Frontiers in alopecia areata pathobiology research

Interleukin-15 is a hair follicle immune privilege guardian

The autoimmunity-promoting cytokine, Interleukin-15 (IL-15), is often claimed to be a key pathogenic cytokine in alopecia areata (AA). Yet, rhIL-15 promotes human hair follicle (HF) growth ex vivo. We have asked whether the expression of IL-15 and its receptor (IL-15R) isoforms is altered in human AA and how IL-15 impacts on human HF immune privilege (HF-IP) in the presence/absence of interferon-γ (IFNγ), the well-documented key AA-pathogenic cytokine, as well as on hair regrowth after experimental AA induction in vivo. Quantitative immunohistomorphometry showed the number of perifollicular IL-15+ T cells in AA skin biopsies to be significantly increased compared to healthy control skin, while IL-15, IL-15Rα, and IL-15Rγ protein expression within the hair bulb were significantly down-regulated in AA HFs. In organ-cultured human scalp HFs, rhIL-15 significantly reduced hair bulb expression of MICA, the key "danger" signal in AA pathogenesis, and increased production of the HF-IP guardian, α-MSH. Crucially, ex vivo, rhIL-15 prevented IFNγ-induced HF-IP collapse, restored a collapsed HF-IP by IL-15Rα-dependent signaling (as documented by IL-15Rα-silencing), and protected AA-preventive immunoinhibitory iNKT10 cells from IFNγ-induced apoptosis. rhIL-15 even promoted hair regrowth after experimental AA induction in human scalp skin xenotransplants on SCID/beige mice in vivo. Our data introduce IL-15 as a novel, functionally important HF-IP guardian whose signaling is constitutively defective in scalp HFs of AA patients. Our data suggest that selective stimulation of intrafollicular IL-15Rα signaling could become a novel therapeutic approach in AA management, while blocking it pharmacologically may hinder both HF-IP restoration and hair re-growth and may thus make HFs more vulnerable to AA relapse.

Pathogenesis of Alopecia Areata and Vitiligo: Commonalities and Differences

Both alopecia areata (AA) and vitiligo are distinct, heterogenous, and complex disease entities, characterized by nonscarring scalp terminal hair loss and skin pigment loss, respectively. In AA, inflammatory cell infiltrates are in the deep reticular dermis close to the hair bulb (swarm of bees), whereas in vitiligo the inflammatory infiltrates are in the epidermis and papillary dermis. Immune privilege collapse has been extensively investigated in AA pathogenesis, including the suppression of immunomodulatory factors (e.g., transforming growth factor-β (TGF-β), programmed death-ligand 1 (PDL1), interleukin-10 (IL-10), α-melanocyte-stimulating hormone (α-MSH), and macrophage migration inhibitory factor (MIF)) and enhanced expression of the major histocompatibility complex (MHC) throughout hair follicles. However, immune privilege collapse in vitiligo remains less explored. Both AA and vitiligo are autoimmune diseases that share commonalities in pathogenesis, including the involvement of plasmacytoid dendritic cells (and interferon-α (IFN- α) signaling pathways) and cytotoxic CD8+ T lymphocytes (and activated IFN-γ signaling pathways). Blood chemokine C-X-C motif ligand 9 (CXCL9) and CXCL10 are elevated in both diseases. Common factors that contribute to AA and vitiligo include oxidative stress, autophagy, type 2 cytokines, and the Wnt/β-catenin pathway (e.g., dickkopf 1 (DKK1)). Here, we summarize the commonalities and differences between AA and vitiligo, focusing on their pathogenesis.

Causal role of immune cells in alopecia areata: A two-sample Mendelian randomization study

BACKGROUND

Previous research has highlighted an association between alopecia areata (AA) and the collapse of hair follicle immune privilege, however, the causal linkage to specific immune cell traits remains to be elucidated. This study aimed to investigate the causal influence of immune cell traits on AA utilizing a two-sample Mendelian randomization (MR) approach.

METHODS

Leveraging GWAS summary statistics of 731 immunological traits (n = 3757) and AA data (n = 211,428), MR analyses were conducted employing inverse-variance weighted (IVW), weighted median, and MR-Egger regression methodologies. Sensitivity analyses were undertaken using Cochran's Q test, MR-Egger intercept test, and MR-PRESSO analysis. A reverse MR analysis was performed for immune cell traits identified in the initial MR analysis.

RESULTS

Our study unveiled multiple immune traits associated with AA. Protective associations were observed for CD62L- CD86+ myeloid dendritic cells (DCs), TD CD4+%CD4+ T cells, and others, with ORs ranging from 0.63 to 0.78. Conversely, traits like CD62L on CD62L+ plasmacytoid DCs, HLA-DR on CD14- CD16+ monocytes, HLA-DR on monocytes, and others, were determined to augment the risk of AA, with ORs ranging from 1.13 to 1.46. Reverse MR analysis signified a reduction in BAFF-R on IgD-CD24-B cells post-AA onset (OR: 0.97, 95% CI: 0.95-1.00), with no identified heterogeneity or horizontal pleiotropy among the instrumental variables (IVs).

CONCLUSIONS

Our findings suggests that CD62L on certain subpopulations of DCs and HLA-DR on monocytes may epitomize risk factors for AA, offering potential therapeutic targets for alleviating AA.

Alopecia areata: What's new in the epidemiology, comorbidities, and pathogenesis?

BACKGROUND

Alopecia areata (AA) is a common, acquired, and nonscarring type of hair loss that affects people of every generation and is intractable in severe and relapsing cases. Patients with AA, especially those with greater scalp involvement, have poor health-related quality-of-life scores.

PURPOSE

Following our previous review article in the April 2017 issue of the Journal of Dermatological Science, we aim to provide a pair of review articles on recent progress in multidisciplinary approaches to AA.

MAIN FINDINGS

We found more than 1800 publications on AA from July 2016 to December 2022.

CONCLUSIONS

In this review, we focused on the latest information on the epidemiology, comorbidities, and pathogenesis of AA.

Inhibition of T-cell activity in alopecia areata: recent developments and new directions

Alopecia areata (AA) is an autoimmune disease that has a complex underlying immunopathogenesis characterized by nonscarring hair loss ranging from small bald patches to complete loss of scalp, face, and/or body hair. Although the etiopathogenesis of AA has not yet been fully characterized, immune privilege collapse at the hair follicle (HF) followed by T-cell receptor recognition of exposed HF autoantigens by autoreactive cytotoxic CD8+ T cells is now understood to play a central role. Few treatment options are available, with the Janus kinase (JAK) 1/2 inhibitor baricitinib (2022) and the selective JAK3/tyrosine kinase expressed in hepatocellular carcinoma (TEC) inhibitor ritlecitinib (2023) being the only US Food and Drug Administration-approved systemic medications thus far for severe AA. Several other treatments are used off-label with limited efficacy and/or suboptimal safety and tolerability. With an increased understanding of the T-cell-mediated autoimmune and inflammatory pathogenesis of AA, additional therapeutic pathways beyond JAK inhibition are currently under investigation for the development of AA therapies. This narrative review presents a detailed overview about the role of T cells and T-cell-signaling pathways in the pathogenesis of AA, with a focus on those pathways targeted by drugs in clinical development for the treatment of AA. A detailed summary of new drugs targeting these pathways with expert commentary on future directions for AA drug development and the importance of targeting multiple T-cell-signaling pathways is also provided in this review.

