areata

Neurotrophins comprise a family of structurally and functionally related proteins that are critical for the development and maintenance of cutaneous innervation. They also fulfill multiple non-neurotrophic functions in skin, including regulation of epidermal proliferation and apoptosis, control of hair follicle development and cycling, and melanogenesis. Numerous indications suggest that neurotrophins play an important role in the pathogenesis of a variety of autoimmune diseases. In this review, we focus on the role of neurotrophins in the pathogenesis of alopecia areata, an autoimmune disorder that affects actively growing hair follicles. Recent data suggest that neurotrophins and their receptors are differentially expressed among the subsets of immune cells in alopecia areata-affected skin. Experimental data suggest that neurotrophins may regulate both the cyclic activity of the hair follicle and the functions of immune cells of inflammatory infiltrates. Additional research is required to bridge the gap between our current knowledge of neurotrophin functions in skin affected by alopecia areata and our knowledge of their potential clinical applications. Progress in this area of research will hopefully lead to the development of multiple applications for neurotrophins and their agonists/antagonists in alopecia areata and other hair growth disorders.

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 pathogenesis of alopecia areata in rodent models

Rodent models of human disease provide an important tool in the investigation of genetic and environmental activation factors, disease pathogenesis, and the development of new and improved treatments. Up to 20% of aged C3H/HeJ mice and 70% of Dundee Experimental Bald Rats (DEBR) develop alopecia areata (AA), a nonscarring, inflammatory hair loss disease with a suspected autoimmune pathogenesis. These rodent models are currently employed in determining the genetic basis of AA, understanding the mechanisms of disease initiation and progression, and defining potential endogenous and environmental influences. Induction of AA by skin graft transfer between affected and unaffected mice has been employed to examine skin and immune system changes during AA pathogenesis. Manipulation of inflammatory cells in vivo indicates AA is primarily a cell mediated disease with auto-antibody production as a secondary event. Whether the AA activating factors are exogenous or endogenous antigens, or involve normal or aberrant epitope expression remains to be elucidated. However, current research suggests a self contained disease cycle involving four key events: (1) Failure of the putative anagen stage hair follicle immune privilege and exposure of hair follicle located AA inciting epitopes to the immune system; (2) Antigen presentation, costimulation, and activation of responsive lymphocytes by antigen presenting cells; (3) Activated inflammatory cell migration to, and infiltration of, hair follicles; (4) The subsequent disruptive actions of the inflammatory cell infiltrate on the hair follicles. Each of these events is vulnerable to therapeutic intervention, and rodent models will be fundamentally involved in developing new treatments for AA.

Transfer of alopecia areata in the human scalp graft/Prkdc(scid) (SCID) mouse system is characterized by a TH1 response

Alopecia areata is an autoimmune condition directed at hair follicles, which results in loss of hair. We have previously demonstrated that it is possible to transfer hair loss, along with the immunohistologic findings of alopecia areata, to human scalp grafts on Prkdc(scid) (SCID) mice by injection of autologous activated lesional T-cells. This study examines the cytokine profile of T-cells and follicular epithelium following transfer of hair loss. Two consistent findings significantly (P < 0.01) associated with hair loss were production of interferon-gamma-inducible protein-10 kDa (IP-10) by follicular epithelium (13/13), and production of INF-gamma by infiltrating T-cells (10/12). Noninjected control grafts regrew hair, and were generally negative for IP-10 (positive 2/9), and INF-gamma (positive 2/9), but expressed of IL-10 on the follicular epithelium (7/9). These data support an INF-gamma TH1 pathogenesis for hair loss in alopecia areata.

