Efficacy and safety of secukinumab treatment in adults with extensive alopecia areata

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.

Recent approaches of antibody therapeutics in androgenetic alopecia

Therapeutic antibodies (Abs) have been anticipated as promising alternatives to conventional treatments such as topical minoxidil and oral finasteride for androgenetic alopecia (AGA). Due to the high molecular weight of typical Abs, the half-life of subcutaneous Abs exceeds 2 weeks, allowing an administration intervals of once a month or longer. Direct injection into the areas of hair loss is also feasible, potentially enhancing treatment efficacy while minimizing systemic side effects. However, therapeutic Abs are rarely developed for AGA therapy due to the requirement to be responsiveness to androgens and to exist in the extracellular fluid or cell surface surrounding the hair follicle. In this review, we introduce recent progress of antibody therapeutics in AGA targeting the prolactin receptor, Interleukin-6 receptor, C-X-C motif chemokine ligand 12, and dickkopf 1. As therapeutic Abs for AGA are still in the early stages, targets need further validation and optimization for clinical application.

Novel investigational drugs for alopecia areata and future perspectives

INTRODUCTION

Alopecia areata (AA) is an immune-mediated disease that causes non-scarring hair loss. While acute, solitary patches often spontaneously remit, developing secondary patches or failure of the disease to resolve within 6-12 months predicts a poor prognosis, with an increased risk of alopecia totalis or universalis. Chronic AA increases the risk of depression and suicidality and reduces quality of life. Treatment options for chronic or acute diffuse AA were previously limited to corticosteroids and traditional immunomodulators. Two Janus Kinase (JAK) inhibitors are now approved for the treatment of chronic AA.

AREAS COVERED

The results of landmark phase 3 trials for three JAK inhibitors, baricitinib, ritlecitinib, and deuruxolitinib are discussed. Evidence for other JAK inhibitors, biologics, and phosphodiesterase-4 inhibitors are also presented. Therapies currently undergoing clinical trials are listed.

EXPERT OPINION

JAK inhibitors are a safe and efficacious treatment of moderate-to-severe AA. Early intervention, regardless of severity, allows for improved treatment efficacy. It is uncertain how long patients should remain on JAK inhibitors; discontinuation often leads to relapse. A black-box warning for JAK inhibitors was extrapolated from safety data in a rheumatoid arthritis cohort; recent meta-analyses of JAK inhibitors used in dermatology cohorts do not demonstrate the same risk profile.

Ophiasis Alopecia Areata in a Patient With Spondyloarthritis on Secukinumab: A Case Report and Review of the Literature

Secukinumab (Cosentyx), an interleukin-17A-targeting biological agent, is commonly prescribed for psoriasis, psoriatic arthritis, and spondyloarthritis (SpA). Alopecia areata (AA), an IL-17-mediated autoimmune disorder characterized by nonscarring hair loss, particularly in an ophiasis pattern, represents a rare adverse effect associated with secukinumab therapy. We present a case of a 46-year-old female with SpA undergoing secukinumab treatment, who developed an ophiasis pattern of AA, subsequently experiencing regrowth upon medication discontinuation. The patient's clinical course and treatment response are detailed, alongside a discussion on the potential pathophysiological mechanisms underlying secukinumab-induced AA. Additionally, we provide a review of existing literature, discussing similar cases and proposing hypotheses on the immunological basis of this adverse event. This report underscores the importance of recognizing and managing secukinumab-induced AA, highlighting the need for further investigation and tailored therapeutic approaches in affected patients.

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.

Treatments for alopecia areata: a network meta-analysis

BACKGROUND

Alopecia areata is an autoimmune disease leading to nonscarring hair loss on the scalp or body. There are different treatments including immunosuppressants, hair growth stimulants, and contact immunotherapy.

OBJECTIVES

To assess the benefits and harms of the treatments for alopecia areata (AA), alopecia totalis (AT), and alopecia universalis (AU) in children and adults.

SEARCH METHODS

The Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, ClinicalTrials.gov and WHO ICTRP were searched up to July 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that evaluated classical immunosuppressants, biologics, small molecule inhibitors, contact immunotherapy, hair growth stimulants, and other therapies in paediatric and adult populations with AA.

DATA COLLECTION AND ANALYSIS

We used the standard procedures expected by Cochrane including assessment of risks of bias using RoB2 and the certainty of the evidence using GRADE. The primary outcomes were short-term hair regrowth ≥ 75% (between 12 and 26 weeks of follow-up), and incidence of serious adverse events. The secondary outcomes were long-term hair regrowth ≥ 75% (greater than 26 weeks of follow-up) and health-related quality of life. We could not perform a network meta-analysis as very few trials compared the same treatments. We presented direct comparisons and made a narrative description of the findings.