Alopecia Areata: Current Treatments and New Directions

Alopecia areata is an autoimmune hair loss disease that is non-scarring and is characterized by chronic inflammation at the hair follicle level. Clinically, patients' presentation varies from patchy, circumscribed scalp involvement to total body and scalp hair loss. Current management is guided by the degree of scalp and body involvement, with topical and intralesional steroid injections as primarily first-line for mild cases and broad immunosuppressants as the mainstay for more severe cases. Until recently, the limited number of blinded, randomized, placebo-controlled clinical trials for this disease had made establishing an evidence-based treatment paradigm challenging. However, growing insights into the pathogenesis of alopecia areata through blood and tissue analysis of human lesions have identified several promising targets for therapy. T-helper (Th) 1/interferon skewing has traditionally been described as the driver of disease; however, recent investigations suggest activation of additional immune mediators, including the Th2 pathway, interleukin (IL)-9, IL-23, and IL-32, as contributors to alopecia areata pathogenesis. The landscape of alopecia areata treatment has the potential to be transformed, as several novel targeted drugs are currently undergoing clinical trials. Given the recent US FDA approval of baricitinib and ritlecitinib, Janus kinase (JAK) inhibitors are a promising drug class for treating severe alopecia areata cases. This article will review the efficacy, safety, and tolerability of current treatments for alopecia areata, and will provide an overview of the emerging therapies that are leading the revolution in the management of this challenging disease.

Regulatory T cells in skin regeneration and wound healing

As the body's integumentary system, the skin is vulnerable to injuries. The subsequent wound healing processes aim to restore dermal and epidermal integrity and functionality. To this end, multiple tissue-resident cells and recruited immune cells cooperate to efficiently repair the injured tissue. Such temporally- and spatially-coordinated interplay necessitates tight regulation to prevent collateral damage such as overshooting immune responses and excessive inflammation. In this context, regulatory T cells (Tregs) hold a key role in balancing immune homeostasis and mediating cutaneous wound healing. A comprehensive understanding of Tregs' multifaceted field of activity may help decipher wound pathologies and, ultimately, establish new treatment modalities. Herein, we review the role of Tregs in orchestrating the regeneration of skin adnexa and catalyzing healthy wound repair. Further, we discuss how Tregs operate during fibrosis, keloidosis, and scarring.

Clinical characteristics and immune profiles of patients with immune-mediated alopecia associated with COVID-19 vaccinations

BACKGROUND

The clinical characteristics and pathomechanism for immune-mediated alopecia following COVID-19 vaccinations are not clearly characterized.

OBJECTIVE

We investigated the causality and immune mechanism of COVID-19 vaccines-related alopecia areata (AA).

STUDY DESIGN

27 new-onset of AA patients after COVID-19 vaccinations and 106 vaccines-tolerant individuals were enrolled from multiple medical centers for analysis.

RESULTS

The antinuclear antibody, total IgE, granulysin, and PARC/CCL18 as well as peripheral eosinophil count were significantly elevated in the patients with COVID-19 vaccines-related AA compared with those in the tolerant individuals (P = 2.03 × 10-5-0.039). In vitro lymphocyte activation test revealed that granulysin, granzyme B, and IFN-γ released from the T cells of COVID-19 vaccines-related AA patients could be significantly increased by COVID-19 vaccine excipients (polyethylene glycol 2000 and polysorbate 80) or spike protein (P = 0.002-0.04).

CONCLUSIONS

Spike protein and excipients of COVID-19 vaccines could trigger T cell-mediated cytotoxicity, which contributes to the pathogenesis of immune-mediated alopecia associated with COVID-19 vaccines.

Oxidative stress and alopecia areata

Alopecia areata (AA) is an inflammatory autoimmune disease characterized by non-scarring hair loss on the scalp or any other part of the hair-bearing skin. While the collapse of the immune privilege is considered as one of the most accepted theories accounting for AA, the exact pathogenesis of this disease remains unclear by now. Other factors, such as genetic predisposition, allergies, microbiota, and psychological stress, also play an important role in the occurrence and development of AA. Oxidative stress (OS), an unbalance between the oxidation and antioxidant defense systems, is believed to be associated with AA and may trigger the collapse of hair follicle-immune privilege. In this review, we examine the evidence of oxidative stress in AA patients, as well as the relationship between the pathogenesis of AA and OS. In the future, antioxidants may play a new role as a supplementary therapy for AA.

A novel predictive model for the recurrence of pediatric alopecia areata by bioinformatics analysis and a single-center prospective study

Background

Alopecia areata (AA) is a disease featured by recurrent, non-scarring hair loss with a variety of clinical manifestations. The outcome of AA patients varies greatly. When they progress to the subtypes of alopecia totalis (AT) or alopecia universalis (AU), the outcome is unfavorable. Therefore, identifying clinically available biomarkers that predict the risk of AA recurrence could improve the prognosis for AA patients.

Methods

In this study, we conducted weighted gene co-expression network analysis (WGCNA) and functional annotation analysis to identify key genes that correlated to the severity of AA. Then, 80 AA children were enrolled at the Department of Dermatology, Wuhan Children's Hospital between January 2020 to December 2020. Clinical information and serum samples were collected before and after treatment. And the serum level of proteins coded by key genes were quantitatively detected by ELISA. Moreover, 40 serum samples of healthy children from the Department of Health Care, Wuhan Children's Hospital were used for healthy control.

Results

We identified four key genes that significantly increased (CD8A, PRF1, and XCL1) or decreased (BMP2) in AA tissues, especially in the subtypes of AT and AU. Then, the serum levels of these markers in different groups of AA patients were detected to validate the results of bioinformatics analysis. Similarly, the serum levels of these markers were found remarkedly correlated with the Severity of Alopecia Tool (SALT) score. Finally, a prediction model that combined multiple markers was established by conducting a logistic regression analysis.

Conclusion

In the present study, we construct a novel model based on serum levels of BMP2, CD8A, PRF1, and XCL1, which served as a potential non-invasive prognostic biomarker for forecasting the recurrence of AA patients with high accuracy.

Construction of regulatory network for alopecia areata progression and identification of immune monitoring genes based on multiple machine-learning algorithms

Objectives

Alopecia areata (AA) is an autoimmune-related non-cicatricial alopecia, with complete alopecia (AT) or generalized alopecia (AU) as severe forms of AA. However, there are limitations in early identification of AA, and intervention of AA patients who may progress to severe AA will help to improve the incidence rate and prognosis of severe AA.