Resistance to alopecia areata in C3H/HeJ mice is associated with increased expression of regulatory cytokines and a failure to recruit CD4+ and CD8+ cells

Grafting alopecia areata affected C3H/HeJ mouse skin to littermates induces alopecia areata, but high dietary soy oil reduces alopecia areata susceptibility. Alopecia areata affected and resistant mice were characterized to evaluate possible mechanisms involved in alopecia areata resistance. Of 44 mice that received alopecia areata affected skin grafts but failed to develop alopecia areata, only two of 22 receiving further alopecia areata affected skin grafts developed alopecia areata, whereas 39 of 44 controls developed alopecia areata. Alopecia areata affected skin contained increased numbers of CD4+ and CD8+ cells, increases in pro inflammatory T helper 1 and T helper 2 type cytokines, and upregulation of CD28, CD40L, and their ligands. In draining lymph nodes, a relatively high number of antigen-presenting cells was recovered, whereas several CD44v variants were downregulated. In contrast, alopecia areata resistant mouse skin did not display increased numbers of CD4+ and CD8+ cells, whereas counter-regulatory cytokines interleukins 4 and 10 were upregulated. High expression of CD28, CD80, CD86, CD40, CTLA4, CD44v variants, and FasL occurred in alopecia areata resistant mouse spleens. In vitro, lymph node cells of susceptible and resistant mice responded equally to a mitogenic stimulus, but only lymph node cells from alopecia areata affected mice displayed an increased response with T cell receptor stimulation via anti-CD3 cross-linking. These results suggest alopecia areata is a cell-mediated autoimmune disease, but alopecia areata affected skin graft hosts may resist alopecia areata onset through active counter-regulatory mechanisms. Because alopecia areata resistant mice showed unimpaired responsiveness and a transient inflammatory response towards the graft, it is suggested that alopecia areata develops as a consequence of an inappropriate immune response regulation.

Melanocyte-associated T cell epitopes can function as autoantigens for transfer of alopecia areata to human scalp explants on Prkdc(scid) mice

Alopecia areata is a tissue restricted autoimmune condition affecting the hair follicle, resulting in hair loss. The goal of this study was to test the hypothesis that the autoantigen of alopecia areata is melanocyte associated. Potential autoantigens were tested in the human scalp explant/Prkd(scid) CB-17 mouse transfer system. Scalp T cells from lesional (bald) alopecia areata scalp were cultured with antigen-presenting cells, and antigen, along with interleukin-2. The T cells were then injected into autologous lesional scalp grafts on SCID mice, and hair regrowth was measured. Hair follicle homogenate was used as an autoantigen control. T cells cultured with melanoma homogenate induced statistically significant reduction in hair growth (p <0.01 by ANOVA). HLA-A2-restricted melanocyte peptide epitopes were then tested with lesional scalp T cells from HLA-A2-positive alopecia areata patients. Melanocyte-peptide-activated T cells significantly reduced the number of hairs regrowing in two experiments with six patients (p <0.001 by ANOVA). Injected scalp grafts showed histologic and immunochemical changes of alopecia areata. The most consistent peptide autoantigens were the Gp100-derived G9-209 and G9-280 peptides, as well as MART-1 (27-35). Melanocyte peptide epitopes can function as autoantigens for alopecia areata. Multiple peptides were recognized, suggesting epitope spreading.

Role of cytotoxic T cells in chronic alopecia areata

Cytokines play a role in alopecia areata. We used immunohistochemical and in situ hybridization studies to demonstrate the persistence of pro-inflammatory as well as apoptotic mechanisms in skin biopsies from patients with chronic alopecia areata. In situ hybridization allows the visualization of the distribution of immunocompetent cells in vivo. We studied skin biopsies from 11 untreated alopecia areata patients and two normal controls. In situ hybridization was performed on frozen sections using 35S-radio-labeled riboprobes, specific for IL-1beta, IL-2, IL-6, INFgamma, and granzyme B mRNA. Immunohistochemistry was carried out using an anti-IL-1beta monoclonal antibody, and a monoclonal antibody directed against the human Fas protein. We demonstrated the presence of cells labeled with IL-1beta, IL-6, INFgamma, and granzyme B antisense probes. Similarly, cells labeled with anti-IL-1beta were found in 10 of 11 cases. The labeled cells were located in the mononuclear peri- and intrafollicular infiltrate. Cells expressing granzyme B were found in close contact with the follicle. Fas positivity was demonstrated in four of four cases at the level of the cytoplasmic membrane of the hair follicle keratinocytes. These results, based on visualizing the labeled cells, demonstrate that pro-inflammatory cytokines are produced by the mononuclear cell infiltrate in close contact with follicles in alopecia areata. Furthermore, they demonstrate for the first time that apoptotic mechanisms involving granzyme B and Fas-Fas ligand pathways may play a major role in the persistence of chronic alopecia areata.