MAIN RESULTS

We included 63 studies that tested 47 different treatments in 4817 randomised participants. All trials used a parallel-group design except one that used a cross-over design. The mean sample size was 78 participants. All trials recruited outpatients from dermatology clinics. Participants were between 2 and 74 years old. The trials included patients with AA (n = 25), AT (n = 1), AU (n = 1), mixed cases (n = 31), and unclear types of alopecia (n = 4). Thirty-three out of 63 studies (52.3%) reported the proportion of participants achieving short-term hair regrowth ≥ 75% (between 12 and 26 weeks). Forty-seven studies (74.6%) reported serious adverse events and only one study (1.5%) reported health-related quality of life. Five studies (7.9%) reported the proportion of participants with long-term hair regrowth ≥ 75% (greater than 26 weeks). Amongst the variety of interventions found, we prioritised some groups of interventions for their relevance to clinical practice: systemic therapies (classical immunosuppressants, biologics, and small molecule inhibitors), and local therapies (intralesional corticosteroids, topical small molecule inhibitors, contact immunotherapy, hair growth stimulants and cryotherapy). Considering only the prioritised interventions, 14 studies from 12 comparisons reported short-term hair regrowth ≥ 75% and 22 studies from 10 comparisons reported serious adverse events (18 reported zero events and 4 reported at least one). One study (1 comparison) reported quality of life, and two studies (1 comparison) reported long-term hair regrowth ≥ 75%. For the main outcome of short-term hair regrowth ≥ 75%, the evidence is very uncertain about the effect of oral prednisolone or cyclosporine versus placebo (RR 4.68, 95% CI 0.57 to 38.27; 79 participants; 2 studies; very low-certainty evidence), intralesional betamethasone or triamcinolone versus placebo (RR 13.84, 95% CI 0.87 to 219.76; 231 participants; 1 study; very low-certainty evidence), oral ruxolitinib versus oral tofacitinib (RR 1.08, 95% CI 0.77 to 1.52; 80 participants; 1 study; very low-certainty evidence), diphencyprone or squaric acid dibutil ester versus placebo (RR 1.16, 95% CI 0.79 to 1.71; 99 participants; 1 study; very-low-certainty evidence), diphencyprone or squaric acid dibutyl ester versus topical minoxidil (RR 1.16, 95% CI 0.79 to 1.71; 99 participants; 1 study; very low-certainty evidence), diphencyprone plus topical minoxidil versus diphencyprone (RR 0.67, 95% CI 0.13 to 3.44; 30 participants; 1 study; very low-certainty evidence), topical minoxidil 1% and 2% versus placebo (RR 2.31, 95% CI 1.34 to 3.96; 202 participants; 2 studies; very low-certainty evidence) and cryotherapy versus fractional CO2 laser (RR 0.31, 95% CI 0.11 to 0.86; 80 participants; 1 study; very low-certainty evidence). The evidence suggests oral betamethasone may increase short-term hair regrowth ≥ 75% compared to prednisolone or azathioprine (RR 1.67, 95% CI 0.96 to 2.88; 80 participants; 2 studies; low-certainty evidence). There may be little to no difference between subcutaneous dupilumab and placebo in short-term hair regrowth ≥ 75% (RR 3.59, 95% CI 0.19 to 66.22; 60 participants; 1 study; low-certainty evidence) as well as between topical ruxolitinib and placebo (RR 5.00, 95% CI 0.25 to 100.89; 78 participants; 1 study; low-certainty evidence). However, baricitinib results in an increase in short-term hair regrowth ≥ 75% when compared to placebo (RR 7.54, 95% CI 3.90 to 14.58; 1200 participants; 2 studies; high-certainty evidence). For the incidence of serious adverse events, the evidence is very uncertain about the effect of topical ruxolitinib versus placebo (RR 0.33, 95% CI 0.01 to 7.94; 78 participants; 1 study; very low-certainty evidence). Baricitinib and apremilast may result in little to no difference in the incidence of serious adverse events versus placebo (RR 1.47, 95% CI 0.60 to 3.60; 1224 participants; 3 studies; low-certainty evidence). The same result is observed for subcutaneous dupilumab compared to placebo (RR 1.54, 95% CI 0.07 to 36.11; 60 participants; 1 study; low-certainty evidence). For health-related quality of life, the evidence is very uncertain about the effect of oral cyclosporine compared to placebo (MD 0.01, 95% CI -0.04 to 0.07; very low-certainty evidence). Baricitinib results in an increase in long-term hair regrowth ≥ 75% compared to placebo (RR 8.49, 95% CI 4.70 to 15.34; 1200 participants; 2 studies; high-certainty evidence). Regarding the risk of bias, the most relevant issues were the lack of details about randomisation and allocation concealment, the limited efforts to keep patients and assessors unaware of the assigned intervention, and losses to follow-up.

AUTHORS' CONCLUSIONS

We found that treatment with baricitinib results in an increase in short- and long-term hair regrowth compared to placebo. Although we found inconclusive results for the risk of serious adverse effects with baricitinib, the reported small incidence of serious adverse events in the baricitinib arm should be balanced with the expected benefits. We also found that the impact of other treatments on hair regrowth is very uncertain. Evidence for health-related quality of life is still scant.

