Long-term safety and efficacy of ritlecitinib in adults and adolescents with alopecia areata and at least 25% scalp hair loss: Results from the ALLEGRO-LT phase 3, open-label study

BACKGROUND

ALLEGRO-LT is an ongoing, long-term, open-label, multicentre, phase 3 study of ritlecitinib in adults and adolescents with alopecia areata (AA).

OBJECTIVES

To evaluate ritlecitinib safety and efficacy through Month 24 in patients with AA and ≥25% scalp hair loss.

METHODS

ALLEGRO-LT enrolled rollover patients who previously received study intervention in either ALLEGRO phase 2a or 2b/3 studies and de novo patients who had not received treatment in either study. The de novo cohort results are reported here. Patients aged ≥12 years with AA and ≥25% scalp hair loss received a daily, 4-week 200-mg ritlecitinib loading dose, followed by daily 50-mg ritlecitinib. Analyses are based on data up to the cut-off (December 2022). Efficacy outcomes included proportions of patients achieving Severity of Alopecia Tool (SALT) scores ≤20 and ≤10, Patient Global Impression of Change (PGI-C) score of 'moderately improved' or 'greatly improved' and eyebrow assessment (EBA) and eyelash assessment (ELA) response (≥2-grade improvement from baseline or normal score in patients with abnormal baseline EBA/ELA).

RESULTS

Mean (SD) ritlecitinib exposure among the 449 de novo patients enrolled was 728.7 (273.81) days. At Month 24 (as observed), 73.5% and 66.4% of patients achieved SALT score ≤20 and ≤10; 82.4% had PGI-C response; 60.8% and 65.7% had EBA and ELA response. 86.1% of patients reported treatment-emergent adverse events (AEs); most were mild or moderate in severity, with the most frequent being positive SARS-CoV-2 test (24.2%), headache (20.8%) and pyrexia (13.0%). Rates of serious AEs, severe AEs and treatment discontinuations were 4.9%, 6.0% and 6.5%, respectively. Herpes zoster infection occurred in six patients, serious infections in four, malignancies (excluding nonmelanoma skin cancer) in three and major adverse cardiovascular events in three.

CONCLUSIONS

In patients with AA and ≥25% scalp hair loss, ritlecitinib demonstrated clinical efficacy and had an acceptable safety profile with long-term treatment.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT04006457.

Patterns of clinical response in patients with alopecia areata treated with ritlecitinib in the ALLEGRO clinical development programme

BACKGROUND

Ritlecitinib, an oral JAK3/TEC family kinase inhibitor, demonstrated efficacy over 48 weeks in patients with alopecia areata (AA) in the ALLEGRO phase 2b/3 study.

OBJECTIVES

This post hoc analysis evaluated individual Severity of Alopecia Tool (SALT) score trajectories in patients who received ritlecitinib 50 mg and rolled over from Phase 2b/3 into the ongoing, open-label, Phase 3 ALLEGRO-LT study to describe long-term response patterns and associated baseline disease characteristics.

METHODS

Patients aged ≥12 years with ≥50% scalp hair loss received ritlecitinib 50 mg once daily in both studies. SALT score trajectories from baseline to Month 24 were used to categorise patients as early (SALT score ≤20 at Week 24 and Months 12 and 24), middle (≤20 at Months 12 and 24) or late responders (≤20 by Month 24) or as partial responders (maintained 30% improvement), relapsers (achieved but did not maintain 30% improvement) or non-responders (did not achieve 30% improvement). The proportions of patients achieving sustained response (achieved and maintained SALT score ≤20 at all subsequent available time points through Month 24) and complete response (SALT score 0 at ≥1 time point through Month 24) were evaluated. Multivariable logistic regression assessed variables associated with response.

RESULTS

Of 191 patients treated with ritlecitinib 50 mg, 87 (45.5%) were responders (SALT score ≤20), 24 (12.6%) were partial responders, 24 (12.6%) were relapsers and 56 (29.3%) were non-responders. Of 87 patients categorised as responders, 81 (93.1%) sustained their clinical response and 47 (46.0%) achieved complete response. Factors associated with treatment response included female sex and less extensive and shorter duration of hair loss.

CONCLUSIONS

Approximately 45% of patients were SALT score responders, with up to 11% requiring >1 year of ritlecitinib treatment to achieve response, highlighting the importance of extended treatment duration.

CLINICALTRIALS

GOV REGISTRATION

ALLEGRO phase 2b/3 study (NCT03732807); ALLEGRO-LT study (NCT04006457).

The AhR pathway is dysregulated in alopecia areata

Despite significant progress in the treatment of alopecia areata (AA), many aspects of its immune-based pathogenesis remain unexplored. IFN-γ, primarily produced by CD8+ T cells and NK cells, is considered central to AA pathogenesis. However, the complex immune signaling network contributes to therapeutic resistance and frequent disease flares after treatment discontinuation. The aryl hydrocarbon receptor (AhR) pathway, upregulated by IFN-γ, modulates Th17 responses, but its inhibitory effects on IFN-γ remain unclear. Although IL-17 levels are elevated in AA, clinical trials indicate that IL-17A inhibitors are ineffective. AhR expression is known to induce immune checkpoints (ICPs) such as PD-1, suggesting a potential role as a negative feedback mechanism. This study investigated AhR expression in lymphocytes from AA patients and its association with clinical and laboratory markers of disease activity. AhR expression was significantly reduced in CD4, CD8, Th1, and Th17 lymphocytes in AA patients compared to healthy controls (p < 0.005), and it correlated inversely with SALTII scores (p < 0.05). ROC analysis showed that AhR levels in CD8 cells could differentiate mild AA from healthy controls with a sensitivity of 82.35 % and specificity of 86.84 %, suggesting potential diagnostic utility. Lower AhR levels were associated with increased IFN-γ+ lymphocytes and decreased IL-17+ immune cells. Interestingly, immune profiles differed between atopic and non-atopic patients: in severe AA, higher AhR expression was linked to increased sPD-1 concentrations, whereas in limited AA, AhR failed to upregulate any investigated ICP. These findings highlight the significant downregulation of the AhR pathway in AA and suggest its potential as a therapeutic target. Future research should explore the development of AhR agonists or antagonists to modulate immune responses in AA.

High-Resolution Spatial Map of the Human Facial Sebaceous Gland Reveals Marker Genes and Decodes Sebocyte Differentiation

The sebaceous gland is essential for skin homeostasis by producing sebum to lubricate and protect the skin. Dysfunctions in sebaceous gland activity are associated with skin disorders such as acne, seborrheic dermatitis, and alopecia. However, its cellular and molecular mechanisms in humans remain poorly understood as most studies have been conducted in mouse models. This study provides a comprehensive molecular analysis of the human sebaceous gland, focusing on cellular interactions, sebocyte differentiation, and, to our knowledge, previously unreported gene markers. By integrating Stereo-seq spatial transcriptomics, single-cell RNA sequencing, and validation by MERFISH, we identified four distinct stages of sebocyte differentiation, each characterized by unique gene signatures. These results reveal that sebocyte differentiation is a dynamic and complex process. Our findings enhance the understanding of sebaceous gland biology and provide a valuable reference for future research and the development of therapies for sebaceous gland-related disorders, including acne.

Oxyresveratrol enhances hair regeneration in human dermal papilla cell and androgenetic alopecia mouse model

Alopecia, or hair loss, is a common dermatological condition caused by multiple factors. Oxyresveratrol (ORV), a compound derived from the heartwood of Artocarpus lakoocha, is recognized for its potent antioxidant properties, with recent studies highlighting its anti-inflammatory effect across various cell types. This study aims to explore the therapeutic potential of ORV in treating alopecia. We evaluated the effects of ORV on Human Follicle Dermal Papilla Cells (HFDPCs) and an androgenetic alopecia (AGA) mouse model. Oxidative stress in HFDPCs was induced using hydrogen peroxide (H2O2), and dihydrotestosterone (DHT) was used to simulate AGA in both HFDPCs and C57BL/6NJcl mice. Our finding demonstrated that ORV significantly enhanced HFDPCs proliferation. In H2O2-induced oxidative stress conditions, pretreatment with ORV decreased reactive oxygen species (ROS) levels and reduced the production of pro-inflammatory cytokine. In the AGA model, ORV inhibited β-Catenin phosphorylation in HFDPCs, thereby promoting hair growth and maintaining skin thickness, hair bulb size, and count in mice. Overall, ORV demonstrated anti-inflammatory and hair-regenerative effects in both in vitro and in vivo models of alopecia. These findings suggest that ORV is a promising candidate for the treatment of hair loss.

Enhanced therapeutic effects of all-trans retinoic acid nanostructured lipid carrier composite gel drug delivery system for alopecia areata

BACKGROUND

Alopecia areata (AA) affects approximately 2% of the global population and causes psychological distress. All-trans retinoic acid (ATRA) has the potential to promote hair regeneration; however, its clinical use is limited by skin irritation and low targeting specificity. To address these limitations, we designed an ATRA-loaded nanostructured lipid carrier gel (ATRA-NLC-Gel) drug delivery system to enhance the therapeutic effects of ATRA in AA.