Lichen planopilaris-like changes arising within an epidermal nevus: does this case suggest clues to the etiology of lichen planopilaris?

BACKGROUND

Lichen planopilaris shows a perifollicular lymphocytic infiltrate at the level of infundibulum and the isthmus of the hair bulge resulting in necrotic changes within keratinocytes and eventually hair loss.

OBJECTIVE

We present a 14-year-old black male with a history of a raised epidermal lesion on the scalp that was present at birth. Over the past few years, the patient developed gradual hair loss and increased verrucous changes of the skin within the original lesion. Histologic sections of the area showed features consistent with an epidermal nevus peripherally, with a central area showing some features characteristic of those seen in lichen planopilaris. In addition, there was marked hyperkeratosis with increased yeast and bacteria within the follicles.

CONCLUSIONS

Initiating factors in lichen planopilaris are not well defined. Overgrowth of microorganisms with hyperkeratosis results in factors that disrupt the immune privilege of the hair follicle, leading to an immunologic reaction that is limited to the follicle and spares surrounding eccrine structures. This case suggests possible mechanisms involved in the induction of lichen planopilaris.

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

In the autosomal recessively inherited autoimmune polyendocrine syndrome type I (APS I) patients have autoantibodies directed against several endocrine and nonendocrine organs. Alopecia areata is present in about one-third of the patients and usually in the more severe forms, alopecia universalis or totalis. Sera from 39 patients with APS I, diluted 1:150, were used in indirect immunofluorescence staining of cryo-sections from normal human scalp. Two hair follicle staining patterns were observed. A cytoplasmic staining of the differentiating matrix, cuticle, and cortex keratinocytes in the anagen hair follicle was seen in five (13%) APS I sera. All these five patients had alopecia totalis, representing 63% of the eight patients with alopecia totalis (p < 0.0001). Furthermore, four (10%) of the APS I sera stained the nuclei of the melanocytes in the hair follicle. Two of these patients had vitiligo. None of 20 healthy control sera stained the keratinocyte cells or the melanocyte nuclei. These data show that many patients with APS I have high-titer autoantibodies directed against the anagen matrix, cuticle, and cortex keratinocytes and a melanocyte nuclear antigen, and also that the hair follicle keratinocyte staining is associated with alopecia, especially alopecia totalis. This study emphasizes the role of the differentiating anagen keratinocytes as an important structure in the autoimmune etiology of alopecia, both in APS I and at least in a subgroup of patients with alopecia areata unrelated to APS I.

Alopecia areata: an autoimmune disease?

A wide range of hypotheses such as focal infection, trophoneuroses, and endocrine dysfunction, have been previously proposed to explain the pathogenesis of alopecia areata (AA). Currently, the most widely held belief is that AA is an autoimmune disease with cellular and/or humoral immunity directed against anagen hair follicle antigen(s). However, until recently evidence in support of an autoimmune mechanism of AA has been largely circumstantial. More fundamental evidence has recently been amassed in support of AA as an autoimmune disease by using animal models. These data include: 1) identification of cross-species hair follicle specific IgG autoantibodies, 2) The ability to induce AA in an animal model with transfer of skin from affected to naive individuals, and 3) the induction of disease by transfer of lymphocytes to human skin grafted to severe combined immunodeficiency mutant mice. A review of the previous and current data related to the autoimmune basis of AA is provided to put into perspective the future studies needed to definitively determine whether AA is an autoimmune disease.