Methods

We obtained two AA-related datasets from the gene expression omnibus database, identified the differentially expressed genes (DEGs), and identified the module genes most related to severe AA through weighted gene co-expression network analysis. Functional enrichment analysis, construction of a protein-protein interaction network and competing endogenous RNA network, and immune cell infiltration analysis were performed to clarify the underlying biological mechanisms of severe AA. Subsequently, pivotal immune monitoring genes (IMGs) were screened through multiple machine-learning algorithms, and the diagnostic effectiveness of the pivotal IMGs was validated by receiver operating characteristic.

Results

A total of 150 severe AA-related DEGs were identified; the upregulated DEGs were mainly enriched in immune response, while the downregulated DEGs were mainly enriched in pathways related to hair cycle and skin development. Four IMGs (LGR5, SHISA2, HOXC13, and S100A3) with good diagnostic efficiency were obtained. As an important gene of hair follicle stem cells stemness, we verified in vivo that LGR5 downregulation may be an important link leading to severe AA.

Conclusion

Our findings provide a comprehensive understanding of the pathogenesis and underlying biological processes in patients with AA, and identification of four potential IMGs, which is helpful for the early diagnosis of severe AA.

Platelet-rich plasma in the treatment of alopecia areata after COVID-19 vaccination

Key Clinical Message

Alopecia areata may develop in patients after COVID-19 vaccination. Platelet-rich plasma (PRP) has an outstanding anti-inflammatory effect and could be an alternative treatment for alopecia patients who are refractory or intolerant to corticosteroids.

Abstract

A 34-year-old female with no systemic illness presented with non-scarring hair loss after the second COVID-19 vaccination shot 4 weeks ago. The hair loss worsened and progressed to severe alopecia areata. We started double-spin PRP therapy. Her hair recovered completely after six courses of PRP treatment.

Involvement of ILC1-like innate lymphocytes in human autoimmunity, lessons from alopecia areata

Here, we have explored the involvement of innate lymphoid cells-type 1 (ILC1) in the pathogenesis of alopecia areata (AA), because we found them to be significantly increased around lesional and non-lesional HFs of AA patients. To further explore these unexpected findings, we first co-cultured autologous circulating ILC1-like cells (ILC1lc) with healthy, but stressed, organ-cultured human scalp hair follicles (HFs). ILClc induced all hallmarks of AA ex vivo: they significantly promoted premature, apoptosis-driven HF regression (catagen), HF cytotoxicity/dystrophy, and most important for AA pathogenesis, the collapse of the HFs physiological immune privilege. NKG2D-blocking or IFNγ-neutralizing antibodies antagonized this. In vivo, intradermal injection of autologous activated, NKG2D+/IFNγ-secreting ILC1lc into healthy human scalp skin xenotransplanted onto SCID/beige mice sufficed to rapidly induce characteristic AA lesions. This provides the first evidence that ILC1lc, which are positive for the ILC1 phenotype and negative for the classical NK markers, suffice to induce AA in previously healthy human HFs ex vivo and in vivo, and further questions the conventional wisdom that AA is always an autoantigen-dependent, CD8 +T cell-driven autoimmune disease.

Novel potential therapeutic targets of alopecia areata

Alopecia areata (AA) is a non-scarring hair loss disorder caused by autoimmunity. The immune collapse of the hair follicle, where interferon-gamma (IFN-γ) and CD8+ T cells accumulate, is a key factor in AA. However, the exact functional mechanism remains unclear. Therefore, AA treatment has poor efficacy maintenance and high relapse rate after drug withdrawal. Recent studies show that immune-related cells and molecules affect AA. These cells communicate through autocrine and paracrine signals. Various cytokines, chemokines and growth factors mediate this crosstalk. In addition, adipose-derived stem cells (ADSCs), gut microbiota, hair follicle melanocytes, non-coding RNAs and specific regulatory factors have crucial roles in intercellular communication without a clear cause, suggesting potential new targets for AA therapy. This review discusses the latest research on the possible pathogenesis and therapeutic targets of AA.

The potential of regulatory T cell-based therapies for alopecia areata

Cytotoxic T lymphocyte has been a concern for the etiopathogenesis of alopecia areata (AA), some recent evidence suggests that the regulatory T (T_reg) cell deficiency is also a contributing factor. In the lesional scalp of AA, T_reg cells residing in the follicles are impaired, leading to dysregulated local immunity and hair follicle (HF) regeneration disorders. New strategies are emerging to modulate T_reg cells' number and function for autoimmune diseases. There is much interest to boost T_reg cells in AA patients to suppress the abnormal autoimmunity of HF and stimulate hair regeneration. With few satisfactory therapeutic regimens available for AA, T_reg cell-based therapies could be the way forward. Specifically, CAR-T_reg cells and novel formulations of low-dose IL-2 are the alternatives.

Ex Vivo Treatment with Allogenic Mesenchymal Stem Cells of a Healthy Donor on Peripheral Blood Mononuclear Cells of Patients with Severe Alopecia Areata: Targeting Dysregulated T Cells and the Acquisition of Immunotolerance

Alopecia areata (AA) is an autoimmune condition related to the collapse of the immune privilege of hair follicles. Certain AA populations present severe clinical manifestations, such as total scalp hair or body hair loss and a treatment refractory property. The aim of this study was to assess the effects of allogenic human mesenchymal stem cells (hMSCs) from healthy donors on the peripheral blood mononuclear cells (PBMCs) of severe AA patients, with a focus on the change in the cell fraction of Th1, Th17, and Treg cells and immunomodulatory functions. PBMCs of 10 AA patients and eight healthy controls were collected. Levels of Th17, Th1, and Treg subsets were determined via flow cytometry at baseline, activation status, and after co-culturing with hMSCs. All participants were severe AA patients with SALT > 50 and with a long disease duration. While the baseline Th1 and Treg levels of AA patients were comparable to those of healthy controls, their Th17 levels were significantly lower than those of the controls. When stimulated, the levels of CD4+IFN-γ+ T cells of the AA patients rose sharply compared to the baseline, which was not the case in those of healthy controls. The cell fraction of CD4+Foxp3+ regulatory T cells also abruptly increased in AA patients only. Co-culturing with allogenic hMSCs in activated AA PBMCs slightly suppressed the activation levels of CD4+INF-γ+ T cells, whereas it significantly induced the differentiation of CD4+Foxp3+ regulatory T cells. However, these changes were not prominent in the PBMCs of health controls. To examine the pathomechanisms, PBMCs of healthy donors were treated with IFN-γ to induce AA-like environment and then treated with allogenic grants and compared with ruxolitinib as a positive treatment control. hMSC treatment was shown to significantly inhibit the mRNA levels of proinflammatory cytokines, such as IFN-γ, TNF-α, IL-1α, IL-2R, IL-15, and IL-18, and chemokines, such as CCR7 and CCR10, in IFN-treated PBMCs. Interestingly, hMSCs suppressed the activation of JAK/STAT signaling by IFN in PBMCs with an effect that was comparable to that of ruxolitinib. Furthermore, the hMSC treatment showed stronger efficacy in inducing Foxp3, IL-10, and TGF-β mRNA transcription than ruxolitinib in IFN-treated PBMCs. This study suggests that allogenic hMSC treatments have therapeutic potential to induce immune tolerance and anti-inflammatory effects in severe AA patients.

