A Comprehensive Literature Review of JAK Inhibitors in Treatment of Alopecia Areata

Treatment preferences of adults and adolescents with alopecia areata: A discrete choice experiment

PRODUCTS with janus kinase (JAK) inhibition have been shown to promote hair regrowth in patients with alopecia areata (AA). To guide drug-approval and treatment decisions, it is important to understand patients' willingness to accept the potential risks of JAK inhibition in exchange for potential benefits. We quantified the treatment preferences of adult (≥18 years) and adolescent patients (12-17 years) with AA in the US and Europe to determine the trade-offs they are willing to make between benefits and risks. Preferences for oral AA treatment attributes were elicited using a discrete choice experiment consisting of 12 tasks in which patients chose between two hypothetical treatment alternatives and no treatment. Benefits included the probability of 80%-100% scalp hair regrowth (Severity of Alopecia Tool score ≤ 20) and achieving moderate-to-normal eyebrow and eyelash hair. Treatment-related risks included 3-year probabilities of serious infection, cancer, and blood clots. Preference estimates were used to calculate the maximum level of each risk that patients were willing to accept for increases in treatment benefits. The most important attribute to both adults (n = 201) and adolescents (n = 120) was a 50% probability of achieving hair regrowth on most or all the scalp; however, adolescents placed greater relative importance on this attribute than did adults. Adults were averse to the risks of serious infection, cancer, and blood clots, whereas adolescents were averse to the risk of cancer. For a 20% increase in the probability of 80%-100% scalp hair regrowth, adults were willing to accept a mean (95% confidence interval) 3-year risk of serious infection, cancer, and blood clots of 7.4% (5.5-9.3), 2.5% (1.9-3.1), and 9.3% (6.4-12.2). Adolescents were willing to accept a 3-year risk of cancer of 3.3% (2.4-4.2). Patients with AA in the US and Europe are willing to accept substantial risks to obtain an effective treatment.

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.

Nanodrug Delivery Strategies to Signaling Pathways in Alopecia

Over 50% of the global population suffers from hair loss. The mixed results in the treatment of hair loss reveal the limitations of conventional commercial topical drugs. One the one hand, the definite pathogenesis of hair loss is still an enigma. On the other hand, targeted drug carriers ensure the drug therapeutic effect and low side effects. This review highlights the organization and overview of nine crucial signaling pathways associated with hair loss, as well as the development of nanobased topical delivery systems loading the clinical drugs, which will fuel emerging hair loss treatment strategies.

Efficacy and safety of baricitinib in patients with alopecia areata: evidence to date

Alopecia areata (AA) is a chronic, tissue-specific autoimmune disorder, characterized by non-scaring hair loss, with a global prevalence of approximately 2%. Typically, it affects a young population, with initial onset frequently occurring before the age of 30 years. Even though the exact pathogenesis of AA remains unclear, the predominant hypothesis is the breakdown of immune privilege of the hair follicle, resulting in increased self-antigen and major histocompatibility complex expression in the follicular epithelium. The relapsing nature of the disease negatively impacts patients' quality of life and makes them more susceptible to developing psychiatric comorbidities. Although many treatment modalities have been proposed, there are no currently available treatments able to induce and sustain disease remission. Traditional treatment modalities, despite being widely used, present limited results and a high risk of adverse effects. Hence, there exists an unfulfilled requirement for treatments that are both more efficient and safer. The latest understanding of the pathophysiology of AA and its connection to the JAK-STAT pathway has prompted the advancement of JAK inhibitors. These small-molecule agents function by obstructing the JAK-STAT intracellular signalling pathway. Baricitinib an orally administered, selective JAK1 and JAK2 inhibitor is a promising alternative to the available treatments, and is already approved for the treatment of AA.