Successful treatment of alopecia areata-like hair loss with the contact sensitizer squaric acid dibutylester (SADBE) in C3H/HeJ mice

A type of hair loss closely resembling human alopecia areata has been described in C3H/HeJ mice. In order to test the assumed analogy with human alopecia areata, we investigated the efficacy of treatment with the contact allergen squaric acid dibutylester. In 12 C3H/HeJ mice with alopecia areata an allergic contact dermatitis was induced and elicited weekly on one side of the back by topical applications of squaric acid dibutylester. Overt hair regrowth was observed only on the treated side of the back in nine of 12 mice. Histopathologic examination revealed a change in the distribution of the inflammatory infiltrate from a dense perifollicular lymphocytic infiltrate around the mid and lower regions of hair follicles in untreated skin to a uniform presence in the upper dermis in treated skin. Immunohistomorphometric studies revealed that treatment with squaric acid dibutylester increased the CD4+/CD8+ ratio from approximately 1:2 in untreated alopecia areata to 1:1 in treated alopecia areata. Additional immunohistochemical investigations showed an aberrant expression of major histocompatibility complex class I, major histocompatibility complex class II and intercellular adhesion molecule 1 on keratinocytes of the mid and lower parts of hair follicles in untreated alopecia areata. In successfully treated skin ectopic major histocompatibility complex class I and II expression was clearly reduced, whereas intercellular adhesion molecule 1 expression showed only minor changes. In conclusion, alopecia areata-like hair loss in C3H/HeJ mice responded to treatment with the contact sensitizer squaric acid dibutylester analogous to human alopecia areata. Moreover, successful treatment changes the aberrant expression of major histocompatibility complex class I and II in a way similar to that observed in human alopecia areata. These observations support the concept that alopecia areata-like hair loss in C3H/HeJ mice can be utilized as an appropriate model for the study of human alopecia areata.

Severe alopecia areata treated with systemic corticosteroids

BACKGROUND

Treatment of severe alopecia areata is difficult, and most efforts to successfully treat this condition have been disappointing. Systemic corticosteroids have been demonstrated as an effective treatment of severe alopecia areata.

METHODS

Eighteen patients with alopecia areata (extensive patchy and totalis universalis types) were treated with systemic corticosteroids.

RESULTS

Satisfactory hair regrowth was achieved in seven patients (38.9%). Hair fall subsequently occurred in all of these patients on discontinuation or tapering of corticosteroid therapy.

CONCLUSIONS

Systemic corticosteroid therapy does not prevent the spread or relapse of severe alopecia areata and, when complete regrowth is obtained, it is rarely maintained off therapy.

Alopecia areata and cytomegalovirus infection in twins: genes versus environment?

BACKGROUND

Alopecia areata (AA) is hypothesized to be an organ-specific autoimmune disease mediated by T cells directed to the hair follicle. Genetic susceptibility may be conferred by HLA, and an environmental trigger, such as a viral infection, is suspected. The incidence of AA in the population is estimated to be 1.7%, with an average of one in four patients having a positive family history.

OBJECTIVE

Our purpose was to examine the concordance rate of AA among identical versus fraternal twins and the correlation between stress, cytomegalovirus (CMV) infection, and disease.

METHODS

Families with AA were solicited from dermatologists in the United States and through a Website on the Internet. HLA class 2 typing and identification of CMV early and late genes were performed by polymerase chain reaction (PCR) on genomic peripheral blood DNA. Serum antibodies for CMV were determined by enzyme-linked immunosorbent assay.

RESULTS

From 114 families, we identified 11 sets of monozygotic twins and 3 sets of dizygotic twins. The concordance rate was 55% for monozygotic twins and 0% for fraternal twins. Most identical twins were male. The severity of the AA phenotype varied and appeared most severe in the first affected twin. Five of 24 twins were CMV seropositive but CMV DNA was not detected in blood lymphocytes of any of the subjects when studied after the onset of AA. The presence of AA in twins was not correlated with evidence of CMV.

CONCLUSION

A 55% concordance rate in identical twins and AA occurring in families support a genetic component as well as possible environmental triggers that remain unknown.