Efficacy and safety of JAK inhibitors in the treatment of alopecia areata in children: a systematic review and meta-analysis

BACKGROUND

Alopecia areata (AA) is a non-scarring hair loss mediated by T lymphocytes. Recently, a growing number of studies have shown that Janus kinase inhibitors are effective in the treatment of AA in children.

METHODS

A systematic review and meta-analysis were performed according to the PRISMA guidelines. Good response was defined as more than 50% decrease in Severity of Alopecia Tool (SALT) score or complete regrowth or more than 50% regrowth. Partial response was defined as 5-50% decrease in SALT score. Any response to treatment was defined as more than 5% in SALT score decrease.

RESULTS

There were 81.9% responders, 68.5% good responders, and 7.7% partial responders among the 10 included studies. The treatment duration was longer in good responders than in partial responders (p = .009). Oral route was linked to a better response to topical medication, with an odds ratio of 7.8 (95%CI 1.655-36.76). In terms of toxicity, reported adverse events included only mild symptoms. Liver transaminase elevation, upper respiratory tract infection, and eosinophilia were the most common adverse events.

CONCLUSIONS

Janus kinase inhibitors demonstrated promise in the treatment of AA in children, with the most common side effects being minor and reversible.

Hair Follicle Melanocytes Initiate Autoimmunity in Alopecia Areata: a Trigger Point

Alopecia areata (AA) is characterized by common non-scarring alopecia due to autoimmune disorders. To date, the specific pathogenesis underlying AA remains unknown. Thus, AA treatment in the dermatological clinic is still a challenge. Numerous clinical observations and experimental studies have established that melanocytes may be the trigger point that causes hair follicles to be attacked by the immune system. A possible mechanism is that the impaired melanocytes, under oxidative stress, cannot be repaired in time and causes apoptosis. Melanocyte-associated autoantigens are released and presented, inducing CD8⁺ T cell attacks. Thereafter, amplification of the immune responses further spreads to the entire hair follicle (HF). The immune privilege of HF subsequently collapses, leading to AA. Herein, we present a narrative review on the roles of melanocytes in AA pathogenesis, aiming to provide a better understanding of this disease from the melanocyte's perspective.

Heat Shock Protein 90 (Hsp90) and Hsp70 as Potential Therapeutic Targets in Autoimmune Skin Diseases

Over a hundred different autoimmune diseases have been described to date, which can affect every organ in the body, including the largest one, the skin. In fact, up to one-fifth of the world's population suffers from chronic, noninfectious inflammatory skin diseases, the development of which is significantly influenced by an autoimmune response. One of the hallmarks of autoimmune diseases is the loss of immune tolerance, which leads to the formation of autoreactive lymphocytes or autoantibodies and, consequently, to chronic inflammation and tissue damage. The treatment of autoimmune skin diseases mainly focuses on immunosuppression (using, e.g., corticosteroids) but almost never leads to the development of permanent mechanisms of immune tolerance. In addition, current therapies and their long-term administration may cause serious adverse effects. Hence, safer and more effective therapies that bring sustained balance between pro- and anti-inflammatory responses are still desired. Both intra- and extracellular heat shock proteins (Hsps), specifically well-characterized inducible Hsp90 and Hsp70 chaperones, have been highlighted as therapeutic targets for autoimmune diseases. This review presents preclinical data on the involvement of Hsp90 and Hsp70 in modulating the immune response, specifically in the context of the treatment of selected autoimmune skin diseases with emphasis on autoimmune bullous skin diseases and psoriasis.

Short communication: Comments on hair disorders associated with dupilumab based on VigiBase

Background

Dupilumab is a human antibody that blocks the signaling of both interleukin-4 and interleukin-13 receptors. It has been approved for the treatment of moderate-to-severe atopic dermatitis. However, several case reports have reported conflicting effects of dupilumab on alopecia.

Objectives

This study aimed to examine dupilumab-related hair disorders using the large real-world database, VigiBase.

Methods

All individual case safety reports associated with dupilumab in the Uppsala Monitoring Center VigiBase until December 29, 2019, were analyzed. Hair disorder-related terms were defined in High Level Terms with “alopecias,” “pilar disorders NEC (not elsewhere classified),” and “hypertrichoses,” using the Medical Dictionary for Regulatory Activities Hierarchy. Hair disorder reports associated with dupilumab and other biologics that inhibit the Th2 axis (omalizumab, mepolizumab, reslizumab, and benralizumab) were analyzed to determine their association with hair disorders. Disproportionality analysis was performed based on the proportional reporting ratio, reporting odds ratio, and information components.

Results

Among the 20,548 total dupilumab adverse event (AE) reports, hair disorders were reported in 462 dupilumab cases (2.2%), most of which reported hair loss, and only eight cases reported an increase in hair growth. The paradoxical trend in hair loss and growth after dupilumab use was confirmed using a disproportionality analysis. Among the other investigated biologics on Th2 immunity, only omalizumab was associated with hair loss. Additionally, hair disorders after dupilumab treatment were more frequently reported in women than in men. The proportion of hair disorder cases was high in Europe, accounting for 20.8% of hair disorder reports, whereas only 9.7% of all dupilumab-related AEs were reported in Europe. In conclusion, our analysis using a large real-world database confirmed that dupilumab is associated with hair disorders.

Oral Tofacitinib and Systemic Corticosteroids, Alone or in Combination, in Patients With Moderate-to-Severe Alopecia Areata: A Retrospective Study

Introduction

Alopecia areata (AA) is an autoimmune hair loss mediated by CD8 + T cells. Treatment for moderate-to-severe AA is still challenging. Janus kinase inhibitors, such as tofacitinib, have been recently investigated as a promising treatment option for AA. Evidence on the combination use of oral tofacitinib and systemic corticosteroids (SCs) for AA is still lacking.

Objective

To compare the efficacy and safety of monotherapy of oral tofacitinib and SCs, as well as their combination in patients with moderate-to-severe AA.

Methods

Patients with moderate-to-severe AA, who have been treated with at least 3 months of monotherapy of tofacitinib or SCs, or in their combination, were included in this study. The efficacy and adverse events of these treatments were retrospectively analyzed.

Results

Sixty-one patients with moderate-to-severe AA were included in this study. There were 12 (66.7%) of 18 patients in the SCs group, 12 (60.0%) of 20 patients in the tofacitinib group, and 18 (78.3%) of 23 patients achieved SALT50, with no significant difference among the three groups. The ratio of patients who achieved SALT50 was significantly higher in patients with a short duration of current hair loss episode (≤2 years) than in those with a duration of current hair loss episode (>2 years) in all the three groups. There were 66.7% patients in the SCs group, 35.0% patients in the tofacitinib group, and 56.5% patients in the combined group that showed adverse effects.