Dissolving microneedles for alopecia treatment

Alopecia is a treatable benign disease, however, approximately 15-30% of women and 50% of men suffer from alopecia, which greatly affects patient's self-esteem and quality of life. Currently, commercial products for alopecia treatment include topical minoxidil solution, oral finasteride tablets and oral baricitinib tablets. However, the barrier of stratum corneum, systemic adverse effects and poor cure rate limit the application of commercial products. Therefore, researchers investigated the mechanism of alopecia, and developed new drugs that could target lactate dehydrogenase-related pathways, remove excessive reactive oxygen in hair follicles, and reduce the escape of hair follicle stem cells, thus injecting new strength into the treatment of alopecia. Moreover, starting from improving drug stratum corneum penetration and reducing side effects, researchers have developed hair loss treatment strategies based on dissolved microneedles (MNs), such as drug powders/microparticles, nanoparticles, biomimetic cell membranes, phototherapy and magnetically responsive soluble microneedles, which show exciting alopecia treatment effects. However, there are still some challenges in the practical application of the current alopecia treatment strategy with soluble microneedles, and further studies are needed to accelerate its clinical translation.

Which is the Ideal JAK Inhibitor for Alopecia Areata - Baricitinib, Tofacitinib, Ritlecitinib or Ifidancitinib - Revisiting the Immunomechanisms of the JAK Pathway

Alopecia areata (AA) is an immune-mediated condition, clinically manifesting as non-cicatricial patches of alopecia. It is often a self-limiting condition; however, regrowth of hair can take a long period of time, resulting in significant psychological comorbidity. With the recent advances in pathomechanisms of AA, the therapeutic approach to the condition has become more specific, and targeted therapy with small molecules is probably the ideal intervention. Many therapies exist for AA, but none of the systemic agents were approved, until recently, when baricitinib (Janus kinase (JAK1 and JAK2 inhibitor) gained FDA approval for the treatment of adult patients with severe AA. JAK inhibitors (JAKibs) target the γc cytokine and interferon-gamma (IFN-γ) signaling pathway, which is critical to the immunopathogenesis of AA and thus can reverse the hair loss in AA. Although JAKibs are emerging as a promising treatment modality for AA, the ideal JAKib is not yet settled, as there is scant data on H-2-H (head-to-head) comparisons of JAK inhibitors in AA. Moreover, the response achieved with JAKibs is not sustained after treatment discontinuation, with many studies showing a high recurrence rate with tofacitinib and ruxolitinib post-treatment. Also, recent studies have hypothesized that JAK2, with its ubiquitous expression, can cause adverse effects, unlike JAK1, which is associated with multiple major cytokine receptor families and JAK3, which is exclusively associated with the γc cytokine receptor. Thus, JAK3ibs may be associated with a better side effect profile and, in conjunction with their specificity, may replace other JAKibs as the treatment of choice for AA. We herein discuss the role of the JAK/STAT (signal transducer and activator of transcription) pathway in AA, the intricacies of various JAKibs in the management of AA, and emphasize the need for studies on tissue JAK and cytokine expression before arriving at the ideal JAKibs for AA.

An Assessment of Current Clinician-Reported and Patient-Reported Outcome Measures for Alopecia Areata: A Scoping Review

Although progress has been made in developing outcome measures for AA, the use of these measures remains unstandardized. A scoping review was conducted to identify the clinician-reported outcome measures (ClinROMs) and patient-reported outcome measures (PROMs) used in assessing and treating AA, the results of which revealed heterogeneity in AA outcome measures. Of 23 research studies ultimately included, only 2 ClinROMs were used by >15% of studies; likewise, of 110 clinical trials evaluated, numerous outcome instruments were used, but only one ClinROM was used by >5% of trials (Severity of Alopecia Tool). These results suggest the need for consensus and standardization in both research and trial settings.

Treatment Patterns and Unmet Needs in the Management of Alopecia Areata: Results of a Physician's Survey in the Middle East

INTRODUCTION

Alopecia areata (AA) is an autoimmune disease characterized by nonscarring hair loss involving the scalp, face, and/or body. Literature on the prevalence, patient characteristics, management approaches, and challenges faced by patients with AA across the Middle East is limited. Therefore, a greater understanding of the current AA landscape within the region is needed. This cross-sectional study surveyed dermatologists from four countries to assess dermatologists' perspectives on the prevalence of AA within the Middle East, as well as patient characteristics, unmet needs, and management strategies.