Autoimmune hair loss (alopecia areata) transferred by T lymphocytes to human scalp explants on SCID mice

Alopecia areata is a tissue-restricted autoimmune disease of the hair follicle, which results in hair loss and baldness. It is often psychologically devastating. The role of T lymphocytes in this disorder was investigated with cell transfer experiments. Scalp explants from patients were transplanted to severe combined immunodeficiency (SCID) mice and injected with autologous T lymphocytes isolated from involved scalp. T lymphocytes which had been cultured with hair follicle homogenate along with antigen-presenting cells were capable of inducing the changes of alopecia areata, including hair loss and perifollicular infiltrates of T cells, along with HLA-DR and ICAM-1 expression of the follicular epithelium. Similar changes were not noted in grafts injected with scalp-derived T cells that had not been cultured with follicular homogenate. These data indicate that alopecia areata is mediated by T cells which recognize a follicular autoantigen.

Genetic control of cytokines. Cytokine gene polymorphisms in alopecia areata

It is likely that alopecia areata is a multifactorial disease determined by a combination of genetic and environmental factors. The interaction of susceptibility genes with environmental factors gives rise to the disease phenotype, and then genetic modifying factors determine the extent of the inflammatory response and thereby the clinical outcome. Cytokines regulate the inflammatory response. Polymorphisms in these genes may therefore determine the amount of a cytokine that is produced in response to an environmental trigger such as a bacterial or viral infection.

The pathogenesis of alopecia areata

Knowledge of the disease mechanisms in alopecia areata is discussed in the light of progress in hair biology, immunology, and genetics. A disease model is presented incorporating polygenic determination of disease severity and susceptibility with largely unknown trigger factors responsible for initiating clinical disease expression. Experimental systems including animal models for alopecia areata offer new opportunities for investigation of alopecia areata and developing novel therapies.

Clinical and histopathologic features of hair loss in patients with HIV-1 infection

BACKGROUND

Hair loss is common in patients with HIV-1 infection, and in black patients this loss may be associated with straightening. Possible causes are frequently present in patients with HIV-1. These causes include chronic HIV-1 infection itself and recurrent secondary infections, nutritional deficiencies, immunologic and endocrine dysregulation, and exposure to multiple drugs. However, histopathologic features have rarely been reported in these patients.

OBJECTIVE

The objective was to evaluate the changes in the hairs of a group of these patients and to identify the light microscopic and ultrastructural changes in the hairs and the histologic changes in the scalp.

METHODS

Hair plucks and pulls with scanning electron microscopy of the hairs were done on 10 patients with late-stage HIV-1 infection. In addition, scalp biopsy specimens were examined in both vertical and transverse sections.

RESULTS

All patients had telogen effluvium. Numerous apoptotic or necrotic keratinocytes were seen in the upper external root sheath follicular epithelium in addition to a mild to moderate perifollicular mononuclear cell infiltrate often containing eosinophils. Variable dystrophy of the hair shafts was also a consistent feature.

CONCLUSION

Although telogen effluvium is a common response to a wide spectrum of biologic stresses, the presence of apoptotic or necrotic keratinocytes within the upper end of the external root sheath epithelium and dystrophy of hairs may be markers of hair loss in patients with HIV-1 infection.

Human leukocyte antigen-DQB1*03 alleles are associated with alopecia areata

Alopecia areata (AA) is characterized by hair loss in patches (patchy AA), over the entire scalp (AT, totalis), or universally (AU). An autoimmune mechanism has been hypothesized, because the inflammatory infiltrate targeted to the hair follicles includes activated T cells. To investigate whether or not genetic polymorphism of the human leukocyte antigen (HLA) region contributes to disease susceptibility, we used sequence-specific oligonucleotides and amplified genomic DNA to define HLA-DQA1, -DQB1, and -DPB1 alleles in a cohort of 85 white patients. The frequency of DQB1*0301 was significantly increased to 41% in all patients, and to 47% in AT/AU patients relative to controls (27%). Analyzed together, DQB1*03 alleles (DQB1*0301-*0303) were increased to 80% (all patients) and to 92% (AT/AU) (odds ratio = 12.14, p = 0.00003, corrected). This striking association implicates the DQB1*03 alleles in the pathogenesis of AA. DQB1*06 was decreased relative to controls (56%) in all patients (32%, odds ratio = 0.37, p = 0.0045, corrected). An increase was observed in the HLA-DRB1*11(DR5) allele DRB1*1104, which may result from linkage disequilibrium with DQB1 alleles. Sequence comparison among the allele products associated with AA indicates that the DQB1*03 alleles carry a unique proline at position 55 that is not present in alleles that are neutral or negatively associated with the disease. This highly significant association may exert considerable control over immune responsiveness and the initiation or persistence of a T-cell autoimmune response against the hair follicle.