Conclusion

Tofacitinib was an effective treatment for patients with moderate-to-severe AA, and it was more tolerated than SCs. A combination of tofacitinib and SCs may have higher efficacy than SCs alone. Efficacy significantly decreased in patients with a current episode of disease for more than 2 years.

Selective Expansion of Tregs Using the IL-2 Cytokine Antibody Complex Does Not Reverse Established Alopecia Areata in C3H/HeJ Mice

Alopecia areata (AA) is an autoimmune disease mediated by NKG2D-expressing cytotoxic T lymphocytes destroying hair follicles in the skin. It is one of the most common autoimmune diseases, but there is no effective treatment modality approved by the FDA. Regulatory T cells (Tregs) are crucial for suppressing autoreactive T cells, and in the skin, they promote hair growth by inducing anagen. Based on this, we tested the therapeutic potential of expanded Tregs in AA using the C3H/HeJ mouse model. In mice with AA, NKG2D-expressing CD8 T cells widely infiltrate both haired and hairless skin areas, which have tissue-resident memory T-cell phenotypes. Tregs in the skin express CD25, CTLA-4, GATA-3, and Jagged1 and efficiently proliferate with IL-2 cytokine antibody complex. However, expanding Tregs in the skin did not induce anagen in normal mice, indicating that they are necessary but not sufficient for anagen induction. Also, they fail to suppress autoreactive CD8 T cells in the skin to reverse established AA in C3H/HeJ mice. These results suggest that Treg expansion alone is not sufficient for AA treatment, and combined immunotherapy is required.

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.

Dupilumab-Associated Adverse Events During Treatment of Allergic Diseases

Among the new biological therapies for atopic diseases, dupilumab is a fully human monoclonal antibody directed against IL-4Rα, the common chain of interleukin-4 and interleukin-13 receptors. Dupilumab showed clinical improvements in patients with atopic dermatitis, asthma, and chronic rhinosinusitis and is currently under development for other indications. While dupilumab is considered to be well tolerated, a number of recent publications have reported various adverse events. This review aims to summarize the current knowledge about these adverse events, which may help clinicians to improve the follow-up of patients on dupilumab. Injection-site reactions are the most common reported adverse event. However, dupilumab has also been shown to cause ophthalmic complications (e.g., dry eyes, conjunctivitis, blepharitis, keratitis, and ocular pruritus), head and neck dermatitis, onset of psoriatic lesions, progression of cutaneous T-cell lymphoma exacerbation, alopecia areata, hypereosinophilia, and arthritis. Most are managed during dupilumab treatment continuation, but some (e.g., severe conjunctivitis) may result in a discontinuation of treatment. Their molecular origin is unclear and requires further investigations. Among other hypothesis, it has been suggested that T helper (Th)2-mediated pathway inhibition may worsen Th1/Th17-dependent immune responses. An ophthalmological examination for the presence of potential predictive indicators of ophthalmic adverse events is recommended before initiation of dupilumab therapy.

Frontiers in Lichen Planopilaris and Frontal Fibrosing Alopecia Research: Pathobiology Progress and Translational Horizons

Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are primary, lymphocytic cicatricial hair loss disorders. These model epithelial stem cell (SC) diseases are thought to result from a CD8⁺ T-cell‒dominated immune attack on the hair follicle (HF) SC niche (bulge) after the latter has lost its immune privilege (IP) for as yet unknown reasons. This induces both apoptosis and pathological epithelial‒mesenchymal transition in epithelial SCs, thus depletes the bulge, causes fibrosis, and ultimately abrogates the HFs' capacity to regenerate. In this paper, we synthesize recent progress in LPP and FFA pathobiology research, integrate our limited current understanding of the roles that genetic, hormonal, environmental, and other factors may play, and define major open questions. We propose that LPP and FFA share a common initial pathobiology, which then bifurcates into two distinct clinical phenotypes, with macrophages possibly playing a key role in phenotype determination. As particularly promising translational research avenues toward direly needed progress in the management of these disfiguring, deeply distressful cicatricial alopecia variants, we advocate to focus on the development of bulge IP and epithelial SC protectants such as, for example, topically effective, HF‒penetrating and immunoinhibitory preparations that contain tacrolimus, peroxisome proliferator-activated receptor-γ, and/or CB1 agonists.

Genetic predisposition of alopecia areata in jordanians: A case-control study

Alopecia areata (AA) is a common non-scarring hair loss disease of defined patterns with varied patches size and body sites. The etiology of AA has a complex basis of autoimmunity, environment, and genetic variations. The latter factor is found to play a crucial role in AA risk. Thus, this study aimed to investigate the potential impact of specific immune-related gene polymorphisms among a cohort of Jordanian patients, which was previously reported in other populations. Blood samples of AA patients and control subjects were collected for genomic DNA (gDNA) extraction. Targeted single nucleotide polymorphisms (SNPs) of MASP2, TLR1, CTLA4, and C11orf30 were genotyped in duplicate using the Sequenom MassARRAY® system (iPLEX GOLD). Genotype and allele analysis reveals statistical differences in TLR1 rs4833095 (allele C, P = 0.044), MASP2 rs2273346 (genotype AA, P = 0.0026), and C11orf30 rs2155219 (genotype GG, P = 0.0069) distribution. These findings present the significant contribution of genetic variations in AA susceptibility in the Jordanian population, which is infrequently studied.

Application of Baricitinib in Dermatology

There are four JAK subtypes: JAK1, JAK2, JAK3, and tyrosine kinase 2 (TYK2). Small molecule Janus tyrosine kinase (JAK) inhibitors can inhibit a variety of pro-inflammatory cytokines. Baricitinib is the first generation of JAK1/2 inhibitor targeting the ATPase of JAK, which blocks the intracellular transmission of cytokines through JAK-STATs. Thus far, it has been approved for the treatment of rheumatoid arthritis (RA); however, an increasing number of studies have suggested that baricitinib can be used to treat dermatological diseases, such as atopic dermatitis (AD), psoriasis, vitiligo, and alopecia areata. Baricitinib can be a new choice for the treatment of dermatological diseases, which cannot be treated with conventional drugs. We reviewed the application, efficacy, side effects, precautions, limitations and prospect of baricitinib in atopic dermatitis, psoriasis, vitiligo and alopecia areata (AA) in recent 5 years including clinical trials and case reports. Among them, the application in the field of alopecia areata is the most encouraging, and we reviewed the mechanism in detail.

Immunopathology and Immunotherapy of Inflammatory Skin Diseases

Recently, there have been impressive advancements in understanding of the immune mechanisms underlying cutaneous inflammatory diseases. To understand these diseases on a deeper level and clarify the therapeutic targets more precisely, numerous studies including in vitro experiments, animal models, and clinical trials have been conducted. This has resulted in a paradigm shift from non-specific suppression of the immune system to selective, targeted immunotherapies. These approaches target the molecular pathways and cytokines responsible for generating inflammatory conditions and reinforcing feedback mechanisms to aggravate inflammation. Among the numerous types of skin inflammation, psoriasis and atopic dermatitis (AD) are common chronic cutaneous inflammatory diseases. Psoriasis is a IL-17–mediated disease driven by IL-23, while AD is predominantly mediated by Th2 immunity. Autoimmune bullous diseases are autoantibody-mediated blistering disorders, including pemphigus and bullous pemphigoid. Alopecia areata is an organ-specific autoimmune disease mediated by CD8⁺ T-cells that targets hair follicles. This review will give an updated, comprehensive summary of the pathophysiology and immune mechanisms of inflammatory skin diseases. Moreover, the therapeutic potential of current and upcoming immunotherapies will be discussed.