The IL-17 family in diseases: from bench to bedside

The interleukin-17 (IL-17) family comprises six members (IL-17A-17F), and recently, all of its related receptors have been discovered. IL-17 was first discovered approximately 30 years ago. Members of this family have various biological functions, including driving an inflammatory cascade during infections and autoimmune diseases, as well as boosting protective immunity against various pathogens. IL-17 is a highly versatile proinflammatory cytokine necessary for vital processes including host immune defenses, tissue repair, inflammatory disease pathogenesis, and cancer progression. However, how IL-17 performs these functions remains controversial. The multifunctional properties of IL-17 have attracted research interest, and emerging data have gradually improved our understanding of the IL-17 signaling pathway. However, a comprehensive review is required to understand its role in both host defense functions and pathogenesis in the body. This review can aid researchers in better understanding the mechanisms underlying IL-17's roles in vivo and provide a theoretical basis for future studies aiming to regulate IL-17 expression and function. This review discusses recent progress in understanding the IL-17 signaling pathway and its physiological roles. In addition, we present the mechanism underlying IL-17's role in various pathologies, particularly, in IL-17-induced systemic lupus erythematosus and IL-17-related tumor cell transformation and metastasis. In addition, we have briefly discussed promising developments in the diagnosis and treatment of autoimmune diseases and tumors.

Inheritance-Specific Dysregulation of Th1- and Th17-Associated Cytokines in Alopecia Areata

Autoimmune diseases tend to cluster in families, suggesting genetic predisposition to autoimmunity associated with familial background. We have previously reported similarities in gene expression patterns and PTPN22 polymorphisms between alopecia areata (AA) patients and their healthy relatives, but not unrelated healthy controls. However, the spectrum of disease promoting (or preventing) pathways that may be activated in blood relatives of AA patients remains to be defined. Here, we investigated the extent to which cytokines associated with the Th1 and Th17 pathway are differentially expressed in the blood of patients with AA and its clinical subtypes in comparison to both healthy relatives as well as unrelated healthy controls. A comprehensive set of Th1- and Th17-related cytokines were evaluated by ELISA. We found a significant elevation of the Th17 inducer IL-23, the Th17 product IL-17A, the Th1 hallmark cytokine IFNγ, and TNFα, a Th1 cytokine with relevance to the Th17 pathway in AA patients, regardless of disease subtype, compared to healthy individuals. On further examination, we found that healthy family members grouped together with patients in terms of elevated Th1- and Th17-pathway cytokines in an inheritance-specific manner, distinct from unrelated controls. The elevation of Th17-associated cytokines in healthy controls related to AA patients indicates that Th1 and Th17 dysregulation in AA may be genetically based. Of note, one unrelated control displayed elevated levels of IL-17A and IL-23 similar to those detected in patients. One year after initial blood draw, areas of beard hair loss consistent with the diagnosis of AA were reported by this individual, indicating that the elevation in Th17-related cytokines may have predictive value.

Alopecia Areata After Initiation of Secukinumab Therapy for Plaque Psoriasis

The development of psoriasis and alopecia areata (AA) is multifactorial. The interleukin-17 (IL-17) cytokine is believed to be associated with the pathophysiology of both diseases. This case report demonstrates a 64-year-old female patient who experienced a new onset of AA after the initiation of IL-17A inhibitor, secukinumab, for the treatment of her psoriasis. To our knowledge, there are only three case reports specifically discussing IL-17A inhibitors and AA. This case report highlights a potential rare but significant side effect of IL-17A inhibitors.

MicroRNA-1246 Inhibits NFATc1 Phosphorylation and Regulates T Helper 17 Cell Activation in the Pathogenesis of Severe Alopecia Areata

BACKGROUND

We found microRNA (miR)-1246 to be significantly differentially expressed between severe active alopecia areata (AA) patients and healthy individuals.

OBJECTIVE

To explore the role and mechanism of miR-1246 in severe AA.

METHODS

Expression of miR-1246, dual-specific tyrosine phosphorylation-regulated kinase 1A (DYRK1A), and nuclear factor of activated T cells 1c (NFATc1) in peripheral CD4⁺ T cells and in scalp tissues of patients were detected using RT-qPCR, Western blot, and immunohistochemistry assays. Peripheral CD4⁺ T cells from the AA patients were transfected with lentiviral vectors overexpressing miR-1246. RT-qPCR and Western blot analysis were used to measure mRNA or protein expression of retinoic-acid-receptor-related orphan nuclear receptor gamma (ROR-γt), interleukin (IL)-17, DYRK1A, NFATc1, and phosphorylated NFATc1. Flow cytometry was used to assay the CD4⁺IL-17⁺ cells proportion. ELISA was used to measure cytokine levels.

RESULTS

miR-1246 levels decreased and DYRK1A and NFATc1 mRNA levels significantly increased in the peripheral CD4⁺ T cells and scalp tissues of severe active AA samples. NFATc1 protein expression was also significantly increased in the peripheral CD4⁺ T cells but not in the scalp tissues. NFATc1 positive cells were mainly distributed among infiltrating inflammatory cells around hair follicles. In peripheral CD4⁺ T cells of severe active AA, overexpression of miR-1246 resulted in significant downregulation of DYRK1A, NFATc1, ROR-γt, and IL-17 mRNA and phosphorylated NFATc1 protein, as well as a decrease in the CD4⁺IL-17⁺ cells proportion and the IL-17F level.