METHODS

This blinded, quantitative, observational study surveyed practicing dermatologists in Egypt, Lebanon, Saudi Arabia, and the United Arab Emirates. The survey was conducted between September 2021 and January 2022 and comprised 47 closed-ended, multiple-choice questions as well as Likert scale responses. These questions assessed the characteristics of physicians and the patients in their practices, physicians' familiarity with treatment, and physicians' treatment approaches.

RESULTS

The estimated prevalence of AA varied across the region. Across all age groups treated for AA, the majority of patients had AA of mild severity (pediatric: 63%; adolescent: 60%; adult: 54%) and the scalp was reported as the most affected area (65%). Potent topical corticosteroids were the most frequently used treatment for mild to moderate and severe AA (92% and 78%, respectively). There was a lack of awareness of investigative treatments, with only 33% of dermatologists aware of these options. The greatest unmet needs in treating AA included long-term disease control, improved efficacy, faster onset of action, and better safety profiles (62%, 53%, 52%, and 51%, respectively).

CONCLUSIONS

This study provided insight into the diagnosis and management of AA in the Middle East. Treatment strategies were similar regardless of the severity of AA. Long-term disease control and improved efficacy and safety profiles were identified as key unmet needs in the treatment of AA.

Baricitinib: A Review in Severe Alopecia Areata

Baricitinib (Olumiant^®), a Janus kinase (JAK) inhibitor, is the first drug approved for the treatment of severe alopecia areata in the USA and the EU. Severe alopecia areata is usually difficult to treat and relapse is common. Patients with this disorder are more likely to suffer from anxiety and depression. In two pivotal placebo-controlled phase 3 clinical trials in adults with severe alopecia areata, oral baricitinib once daily was associated with clinically meaningful scalp, eyebrow, and eyelash hair regrowth over 36 weeks. Baricitinib was generally well tolerated with the most common adverse events being infections, headaches, acne, and elevated levels of creatine phosphokinase. While longer-term data will be necessary to more fully understand the benefits and risks of the drug, currently available data suggest that baricitinib is a useful treatment for patients with severe alopecia areata.

Impact and Management of Loss of Eyebrows and Eyelashes

Eyelashes and eyebrows have different functions, ranging from practical purposes such as protecting the eye apparatus from external hazards to the definition of our facial expression. For this reason, their loss could have both functional and psychological impact on patients' quality of life. Complete or partial loss can occur any time during life, and identifying the cause is mandatory to establish a correct and prompt treatment. The aim of this paper is to create a practical guide for the management of the most common causes of madarosis to the best of our knowledge.

Design and Characterization of Baricitinib Incorporated PLA 3D Printed Pills by Fused Deposition Modeling: An Oral Pill for Treating Alopecia Areata

This study aimed to develop three-dimensional (3D) baricitinib (BAB) pills using polylactic acid (PLA) by fused deposition modeling. Two strengths of BAB (2 and 4% w/v) were dissolved into the (1:1) PEG-400 individually, diluting it with a solvent blend of acetone and ethanol (27.8:18:2) followed by soaking the unprocessed 200 cm~6157.94 mg PLA filament in the solvent blend acetone-ethanol. FTIR spectrums of the 3DP1 and 3DP2 filaments calculated and recognized drug encapsulation in PLA. Herein, 3D-printed pills showed the amorphousness of infused BAB in the filament, as indicated by DSC thermograms. Fabricated pills shaped like doughnuts increased the surface area and drug diffusion. The releases from 3DP1 and 3DP2 were found to be 43.76 ± 3.34% and 59.14 ± 4.54% for 24 h. The improved dissolution in 3DP2 could be due to the higher loading of BAB due to higher concentration. Both pills followed Korsmeyer-Peppas' order of drug release. BAB is a novel JAK inhibitor that U.S. FDA has recently approved to treat alopecia areata (AA). Therefore, the proposed 3D printed tablets can be easily fabricated with FDM technology and effectively used in various acute and chronic conditions as personalized medicine at an economical cost.

