Vitiligo: Mechanisms of Pathogenesis and Treatment.

Vitiligo is an autoimmune disease of the skin that targets pigment-producing melanocytes and results in patches of depigmentation that are visible as white spots. Recent research studies have yielded a strong mechanistic understanding of this disease. Autoreactive cytotoxic CD8+ T cells engage melanocytes and promote disease progression through the local production of IFN-γ, and IFN-γ-induced chemokines are then secreted from surrounding keratinocytes to further recruit T cells to the skin through a positive-feedback loop. Both topical and systemic treatments that block IFN-γ signaling can effectively reverse vitiligo in humans; however, disease relapse is common after stopping treatments. Autoreactive resident memory T cells are responsible for relapse, and new treatment strategies focus on eliminating these cells to promote long-lasting benefit. Here, we discuss basic, translational, and clinical research studies that provide insight into the pathogenesis of vitiligo, and how this insight has been utilized to create new targeted treatment strategies.

Activation of the NLRP1 inflammasome in human keratinocytes by the dsDNA mimetic poly(dA:dT).

The accrual of cytosolic DNA leads to transcription of type I IFNs, proteolytic maturation of the IL-1 family of cytokines, and pyroptotic cell death. Caspase-1 cleaves pro-IL1ß to generate mature bioactive cytokine and gasdermin D which facilitates IL-1 release and pyroptotic cell death. Absent in melanoma-2 (AIM2) is a sensor of dsDNA leading to caspase-1 activation, although in human monocytes, cGAS-STING acting upstream of NLRP3 mediates the dsDNA-activated inflammasome response. In healthy human keratinocytes, AIM2 is not expressed yet caspase-1 is activated by the synthetic dsDNA mimetic poly(dA:dT). Here, we show that this response is not mediated by either AIM2 or the cGAS-STING-NLRP3 pathway and is instead dependent on NLRP1. Poly(dA:dT) is unique in its ability to activate NLRP1, as conventional linear dsDNAs fail to elicit NLRP1 activation. DsRNA was recently shown to activate NLRP1 and prior work has shown that poly(dA:dT) is transcribed into an RNA intermediate that stimulates the RNA sensor RIG-I. However, poly(dA:dT)-dependent RNA intermediates are insufficient to activate NLRP1. Instead, poly(dA:dT) results in oxidative nucleic acid damage and cellular stress, events which activate MAP3 kinases including ZAKα that converge on p38 to activate NLRP1. Collectively, this work defines a new activator of NLRP1, broadening our understanding of sensors that recognize poly(dA:dT) and advances the understanding of the immunostimulatory potential of this potent adjuvant.

Two Phase 3, Randomized, Controlled Trials of Ruxolitinib Cream for Vitiligo.

BACKGROUND: Vitiligo is a chronic autoimmune disease that causes skin depigmentation. A cream formulation of ruxolitinib (an inhibitor of Janus kinase 1 and 2) resulted in repigmentation in a phase 2 trial involving adults with vitiligo. METHODS: We conducted two phase 3, double-blind, vehicle-controlled trials (Topical Ruxolitinib Evaluation in Vitiligo Study 1 [TRuE-V1] and 2 [TRuE-V2]) in North America and Europe that involved patients 12 years of age or older who had nonsegmental vitiligo with depigmentation covering 10% or less of total body-surface area. Patients were randomly assigned in a 2:1 ratio to apply 1.5% ruxolitinib cream or vehicle control twice daily for 24 weeks to all vitiligo areas on the face and body, after which all patients could apply 1.5% ruxolitinib cream through week 52. The primary end point was a decrease (improvement) of at least 75% from baseline in the facial Vitiligo Area Scoring Index (F-VASI; range, 0 to 3, with higher scores indicating a greater area of facial depigmentation), or F-VASI75 response, at week 24. There were five key secondary end points, including improved responses on the Vitiligo Noticeability Scale. RESULTS: A total of 674 patients were enrolled, 330 in TRuE-V1 and 344 in TRuE-V2. In TRuE-V1, the percentage of patients with an F-VASI75 response at week 24 was 29.8% in the ruxolitinib-cream group and 7.4% in the vehicle group (relative risk, 4.0; 95% confidence interval [CI], 1.9 to 8.4; P<0.001). In TRuE-V2, the percentages were 30.9% and 11.4%, respectively (relative risk, 2.7; 95% CI, 1.5 to 4.9; P<0.001). The results for key secondary end points showed superiority of ruxolitinib cream over vehicle control. Among patients who applied ruxolitinib cream throughout 52 weeks, adverse events occurred in 54.8% in TRuE-V1 and 62.3% in TRuE-V2; the most common adverse events were application-site acne (6.3% and 6.6%, respectively), nasopharyngitis (5.4% and 6.1%), and application-site pruritus (5.4% and 5.3%). CONCLUSIONS: In two phase 3 trials, application of ruxolitinib cream resulted in greater repigmentation of vitiligo lesions than vehicle control through 52 weeks, but it was associated with acne and pruritus at the application site. Larger and longer trials are required to determine the effect and safety of ruxolitinib cream in patients with vitiligo. (Funded by Incyte; TRuE-V1 and TRuE-V2 ClinicalTrials.gov numbers, NCT04052425 and NCT04057573.).