Severity of alopecia areata is associated with a polymorphism in the interleukin-1 receptor antagonist gene

One of the most potent pro-inflammatory mediators is the early-acting cytokine interleukin-1. Its actions are regulated by a structurally related anti-inflammatory cytokine known as the interleukin-1 receptor antagonist. We have previously characterized a DNA polymorphism in this gene (IL-1rn) and have found associations between allele 2 and several chronic inflammatory diseases. In the present study, we tested the frequency of allele 2 of the IL-1rn gene in 90 patients with alopecia areata compared with 261 healthy controls. There was a significant association between allele 2 of the polymorphism and the severity of alopecia areata. The frequency of allele 2 increased from 24.1% in the control population to 25.9% in patchy alopecia areata, 36.1% in alopecia totalis, and 47.2% in alopecia universalis (p = 0.005). This severity association is similar to that found in other epithelial-related diseases, including inflammatory bowel disease, lichen sclerosus, and systemic lupus erythematosus.

Comparative analysis of surface antigens in cultured human outer root sheath cells and epidermal keratinocytes: persistence of low expression of class I MHC antigens in outer root sheath cells in vitro

In the anagen human hair follicle, the epithelial cells from the infrainfundibular portion and the hair matrix cells express markedly lower numbers of major histocompatibility complex class I molecules than interfollicular epidermal keratinocytes. During the catagen phase of the hair cycle, class I expression on these cells increases, and activated macrophages aggregate around the follicle, which has led to the hypothesis that the cells to be resorbed are recognized by virtue of their low class I antigen expression. In the present study, we showed that, in vitro, outer root sheath cells also maintain a lower constitutive expression of MHC class I molecules compared with epidermal keratinocytes. In contrast, other surface antigens such as HLA-DR, -DP and -DQ, ICAM-1, LFA-3 and CD29, which are all known to participate in leucocyte-keratinocyte interactions, were similarly expressed in both cell types. Furthermore, interferon gamma strongly upregulated MHC class I and II and ICAM-1 expression in both cell types, whereas CD29 and LFA-3 remained unaffected. Tumour necrosis factor alpha, to a lesser extent, also upregulated MHC class I and ICAM-1 expression, but not class II expression. The differences in constitutive surface antigen expression of infrainfundibular outer root sheath cells compared with interfollicular epidermal keratinocytes emphasizes a distinct role of this cell type in the hair cycle, and possibly also in alopecia areata.

The aetiology and pathogenesis of alopecia areata

In common with a number of inflammatory autoimmune diseases, genetic factors including HLA class II associations have been identified in alopecia areata. No consensus has been reached on the identity of a specific disease target within the hair follicle in alopecia areata. Suggested candidate cell types include the dermal papilla cells, the keratinocytes of the matrix and presumptive cortex and the hair bulb melanocytes, but these need not be mutually exclusive. The pathogenesis is known to involve disturbance of immune function but there is no proof that an autoimmune mechanism is fundamental. We propose a pathogenetic model incorporating polygenic determination of disease susceptibility and severity with additional, possibly environmental, factors as triggers for disease expression.

Immunohistological study of the development of the cellular infiltrate in the pelage follicles of the DEBR model for alopecia areata