RESULTS

ATRA-NLC showed a uniform nanoparticle size distribution and excellent biocompatibility. In vitro, they enhanced the uptake ability of dermal papilla cells, increased cell viability, and promoted cell proliferation by facilitating the cell cycle process. Compared to ATRA cream, ATRA-NLC-Gel significantly reduced skin irritation, prolonged residence time on the skin, and achieved a sustained and slow release of ATRA. Treatment with ATRA-NLC-Gel enhanced transdermal penetration and targeted enrichment in the hair follicle region, thereby significantly promoting hair regrowth. ATRA-NLC-Gel improved AA symptoms by upregulating CD200 and Ki-67 expression, activating the Wnt/β-catenin pathway.

CONCLUSIONS

ATRA-NLC-Gel enhanced the transdermal permeability and follicle-targeting efficacy of ATRA, alleviated ATRA-induced skin dryness and irritation, and effectively improved the symptoms of AA in AA model mice. ATRA-NLC-Gel offers a highly promising strategy for transdermal treatment of AA in clinical setting.

Alopecia Areata: Pathogenesis, Diagnosis, and Therapies

Alopecia areata (AA) is a complex, chronic inflammatory skin disorder characterized by unpredictable, nonscarring hair loss, affecting millions worldwide. Its pathogenesis remains poorly understood, driven by intricate interactions among immune dysregulation, genetic predisposition, and environmental triggers. Despite significant advances in identifying these contributing factors, substantial gaps persist in our understanding of the full spectrum of AA's molecular mechanisms and in the development of effective therapeutic approaches. This review aims to comprehensively explore the immunological, genetic, epigenetic, and environmental factors underlying AA, with a focus on immune-mediated mechanisms. We also evaluate diagnostic approaches and recent advancements in assessing disease severity. Furthermore, the review discusses evolving therapeutic options, including traditional therapies, biologics, small-molecule agents, and emerging treatments. The academic value of this work lies in its synthesis of current knowledge on the multifaceted nature of AA, providing insights for future research and clinical practice. By elucidating the interconnected factors underlying AA, this review seeks to advance both understanding and management of this prevalent, clinically challenging disorder.

Modulating immune responses in alopecia: therapeutic insights and potential targets of antisense oligonucleotides

BACKGROUND

Alopecia areata (AA) are hair loss disorders with distinct pathogenetic mechanisms involving immune dysregulation and microRNA modulation. AA, a T cell-mediated autoimmune disease, is characterized by sudden hair loss, with interferon-gamma (IFN-γ) playing a pivotal role in pathogenesis. The upregulation of IFN response genes, including IFN-inducible chemokines CXCL9, CXCL10, and CXCL11, in lesional skin reflects the activation of the IFN response pathway and contributes to immune cell recruitment and inflammation.

RESULTS

Recent research highlights the role of SIRT1, a class III histone deacetylase, in modulating immune responses in AA. SIRT1 inhibition promotes the production of Th1 cytokines and chemokines, impairing inflammation, while SIRT1 activation suppresses autoreactive responses through NF-κB deacetylation and STAT3 phosphorylation. Additionally, antisense oligonucleotides (ASOs) targeting miR-485-3p show therapeutic potential in promoting hair regrowth and mitigating inflammation in murine models of androgenic alopecia (AGA) and AA.

CONCLUSION

Understanding chemokine dysregulation provides key insights into AA pathogenesis and highlights TAMI-M as a potential therapy for reducing inflammation and promoting hair regeneration. These findings advance the exploration of immune, microRNA, and SIRT1 pathways as targets for novel hair loss treatments.

Botulinum Toxin in the Treatment of Hair and Scalp Disorders: Current Evidence and Clinical Applications

Botulinum toxin (BoNT) is well-recognized throughout dermatology for its cosmetic indications and growing therapeutic value. Recent studies have trialed BoNT in the treatment of hair and scalp disorders, many of which lack long-term effective treatments and significantly impact quality of life. In this review, we summarize the current clinical literature on this topic to comprehensively evaluate the efficacy, safety, and clinical value of BoNT in treating hair and scalp conditions. A literature search on PubMed/MEDLINE and Scopus identified 40 articles reporting the use of 25-200 units of BoNT-A or B in 689 patients with hair loss (79.5%), scalp seborrheic dermatitis/hyperseborrhea (10%), craniofacial hyperhidrosis (9%), folliculitis decalvans/dissecting folliculitis (0.86%), scalp pain (0.43%), or linear scleroderma (0.29%). Most studies on BoNT therapy for androgenetic alopecia (AGA) reported mild or non-significant hair growth; however, considerable variability in outcome measures complicates the ability to draw definitive conclusions or justify the use of BoNT over established AGA therapies. BoNT-A and B showed consistent efficacy in treating craniofacial hyperhidrosis with minimal side effects. Additional scalp conditions may benefit from BoNT therapy, but the evidence is limited, and larger, controlled studies are needed to better understand BoNT's clinical value in these conditions.

Effect of Free Long-Chain Fatty Acids on Anagen Induction: Metabolic or Inflammatory Aspect?

Hair growth is a highly complex process regulated at multiple levels, including molecular pathways, stem cell behavior, metabolic processes, and immune responses. The hair follicle exhibits metabolic compartmentalization, with some cells relying on glycolysis and others on oxidative phosphorylation. Interestingly, in mice, the onset of the anagen phase can be stimulated by locally suppressing oxidative phosphorylation in the skin. This study showed that topical application of palmitate or oleate accelerated the onset of anagen in mice, while lactate, the end product of glycolysis, delayed it. We also investigated the effects of fatty acids on cytokine production in various human cell cultures. Fatty acids did not induce a cytokine response in fibroblasts or keratinocytes but significantly affected monocytes. Specifically, palmitic acid induced the production of TNF-α, IL-8, and CCL2. Oleic acid, however, elicited almost no response. By comparing the "metabolic" and "inflammatory" hypotheses of anagen stimulation, the results of our study suggest that metabolic regulation holds significant promise for influencing hair growth.

Epistasis of ERAP1 With 4 Major Histocompatibility Complex Class I Alleles in Frontal Fibrosing Alopecia: A Genome-Wide Association Study Meta-Analysis

Importance

Frontal fibrosing alopecia (FFA) is an inflammatory and scarring form of hair loss of increasing prevalence that most commonly affects women. An improved understanding of the genetic basis of FFA will support the identification of pathogenic mechanisms and therapeutic targets.

Objective

To identify novel genomic loci at which common genetic variation affects FFA susceptibility and assess nonadditive effects on genetic risk between susceptibility loci.

Design, Setting, and Participants

Four genome-wide association studies were combined using an SE-weighted meta-analysis. Within the major histocompatibility complex (MHC) locus, stepwise conditional analysis was undertaken to determine independently associated classical MHC class I alleles. Statistical tests for epistatic interaction were performed between risk alleles at the MHC and endoplasmic reticulum aminopeptidase 1 (ERAP1) loci.

Main Outcomes and Measures

Genome-wide significant locus associated with FFA and nonadditive effects on genetic risk between susceptibility loci.

Results

Of 6668 included patients, there were 1585 European female individuals with FFA and 5083 controls. Genome-wide significant associations were identified at 4 genomic loci, including a novel susceptibility locus at 5q15, and the association signal could be fine-mapped to a single nucleotide substitution (rs10045403) in the 5' untranslated region of ERAP1 (rs10045403; odds ratio, 1.30; 95% CI, 1.19-1.43; P = 3.6 × 10-8). Within the MHC, FFA risk was statistically independently associated with HLA-A*11:01, HLA-A*33:01, HLA-B*07:02, and HLA-B*35:01. FFA risk was affected by genetic variation at the ERAP1 locus only in individuals who carried at least 1 of the MHC class I risk alleles.

Conclusions and Relevance

In this genome-wide meta-analysis, a supra-additive effect of genetic variation was found that affected peptide trimming and antigen presentation on FFA susceptibility. Patients with FFA may benefit from emerging therapeutic approaches that modulate ERAP-mediated processes.

Protective Effects of Korean Red Ginseng Against Oxidative Stress-Induced Damage in Human Hair

BACKGROUND

Oxidative stress causes fatal damage to follicular keratinocytes (FKCs) and is a common pathophysiology of many hair disorders.

OBJECTIVE

This study investigated the protective effects of Red ginseng extract (RGE) and its main ginsenosides against oxidative hair damage using an in vitro organ model of human hair follicles.

METHODS

We examined whether RGE and its constituent ginsenosides could prevent oxidative damage induced by H₂O₂ in FKCs by suppressing apoptosis and promoting hair growth.

RESULTS

RGE and its main ginsenoside, G-Rb1, significantly inhibited reactive oxygen species production and apoptosis in FKCs. Furthermore, they effectively alleviated the inhibition of hair growth induced by oxidative damage and inhibited the transition of hair from the anagen to the telogen stage. The hair cycle and apoptosis were associated with the modulation of p53 and Bax/Bcl2 signaling.