Comparing the burden of illness in patients with alopecia areata vs atopic dermatitis in the US population from a payer perspective

BACKGROUND: Alopecia areata (AA) is an autoimmune disease characterized by nonscarring hair loss. AA frequently co-occurs with other inflammatory autoimmune conditions, presenting a significant clinical burden. OBJECTIVE: To compare the burden of illness, direct and indirect costs in adult patients with AA vs atopic dermatitis (AD). METHODS: This retrospective cohort study used US administrative claims data from the Merative MarketScan Commercial Claims and Encounters Database to compare commercially insured adults with AA to those with AD. Patients with an AA diagnosis between January 2017 and September 2019 were propensity score matched to patients with AD. Comorbidity burden, medication use, health care resource utilization, health care costs, and indirect costs during a 12-month follow-up period were compared between cohorts. RESULTS: Overall, 25,446 adult patients with AA were selected for the matched analysis with the AD cohort. Patients with AA generally had lower comorbidity burden than patients with AD; mean Deyo-Charlson Comorbidity Index scores were 0.36 (SD = 0.99) and 0.39 (SD = 0.92), for AA and AD, respectively (P = 0.007). Patients with AA had significantly lower proportions of allergic rhinitis, asthma, pruritus, skin infections, and urticaria, but higher proportions of thyroid disease, when compared with patients with AD (all P < 0.001). A smaller proportion of patients with AA had prescriptions for topical (45.3% vs 64.8%; P < 0.001) and oral (20.3% vs 29.6%; P < 0.001) corticosteroids and antianxiety and/or antidepressants (24.7% vs 29.7%; P < 0.001), but a significantly larger proportion for intralesional corticosteroids (triamcinolone) (49.6% vs 21.7%; P < 0.001), compared with patients with AD. Despite a lower comorbidity burden and generally less medication usage in patients with AA, total all-cause health care costs did not significantly differ between the AA and AD cohorts ($10,705 vs $10,816; P = 0.712), and outpatient costs were higher in patients with AA ($6,297 vs $5,859; P = 0.014). Female patients with AA had significantly greater costs for both outpatient and outpatient pharmacy when compared with female patients with AD. Patients with AA were more likely to have a claim for long-term disability (0.6% vs 0.3%; P = 0.001) and higher long-term disability-associated indirect costs ($73 [SD = $1,442] vs $25 [SD = $774]; P = 0.004) compared with patients with AD. CONCLUSIONS: We found similar total health care costs in patients with AA and AD, despite a lower proportion of comorbidities and prescription use in patients with AA. Outpatient costs were also significantly higher overall in patients with AA. Although often dismissed as a cosmetic condition, AA, an autoimmune disease, has a similar level of medical expenditure as AD. DISCLOSURES: This study was funded by Eli Lilly and Company. Mr Fenske and Drs Ding, Morrow, and Smith are employed by Eli Lilly and Company. Drs Manjelievskaia, Moynihan, and Silver are employed by Merative. Drs Manjelievskaia, Moynihan, and Silver were employed by IBM Watson Health at the time of study completion. IBM Watson Health received funding from Eli Lilly and Company to conduct this study.

Recent advances in the genetics of alopecia areata

Alopecia areata (AA) is a common autoimmune-mediated hair loss disorder in humans with an estimated lifetime risk of approximately 2 %. Episodes of hair loss usually begin with isolated hairless patches that may progress to complete hair loss over the entire body. A familial occurrence of AA is well established, with recurrence risks of about 6-8 % in first-degree relatives. AA is a multifactorial disorder involving both environmental and genetic risk factors. Previous research has identified 14 susceptibility loci, most of which implicate genes involved in the immune response. The following review presents a summary of the latest findings from genome-wide association, sequencing and gene expression studies of AA, as well as their contribution to the recent therapeutic developments.

JAK inhibitors in dermatology: the road travelled and path ahead, a narrative review

INTRODUCTION

Numerous cutaneous dermatoses mediated by cytokines depend on the JAK STAT pathway for intracellular signaling. JAK inhibitors form a useful therapeutic approach in treating these conditions. The literature on effectiveness of JAK inhibitors in treatment of alopecia areata, vitiligo, atopic dermatitis, psoriasis and several other inflammatory and autoimmune diseases is growing, although very few conditions have sufficiently well performed studies to their credit and barring a few indications, their use in rest remains empirical as yet.