Association between genetically predicted leukocyte telomere length and non-scarring alopecia: A two-sample Mendelian randomization study

Background

The most commonly acknowledged non-scarring alopecia are androgenetic alopecia (AGA) and alopecia areata (AA). Previous studies have revealed various risk factors associated with alopecia. However, the relationship between leukocyte telomere length (LTL) and non-scarring alopecia remains unclear.

Methods

A two-sample Mendelian randomization (MR) analysis was performed to evaluate the causality between genetically predicted LTL and the risk of non-scarring alopecia. MR analyses were performed using the inverse variance-weighted (IVW) method and complemented with other MR methods.

Results

The summary statistics of the genome-wide association studies (GWAS) for AGA and AA were obtained from the FinnGen biobank, which included 119,185 and 211,428 individuals, respectively. A total of 126 single nucleotide polymorphisms (SNPs) with genome-wide significance were selected as the instrumental variables for LTL. The MR analyses suggested a causal relationship between LTL and AGA, and the risk of AGA increased by 3.19 times as the genetically predicted LTL was shortened by one standard deviation in log transformed form under the IVW method (OR = 4.19, 95% CI = 1.20-14.61, p = 0.024). The other MR methods also demonstrated a similar trend of the effect of LTL on AGA. There was no causal relationship between LTL and AA (p > 0.05). Sensitivity analyses further demonstrated that the current results were less likely to be affected by confounders and bias.

Conclusion

Our results suggested a potential causal relationship between LTL and AGA, and shortened LTL was associated with an increased risk of AGA.

Dietary Habits in Japanese Patients with Alopecia Areata

Purpose

Alopecia areata (AA) is characterized by non-scarring, patchy hair loss caused by autoimmune reactions to anagen hair follicles. The pathogenesis of AA may be affected by the diet. However, the dietary habits of patients with AA have not been precisely examined. Therefore, the aim of this study was to investigate the dietary habits of patients with AA in comparison to those of healthy controls.

Patients and Methods

We evaluated the dietary habits of 70 adult Japanese patients with AA using a brief-type self-administered diet history questionnaire and compared them to the habits of age- and sex-matched healthy controls.

Results

Japanese patients with AA had a higher body mass index (BMI) and higher intakes of vitamin C and fruit than the controls. Logistic regression analysis showed that AA was associated with BMI. Retinol intake was positively correlated with severity of alopecia tool (SALT) score, and linear regression analysis revealed that retinol intake was a predictor of SALT score. Retinol intake among patients with moderate to severe AA (ie, a SALT score >25) was higher than that in patients with mild AA (a SALT score ≤25). The mean age of AA patients with atopic dermatitis (AD) was lower than that of AA patients without AD; however, there were no differences in nutrient or food intake between these two groups. Logistic regression analysis showed that the comorbidity AD was negatively associated with age.

Conclusion

AA was associated with a high BMI, and high retinol intake was a predictor of SALT score. Further studies should be conducted to clarify whether dietary intervention to reduce BMI or limit retinol intake can alter the development or severity of AA.

Pruritus, Allergy and Autoimmunity: Paving the Way for an Integrated Understanding of Psychodermatological Diseases?

Pruritus is a key symptom in allergology and dermatology, contributing to the global and huge impact on quality of life related to skin disorders, both those which are not related to a primary dermatosis (illness) and those which are linked with primary skin lesions (disease). This is particularly evident within psychophysiological dermatoses, a group of psychodermatological diseases where there is a primary dermatosis, where psychological stress plays a role, and where pruritus may represent a major and shared symptom. The etiopathogenesis of pruritus in those disorders sheds light on the link among psychopathological features, psychological stress and the subtle interface between allergic and autoimmune mechanisms, where mast cells play a pivotal role. Allergy has long been recognised as an altered reactivity to exogenous antigens (allergens), defined as an immediate hypersensitivity mediated by immunoglobulin E (IgE). In turn, the immunological understanding of atopy is related to an immediate hypersensitivity reaction to environmental antigens involving T-helper 2 (Th2) responses and the IgE production. Mast cells are major cells in the early phase of allergy, releasing the mediators involved in the symptoms associated with the allergic disease, including pruritus, when the allergen cross-links with IgE, whose mechanisms can be observed in acute urticaria and atopy. Some allergic reactions may persist and allergy may eventually lead to autoimmunity, with the development of a T-helper 1 (Th1) and then IgE-independent inflammation. For instance, in chronic spontaneous urticaria, the mast cell activation may include autoimmune mechanisms, where autoantibodies against the extracellular α subunit of the high-affinity IgE receptor (FcεRIα) and to IgE are observed, with the involvement of Th1 lymphocytes and the production of interferon-γ (INF-γ). The role of autoimmunity is also suggested in the etiopathogenesis of other psychophysiological dermatoses, namely psoriasis, atopic dermatitis and alopecia areata. In the latter, for example, mast cells were reported to be linked with the loss of immune privilege and they are the key cells involved in the experience of pruritus, whose intensity was reported to precede and be correlated with the onset of the hair loss. Furthermore, considering that the role of hair and skin is wide, from psychosocial aspects (communication and social interaction) to vital functions (such as, temperature control), it is straightforward that they are central in our interactions and synchronization with others and the world; thereby, we may admit that the psychophysiological dermatoses could represent a loss of such synchronization. Furthermore, they are often linked with psychopathology which strongly connects with the concept of desynchronization, namely, sleep disorders and depressive symptoms, the clinical expression of a dysfunction in the interplay among mast cells, pineal gland and melatonin, thus the circadian rhythm, as well as their connection with the hypothalamic corticotrophin-releasing hormone (CRH), well-known for its key role in stress response. Moreover, increasing evidence has supported the existence of cutaneous equivalents for these mechanisms, connecting with those central pathways. Thereby, taking all these concepts into consideration, this review intends to look into the updated evidence on the shared biological mechanisms between allergy and autoimmunity, underlining pruritus as a core element, then revisiting the key role of mast cells and discussing the connection with melatonin and immune-inflammatory pathways in the physiopathology of psychophysiological dermatoses, thus paving the way for the understanding of their psychosomatic correlates and a comprehensive psychodermatological approach.