CONCLUSION

RGE and G-Rb1 can effectively mitigate the oxidative damage caused by FKCs, thereby affecting hair growth and hair cycles.

Prevalence of Thyrotropin Receptor Antibodies and Clinical Profile of Patients with Alopecia Areata: A Cross-Sectional Study

Introduction

Alopecia areata (AA) is associated with thyroid dysfunction and abnormal levels of thyroglobulin and thyroid peroxidase autoantibodies. One study detected high prevalence of thyrotropin receptor antibodies (TRAbs) in AA patients. Our aim was to investigate the prevalence of TRAb levels in AA patients and to assess their association with thyroid hormones, other thyroid antibodies, AA severity, and other epidemiological variables.

Methods

In this observational study, 139 patients (97 females, 42 males), aged 12 and above, with newly presenting, relapsing, or treatment-resistant AA were included. Medical histories were reviewed, alopecia severity was assessed using the Severity of Alopecia Tool (SALT), and blood tests measured thyroid hormones and autoantibodies.

Results

The prevalence of TRAb was significantly higher in AA patients (23.6%) compared to the general population (1-2%) (p < 0.001). Elevated TRAb titers did not correlate with diagnosed thyroid dysfunction or treatment, abnormal thyroid function tests and autoantibodies, AA severity, duration, and onset. Male patients exhibited a significantly higher prevalence of abnormal TRAb titers compared to females (75.0% vs. 21.3%, p = 0.002).

Conclusion

A significant proportion of AA patients presented with elevated TRAb levels, independent of thyroid hormone titers, other thyroid autoantibodies, or SALT score. Prevalence of abnormal TRAb levels was higher in males.

Microneedle transdermal delivery of compound betamethasone in alopecia areata-A randomized controlled trial

BACKGROUND

Alopecia areata (AA) places a considerable burden on patients. While intralesional glucocorticoid injection is an important therapy, it can cause severe pain.

OBJECTIVE

To compare the efficacy and pain levels of microneedle transdermal delivery of compound betamethasone versus traditional intralesional injection in mild-to-moderate AA.

METHODS

We conducted a randomized controlled trial in AA patients with a Severity of Alopecia Tool (SALT) score <50. Both groups received monthly compound betamethasone injections: group A via intralesional injections and group B via transdermal microneedle delivery. The primary outcome was the reduction in SALT score after 3 months.

RESULTS

With 80 patients enrolled, baseline SALT scores were similar between group A (9.250 ± 5.300) and group B (10.65 ± 9.445). After 3 months, the mean SALT reduction was 7.000 ± 4.5017 in group A and 8.075 ± 8.014 in group B, with no statistical difference. Remission rates for SALT30/50/75/90 were 92.50/90.00/57.50/42.50% in group A and 95.00/87.50/72.50/40% in group B, with no significant difference. Group B had a significantly lower visual analog scale pain score than group A (4.000 ± 1.174 vs 5.281 ± 2.098, P = .0047).

LIMITATIONS

The study focused on mild-to-moderate patchy AA, limiting insights into severe cases.

CONCLUSION

Microneedle transdermal delivery of compound betamethasone in mild-to-moderate patchy AA demonstrates efficacy comparable to traditional intralesional injection with reduced pain.

Identification of a Novel Three-immunogene Diagnostic Signature for Alopecia Areata

BACKGROUND

Autoimmune mechanisms have important roles in the pathogenesis of alopecia areata (AA).

OBJECTIVE

This study aimed to evaluate the exact biological and clinical importance of immunogenes in AA patients using bioinformatic methods.

METHODS

Five AA scalp gene expression profiles were obtained from the Gene Expression Omnibus database. Differentially-expressed genes (DEGs) between AA and control groups were identified. An immune-related gene diagnostic signature (IRGDS) was established by protein-protein interaction network analysis, least absolute shrinkage and selection operator and logistic regression analysis.

RESULTS

A total of 102 immune-related DEGs were identified. We developed an IRGDS composed of CD8A, CSF1R and CXCL10 for AA molecular pathological assessment and diagnosis (area under the receiver operating characteristic curve [AUC]=0.962). We also validated the diagnostic value of the IRGDS in an external cohort (AUC=0.955). Patients with high IRGDS scores presented with a higher abundance of immune cell infiltration and expression of genes associated with immune recruitment and immune activation, suggesting adverse biological alterations.

CONCLUSION

In our study, an IRGDS model with accurately diagnostic capacity for AA was established, and biological alterations were deciphered in AA. The IRGDS may be used as an auxiliary diagnostic marker for AA.

Nanoparticle Adjuvants Incorporating Haptens Drive Potent Immune Tolerance to Accelerate Hair Regrowth

Alopecia areata (AA) is a prevalent autoimmune condition that causes sudden hair loss and poses significant psychological challenges to affected individuals. Current treatments, including corticosteroids and Janus kinase inhibitors, fail to provide long-term efficacy due to adverse effects and relapse after cessation. This study introduces a nanoparticle (NP) system that codeliver diphenylcyclopropenone (DPCP) and rapamycin (RAPA) prodrugs to induce immune tolerance and promote hair regeneration. The results demonstrated that the coassembled NPs exhibited uniformity and stability, were efficiently taken up by antigen-presenting cells (APCs), and successfully induced dendritic cells (DCs) to differentiate into tolerogenic phenotypes in vitro. In vivo studies on a mouse model of alopecia showed that these NPs significantly accelerated the transition of hair follicles from the telogen phase to the anagen phase, promoting hair regrowth. This research presents a promising therapeutic strategy for AA and offers insights into treating autoimmune diseases where autoantigens are unclear.

Pathogenesis and regenerative therapy in vitiligo and alopecia areata: focus on hair follicle

Vitiligo is an autoimmune disease characterized by the loss of functional melanocytes in the hair follicles and epidermis, leading to white patches on the skin and mucous membranes. Alopecia areata (AA) is a common immune-mediated condition in which autoimmune attack on hair follicles cause non-scarring hair loss. Both diseases significantly impact patients's physical and mental health. Hair follicles, dynamic mini-organs, house diverse stem cell populations that form hair structures. Melanocyte stem cell (McSCs) and hair follicle stem cells (HFSC) located in the hair follicle bulge contribute to follicular structures during each anagen phase of the hair cycle, synchronizing periodic activities to impact color to the hair. Hair follicle dysfunction may contribute to hair loss and could potentially interfere with repigmentation efforts in vitiligo lesions. This article reviews the role of hair follicles in the pathogenesis, clinical manifestations, and therapeutic options for vitiligo and AA, aiming to deepen clinicians' understanding of follicular involvement in these diseases and explore potential treatment avenues.

Identifying effective immune biomarkers in alopecia areata diagnosis based on machine learning methods

BACKGROUND

Alopecia areata (AA) is a common non-scarring hair loss disorder associated with autoimmune conditions. However, the pathobiology of AA is not well understood, and there is no targeted therapy available for AA.  METHODS: In this study, differential gene expression analysis, immune status assessment, weighted correlation network analysis (WGCNA), and functional enrichment analysis were performed to identify shared genes associated with both immunological response and AA. Machine learning methods were then used to identify three hub genes as potential diagnostic markers for AA. External validation was performed, and the correlation of hub genes with immune infiltration, immune checkpoint genes, and key marker genes and pathways were evaluated.

RESULTS

Three hub genes were identified, which accurately predicted the progression of AA and the immune status. The hub genes were found to be diagnostic markers for AA with high predictive accuracy. External validation confirmed the efficacy of these markers in identifying AA patients.

CONCLUSION

Overall, the study provides a novel approach for the diagnosis, prevention, and treatment of AA. The findings could potentially lead to the development of targeted therapies for AA based on the identified hub genes. The study also highlights the potential of machine learning and bioinformatics analysis in identifying new biomarkers for autoimmune diseases.

Unveiling the Effect of Age and IgE Level on Alopecia Areata: Insights from Comparative RNAseq Analysis

Background

Alopecia areata (AA) is a common autoimmune disease, causes sudden hair loss on the scalp, face, and sometimes other areas of the body. Previous studies have suggested more severe manifestations and higher recurrence rates in children than in adults. Moreover, pediatric AA patients with atopic predisposition often exhibit elevated IgE levels, early onset, and a poor prognosis.

Purpose

This study aimed to investigate the impact of age and IgE levels on AA by conducting RNA sequencing on scalp samples from AA patients with atopic predisposition, age-matched healthy controls, and AA samples with varying IgE levels.

Patients and Methods

We employed the single-sample Gene Set Enrichment Analysis (ssGSEA) algorithm in conjunction with gene expression analysis to assess immune infiltration. Differential gene expression analysis was performed using the DESeq package in R. Immunohistochemical staining and qPCR was performed to validate these findings.

Results

Our results revealed a more pronounced inflammatory immune infiltration in AA patients across all age groups compared to healthy controls. Pediatric AA was characterized by an upregulation of genes controlling inflammatory responses, such as the IFN-γ pathway and JAK-STAT cascade, contrasting to adult AA. Compared to age-matched healthy controls, pediatric AA patients exhibited a significant increase in the infiltration of B cell subtypes, mast cells, and regulatory T cells. Additionally, high IgE levels in AA patients led to the upregulation of IFN-γ pathway genes, compared to AA patients with normal IgE levels.