CONCLUSION

miR-1246 can inhibit NFAT signaling and Th17 cell activation, which may be beneficial in the severe AA treatment.

IL-17 and IL-17-producing cells in protection versus pathology

IL-17 cytokine family members have diverse biological functions, promoting protective immunity against many pathogens but also driving inflammatory pathology during infection and autoimmunity. IL-17A and IL-17F are produced by CD4⁺ and CD8⁺ T cells, γδ T cells, and various innate immune cell populations in response to IL-1β and IL-23, and they mediate protective immunity against fungi and bacteria by promoting neutrophil recruitment, antimicrobial peptide production and enhanced barrier function. IL-17-driven inflammation is normally controlled by regulatory T cells and the anti-inflammatory cytokines IL-10, TGFβ and IL-35. However, if dysregulated, IL-17 responses can promote immunopathology in the context of infection or autoimmunity. Moreover, IL-17 has been implicated in the pathogenesis of many other disorders with an inflammatory basis, including cardiovascular and neurological diseases. Consequently, the IL-17 pathway is now a key drug target in many autoimmune and chronic inflammatory disorders; therapeutic monoclonal antibodies targeting IL-17A, both IL-17A and IL-17F, the IL-17 receptor, or IL-23 are highly effective in some of these diseases. However, new approaches are needed to specifically regulate IL-17-mediated immunopathology in chronic inflammation and autoimmunity without compromising protective immunity to infection.

Stratification of alopecia areata reveals involvement of CD4 T cell populations and altered faecal microbiota

Alopecia areata (AA) is an immune-mediated disease that causes non-scarring hair loss. Autoreactive CD8 T cells are key pathogenic effectors in the skin, and AA has been associated both with atopy and with perturbations in intestinal homeostasis. This study aimed to investigate mechanisms driving AA by characterizing the circulating immunophenotype and faecal microbiome, and by stratifying AA to understand how identified signatures associated with heterogeneous clinical features of the condition. Flow cytometric analyses identified alterations in circulating B cells and CD4 T cells, while 16S sequencing identified changes in alpha and beta diversity in the faecal microbiome in AA. The proportions of transitional and naïve B cells were found to be elevated in AA, particularly in AA samples from individuals with >50% hair loss and those with comorbid atopy, which is commonly associated with extensive hair loss. Although significant changes in circulating CD8 T cells were not observed, we found significant changes in CD4+ populations. In individuals with <50% hair loss higher frequencies of CCR6+CD4 ("Th17") and CCR6+CXCR3+CD4 ("Th1/17") T cells were found. While microbial species richness was not altered, AA was associated with reduced evenness and Shannon diversity of the intestinal microbiota, again particularly in those with <50% hair loss. We have identified novel immunological and microbial signatures in individuals with alopecia areata. Surprisingly, these are associated with lower levels of hair loss, and may therefore provide a rationale for improved targeting of molecular therapeutics.

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.

From IL-17 to IFN-γ in inflammatory skin disorders: Is transdifferentiation a potential treatment target?

The targeted inhibition of effector cytokines such as interleukin 17 (IL-17) in psoriasis and IL-13 in atopic dermatitis offers impressive efficacy with a favorable side effect profile. In contrast, the downregulation of interferon gamma (IFN-γ) in T helper (Th) 1-dominant skin disorders may lead to more adverse events, given the crucial role of IFN-γ in antiviral and antitumoral immunity. Modulating Th17 and Th2 cell differentiation is performed by blocking IL-23 and IL-4, respectively, whereas anti-IL-12 antibodies are only moderately effective in downregulating Th1 lymphocyte differentiation. Therefore, a targeted approach of IFN-γ-driven disorders remains challenging. Recent literature suggests that certain pathogenic Th17 cell subsets with Th1 characteristics, such as CD4+CD161+CCR6+CXCR3+IL-17+IFN-y+ (Th17.1) and CD4+CD161+CCR6+CXCR3+IL-17-IFN-y+ (exTh17), are important contributors in Th1-mediated autoimmunity. Differentiation to a Th17.1 or exTh17 profile results in the upregulation of IFN-y. Remarkably, these pathogenic Th17 cell subsets are resistant to glucocorticoid therapy and the dampening effect of regulatory T cells (Treg). The identification of Th17.1/exTh17 cells in auto-immune disorders may explain the frequent treatment failure of conventional immunosuppressants. In this review, we summarize the current evidence regarding the cellular plasticity of Th17 cells in inflammatory skin disorders. A deeper understanding of this phenomenon may lead to better insights into the pathogenesis of various skin diseases and the discovery of a potential new treatment target.