AREAS COVERED

A search of the PubMed database was made using the keywords Janus kinase inhibitors OR JAK inhibitors AND dermatology with the time duration limited to the last 5 years. Here, we review the JAK STAT pathway and the various conditions in which JAK inhibitors are currently used in dermatology and other conditions their use is being explored in.

EXPERT OPINION

The pathology of a large number of dermatological disorders is mediated via inflammatory cytokines which signal via the JAK STAT pathway. JAKinibs have shown great promise in treating cutaneous disorders refractory to conventional therapy. Their current clinical use in dermatology is based on robust evidence (for some), and anecdotal evidence for most other dermatoses.

Cross-specialty identification of the JAK1 inhibitor trial agent filgotinib as a potential therapy for alopecia areata

First report of alopecia areata responding to the selective JAK1 inhibitor filgotinib. This case is a patient with coinciding Crohn’s disease that had failed multiple biologics. It serves as a real-world example of how shared decision making between physicians can greatly improve patient outcomes. It highlights that sharing patient registry datasets between specialties will have great benefits, for example in repurposing of JAK inhibitors for other conditions.

Janus Kinase Inhibitors in the Treatment of Alopecia Areata

Alopecia areata is a disease of autoimmune origin which causes non scarring hair loss. The extent of alopecia varies from a small patch to complete scalp and body hair loss, which can have huge psychosocial impact for those affected. Treatment modalities which have been used so far included nonspecific immunosuppressive medications, such as corticosteroids, cyclosporine, and methotrexate, or topical immunomodulators, such as diphencyprone, dithranol, and squaric acid dibutylester. The recognition of the importance of Janus kinase pathway in alopecia areata pathogenesis enabled more specific approaches in treatment. Positive outcomes of Janus kinase inhibitors in several trials granted approval for baricitinib which became the first on-label treatment for alopecia areata. The aim of this review is to summarize the role, efficacy and safety of several Janus kinase inhibitors in alopecia areata.

JAK Inhibitors as Potential Therapeutic Strategy for the Dilemma of Psoriasis Concurrent with Dermatomyositis in the SARS-CoV-2 Era

Dermatomyositis is a rare inflammatory disease with potentially life-threatening systemic involvement that is treated with systemic corticosteroids. However, when psoriasis coexists with dermatomyositis, the administration of corticosteroids may exacerbate psoriasis after withdrawal, posing a treatment dilemma. Our search of the literature revealed 14 cases where various treatments were used, including methotrexate, corticosteroids, cyclosporin, ustekinumab, mycophenolate mofetil, and azathioprine. While methotrexate showed promise, it carries risks, and corticosteroids were used despite their potential to exacerbate psoriasis. Based on transcriptomic data analysis of psoriasis and dermatomyositis, the type II interferon-mediated signaling pathway was enriched in both diseases. Medication targeting this pathway, such as JAK inhibitors, could be a potential solution for the psoriasis concurrent with dermatomyositis dilemma, as JAK inhibitors have been proven effective in treating both dermatomyositis and psoriasis, with some being FDA-approved for treating COVID-19. Therefore, JAK inhibitors may be a potential therapeutic strategy for psoriasis concurrent with dermatomyositis in the SARS-CoV-2 era.

Emerging role of baricitinib in dermatology practice: All we need to know!

Baricitinib is a competitive inhibitor of the Janus Kinase family of non-receptor protein kinases, predominantly acting against JAK-1 and JAK-2 subtypes. By downregulating transcription of various pro-inflammatory cytokines, this drug has shown efficacy across various dermatoses. Approved for severe cases of alopecia areata and moderate-severe atopic dermatitis in adults, baricitinib is being increasingly tried across many other indications with promising results. It is prudent that dermatologists remain aware of boxed warnings and precautions with the use of this much-discussed molecule, including its infectious, thrombotic, cardiovascular, and malignant ramifications. Long-term data on the use of baricitinib in dermatological conditions are lacking and further research is warranted since most data on safety profile is extrapolated from its use in rheumatology. The present review aims to highlight the immunopathogenic mechanisms of JAK-1/2 blockade, approved and off-label uses in dermatology, along with a concise review of laboratory monitoring and the side-effect profile of baricitinib.