Conclusion

In summary, the heightened immune and inflammatory responses, along with the more significant infiltration of immune cells in pediatric AA with atopic predisposition, may explain the increased clinical severity and recurrence rates. Dissecting these molecular mechanisms sheds some light on the contributions of age and IgE to the pathogenesis and progression of AA, revealing potential age-specific and allergy-related therapeutic targets.

Case Report: Baricitinib improved alopecia areata in a pediatric patient with atopic dermatitis

Alopecia areata (AA) is a common non-scarring hair loss condition whose specific pathogenesis is not yet fully understood. In children, AA often co-occurs with atopic dermatitis (AD), complicating treatment. Here, we report the case of a child with myasthenia gravis who had severe AA and moderate AD. The child had previously been treated with local injections of corticosteroids and developed total hair loss and AD after discontinuing corticosteroid use. After approximately one year of treatment with baricitinib, 4 mg once daily, combined with twice-daily application of a corticosteroid ointment, a significant improvement in the child's condition was observed, with the Severity of Alopecia Tool score dropping from 100 to 24.4 and Eczema Area Severity Index score to 0. New vellus hairs were clearly observable under trichoscopy, which contrasted significantly with the pre-treatment state. Throughout the treatment process, the patient's clinical symptoms, blood cell counts, liver and kidney function, and coagulation functions were essentially normal, with no significant adverse reactions observed except for folliculitis on the scalp. We discuss common targets in the pathogenesis of AA and AD as well as the safety and prospects of Janus kinase inhibitors for the treatment of pediatric patients with these conditions.

Reprogramming of epidermal keratinocytes by PITX1 transforms the cutaneous cellular landscape and promotes wound healing

Cutaneous wound healing is a slow process that often terminates with permanent scarring while oral wounds, in contrast, regenerate after damage faster. Unique molecular networks in epidermal and oral epithelial keratinocytes contribute to the tissue-specific response to wounding, but key factors that establish those networks and how the keratinocytes interact with their cellular environment remain to be elucidated. The transcription factor PITX1 is highly expressed in the oral epithelium but is undetectable in cutaneous keratinocytes. To delineate if PITX1 contributes to oral keratinocyte identity, cell-cell interactions, and the improved wound healing capabilities, we ectopically expressed PITX1 in the epidermis of murine skin. Using comparative analysis of murine skin and oral (buccal) mucosa with single-cell RNA-Seq and spatial transcriptomics, we found that PITX1 expression enhances epidermal keratinocyte migration and proliferation and alters differentiation to a quasi-oral keratinocyte state. PITX1+ keratinocytes reprogrammed intercellular communication between skin-resident cells to mirror buccal tissue while stimulating the influx of neutrophils that establish a pro-inflammatory environment. Furthermore, PITX1+ skin healed significantly faster than control skin via increased keratinocyte activation and migration and a tunable inflammatory environment. These results illustrate that PITX1 programs oral keratinocyte identity and cellular interactions while revealing critical downstream networks that promote wound closure.

Alopecia areata exhibits cutaneous and systemic OX40 activation across atopic backgrounds

BACKGROUND

Alopecia areata (AA) is a chronic, nonscarring hair-loss disorder associated with significant quality-of-life impairment and limited treatment options. AA has been recently linked to atopy and shown to exhibit both Th1- and Th2-driven inflammation. However, a comprehensive molecular and cellular characterization across blood and scalp compartments in both atopic and nonatopic patients is lacking.

METHODS

Lesional and nonlesional scalp biopsies obtained from AA patients with (n = 16) or without (n = 20) atopic history, and 17 demographically matched healthy controls were analyzed with RNA-seq, RT-PCR, and immunohistochemistry. Flow cytometry was also performed on peripheral blood mononuclear cells (PBMCs) from a subset of patients. Differential expression was defined using |fold-change| > 1.5 and false-discovery rate <0.05.

RESULTS

AA scalp exhibited robust upregulation of Th1- (IFNG, CXCL9, CXCL10, CXCL11) and Th2-related products (CCL26, CCR4, IL10, IL13, TSLP, TNFRSF4/OX40) and shared downregulation of hair keratins, regardless of atopic background, with variable Th17/Th22 modulation. AA patients with atopy exhibited greater inflammatory tone and Th2-skewing (IL10, IL13, IL33, CCR4, CCL26). Disease severity correlated significantly with immune and hair keratin biomarkers and with perifollicular cellular infiltrates. Cutaneous OX40/OX40L upregulation was paralleled by increases in circulating OX40+ and OX40L+ leukocytes, regardless of atopic background.

CONCLUSION

Our results suggest some atopy-associated immune differences in AA and highlight the OX40 axis as a potential novel therapeutic target that may broadly benefit AA patients.

Topographical variations in the skin barrier and their role in disease pathogenesis

The skin barrier can be divided into at least four functional units: chemical, microbial, physical and immunological barriers. The chemical and microbial barriers have previously been shown to exhibit different characteristics in topographically distinct skin regions. There is increasing evidence that the physical and immunological barriers also show marked variability in different areas of the skin. Here, we review recent data on the topographical variations of skin barrier components, the contribution of these variations to the homeostatic function of the skin and their impact on the pathogenesis of specific immune-mediated skin diseases (such as atopic dermatitis and papulopustular rosacea). Recognition of these topographical barrier differences will improve our understanding of skin homeostasis and disease pathogenesis and provide a basis for body site-specific targeted therapies.

Innovative strategies for the discovery of new drugs against alopecia areata: taking aim at the immune system

INTRODUCTION

The autoimmune hair loss condition alopecia areata (AA) exacts a substantial psychological and socioeconomic toll on patients. Biotechnology companies, dermatology clinics, and research institutions are dedicated to understanding AA pathogenesis and developing new therapeutic approaches. Despite recent efforts, many knowledge gaps persist, and multiple treatment development avenues remain unexplored.

AREAS COVERED

This review summarizes key AA disease mechanisms, current therapeutic methods, and emerging treatments, including Janus Kinase (JAK) inhibitors. The authors determine that innovative drug discovery strategies for AA are still needed due to continued unmet medical needs and the limited efficacy of current and emerging therapeutics. For prospective AA treatment developers, the authors identify the pre-clinical disease models available, their advantages, and limitations. Further, they outline treatment development opportunities that remain largely unmapped.

EXPERT OPINION

While recent advancements in AA therapeutics are promising, challenges remain, including the lack of consistent treatment efficacy, long-term use and safety issues, drug costs, and patient compliance. Future drug development research should focus on patient stratification utilizing robust biomarkers of AA disease activity and improved quantification of treatment response. Investigating superior modes of drug application and developing combination therapies may further improve outcomes. Spirited innovation will be needed to advance more effective treatments for AA.

Myofibroblasts persist through immune privilege mechanisms to mediate oral submucous fibrosis: Uncovering the pathogenesis

Immune privilege is the ability to tolerate foreign antigens without eliciting an inflammatory immune response. Several mechanisms explain a structure's immune privilege status, which is regulated by innate and adaptive immune responses. The role of myofibroblasts in perpetuating fibrosis by acquiring an immune privileged phenotype against the backdrop of oral submucous fibrosis (OSF) is evolving. Myofibroblasts persist through the Fas/FasL autocrine pathway and induce apoptosis in epithelial cells, explaining the juxtaposition of apoptotic cells in areas of fibrosis. However, increased matrix stiffness, in addition to activating TGF-β, reduces Fas surface expression in myofibroblasts, increasing their resistance to apoptosis. The reciprocal amplification loop between the immune checkpoint proteins programmed death-ligand 1 (PD-L1) and TGF-β involves the YAP-TAZ and SMAD2,3 pathways and dramatically enhances profibrotic signalling. Increased matrix stiffness also enhances cMYC expression, which subsequently amplifies PD-L1 levels on myofibroblasts. The increase in PD-L1 on the myofibroblast microengineers the phenotype of CD4+ T cells homing to fibrotic areas by acting on the programmed cell death protein 1 (PD-1) receptor on the T-cell surface, converting these cells from antifibrotic cells to profibrotic cells that produce IL-17A and TGF-β. This manuscript provides mechanistic insight into how myofibroblasts avoid apoptosis in OSFs by evading the immune system. Targeting an immune-privileged phenotype in myofibroblasts with FAS-FASL pathway-dependent characteristics is an ideal strategy for reversing OSF.

Epidermal growth factor receptor/mitogen-activated kinase inhibitor treatment induces a distinct inflammatory hair follicle response that includes collapse of immune privilege

BACKGROUND

Inhibitors of epidermal growth factor receptor (EGFRi) or mitogen-activated kinase (MEKi) induce a folliculitis in 75-90% of patients, the pathobiology of which remains insufficiently understood.

OBJECTIVES

To characterize changes in the skin immune status and global transcriptional profile of patients treated with EGFRi; to investigate whether EGFRi affects the hair follicle's (HF) immune privilege (IP); and to identify early proinflammatory signals induced by EGFRi/MEKi in human scalp HFs ex vivo.