Resident human dermal γδT-cells operate as stress-sentinels: Lessons from the hair follicle

Murine γδT-cells have stress-surveillance functions and are implicated in autoimmunity. Yet, whether human γδT-cells are also stress sentinels and directly promote autoimmune responses in the skin is unknown. Using a novel (mini-)organ assay, we tested if human dermis resident γδT-cells can recognize stressed human scalp hair follicles (HFs) to promote an alopecia areata (AA)-like autoimmune response. Accordingly, we show that γδT-cells from healthy human scalp skin are activated (CD69⁺), up-regulate the expression of NKG2D and IFN-γ, and become cytotoxic when co-cultured with autologous stressed HFs ex vivo. These autologous γδT-cells induce HF immune privilege collapse, dystrophy, and premature catagen, i.e. three hallmarks of the human autoimmune HF disorder, AA. This is mediated by CXCL12, MICA, and in part by IFN-γ and CD1d. In conclusion, human dermal γδT-cells exert physiological stress-sentinel functions in human skin, where their excessive activity can promote autoimmunity towards stressed HFs that overexpress CD1d, CXCL12, and/or MICA.

Alopecia Areata: an Update on Etiopathogenesis, Diagnosis, and Management

Alopecia areata (AA) is a common chronic tissue-specific autoimmune disease, resulting in hair loss, that affects up to 2% of the general population. The exact pathobiology of AA has still remained elusive, while the common theory is the collapse of the immune privilege of the hair follicle caused by immunological mechanism. Multiple genetic and environment factors contribute to the pathogenesis of AA. There are several clinical treatments for AA, varying from one or multiple well-defined patches to more diffuse or total hair loss of the scalp (alopecia totalis) or hair loss of the entire body (alopecia universalis). The available treatments for AA, such as corticosteroids and other immunomodulators, minoxidil, and contact immunotherapy, are of limited efficacy with a high risk of adverse effects and high recurrence rates, especially for patients with severe AA. Recent insights into the pathogenesis of AA have led to the development of new treatment strategies, such as Janus kinase (JAK) inhibitors, biologics, and several small molecular agents. In addition, modern therapies for AA, including antihistamines, platelet-rich plasma (PRP) injection, and other novel therapies have been well explored. In this review, we discussed the recent advances in the pathogenesis, diagnosis, and treatment of AA.

Reversal of alopecia areata, osteoporosis follow treatment with activation of Tgr5 in mice

BACKGROUND

Alopecia areata is an autoimmune hair loss disease with infiltration of pro-inflammatory cells into hair follicles. The role of Tgr5 in dermatitis has attracted considerable attention. The present study aimed to investigate the effect of Tgr5 in the development of Alopecia areata.

METHODS

The study utilized a comparison control group design with four groups of wild-type group, wild-type+INT777 group, Tgr5-/- group, and Tgr5-/-+INT777 group. The mice were treated with INT777 (30 mg/kg/day) or the carrier solution (DMSO) intraperitoneally for 7 weeks, and the back skin was collected and analyzed by histology and immunohistochemistry staining. The lumbar vertebrae 4 has also been analyzed by DXA and Micro-CT.

RESULTS

Tgr5-/- mice displayed the decreasingly significant in hair area and length, skin thickness, and the ratio of anagen and telogen, collagen, and mast cell number and loss the bone mass than WT group. After treating with INT777, the appearance of alopecia areata and bone microstructure has improved. Immunohistochemistry and qPCR analysis showed that activation of Tgr5 can down-regulate the express of JAK1, STAT3, IL-6, TNF-α, and VEGF.

CONCLUSION

These findings indicate that activation of Tgr5 mediated amelioration of alopecia areata and osteoporosis by down-regulated JAK1-STAT3 signaling pathway.

Exploring the human hair follicle microbiome

Human hair follicles (HFs) carry complex microbial communities that differ from the skin surface microbiota. This likely reflects that the HF epithelium differs from the epidermal barrier in that it provides a moist, less acidic, and relatively ultraviolet light-protected environment, part of which is immune-privileged, thus facilitating microbial survival. Here we review the current understanding of the human HF microbiome and its potential physiological and pathological functions, including in folliculitis, acne vulgaris, hidradenitis suppurativa, alopecia areata and cicatricial alopecias. While reviewing the main human HF bacteria (such as Propionibacteria, Corynebacteria, Staphylococci and Streptococci), viruses, fungi and parasites as human HF microbiome constituents, we advocate a broad view of the HF as an integral part of the human holobiont. Specifically, we explore how the human HF may manage its microbiome via the regulated production of antimicrobial peptides (such as cathelicidin, psoriasin, RNAse7 and dermcidin) by HF keratinocytes, how the microbiome may impact on cytokine and chemokine release from the HF, and examine hair growth-modulatory effects of antibiotics, and ask whether the microbiome affects hair growth in turn. We highlight major open questions and potential novel approaches to the management of hair diseases by targeting the HF microbiome.

The antiinflammatory effects of Xuefu Zhuyu decoction on C3H/HeJ mice with alopecia areata

BACKGROUND

As a traditional and typical prescription of prominently activating blood circulation to remove blood stasis, Xuefu Zhuyu decoction (XZD) consists of 15 kinds of herbal medicine. Clinical investigations have showed that XZD could significantly promote the new hair generation of alopecia areata (AA) patients characterized by Qi stagnation and blood stasis.

PURPOSE

The purpose of this study was executed to determine whether the mechanisms by which XZD stimulated newborn hair were related to its anti-inflammatory effects.

METHODS

Clinical AA individuals were recruited to confirm the efficies of XZD. High performance liquid chromatography (HPLC) analysis was performed to qualitatively and quantitatively determine the contents of 15 compounds in XZD. Schrodinger molecular docking and in vivo surface plasmon resonance (SPR) techniques were used to evaluate the potential binding properties of compounds to target proteins. C3H/HeJ mice were randomly assigned to groups control, AA, and the XZD administration (6.5, 13.0 and 26.0 g/kg/d). Except for mice in control group, all the mice in the other groups were treated with a 21-day chronic unpredictable mild stress (CUMS) induced AA. Hematoxylin-eosin (H&E) staining was performed to determine the degree of pathological damage to the skin. Enzyme-linked immunosorbent assay (ELISA) was performed to detect levels of interleukin-6 (IL-6), interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) and in serum and skin tissues. Western blot, immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were used to examine the expression levels of IL-6, IL-1β, TNF-α and osteopontin proteins and genes in skin tissues.

RESULTS

XZD could visibly promote hair regeneration of AA patients. The potential active ingredients in XZD prescription included at least amygdalin, hydroxysafflor yellow A, kaempferide, ferulic acid, catalpol, verbascoside, β-ecdysone, platycodin D, paeoniflorin, naringin, neohesperidin, liquiritin, glycyrrhizic acid, saikosaponin A and saikosaponin D. The results of molecular docking and SPR analysis showed that verbascoside, liquiritin, kaempferide and amygdalin showed the best potential binding properties with IL-6, IL-1β, TNF-α and osteopontin, respectively. Pathological evaluation showed that compared with the CUMS group, the administration of XZD significantly promoted hair regeneration, evidenced by increased number of skin hair follicles in C3H/HeJ AA mice. Compared with control group, ELISA data showed that the levels of IL-6, IL-1β and TNF-α in serum and skin tissues of CUMS induced AA mice were significantly increased, while XZD administration dramatically restrained the contents of the three pro-inflammatory factors. Western blot, immunohistochemistry, and qRT-PCR results further demonstrated that XZD administration notably down-regulated the protein and gene expression levels of osteopontin, IL-6, IL-1β and TNF-α in comparation with CUMS group.