The dark side of the moon: the immune-mediated adverse events of IL-17A/IL-17R inhibition

As aberrant IL-17 signaling plays a critical role in the pathogenesis of psoriasis, biologic agents targeting this pathway have become an important weapon against this disease. Some biologic agents such as IL-17 inhibitors (secukinumab and ixekizumab) and the IL-17 receptor (IL17R) inhibitor (brodalumab) are relatively safe, tolerable and efficacious drugs. Nevertheless, side effects of IL-17 pathway inhibition occur. This review focuses on the dermatological manifestations linked to these treatments. Paradoxical psoriasis and atopic-like eczema may be the most common cutaneous adverse events, while manifestations such as neutrophilic dermatoses, hypersensitivity reactions, lichenoid eruptions, vasculitides, bullous diseases, lupus-like reactions, pigmentation disorders, adnexal diseases and granulomatous dermatoses have been described less frequently.

The current state of knowledge of the immune ecosystem in alopecia areata

Alopecia areata (AA) is an autoimmune disease that affects approximately 2% of the general population. Patients with AA most commonly present with one or more patches of hair loss on the scalp in defined circular areas. A fraction of patients progress to more severe forms of the disease, in some cases with involvement of all body surfaces. The healthy anagen stage hair follicle is considered an immune privileged site, described as an environment that suppresses inflammatory immune responses. However, in AA, this immune privileged state collapses and marks the hair follicle as a target for the immune system, resulting in peri- and intrafollicular infiltration by lymphocytes. The complexity of the inflammatory ecosystem of the immune response to the hair follicle, and the relationships between the cellular and soluble participants, in AA remains incompletely understood. Many studies have demonstrated the presence of various immune cells around diseased hair follicles; however, often little is known about their respective contributions to AA pathogenesis. Furthering our understanding of the mechanisms of disease in AA is essential for the novel identification of targeted therapeutics that are efficacious and have few unintended effects.

An integrated scalp and blood biomarker approach suggests the systemic nature of alopecia areata

BACKGROUND

Alopecia areata (AA) is characterized by immune dysregulation in both scalp and blood, but a large-scale approach establishing biomarkers of AA incorporating both scalp tissue and serum compartments is lacking. We aimed to characterize the transcriptomic signature of AA lesional and nonlesional scalp compared to healthy scalp and determine its relationship with the blood proteome in the same individuals, with comparative correlations to clinical AA disease severity.

METHODS

We evaluated lesional and nonlesional scalp tissues and serum from patients with moderate-to-severe AA (n = 18) and healthy individuals (n = 8). We assessed 33,118 genes in AA scalp tissue using RNAseq transcriptomic evaluation and 340 inflammatory proteins in serum using OLINK high-throughput proteomics. Univariate and multivariate approaches were used to correlate disease biomarkers with Severity of Alopecia Tool (SALT).

RESULTS

A total of 608 inflammatory genes were differentially expressed in lesional AA scalp (fold change/FCH>1.5, false discovery rate/FDR<0.05) including Th1 (IFNG/IL12B/CXCL11), Th2 (IL13/CCL18), and T-cell activation-related (ICOS) products. Th1/Th2-related markers were significantly correlated with AA clinical severity in lesional/nonlesional tissue, while keratins (KRT35/KRT83/KRT81) were significantly downregulated in lesional compared to healthy scalp (p < .05). Expression of cardiovascular/atherosclerosis-related markers (MMP9/CCL2/IL1RL1/IL33R/ST2/AGER) in lesional scalp correlated with their corresponding serum expression (p < .05). AA scalp demonstrated significantly greater biomarker dysregulation compared to blood. An integrated multivariate approach combining scalp and serum biomarkers improved correlations with disease severity/SALT.

CONCLUSION

This study contributes a unique understanding of the phenotype of moderate-to-severe AA with an integrated scalp and serum biomarker model suggesting the systemic nature of the disease, advocating for the need for immune-based systemic treatment.

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.

Treatments for alopecia areata: A systematic review and network meta-analysis

Existing guidelines form no consensus for alopecia areata (AA) treatment due to the absence of a universal standard treatment and arbitrary selection of reference arms in randomized control trials (RCTs). The aim is to identify the best treatment and to rank treatments using systematic review and network meta-analysis. Data were extracted by the two investigators independently. Odds ratio (OR) of treatment success rate was pooled using the frequentist weighted least squares approach to random-model network meta-analysis. RCTs providing data of treatment success rate from PubMed, EMBASE, Web of Science, and manual search were included. About 54 RCTs consisting of 49 treatments and 3149 patients were included. Pentoxifylline plus topical corticosteroids had the highest treatment success rate compared with "no treatment," followed by pentoxifylline alone, topical calcipotriol plus narrowband ultraviolet radiation B phototherapy, topical calcipotriol, intralesional corticosteroids, systemic corticosteroids, minoxidil plus topical corticosteroids, topical bimatoprost, psoralen ultraviolet radiation A phototherapy, and tofacitinib. Even with the network meta-analysis, the best treatment because of independent loops and wide confidence intervals could not be identified. Treatment options above may be reasonable strategies, but further comparison is required.