METHODS

Scalp biopsies were taken from patients exhibiting folliculitis treated long term with EGFRi ('chronic EGFRi' group, n = 9) vs. healthy scalp skin (n = 9) and patients prior to commencing EGFRi treatment and after 2 weeks of EGFRi therapy ('acute EGFRi' group, n = 5). Healthy organ-cultured scalp HFs were exposed to an EGFRi (erlotinib, n = 5) or a MEKi (cobimetinib, n = 5). Samples were assessed by quantitative immunohistomorphometry, RNA sequencing (RNAseq) and in situ hybridization.

RESULTS

The 'chronic EGFRi' group showed CD8+ T-cell infiltration of the bulge alongside a partial collapse of the HF's IP, evidenced by upregulated major histocompatibility complex (MHC) class I, β2-microglobulin (B2 M) and MHC class II, and decreased transforming growth factor-β1 protein expression. Healthy HFs treated with EGFRi/MEKi ex vivo also showed partial HF IP collapse and increased transcription of human leucocyte antigen (HLA)-A, HLA-DR and B2 M transcripts. RNAseq analysis showed increased transcription of chemokines (CXCL1, CXCL13, CCL18, CCL3, CCL7) and interleukin (IL)-26 in biopsies from the 'chronic EGFRi' cohort, as well as increased IL-33 and decreased IL-37 expression in HF biopsies from the 'acute EGFRi' group and in organ-cultured HFs.

CONCLUSIONS

The data show that EGFRi/MEKi compromise the physiological IP of human scalp HFs and suggest that future clinical management of EGFRi/MEKi-induced folliculitis requires HF IP protection and inhibition of IL-33.

The role of salivary vitamin D and interleukin-6 on non-scarring Alopecia

BACKGROUND

Alopecia, or hair loss, is an emerging global disease. Its etiopathogenesis includes nutritional deficiencies, oxidative stress, and deficiency of physiological factors. Around 2% of the general population has the probability of developing alopecia at any one period. Vitamin D and interleukin-6 (IL-6) have a major role in alopecia. The present goal of research is to investigate the role of vitamin D and IL-6 in the saliva of patients with non-scarring alopecia.

METHODOLOGY

The study involved 51 cases of non-scarring alopecia and 50 healthy controls with an age range between 18 and 40 years. A detailed history and clinical examination were done. Salivary vitamin D and IL-6 were determined to compare within the groups.

RESULTS

The average vitamin D level in cases (104.64 ± 46.95 pmol/L) was significantly lower as compared to controls (223 ± 12.03 pmol/L) (p < 0.001). Whereas the average amount of IL-6 was significantly higher (170.54 ± 63.68 ng/L) than the control group (56.38 ± 46.52 ng/L) (p < 0.001). No correlation of vitamin D level with IL-6 was detected in study subjects.

CONCLUSION

Vitamin D significantly influences the development of non-scarring alopecia. Patients with non-scarring alopecia had low amount of vitamin D indicate its role in etiology of hair loss. IL-6 may cause a collapse of the hair bulb, having a significant part in the pathogenesis of alopecia indicating chronic inflammatory or autoimmune condition. This research will aid in diagnosing scalp disease using salivary biomarkers and improve the treatment of alopecia.

Intranasal sensitization model of alopecia areata using pertussis toxin as adjuvant

BACKGROUND

Nasopharyngeal Bordetella pertussis (BP) colonization is common, with about 5% of individuals having PCR evidence of subclinical BP infection on nasal swab, even in countries with high vaccination rates. BP secretes pertussis toxin (PTx). PTx is an adjuvant commonly used to induce autoimmunity in multiple animal models of human disease. Colocalization of PTx and myelin from myelinated nerves in the nasopharynx may lead to host sensitization to myelin with subsequent autoimmune pathology.

METHODS

C57BL/6J female adult mice were given varied doses and schedules of intranasal PTx, MOG35-55 antigen, or controls to test whether intranasal administration of PTx and myelin oligodendrocyte peptide (MOG35-55) could induce experimental autoimmune encephalomyelitis (EAE) in mice. While we observed systemic cell-mediated immunity against MOG35-55, we did not observe EAE. Unexpectedly, many mice developed alopecia. We systematically investigated this finding.

RESULTS

Patchy alopecia developed in 36.4% of mice with the optimized protocol. Pathology consistent with alopecia areata was confirmed histologically by documenting concomitant reduced anagen phase and increased telogen phase hair follicles (HFs) in biopsies from patches of hair loss in mice with alopecia. We also found reduced CD200 staining and increased CD3+T cells surrounding the HFs of mice with alopecia compared to the mice without alopecia, indicating HF Immune Privilege (HFIP) collapse. Systemic immune responses were also found, with increased proportions of activated T cells and B cells, as well as MHCII+ dendritic cells in peripheral blood and/or splenocytes. Finally, in mice initially exposed to intranasal MOG35-55 and PTx in combination, but not to either agent alone, splenocytes were shown to proliferate after in vitro stimulation by MOG35-55. Consistent with prior investigations, PTx exhibited a dose-response effect on immune cell induction and phenotype, with the lowest PTx dose failing to induce autoimmunity, the highest PTx dose suppressing autoimmunity, and intermediate doses optimizing autoimmunity.

CONCLUSIONS

We propose that this is the first report of an autoimmune disease in an animal model triggered by colocalization of intranasal PTx and autoantigen. This model parallels a natural exposure and potential intranasal sensitization-to-pathology paradigm and supports the plausibility that nasopharyngeal subclinical BP colonization is a cause of alopecia areata.

Dandruff lesional scalp skin exhibits epidermal T cell infiltration and a weakened hair follicle immune privilege

OBJECTIVE

Dandruff is characterised by the presence of perivascular leukocytes and mild inflammation; however, the immune microenvironment of dandruff-affected scalp skin and the potential changes to the hair follicle's (HF) physiological immune privilege (HF IP) remain unknown. Here, we characterised the HF immune microenvironment and immune privilege status in dandruff-affected scalp skin.

METHODS

We assessed relevant key parameters in healthy versus dandruff-affected human scalp biopsies using quantitative immunohistomorphometry, laser capture microdissection, and RNA sequencing.

RESULTS

The number of epidermal CD4+ and CD8+ T cells was increased in lesional dandruff scalp skin, while the number of MHC class II+/CD1a+ Langerhans cells was decreased in the infundibulum. The number of intrafollicular and perifollicular CD4+ T cells and CD8+ T cells, perifollicular CD68+ macrophages, and tryptase+ mast cells remained unchanged. Interestingly, MHC class Ia and ß2-microglobulin protein expression were significantly increased specifically in the suprabulbar outer root sheath (ORS) compartment of dandruff-associated HFs. RNAseq analysis of laser capture micro-dissected suprabulbar ORS compartment revealed antigen presentation pathway as the top regulated canonical pathway, along with the upregulation of HF-IP genes such as HLA-C, HLA-DP, and TAP1, which are normally down-regulated in healthy HFs. Intrafollicular protein expression of known HF IP guardians (CD200 and α-MSH) and 'danger signals' (MICA and CXCL10) remained unaltered at the IP sites of dandruff lesional HFs compared to non-lesional and healthy HFs. Instead, the expression of macrophage migration inhibiting factor (MIF), another HF IP guardian, was reduced.

CONCLUSION

Together, this work shows that dandruff is associated with epidermal T-cell infiltration and a weakened HF IP in the suprabulbar ORS of HFs in dandruff lesional scalp.

Immune-Molecular Link between Thyroid and Skin Autoimmune Diseases: A Narrative Review

Autoimmune skin disorders, including Psoriasis, Lichen Planus, Vitiligo, Atopic Dermatitis, and Alopecia Areata, arise from a combination of genetic predisposition, external factors, and immunological dysfunction. It is well-documented that there is a strong correlation between autoimmune thyroid diseases and a range of dermatological disorders, especially urticaria. This review investigates possible links between autoimmune thyroiditis and a broader spectrum of autoimmune skin conditions, analyzing shared genetic markers, immunological mechanisms, and clinical correlations. Common pathogenic mechanisms include disrupted immune tolerance and oxidative stress, leading to chronic inflammation. Genetic factors, such as IL-23 receptor gene variants, increase the risk for Psoriasis, Alopecia Areata, and Hashimoto's thyroiditis. Additionally, CTLA-4 mutations enhance susceptibility to autoimmune thyroid and skin disorders. Shared genetic susceptibility was also reported in Lichen Planus and Vitilgo, even if different genetic loci might be involved. The breakdown of the immune system can determine a pro-inflammatory state, facilitating the development of autoimmunity and auto-antibody cross-reactions. The presence of similar antigens in skin cells and thyrocytes might explain why both tissues are affected. The significant overlap between these conditions emphasizes the necessity for a comprehensive diagnosis workup and treatment. Future research should focus on clarifying specific immunological pathways and identifying novel biomarkers.