Alopecia Areata: Case report and review of pathophysiology and treatment with Jak inhibitors

Alopecia Areata (AA) is a T-cell mediated autoimmune attack on hair follicles resulting in rapidly developing areas of hair loss involving the scalp and beard that can progress to total scalp hair loss (alopecia totalis) and loss of eyebrows, eyelashes, and total body hair (alopecia universalis). Affected patients have high rates of psychological disorders and decreased quality of life. There are no FDA approved treatments, and the available treatments have a high failure rate. JAK inhibitors are remarkably effective in many autoimmune diseases including Alopecia Areata. Presented is a case report of successful treatment with tofacitinib, and a literature review of the pathophysiology of alopecia areata, the mechanism of action of JAK inhibitors, and the JAK inhibitors in phase 2 and 3 trials.

Emerging drugs for the treatment of alopecia areata

INTRODUCTION

Alopecia Areata (AA) is the second most common non-scarring hair loss disorder, with a prevalence of 1 in 1000 and a lifetime incidence of 2% worldwide. Data from a recent American study shows that from 68,121 patients with the diagnosis of AA, 37,995 (55.8%) were prescribed treatment for AA within a year of diagnosis, however there are still no therapies able to induce permanent remission, or treatments that guarantee hair regrowth/remissions in 100% of cases, especially in longstanding/severe AA. Recently, oral baricitinib has been approved for AA, being the first drug approved for this specific indication.

AREAS COVERED

The current review will provide a summary of current pharmacological approaches and novel therapeutics in development.

EXPERT OPINION

New and very effective drugs have become available for the treatment of severe AA, and many others are expected soon. However, even new, effective treatments are not effective in all patients and recurrence rates after treatment interruption are high. AA is a systemic disease with important impact on quality of life and should not be considered just as an aesthetic problem. Treatment of the disease should take in account and possibly also address treatment of comorbidities.

Upadacitinib for the treatment of alopecia areata and severe atopic dermatitis in a paediatric patient: A case report

This case report describes the first successful treatment of alopecia areata and atopic dermatitis with the Janus kinase 1 inhibitor upadacitinib in a paediatric patient. After minimal response to topical corticosteroids and spironolactone, improvements in hair growth on the scalp and body were noted after only 6 weeks of upadacitinib treatment.

Various Application of Tofacitinib and Ruxolitinib (Janus Kinase Inhibitors) in Dermatology and Rheumatology: A Review of Current Evidence and Future Perspective

INTRODUCTION

Janus kinase inhibitors (JAKi) are anti-inflammatory medications suppressing Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway by inhibiting various cytokines receptors on the membrane of cells. Mutations and polymorphisms on JAK and STAT proteins can cause dysregulation in the balance of immune system, and ultimately result in autoimmune disorders.

OBJECTIVES

To record and summarize the overall efficacy and safety of JAKi in various autoimmune conditions such as alopecia areata (AA), psoriasis vulgaris (PV), psoriatic arthritis (PsA), atopic dermatitis (AD), vitiligo, hidradenitis suppurative (HS), lichen planus (LP), and pyoderma gangrenosum (PG).

METHODS

A thorough review of articles was performed across PubMed and Google Scholar on meta-analyses, systematic reviews, clinical trials and case studies evaluating the treatment of autoimmune disorders such as AA, PV, PsA, AD, vitiligo, LP, HS, and PG with JAKi. Duplicated data and animal experiments or in vitro/ex vivo studies were excluded.

RESULTS

All the reviewed articles reported beneficial effects of tofacitinib and ruxolitinib application in the treatment of disorders mentioned above with the autoimmune predisposition.

CONCLUSIONS

Tofacitinib and ruxolitinib showed potential efficacy in treating several autoimmune disorders. Based on records in the reviewed studies, both medications had acceptable safety profiles; however, physicians are recommended to outweigh the risks and benefits of such treatments for each specific condition.