The IL-23/IL-17 Pathway in Inflammatory Skin Diseases: From Bench to Bedside

Interleukin-17 (IL-17) is an essential proinflammatory cytokine, which is mainly secreted by the CD4⁺ helper T cells (Th17 cells) and subsets of innate lymphoid cells. IL-17A is associated with the pathogenesis of inflammatory diseases, including psoriasis, atopic dermatitis, hidradenitis suppurativa, alopecia areata, pityriasis rubra pilaris, pemphigus, and systemic sclerosis. Interleukin-23 (IL-23) plays a pivotal role in stimulating the production of IL-17 by activating the Th17 cells. The IL-23/IL-17 axis is an important pathway for targeted therapy for inflammatory diseases. Emerging evidence from clinical trials has shown that monoclonal antibodies against IL-23, IL-17, and tumor necrosis factor are effective in the treatment of patients with psoriasis, atopic dermatitis, hidradenitis suppurativa, pityriasis rubra pilaris, pemphigus, and systemic sclerosis. Here, we summarize the latest knowledge about the biology, signaling, and pathophysiological functions of the IL-23/IL-17 axis in inflammatory skin diseases. The currently available biologics targeting the axis is also discussed.

The Alopecia Areata Investigator Global Assessment scale: a measure for evaluating clinically meaningful success in clinical trials

BACKGROUND

Content-valid and clinically meaningful instruments are required to evaluate outcomes of therapeutic interventions in alopecia areata (AA).

OBJECTIVES

To develop an Investigator's Global Assessment (IGA) to interpret treatment response in AA treatment studies.

METHODS

Qualitative interviews were conducted in the USA with expert dermatologists and with patients with AA who had experienced ≥ 50% scalp-hair loss. Thematic data analysis identified critical outcomes and evaluated the content validity of the new IGA.

RESULTS

Expert clinicians (n = 10) judged AA treatment success by the amount of scalp-hair growth (median 80% scalp hair). Adult (n = 25) and adolescent (n = 5) patients participated. Scalp-hair loss was the most bothersome AA sign/symptom for most patients. Perceived treatment success - short of 100% scalp hair - was the presence of ~ 70-90% scalp hair (median 80%). Using additional clinician and patient insights, the Alopecia Areata Investigator Global Assessment (AA-IGA™) was developed. This clinician-reported outcome assessment is an ordinal, static measure comprising five severity categories of scalp-hair loss. Nearly all clinicians and patients in this study agreed that, for patients with ≥ 50% scalp-hair loss, successful treatment would be hair regrowth resulting in ≤ 20% scalp-hair loss.

CONCLUSIONS

We recommend using the Severity of Alopecia Tool to assess the extent (0-100%) of scalp-hair loss. The AA-IGA is a robust ordinal measure providing distinct and clinically meaningful gradations of scalp-hair loss that reflects patients' and expert clinicians' perspectives and treatment expectations. What is already known about this topic? The Severity of Alopecia Tool is widely used to assess the extent of scalp-hair loss in patients with alopecia areata. Guidelines define treatment success as a 50% improvement in scalp hair, and clinical trials have used dynamic thresholds of 50% and 90%. However, there is no clinical consensus on these endpoints, and patient perspectives on treatment success are unknown. What does this study add? Through qualitative interviews with 10 expert dermatologists and 30 patients with alopecia areata who had experienced ≥ 50% scalp-hair loss, we developed the Alopecia Areata Investigator Global Assessment (AA-IGA™) to measure five clinically meaningful gradations of alopecia areata scalp-hair loss that reflects patients' and clinicians' perspectives and expectations of treatment success in alopecia areata treatment studies. What are the clinical implications of this work? The AA-IGA is a robust ordinal measure that can inform clinical evaluation of alopecia areata treatment outcomes. The AA-IGA can be used to determine clinically meaningful treatment success for alopecia areata, with success defined by patients and clinicians as reaching ≤ 20% scalp-hair loss. Linked Comment: Blome. Br J Dermatol 2020; 183:609.

Transdermal Drug Delivery for Hair Regrowth

Today, about 50% of men and 15-30% of women suffer from hair loss as well as the associated psychological impact. Drug therapy, especially through topical administration, is the main treatment strategy for stimulating hair regrowth. However, challenges exist due to the skin barrier that hinders drug penetration. To this end, many efforts have been made to enhance drug penetration efficiency. This review focuses on the advancement of the transdermal drug delivery strategies for hair loss therapy reported in the last five years, especially those via nanoformulations for topical administration and microneedles for transdermal delivery. In addition, physical or chemical penetration enhancers are also introduced, which are often applied with the drug delivery systems to achieve a synergy effect.

Cross-sectional study of blood biomarkers of patients with moderate to severe alopecia areata reveals systemic immune and cardiovascular biomarker dysregulation

BACKGROUND

Although there is increased understanding of the alopecia areata (AA) pathogenesis based on studies in scalp tissues, little is known about its systemic profile.

OBJECTIVE

To evaluate the blood proteomic signature of AA and determine biomarkers associated with increased disease severity.