Amygdalin ameliorates alopecia areata on C3H/HeJ mice by inhibiting inflammation through JAK2/STAT3 pathway

BACKGROUND

Evidence has demonstrated that Chinese medicine formula Xuefu Zhuyu decoction can markedly promote the formation of new hair in patients and mice with alopecia areata (AA). Amygdalin is one of the active components of Xuefu Zhuyu decoction, but its therapeutic effects and the underlying mechanisms on AA remains largely unrevealed.

PURPOSE

Therefore, this study aims to investigate the therapeutic effects and to probe its molecular mechanisms of inflammation and immune regulation on AA model of C3H/HeJ mice.

STUDY DESIGN

The C3H/HeJ female mice were divided into control, AA, rusolitinib (60 mg/kg), and amygdalin groups (60, 90, and 120 mg/kg, 0.2 ml/10 g, i.g.).

METHODS

The optical microscope was used to observe the feature of the local skin, and the number of lanugo and terminal hair. H&E staining was performed to determine the degree of pathological damage to the skin. ELISA was performed to detect levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in mice serum. Flow cytometry was carried out to analyze the CD4+CD25+FOXP3+, CD4+ and CD8+ of skin tissue. And the levels of CD4+ and CD8+, p-JAK/JAK2, p-STAT3/STAT, and SOCS3 were detected by immunohistochemistry. Western blot and qRT-PCR were employed to examine the expression levels of IL-6, TNF-α, IFN-γ, JAK2, p-JAK, STAT, p-STAT3 and SOCS3 proteins and genes in skin tissues.

RESULTS

Compared with AA group, amygdalin immensely increased the number of vellus hairs and decreased the number of terminal hairs determined by skin microscopy and H&E staining. ELISA, Western blot and qRT-PCR data showed that the levels of IL-6, TNF-α and IFN-γ in serum and skin tissues of AA mice were significantly increased, while amygdalin administration dramatically restrained the contents of the three pro-inflammatory factors. Flow cytometry and immunohistochemistry hinted that amygdalin observably enhanced the number of CD4+CD25+FOXP3+ and CD4+ cells, while inhibited the number of CD8+ positive cells in mice with AA. Moreover, amygdalin signally reduced JAK2/STAT3 pathway-related protein and gene levels in AA mice.

CONCLUSION

Amygdalin could inhibit inflammatory response and improve immune function in the treatment of AA. The underlying molecular mechanism may be related to inhibition of JAK2/STAT3 pathway.

The value of immunohistochemical expression of SOX9 and CD34 in alopecia areata

BACKGROUND

Alopecia areata (AA), an immune-mediated disorder, is marked by temporary, nonscarring hair loss. The bulge area is protected from immune attacks by immune privilege; however, recent studies demonstrated immune cells infiltrating the bulge area.

OBJECTIVE

This study aims to investigate the immunohistochemical expression of the sex-determining region Y-box 9 (SOX9) and cluster of differentiation 34 (CD34) in AA patients as markers of hair follicle stem cells (HFSCs) and progenitor cells, respectively.

METHODS

Immunohistochemical staining of SOX9 and CD34 was applied on skin samples of 20 AA patients and 20 healthy controls.

RESULTS

SOX9 and CD34 were significantly lower in lesional samples of cases compared to perilesional and control skin biopsies. Furthermore, SOX9 level was negatively correlated with the severity of alopecia tool score (SALT score) among the studied AA patients. Moreover, lowered SOX9 expression was present in patients with recurrent attacks.

CONCLUSIONS

The significant reduction of stem cell markers (SOX9 and CD34) in our studied AA cases signifies the pathological affection of HFSCs and their progeny in AA. This is thought to cause a loss of competence in generating new hair in some AA cases, which needs to be validated in further research.

LIMITATIONS OF THE STUDY

This study has a small sample size.

Immunoexpression Patterns of Adhesion Molecules (E-cadherin, β-catenin, CD56) and Cytokeratins (CK19, CK20, HMWCK, CAM5.2) During Hair Development in Human Fetuses Compared With Adults

ABSTRACT

Abnormalities in the expression of cytokeratins or adhesion molecules have been associated with hair disorders. The expression patterns of these molecules in the hair follicles of developing human fetuses are not obvious. We aimed to investigate the expression patterns of some cytokeratins and adhesion molecules in the hair follicle of human fetuses and compared them with adults. Forty-eight fetuses of >16 gestational weeks and 22 adult cases with total excisions of benign nevi or cysts were enrolled. The skin samples were taken from both the scalp and back of the fetuses. The histopathologically normal skin areas were evaluated in adults. CK19, CK20, CAM5.2, high-molecular-weight cytokeratin, E-cadherin, β-catenin, and CD56 immunohistochemical stainings were performed. In the fetus group, the staining scores declined in the third trimester but elevated and reached the highest level in adults, except for CD56, which did not stain any adult samples. All stainings were mostly observed in the outer root sheath, except CD56 that stained the perifollicular dermal sheath only in fetuses. E-cadherin, β-catenin, and high-molecular-weight cytokeratin strongly and diffusely stained all adult samples. CAM5.2 and CK19 scores were correlated in fetuses (scalp scores: r s = 0.405, P = 0.004; back scores: r s = 0.422, P = 0.003) and adults (back scores: r s = 0.562, P = 0.046). CD56 negativity indicated the immune-privilege feature of adult hair follicles. As CK19, CAM5.2 may be used to find the regions of stem cells or transient amplifying cells.

Spatial Transcriptomics Identifies Cellular and Molecular Characteristics of Scleroderma Skin Lesions: Pilot Study in Juvenile Scleroderma

Juvenile localized and systemic scleroderma are rare autoimmune diseases which cause significant disability and morbidity in children. The mechanisms driving juvenile scleroderma remain unclear, necessitating further cellular and molecular level studies. The Visium CytAssist spatial transcriptomics (ST) platform, which preserves the spatial location of cells and simultaneously sequences the whole transcriptome, was employed to profile the histopathological slides from skin lesions of juvenile scleroderma patients. (1) Spatial domains were identified from ST data and exhibited strong concordance with the pathologist's annotations of anatomical structures. (2) The integration of paired ST data and single-cell RNA sequencing (scRNA-seq) from the same patients validated the comparable accuracy of the two platforms and facilitated the estimation of cell type composition in ST data. (3) The pathologist-annotated immune infiltrates, such as perivascular immune infiltrates, were clearly delineated by the ST analysis, underscoring the biological relevance of the findings. This is the first study utilizing spatial transcriptomics to investigate skin lesions in juvenile scleroderma patients. The validity of the ST data was corroborated by gene expression analyses and the pathologist's assessments. Integration with scRNA-seq data facilitated the cell type-level analysis and validation. Analyses of immune infiltrates through combined ST data and pathological review enhances our understanding of the pathogenesis of juvenile scleroderma.

Microneedle-Mediated Delivery of Immunomodulators Restores Immune Privilege in Hair Follicles and Reverses Immune-Mediated Alopecia

Disorders in the regulatory arm of the adaptive immune system result in autoimmune-mediated diseases. While systemic immunosuppression is the prevailing approach to manage them, it fails to achieve long-lasting remission due to concomitant suppression of the regulatory arm and carries the risk of heightened susceptibility to infections and malignancies. Alopecia areata is a condition characterized by localized hair loss due to autoimmunity. The accessibility of the skin allows local rather than systemic intervention to avoid broad immunosuppression. It is hypothesized that the expansion of endogenous regulatory T cells (Tregs) at the site of antigen encounter can restore the immune balance and generate a long-lasting tolerogenic response. A hydrogel microneedle (MN) patch is therefore utilized for delivery of CCL22, a Treg-chemoattractant, and IL-2, a Treg survival factor to amplify them. In an immune-mediated murine model of alopecia, local bolstering of Treg numbers is shown, leading to sustained hair regrowth and attenuation of inflammatory pathways. In a humanized skin transplant mouse model, expansion of Tregs within human skin is confirmed without engendering peripheral immunosuppression. The patch offers high-loading capacity and shelf-life stability for prospective clinical translation. By harmonizing immune responses locally, the aim is to reshape the landscape of autoimmune skin disease management.

Current Protocols: Alopecia Areata Mouse Models for Drug Efficacy and Mechanism Studies

Alopecia areata is the second most common form of hair loss in humans after androgenetic alopecia. Although a variety of animal models for alopecia areata have been described, currently the C3H/HeJ mouse model is the most commonly used and accepted. Spontaneous hair loss occurs in 15%-25% of older mice in which the lesions wax and wane, similar to the human disease, with alopecia being more common and severe in female mice. Full-thickness skin grafts from mice with spontaneous alopecia areata to young, normal-haired, histocompatible mice provide a highly reproducible model with progressive lesions that makes it useful for drug efficacy and mechanism-based studies. As alopecia areata is a cell-mediated autoimmune disease, transfer of cultured lymph node cells from affected mice to unaffected, histocompatible recipients also promotes disease development and provides an alternative, nonsurgical protocol. Protocols are presented to produce these models such that they can be used to study alopecia areata and to develop novel drug therapies. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Full-thickness skin grafts to reproducibly induce alopecia areata in C3H/HeJ mice Basic Protocol 2: Adoptive transfer of cultured lymphoid cells provides a nonsurgical method to induce alopecia areata in C3H/HeJ mice.