CONCLUSION

XZD could dramatically ameliorate CUMS-induced AA damage in the skin of C3H/HeJ mice, possibly by suppressing the levels of IL-6, IL-1β, TNF-α and osteopontin.

Hormonal Regulation of the MHC Class I Gene in Thyroid Cells: Role of the Promoter "Tissue-Specific" Region

In previous studies we have demonstrated that the expression of the Major Histocompatibility Complex (MHC) class I gene in thyrocytes is controlled by several hormones, growth factors, and drugs. These substances mainly act on two regions of the MHC class I promoter a "tissue-specific" region (-800 to -676 bp) and a "hormone/cytokines-sensitive" region (-500 to -68 bp). In a previous study, we have shown that the role of the "tissue-specific" region in the MHC class I gene expression is dominant compared to that of the "hormone/cytokines-sensitive" region. In the present report we further investigate the dominant role of the "tissue-specific" region evaluating the effect of thyroid stimulating hormone (TSH), methimazole (MMI), phenylmethimazole (C10), glucose and thymosin-α1. By performing experiments of electrophoretic mobility shift assays (EMSAs) we show that TSH, MMI and C10, which inhibit MHC class I expression, act on the "tissue-specific" region increasing the formation of a silencer complex. Glucose and thymosin-α1, which stimulate MHC class I expression, act decreasing the formation of this complex. We further show that the silencer complex is formed by two distinct members of the transcription factors families activator protein-1 (AP-1) and nuclear factor-kB (NF-kB), c-jun and p65, respectively. These observations are important in order to understand the regulation of MHC class I gene expression in thyroid cells and its involvement in the development of thyroid autoimmunity.

Pro-inflammatory Vδ1+T-cells infiltrates are present in and around the hair bulbs of non-lesional and lesional alopecia areata hair follicles

BACKGROUND

It is widely accepted that NKG2D⁺cells are critically involved in alopecia areata (AA) pathogenesis. However, besides being expressed in CD8⁺T-cells and NK cells, NKG2D is also found in human γδT-cells. AA lesional hair follicles (HFs) overexpress NKG2D and γδTCR activating ligands, e.g. MICA and CD1d, and chemoattractants for γδT-cells, such as CXCL10.

OBJECTIVE

To investigate whether abnormal activities of γδT-cells may be involved in AA pathogenesis.

METHODS

We analyzed the number and activation status of γδT-cells in human healthy, lesional and non-lesional AA scalp biopsies by FACS and/or quantitative (immuno-)histomorphometry.

RESULTS

In healthy human scalp skin, the few skin-resident γδT-cells were found to be mostly Vδ1⁺, non-activated (CD69^-NKG2D^dim) and positive for CXCL10, and CXCL12 receptors. These Vδ1⁺T-cells predominantly localized in/around the HF infundibulum. In striking contrast, the number of Vδ1⁺T-cells was significantly higher around and even inside the proximal (suprabulbar and bulbar) epithelium of lesional AA HFs. These cells also showed a pro-inflammatory phenotype, i.e. higher NKG2D, and IFN-γ and lower CD200R expression. Importantly, more pro-inflammatory Vδ1⁺T-cells were seen also around non-lesional AA HFs. Lesional AA HFs also showed significantly higher expression of CXCL12.

CONCLUSION

Our pilot study introduces skin-resident γδT-cells as a previously overlooked, but potentially important, mostly (auto-)antigen-independent, new innate immunity protagonist in AA pathobiology. The HF infiltration of these activated, IFN-γ-releasing cells already around non-lesional AA HFs suggest that Vδ1⁺T-cells are involved in the early stages of human AA pathobiology, and may thus deserve therapeutic targeting for optimal AA management.

Association of Alopecia Areata with Vitamin D and Calcium Levels: A Systematic Review and Meta-analysis

Introduction

To investigate the associations of alopecia areata (AA) with serum vitamin D and calcium levels.

Methods

A systematic review of all relevant articles published up to February 2020 in PubMed, Embase, and Cochrane Library databases was conducted. Primary endpoints were serum 25-hydroxyvitamin D [25(OH)D] levels and vitamin D deficiency, and the secondary endpoint was serum calcium level. Odds ratio (OR) and standardized mean difference (SMD) with 95% CI across studies were analyzed.

Results

Data on 1585 patients with AA and 1114 controls from 16 case–control studies and three cross-sectional studies were included in this meta-analysis. A pooled meta-analysis was conducted using the random-effects model because of inter-study heterogeneity (vitamin D level, I² = 87.90%; vitamin D deficiency, I² = 81.10%; serum calcium level, I² = 83.80%). A combined analysis revealed that patients with AA had significantly lower mean serum 25(OH)D level compared with control (WMD − 9.08, 95% CI − 11.65, − 6.50, p < 0.001), and were more likely to have vitamin D deficiency (OR 4.14, 95% CI 2.34, 7.35, p < 0.001). However, the pooled analysis revealed that patients with AA did not have significantly lower serum calcium levels compared with control (WMD − 0.17, 95% CI − 0.40, 0.06, p = 0.143). Subgroup analysis suggested that matched control, mean age, and country might contribute to the heterogeneity of serum vitamin D level, while study design, matched control, and country might contribute to the heterogeneity of vitamin D deficiency.

Conclusion

Deficiency of serum 25(OH)D level, rather than calcium level, was present in patients with AA. Screening for vitamin D deficiency and vitamin D supplementation may be beneficial in the treatment of patients with AA.

Electronic supplementary material

The online version of this article (10.1007/s13555-020-00433-4) contains supplementary material, which is available to authorized users.

Toward Predicting the Spatio-Temporal Dynamics of Alopecia Areata Lesions Using Partial Differential Equation Analysis

Hair loss in the autoimmune disease, alopecia areata (AA), is characterized by the appearance of circularly spreading alopecic lesions in seemingly healthy skin. The distinct spatial patterns of AA lesions form because the immune system attacks hair follicle cells that are in the process of producing hair shaft, catapults the mini-organs that produce hair from a state of growth (anagen) into an apoptosis-driven regression state (catagen), and causes major hair follicle dystrophy along with rapid hair shaft shedding. In this paper, we develop a model of partial differential equations (PDEs) to describe the spatio-temporal dynamics of immune system components that clinical and experimental studies show are primarily involved in the disease development. Global linear stability analysis reveals there is a most unstable mode giving rise to a pattern. The most unstable mode indicates a spatial scale consistent with results of the humanized AA mouse model of Gilhar et al. (Autoimmun Rev 15(7):726-735, 2016) for experimentally induced AA lesions. Numerical simulations of the PDE system confirm our analytic findings and illustrate the formation of a pattern that is characteristic of the spatio-temporal AA dynamics. We apply marginal linear stability analysis to examine and predict the pattern propagation.