METHODS

In a cross-sectional study, we assessed 350 inflammatory and cardiovascular proteins using OLINK high-throughput proteomics in patients with moderate to severe AA (n = 35), as compared with healthy individuals (n = 36), patients with moderate to severe psoriasis (n = 19), and those with atopic dermatitis (n = 49).

RESULTS

Seventy-four proteins were significantly differentially expressed between AA and control individuals (false discovery rate, <.05) including innate immunity (interleukin [IL] 6/IL-8), T helper (Th) type 1 (interferon [IFN] γ/CXCL9/CXCL10/CXCL11), Th2 (CCL13/CCL17/CCL7), Th17 (CCL20/PI3/S100A12), and cardiovascular-risk proteins (OLR1/OSM/MPO/PRTN3). Eighty-six biomarkers correlated with AA clinical severity (P < .05), including Th1/Th2, and cardiovascular/atherosclerosis-related proteins, including SELP/PGLYRP1/MPO/IL-18/OSM (P < .05). Patients with AA totalis/universalis showed the highest systemic inflammatory tone, including cardiovascular risk biomarkers, compared to control individuals and even to patients with atopic dermatitis and those with psoriasis. The AA profile showed some Th1/Th2 differences in the setting of concomitant atopy.

LIMITATIONS

Our analysis was limited to 350 proteins.

CONCLUSION

This study defined the abnormalities of moderate to severe AA and associated circulatory biomarkers. It shows that AA has systemic immune, cardiovascular, and atherosclerosis biomarker dysregulation, suggesting the need for systemic treatment approaches.

Off-label dermatologic uses of IL-17 inhibitors

IL-17 inhibitors, including secukinumab, brodalumab, and ixekizumab, have been U.S. Food and Drug Administration (FDA) approved for the treatment of psoriasis. In addition to psoriasis, IL-17 has been implicated in the pathophysiology of other inflammatory skin conditions. This review aims to synthesize and interpret the literature evaluating the off-label dermatologic uses of IL-17 inhibitors. We performed searches in PubMed and ClinicalTrials.gov for clinical trials, observational studies, case series, and case reports evaluating non-psoriatic uses of the three IL-17 inhibitors. Studies evaluated the efficacy of IL-17 inhibitors for the following conditions: hidradenitis suppurativa (HS), pityriasis rubra pilaris (PRP), Behçet's disease, alopecia areata, and allergic contact dermatitis. Based on the available literature, secukinumab appears to be a potential treatment for HS, PRP, and Behçet's disease, while ixekizumab appears to be a potential treatment for HS and PRP. However, more clinical trials data are needed to adequately assess the safety and efficacy of IL-17 inhibitors for the treatment of these conditions.

Frontiers in alopecia areata pathobiology research

This current review explores selected and as yet insufficiently investigated frontiers in current alopecia areata (AA) pathobiology research, with an emphasis on potential "new" players in AA pathobiology that deserve more systematic exploration and therapeutic targeting. Indeed, new evidence suggests that CD8⁺ T cells, which have long been thought to be the central players in AA pathobiology, are not the only drivers of disease. Instead, subsets of natural killer (NK) and so-called "unconventional" T cells (invariant NK T cells, γδ T cells, classic NK cells, and type 1 innate lymphoid cells), all of which can produce large amounts of IFN-γ, might also drive AA pathobiology independent of classical, autoantigen-dependent CD8⁺ T-cell functions. Another important new frontier is the role of regulatory lymphocyte subsets, such as regulatory T cells, γδ regulatory T cells, NKT10 cells, and perifollicular mast cells, in maintaining physiologic hair follicle immune privilege (IP); the extent to which these functions are defective in patients with AA; and how this IP-protective role could be restored therapeutically in patients with established AA. Broadening our AA research horizon along the lines suggested above promises not only to open the door to innovative and even more effective immunotherapy strategies for AA but will also likely be relevant for other autoimmune disorders in which pathobiology, ectopic MHC class I expression, and IP collapse play an important role.

Learning From Success and Failure: Biologics for Non-approved Skin Diseases

The impressive potential of biologics has been demonstrated in psoriasis, hidradenitis suppurativa, and urticaria. Numerous biologicals are entering the field for a restricted number of skin disorders. Off-label use of biologics in other recalcitrant skin diseases has increased. Mounting data point to the potential of already existing biologics acting on the IL-17/IL-23 pathway in skin disorders with epidermal hyperkeratosis (e.g., pityriasis rubra pilaris), acneiform inflammation (e.g., hidradenitis suppurativa), and loss of mucosal integrity (e.g., aphthosis). TNF-α blockers are also effective in the latter conditions but seem of particular value in granulomatous (e.g., granuloma annulare) and neutrophilic disorders (e.g., pyoderma gangrenosum). Failure of IL-17 blockade in skin diseases resulting from immune-mediated cell destruction (e.g., alopecia areata and vitiligo) illustrates its limited involvement in Th1-dependent skin immunology. Overall, disappointing results of TNF-α blockers in alopecia areata and vitiligo point to the same conclusion although promising results in toxic epidermal necrolysis suggest TNF-α exerts at least some in vivo Th1-related activities. Acting on both the Th1 and Th17 pathway, ustekinumab has a rather broad potential with interesting results in lupus and alopecia areata. The efficacy of omalizumab in bullous pemphigoid has revealed an IgE-mediated recruitment of eosinophils leading to bullae formation. Reconsidering reimbursement criteria for less common but severe diseases seems appropriate if substantial evidence is available (e.g., pityriasis rubra pilaris). For other disorders, investigator- and industry-initiated randomized clinical trials should be stimulated. They are likely to improve patient outcome and advance our understanding of challenging skin disorders.