A phase 2a study investigating the effects of ritlecitinib on brainstem auditory evoked potentials and intraepidermal nerve fiber histology in adults with alopecia areata

Reversible axonal swelling and brainstem auditory evoked potential (BAEP) changes were observed in standard chronic (9-month) toxicology studies in dogs treated with ritlecitinib, an oral Janus kinase 3/tyrosine kinase expressed in hepatocellular carcinoma family kinase inhibitor, at exposures higher than the approved 50-mg human dose. To evaluate the clinical relevance of the dog toxicity finding, this phase 2a, double-blind study assessed BAEP changes and intraepidermal nerve fiber (IENF) histology in adults with alopecia areata treated with ritlecitinib. Patients were randomized to receive oral ritlecitinib 50 mg once daily (QD) with a 4-week loading dose of 200 mg QD or placebo for 9 months (placebo-controlled phase); they then entered the active-therapy extension and received ritlecitinib 50 mg QD (with a 4-week loading dose of 200 mg in patients switching from placebo). Among the 71 patients, no notable mean differences in change from baseline (CFB) in Waves I-V interwave latency (primary outcome) or Wave V amplitude on BAEP at a stimulus intensity of 80 dB nHL were observed in the ritlecitinib or placebo group at Month 9, with no notable differences in interwave latency or Wave V amplitude between groups. The CFB in mean or median IENF density and in percentage of IENFs with axonal swellings was minimal and similar between groups at Month 9. Ritlecitinib treatment was also not associated with an imbalanced incidence of neurological and audiological adverse events. These results provide evidence that the BAEP and axonal swelling finding in dogs are not clinically relevant in humans.

Subclinical Atherosclerosis in Alopecia Areata: Usefulness of Arterial Ultrasound for Disease Diagnosis and Analysis of Its Relationship with Cardiometabolic Parameters

Background/Objectives: Chronic systemic inflammation is a risk factor that increases the development of atherosclerosis and predisposes to cardiovascular diseases (CVDs). The systemic inflammatory profile of alopecia areata (AA) regarding IFNγ and Th1 cytokine dysregulation has previously been described, suggesting an increased incidence of CVDs in this population. No previous studies investigated the possible relationship between atherosclerosis and AA by cardiovascular imaging techniques. To determine the prevalence, distribution and burden of subclinical atherosclerosis in AA.

METHODS

We conducted a case-control study in 62 participants, including 31 patients with severe AA (SALT > 75) and 31 healthy controls, matched for age, sex and body mass index (BMI). The participants underwent a detailed history assessment and were subjected to the measurement of weight, height, abdominal circumference and blood pressure. A fasting blood sample was also collected. Subclinical atherosclerosis was evaluated by ultrasonography of the bilateral femoral and carotid arteries.

RESULTS

The AA patients had an increased prevalence of subclinical atherosclerosis (54.7%) compared to the healthy controls (22.6%, p = 0.010). The prevalence of atheroma plaques was significantly higher in the carotid arteries (41.90% vs. 12.9%, p = 0.009), while no significant differences were found in femoral plaque prevalence. The AA patients with atherosclerotic plaques were older (p < 0.001) and had a longer time since AA diagnosis (p = 0.11) and increased serum levels of glycated hemoglobin (p = 0.029) and triglycerides (p = 0.009). In a regression analysis, duration of disease and neutrophil/lymphocyte ratio were the main predictors of atherosclerosis.

CONCLUSIONS

AA patients have an increased prevalence of carotid subclinical atherosclerosis. The duration of AA, systemic inflammation and insulin resistance appear to play a role in the development of subclinical atherosclerosis in this population.

The causal relationship between gut microbiota and alopecia areata: a Mendelian randomization analysis

Background

Increasing evidence suggests a robust correlation between the gut microbiome and alopecia areata. In light of the extensive diversity of gut microbiota, this study aims to utilize state-of-the-art and comprehensive data to explore the causative association between gut microbiota and alopecia areata.

Objective

We conducted a Mendelian randomization (MR)-based two-sample study to elucidate the causal relationship between gut microbiota and alopecia areata.

Method

Summary information on Ncase = 767 and Ncontrol = 394,105 cases of alopecia areata was obtained from the FinnGen study. A total of 473 gut microbial taxa were summarized from the genome-wide association study (GWAS) catalog. The study comprised a forward Mendelian randomization (MR) analysis with the gut microbiome as the exposure factor and alopecia areata as the outcome, as well as a reverse MR analysis with alopecia areata as the exposure factor and the gut microbiome as the outcome. Various analytical methods including inverse variance weighting (IVW), Weighted Median, MR-Egger, Weighted Mode, and Simple Mode were employed. Subsequently, sensitivity analysis was conducted to ensure the robustness of our research findings.

Result

This study has established a causal relationship between gut microbiota and alopecia areata. Forward causal analysis revealed causality relationships between 16 gut microbial taxa and alopecia areata, while reverse causal analysis found that there may be a causal relationship between alopecia areata and 16 gut microbial taxa (not statistically significant).

Conclusion

Our study findings suggest a causal relationship between gut microbiota and alopecia areata, providing potential guidance for future clinical trials.

Patient-Reported Satisfaction with Hair Regrowth in a Study of Ritlecitinib in Alopecia Areata: Results from ALLEGRO-2b/3

INTRODUCTION

Patients with alopecia areata (AA) report high levels of dissatisfaction with commonly used treatments. Patient-reported outcomes are essential to understanding patients' experiences with AA treatments. The objective of this study was to evaluate patient-reported satisfaction with hair growth among patients with AA receiving ritlecitinib or placebo and the correlation between clinician-assessed efficacy and patient-reported satisfaction.

METHODS

In the ALLEGRO-2b/3 (NCT03732807) trial, patients with AA and ≥50% scalp hair loss were randomized to daily ritlecitinib or placebo for 24 weeks, with a 24-week extension of continued ritlecitinib or switch from placebo to ritlecitinib. The Patient Satisfaction with Hair Growth (P-Sat) measure evaluated patients' satisfaction with hair growth in 3 domains: amount, quality, and overall satisfaction with hair growth. The prespecified analysis evaluated the proportion of patients who were slightly, moderately, or very satisfied with hair growth. Several post hoc analyses assessed the proportion of patients who were moderately/very satisfied and moderately/very dissatisfied and calculated polyserial correlations between change from baseline (CFB) in Severity of Alopecia Tool (SALT) and P-Sat scores at weeks 24 and 48.

RESULTS

At week 24, the proportion of patients (N = 718) reporting satisfaction (slightly, moderately, or very satisfied) overall with their hair growth ranged from 36.4% in the ritlecitinib 10-mg group (evaluated for dose ranging only) to 67.5% in the 200/50-mg group versus 22.6% in the placebo groups. In patients randomized to ritlecitinib, the proportion who were satisfied increased or was maintained at week 48. A substantially greater proportion of placebo patients who switched to ritlecitinib reported satisfaction at week 48 than at week 24. Similar results were observed for patient satisfaction with the amount and quality of hair growth. In the post hoc analyses defining satisfaction as moderately/very satisfied and dissatisfaction as moderately/very dissatisfied, the benefit of ritlecitinib was also observed. All P-Sat domain scores strongly correlated with CFB-SALT scores at weeks 24 (range 0.73-0.76; p < 0.05) and 48 (0.74-0.77; p < 0.05).

CONCLUSIONS

Patients receiving active ritlecitinib doses reported favorable results versus placebo in satisfaction with hair growth up to week 48. High concordance was observed between improvement in scalp hair growth evaluated by clinicians and patient-reported satisfaction.

Spatial Distribution and Functional Impact of Human Scalp Hair Follicle Microbiota

Human hair follicles (HFs) constitute a unique microbiota habitat that differs substantially from the skin surface. Traditional HF sampling methods fail to eliminate skin microbiota contaminants or assess the HF microbiota incompletely, and microbiota functions in human HF physiology remain ill explored. Therefore, we used laser-capture microdissection, metagenomic shotgun sequencing, and FISH to characterize the human scalp HF microbiota in defined anatomical compartments. This revealed significant compartment-, tissue lineage-, and donor age-dependent variations in microbiota composition. Greatest abundance variations between HF compartments were observed for viruses, archaea, Staphylococcus epidermidis, Cutibacterium acnes, and Malassezia restricta, with the latter 2 being the most abundant viable HF colonizers (as tested by propidium monoazide assay) and, surprisingly, most abundant in the HF mesenchyme. Transfection of organ-cultured human scalp HFs with S. epidermidis-specific lytic bacteriophages ex vivo downregulated transcription of genes known to regulate HF growth and development, metabolism, and melanogenesis, suggesting that selected microbial products may modulate HF functions. Indeed, HF treatment with butyrate, a metabolite of S. epidermidis and other HF microbiota, delayed catagen and promoted autophagy, mitochondrial activity, and gp100 and dermcidin expression ex vivo. Thus, human HF microbiota show spatial variations in abundance and modulate the physiology of their host, which invites therapeutic targeting.