Exploring the natural and treatment history of vitiligo: perceptions of patients and healthcare professionals from the global VALIANT study.

BACKGROUND: Vitiligo is a chronic autoimmune disease affecting melanocytes, resulting in skin depigmentation. Patients with vitiligo often have reduced quality of life and comorbid autoimmune conditions and have reported a lack of available treatments for their vitiligo. OBJECTIVES: The Vitiligo and Life Impact Among International Communities (VALIANT) study is the first global survey to explore the natural history and management of vitiligo from the perspectives of patients and healthcare professionals (HCPs). METHODS: The survey recruited adults (≥ 18 years) diagnosed with vitiligo and HCPs treating patients with vitiligo via an online panel in 17 countries. Patients were queried regarding clinical characteristics and vitiligo treatment. HCPs were queried regarding diagnosis and management of patients with vitiligo. RESULTS: Included in the analysis were 3541 patients and 1203 HCPs. Nearly half (45.2%) of the patients had > 5% affected body surface area; 57.1% reported family history. Patients obtained formal diagnosis after a mean (SD) of 2.4 (4.1) years; 44.9% reported previous misdiagnosis. Many patients (56.7%) reported being told that vitiligo could not be treated; 53.9% of HCPs believed patients who never treated their vitiligo had been told that vitiligo could not be treated. One-quarter of HCPs (26.3%) did not believe that an effective therapy for vitiligo exists; 44.6% of patients reported giving up on finding an effective therapy. Top treatment goals for patients and HCPs, respectively, were reduction or cessation of spread (24.7% and 18.5%) and repigmentation (22.5% and 37.2%). Patient perception of effective care was similar for treatment by dermatologists (66.9%) and primary care HCPs (67.0%). CONCLUSIONS: Patients with vitiligo and HCPs reported similar treatment goals and expressed frustration with the lack of effective therapies. Patients reported high rates of initial misdiagnosis; many ceased seeking healthcare because they perceived that vitiligo could not be treated. The findings highlight the need for earlier diagnosis and improved disease management for vitiligo.

Efficacy and safety of oral ritlecitinib for the treatment of active nonsegmental vitiligo: A randomized phase 2b clinical trial.

BACKGROUND: Vitiligo is a chronic autoimmune disorder characterized by depigmented patches of the skin. OBJECTIVE: To evaluate the efficacy and safety of ritlecitinib, an oral JAK3 (Janus kinase)/TEC (tyrosine kinase expressed in hepatocelluar carcinoma) inhibitor, in patients with active nonsegmental vitiligo in a phase 2b trial (NCT03715829). METHODS: Patients were randomized to once-daily oral ritlecitinib ± 4-week loading dose (200/50 mg, 100/50 mg, 30 mg, or 10 mg) or placebo for 24 weeks (dose-ranging period). Patients subsequently received ritlecitinib 200/50 mg daily in a 24-week extension period. The primary efficacy endpoint was percent change from baseline in Facial-Vitiligo Area Scoring Index at week 24. RESULTS: A total of 364 patients were treated in the dose-ranging period. Significant differences from placebo in percent change from baseline in Facial-Vitiligo Area Scoring Index were observed for the ritlecitinib 50 mg groups with (-21.2 vs 2.1; P < .001) or without (-18.5 vs 2.1; P < .001) a loading dose and ritlecitinib 30 mg group (-14.6 vs 2.1; P = .01). Accelerated improvement was observed after treatment with ritlecitinib 200/50 mg in the extension period (n = 187). No dose-dependent trends in treatment-emergent or serious adverse events were observed across the 48-week treatment. LIMITATIONS: Patients with stable vitiligo only were excluded. CONCLUSIONS: Oral ritlecitinib was effective and well tolerated over 48 weeks in patients with active nonsegmental vitiligo.