Translational impact of omics studies in alopecia areata: recent advances and future perspectives

INTRODUCTION

Alopecia areata (AA) is a non-scarring, hair loss disorder and a common autoimmune-mediated disease with an estimated lifetime risk of about 2%. To date, the treatment of AA is mainly based on suppression or stimulation of the immune response. Genomics and transcriptomics studies generated important insights into the underlying pathophysiology, enabled discovery of molecular disease signatures, which were used in some of the recent clinical trials to monitor drug response and substantiated the consideration of new therapeutic modalities for the treatment of AA such as abatacept, dupilumab, ustekinumab and Janus Kinase (JAK) inhibitors.

AREAS COVERED

In this review, genomics and transcriptomics studies in AA are discussed in detail with particular emphasis on their past and prospective translational impacts. Microbiome studies are also briefly introduced.

EXPERT OPINION

The generation of large datasets using the new high-throughput technologies has revolutionized medical research and AA has also benefited from the wave of omics studies. However, the limitations associated with JAK inhibitors and clinical heterogeneity in AA patients underscore the necessity for continuing omics research in AA for discovery of novel therapeutic modalities and development of clinical tools for precision medicine.

Case Report: Successful Treatment of Alopecia Universalis With Tofacitinib and Increased Cytokine Levels: Normal Therapeutic Reaction or Danger Signal?

Alopecia universalis (AU) is an autoimmune disorder characterized by non-scarring hair loss in the scalp, eyebrows, beard, and nearly the entire body, negatively affecting patient prognosis. Available treatments are usually unsatisfactory. The autoimmune attacks of hair follicles induced by CD8+ T cells and the collapse of hair follicle immune privilege are believed to be the leading causes of AU. Additionally, interferon (IFN)-γ plays an important role in triggering the collapse of hair follicle immune privilege and impairing hair follicle stem cells. Furthermore, the upregulation of Janus kinase (JAK)3 and phospho-signal transducer and activator of transcription (pSTAT)3/STAT1 in alopecia areata patients suggest that JAK inhibitors can be a potentially promising choice for AU patients for the reason that JAK inhibitors can interfere with JAK-STAT signaling pathways and inhibit IFN-γ. Herein, we report a case of AU successfully treated with tofacitinib. However, this beneficial response in the patient was accompanied by a remarkable increase in peripheral blood cytokine levels during tofacitinib treatment.

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

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

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

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

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.

Alopecia areata: Current understanding of the pathophysiology and update on therapeutic approaches, featuring the Japanese Dermatological Association guidelines

Alopecia areata (AA) is a relatively common nonscarring hairloss disease characterized by an autoimmune response to anagen hair follicles (HFs). Accumulated evidence suggests that collapse of the HF immune privilege subsequent to triggering events, represented by viral infection, leads to autoimmune response in which autoreactive cytotoxic CD8+NKG2D+ T cells mainly target exposed HF autoantigens. AA had been recognized as type 1 inflammatory disease, but recent investigations have suggested some roles of type 2- and Th17-associated mediators in AA pathogenesis. The significance of psychological stress in AA pathogenesis is less emphasized nowadays, but psychological comorbidities, such as depression and anxiety, attract greater interest in AA management. In this regard, the disease severity may not solely be evaluated by the extent of hair loss. Use of trichoscopy markedly improved the resolution of the diagnosis and evaluation of the phase of AA, which is indispensable for the optimization of treatment. For the standardization of AA management, the establishment of guidelines/expert consensus is pivotal. Indeed, the Japanese Dermatological Association (JDA) and other societies and expert groups have published guidelines/expert consensus reports, which mostly recommend intralesional/topical corticosteroid administration and contact immunotherapy as first-line treatments, depending on the age, disease severity, and activity of AA. The uniqueness of the JDA guidelines can be found in their descriptions of intravenous corticosteroid pulse therapy, antihistamines, and other miscellaneous domestically conducted treatments. Considering the relatively high incidence of spontaneous regression in mild AA and its intractability in severe subsets, the importance of course observation is also noted. Evidenced-based medicine for AA is currently limited, however, novel therapeutic approaches, represented by JAK inhibitors, are on their way for clinical application. In this review, the latest understanding of the etiopathogenesis and pathophysiology, and update on therapeutic approaches with future perspectives are summarized for AA, following the current version of the JDA AA management guidelines.