Single-cell transcriptome profiling reveals cell type-specific variation and development in HLA expression of human skin

Skin, the largest organ of body, is a highly immunogenic tissue with a diverse collection of immune cells. Highly polymorphic human leukocyte antigen (HLA) molecules have a central role in coordinating immune responses as recognition molecules. Nevertheless, HLA gene expression patterns among diverse cell types within a specific organ, like the skin, have yet to be thoroughly investigated, with stromal cells attracting much less attention than immune cells. To illustrate HLA expression profiles across different cell types in the skin, we performed single-cell RNA sequencing (scRNA-seq) analyses on skin datasets, covering adult and fetal skin, and hair follicles as the skin appendages. We revealed the variation in HLA expression between different skin populations by examining normal adult skin datasets. Moreover, we evaluated the potential immunogenicity of multiple skin populations based on the expression of classical HLA class I genes, which were well represented in all cell types. Furthermore, we generated scRNA-seq data of developing skin from fetuses of 15 post conception weeks (PCW), 17 PCW, and 22 PCW, delineating the dynamic expression of HLA genes with cell type-dependent variation among various cell types during development. Notably, the pseudotime trajectory analysis unraveled the significant variance in HLA genes during the evolution of vascular endothelial cells. Moreover, we uncovered the immune-privileged properties of hair follicles at single-cell resolution. Our study presents a comprehensive single-cell transcriptomic landscape of HLA genes in the skin, which provides new insights into variation in HLA molecules and offers a clue for allogeneic skin transplantation.

Research trends in alopecia areata: a cross-sectional bibliometric analysis of the top cited studies

In the field of alopecia areata research, various focuses including risk factors, epidemiology, molecular pathways, and treatment were constantly improving. However, to date, a bibliometric analysis summarizing the research trend is not available to date. The main objective of this study was to provide researchers with an overview of the research trend on alopecia areata in the past two decades. In Web of Science database, screening and extraction of studies related to alopecia areata has been performed. Within studies related to alopecia areata, the most cited 100 studies were appraised and the information of articles, including the citation amounts, keywords and publication types, was extracted for analyses. On average, each study in the top 100 list was cited 104.72 times. Within the top 100 list, the most focused fields were on the management of alopecia areata (34%), molecular mechanisms (28%) and epidemiological issues (23%). Approximately one third of the management-associated studies focused on Janus kinase (JAK) inhibitors (10 studies) and 5 studies focused on the efficacy of corticosteroids for alopecia areata. According to the results of the keyword analysis, JAK inhibitors had become the most mentioned keywords in the field of alopecia areata research since 2016. The top 100 most referenced papers in the field of alopecia areata mostly focused on essential aspects such as treatment options, pathogenesis, risk factors, and comorbidities. The results of the current study could be considered a potential resource for future research and patient care information.

Elucidating the role of T-Reg related cytokines: serum transforming growth factor beta and interleukin-35 in alopecia areata

Previous studies demonstrated that Th1 cytokines like IL-2, IL-12 and IFN-γ have initiatory role in alopecia areata (AA) and positive correlation with disease severity. They informed that serum levels of Th17 cytokines, IL-17, IL-22, IL-23 increased in active AA patients and corelated, particularly IL-17, with disease severity. In recent reports it was showed the balance between Th17 and Treg cells is crucial for maintaining tolerance to self-antigens, and an imbalance towards Th17 may contribute to the development of autoimmune diseases like AA. But research on serum Treg markers in AA is limited. It was aimed to investigate whether the Treg cells have a role in the pathogenesis of AA analyzing the serum levels of Treg cytokines IL-35 and TGF-β in the patients with AA. 42 AA patients and 38 healthy controls were enrolled. Patient demographics, clinical data, disease severity assessed by Severity of Alopecia Tool (SALT) scores were recorded. Serum samples were collected and analyzed for TGF-β and IL-35 levels using ELISA kits. The cytokine levels in both groups were statistically compared. Their relation with parameters of demographic and severity of disease was evaluated. The patient and control groups had no statistically significant difference, there was 71.4% males and 28.6% females in patient group, while the control group had 63.2% males and 36.8% females, Severity analysis classified 18 patients with mild AA, 19 with moderate AA, and 5 with alopecia totalis/areata universalis. While TGF-β levels exhibited no significant difference between groups, IL-35 levels were significantly elevated in AA patients (p = 0.002). Logistic regression identified IL-35 as a significant parameter influencing disease status (OR = 1.055). Correlation analysis revealed a weak positive correlation between patient age and IL-35 levels (r = 0.436; p = 0.004). Notably, IL-35 levels displayed a significant decrease in individuals with antinuclear antibody (ANA) positivity. No correlations were identified between cytokine levels and disease severity, prognosis, or disease activity. Elevated IL-35 levels suggest that IL-35 and specific Treg cell subsets can play a role in AA pathogenesis. The nuanced roles of TGF-β and IL-35 highlight the need for comprehensive studies to interpret their implications in the complex immunopathogenesis of AA. These findings open avenues for further research, positioning IL-35 as a prospective target for investigating and potentially intervening in AA pathogenesis.

Deciphering the Complex Immunopathogenesis of Alopecia Areata

Alopecia areata (AA) is an autoimmune-mediated disorder in which the proximal hair follicle (HF) attack results in non-scarring partial to total scalp or body hair loss. Despite the growing knowledge about AA, its exact cause still needs to be understood. However, immunity and genetic factors are affirmed to be critical in AA development. While the genome-wide association studies proved the innate and acquired immunity involvement, AA mouse models implicated the IFN-γ- and cytotoxic CD8+ T-cell-mediated immune response as the main drivers of disease pathogenesis. The AA hair loss is caused by T-cell-mediated inflammation in the HF area, disturbing its function and disrupting the hair growth cycle without destroying the follicle. Thus, the loss of HF immune privilege, autoimmune HF destruction mediated by cytotoxic mechanisms, and the upregulation of inflammatory pathways play a crucial role. AA is associated with concurrent systemic and autoimmune disorders such as atopic dermatitis, vitiligo, psoriasis, and thyroiditis. Likewise, the patient's quality of life (QoL) is significantly impaired by morphologic disfigurement caused by the illness. The patients experience a negative impact on psychological well-being and self-esteem and may be more likely to suffer from psychiatric comorbidities. This manuscript aims to present the latest knowledge on the pathogenesis of AA, which involves genetic, epigenetic, immunological, and environmental factors, with a particular emphasis on immunopathogenesis.

Dissecting hair breakage in alopecia areata: the central role of dysregulated cysteine homeostasis

In the initial stages of Alopecia Areata (AA), the predominance of hair breakage or exclamation mark hairs serves as vital indicators of disease activity. These signs are non-invasive and are commonly employed in dermatoscopic examinations. Despite their clinical salience, the underlying etiology precipitating this hair breakage remains largely uncharted territory. Our exhaustive review of the existing literature points to a pivotal role for cysteine-a key amino acid central to hair growth-in these mechanisms. This review will probe and deliberate upon the implications of aberrant cysteine metabolism in the pathogenesis of AA. It will examine the potential intersections of cysteine metabolism with autophagy, ferroptosis, immunity, and psychiatric manifestations associated with AA. Such exploration could illuminate new facets of the disease's pathophysiology, potentially paving the way for innovative therapeutic strategies.

Autophagy Dysfunction: The Kernel of Hair Loss?

Autophagy is recognized as a crucial regulatory process, instrumental in the removal of senescent, dysfunctional, and damaged cells. Within the autophagic process, lysosomal digestion plays a critical role in the elimination of impaired organelles, thus preserving fundamental cellular metabolic functions and various biological processes. Mitophagy, a targeted autophagic process that specifically focuses on mitochondria, is essential for sustaining cellular health and energy balance. Therefore, a deep comprehension of the operational mechanisms and implications of autophagy and mitophagy is vital for disease prevention and treatment. In this context, we examine the role of autophagy and mitophagy during hair follicle cycles, closely scrutinizing their potential association with hair loss. We also conduct a thorough review of the regulatory mechanisms behind autophagy and mitophagy, highlighting their interaction with hair follicle stem cells and dermal papilla cells. In conclusion, we investigate the potential of manipulating autophagy and mitophagy pathways to develop innovative therapeutic strategies for hair loss.

Role of neurogenic inflammation in the pathogenesis of alopecia areata

Alopecia areata refers to an autoimmune illness indicated by persistent inflammation. The key requirement for alopecia areata occurrence is the disruption of immune-privileged regions within the hair follicles. Recent research has indicated that neuropeptides play a role in the damage to hair follicles by triggering neurogenic inflammation, stimulating mast cells ambient the follicles, and promoting apoptotic processes in keratinocytes. However, the exact pathogenesis of alopecia areata requires further investigation. Recently, there has been an increasing focus on understanding the mechanisms of immune diseases resulting from the interplay between the nervous and the immune system. Neurogenic inflammation due to neuroimmune disorders of the skin system may disrupt the inflammatory microenvironment of the hair follicle, which plays a crucial part in the progression of alopecia areata.