Alopecia areata is characterized by dysregulation in systemic type 17 and type 2 cytokines, which may contribute to disease-associated psychological morbidity

BACKGROUND

Alopecia areata (AA) is a common autoimmune disease, causing patchy hair loss that can progress to involve the entire scalp (totalis) or body (universalis). CD8⁺ NKG2D⁺ T cells dominate hair follicle pathogenesis, but the specific mechanisms driving hair loss are not fully understood.

OBJECTIVES

To provide a detailed insight into the systemic cytokine signature associated with AA, and to assess the association between cytokines and depression.

METHODS

We conducted multiplex analysis of plasma cytokines from patients with AA, patients with psoriatic arthritis (PsA) and healthy controls. We used the Hospital Anxiety and Depression Scale (HADS) to assess the occurrence of depression and anxiety in our cohort.

RESULTS

Our analysis identified a systemic inflammatory signature associated with AA, characterized by elevated levels of interleukin (IL)-17A, IL-17F, IL-21 and IL-23 indicative of a type 17 immune response. Circulating levels of the type 2 cytokines IL-33, IL-31 and IL-17E (IL-25) were also significantly increased in AA. In comparison with PsA, AA was associated with higher levels of IL-17F, IL-17E and IL-23. We hypothesized that circulating inflammatory cytokines may contribute to wider comorbidities associated with AA. Our assessment of psychiatric comorbidity in AA using HADS scores showed that 18% and 51% of people with AA experienced symptoms of depression and anxiety, respectively. Using linear regression modelling, we identified that levels of IL-22 and IL-17E are positively and significantly associated with depression.

CONCLUSIONS

Our data highlight changes in both type 17 and type 2 cytokines among people with AA, suggesting that complex systemic cytokine profiles may contribute both to the pathogenesis of AA and to the associated depression. What's already known about this topic? NKG2D⁺ CD8⁺ T cells cause hair loss in alopecia areata (AA) but the immunological mechanisms underlying the disease are not fully understood. AA is associated with changes in levels of interleukin (IL)-6, tumour necrosis factor-α, IL-1β and type 17 cytokines. Psychiatric comorbidity is common among people with AA. What does this study add? People with AA have increased plasma levels of the type 2 cytokines IL-33, IL-31 and IL-17E (IL-25), in addition to the type 17 cytokines IL-17A, IL-21, IL-23 and IL-17F. Levels of IL-17E and IL-22 positively predict depression score. What is the translational message? AA is associated with increased levels of multiple inflammatory cytokines, implicating both type 17- and type 2 immune pathways. Our data indicate that therapeutic strategies for treating AA may need to address the underlying type 17- and type 2 immune dysregulation, rather than focusing narrowly on the CD8⁺ T-cell response. An immunological mechanism might contribute directly to the depression observed in people with AA.

Generalized hypertrichosis due to secukinumab in a patient with moderate psoriasis: A case of serendipity or zemblanity?

After 4 months of therapy with secukinumab, a 67-year-old man with moderate psoriasis developed generalized hypertrichosis, along with PASI 90. The patient denied any drug intake, apart from secukinumab, nor applications of any creams. Moreover, this event did not really bother the patient, thus the therapy was not discontinued and the hypertrichosis is persisting as psoriasis' control.

Hair-Growth Potential of Ginseng and Its Major Metabolites: A Review on Its Molecular Mechanisms

The functional aspect of scalp hair is not only to protect from solar radiation and heat/cold exposure but also to contribute to one's appearance and personality. Progressive hair loss has a cosmetic and social impact. Hair undergoes three stages of hair cycle: the anagen, catagen, and telogen phases. Through cyclical loss and new-hair growth, the number of hairs remains relatively constant. A variety of factors, such as hormones, nutritional status, and exposure to radiations, environmental toxicants, and medications, may affect hair growth. Androgens are the most important of these factors that cause androgenic alopecia. Other forms of hair loss include immunogenic hair loss, that is, alopecia areata. Although a number of therapies, such as finasteride and minoxidil, are approved medications, and a few others (e.g., tofacitinib) are in progress, a wide variety of structurally diverse classes of phytochemicals, including those present in ginseng, have demonstrated hair growth-promoting effects in a large number of preclinical studies. The purpose of this review is to focus on the potential of ginseng and its metabolites on the prevention of hair loss and its underlying mechanisms.