The Dundee experimental bald rat (DEBR) undergoes hair loss associated with perifollicular infiltrates of mononuclear cells (MNC), a pathological characteristic of human alopecia areata (AA). To investigate further the pathogenesis of the disease in this animal model, we have studied the development, composition and extent of the perifollicular MNC infiltration in young (6-week-old), prelesional (3-month-old), active lesional, and established lesional DEBR rats, using 6-week- and 6-month-old Wistar rats as normal controls. The proportions of hair follicles showing infiltration by MNC and their main subsets were determined using immunohistochemical staining of serial cryostat sections of flank skin biopsies. There was a good correlation between the degree of leucocyte (OX-1+) infiltration of anagen hair follicles and the development of hair loss. In 6-week-old DEBR skin, there were few perifollicular cells expressing MHC class II, with positively stained dendritic cells in the dermis above the sebaceous gland. There was a sparse perifollicular distribution of CD4+ cells (W3/25) and macrophages (ED-1+). No CD8+ cells (OX-8+) were seen associated with DEBR hair follicles, and only small numbers were present in Wistar rats. In prelesional DEBR rats there was an increased perifollicular presence of MHC class II+ cells, macrophages, and particularly of CD8+ cells, with little change in CD4+ cells. Active and established lesional rats, i.e. animals with overt loss of hair, showed a significant increase in the degree of MNC infiltration and the proportion of infiltrated follicles, the majority of which were in dystrophic anagen. In the perifollicular infiltrate the CD4+:CD8+ ratio was approximately 2:1. An intrafollicular infiltrate was prominent, and was composed of CD8+ cells and macrophages, with bulbar and suprabulbar keratinocytes expressing MHC class II antigens. CD4+ cells were not detected in follicular epithelium. ICAM-1 expression correlated with MNC infiltration. These results show marked similarities to lesional human AA. They also focus on a possible active role for CD8+ cells in the pathogenesis of hair loss in the DEBR rat.

HLA and ICAM-1 expression in alopecia areata in vivo and in vitro: the role of cytokines

To investigate the hypothesis that aberrant HLA and adhesion molecule expression in alopecia areata (AA) are secondary to local release of interferon-gamma (IFN-gamma) or other cytokines, we have studied HLA ABC, -DQ, -DR and ICAM-1 expression by immunohistochemistry, and compared patterns of expression in lesional tissue sections with those observed in hair follicles maintained in short-term organ culture, both from normal individuals and non-lesional sites in AA patients. The organ cultures were supplemented with IFN-gamma, tumour necrosis factor-alpha (TNF-alpha), and granulocyte-macrophage colony stimulating factor (GM-CSF), in a range of doses. In lesional AA tissue sections, there was close spatial correlation of ICAM-1 with HLA-DR; prominent staining being noted in the pre-cortical matrix and dermal papilla (DP) of lesional anagen follicles. In cultured follicles, dose-dependent induction of HLA class I, DR and ICAM-1 by IFN-gamma, and HLA class I and ICAM-1, but not HLA-DR, by TNF-alpha was observed in follicular epithelium, mainly in the outer root sheath (ORS). The findings in these cultures were the same in follicles derived from normal individuals and AA patients. Cytokine-induced patterns of HLA and ICAM-1 expression observed in vitro in cultured follicles differed significantly from those observed in vivo in lesional tissue sections. In particular, IFN-gamma failed to induce HLA-DR expression in the pre-cortical matrix and dermal papilla (DP), sites where this is usually observed in AA. The results suggest local cytokine release is not the sole determinant of aberrant HLA-DR expression in AA.

Alopecia universalis treated with oral cyclosporine A and prednisolone: immunologic studies

Alopecia universalis is a refractory condition. Although the cause of this disease is unknown, immunologic abnormalities have recently been suspected. Thus, we treated six cases of refractory alopecia universalis with immunotherapy. Oral administration of cyclosporine A (2.5 mg/kg) and prednisolone (5 mg/day) resulted in marked symptomatic improvement. Cyclosporine A did not produce any side effects because the administered dosage was relatively low. At present, more than 6 months after the cessation of treatment, recurrence of alopecia has not been seen. Oral administration of low-dose cyclosporine A and prednisolone is considered to be an effective treatment for this disease. Immunologic examination of peripheral blood demonstrated improvement of immunologic function. In particular, CD8-positive T cells, NK cells, and C3, which had been reduced, were increased. A reduction in active CD4 cells, eosinophils, and circulating immune complexes was observed. Histology with fluorescent antibodies showed T-cell infiltration around the hair matrixes. This phenomenon was no longer observed after treatment. These improvements in immunologic function were seen in parallel with the resolution of the clinical symptoms, indicating that immunologic abnormalities are related to this disease.