RNAi-based modulation of IFN-γ signaling in skin.

Aberrant activation of interferon (IFN)-γ signaling plays a key role in several autoimmune skin diseases, including lupus erythematosus, alopecia areata, vitiligo, and lichen planus. Here, we identify fully chemically modified small interfering RNAs (siRNAs) that silence the ligand binding chain of the IFN-γ receptor (IFNGR1), for the modulation of IFN-γ signaling. Conjugating these siRNAs to docosanoic acid (DCA) enables productive delivery to all major skin cell types local to the injection site, with a single dose of injection supporting effective IFNGR1 protein reduction for at least 1 month in mice. In an ex vivo model of IFN-γ signaling, DCA-siRNA efficiently inhibits the induction of IFN-γ-inducible chemokines, CXCL9 and CXCL10, in skin biopsies from the injection site. Our data demonstrate that DCA-siRNAs can be engineered for functional gene silencing in skin and establish a path toward siRNA treatment of autoimmune skin diseases.

Worldwide expert recommendations for the diagnosis and management of vitiligo: Position statement from the international Vitiligo Task Force-Part 2: Specific treatment recommendations.

BACKGROUND: The treatment of vitiligo can be challenging. Up-to-date agreed consensus recommendations on the use of topical and systemic therapies to facilitate the clinical management of vitiligo are currently lacking. OBJECTIVES: To develop internationally agreed-upon expert-based recommendations for the treatment of vitiligo. METHODS: In this consensus statement, a consortium of 42 international vitiligo experts and four patient representatives participated in different online and live meetings to develop a consensus management strategy for vitiligo. At least two vitiligo experts summarized the evidence for different topics included in the algorithms. A survey was then given to a core group of eight experts to resolve the remaining issues. Subsequently, the recommendations were finalized and validated based on further input from the entire group during two live meetings. RESULTS: The recommendations provided summarize the latest evidence regarding the use of topical therapies (steroids, calcineurin inhibitors and Jak-inhibitors) and systemic therapies, including steroids and other systemic immunomodulating or antioxidant agents. The different modalities of phototherapies (NB-UVB, photochemotherapy, excimer devices and home phototherapy), which are often combined with other therapies, are also summarized. Interventional approaches as well as depigmentation strategies are presented for specific indications. Finally, the status of innovative and targeted therapies under development is discussed. CONCLUSIONS: This international consensus statement culminated in expert-based clinical practice recommendations for the treatment of vitiligo. The development of new therapies is ongoing in vitiligo, and this will likely improve the future management of vitiligo, a disease that still has many unmet needs.

Worldwide expert recommendations for the diagnosis and management of vitiligo: Position statement from the International Vitiligo Task Force Part 1: towards a new management algorithm.

BACKGROUND: The treatment of vitiligo can be challenging and depends on several factors such as the subtype, disease activity, vitiligo extent, and treatment goals. Vitiligo usually requires a long-term approach. To improve the management of vitiligo worldwide, a clear and up-to-date guide based on international consensus with uniform stepwise recommendations is needed. OBJECTIVES: To reach an international consensus on the nomenclature and to develop a management algorithm for the diagnosis, assessment, and treatment of vitiligo. METHODS: In this consensus statement, a consortium of 42 international vitiligo experts and four patient representatives participated in online and live meetings to develop a consensus management strategy for vitiligo. At least two vitiligo experts summarized the evidence of topics included in the algorithms. A survey was utilized to resolve remaining issues among a core group of eight experts. Subsequently, the unanimous recommendations were finalized and validated based on further input from the entire group during two live meetings. RESULTS: The algorithms highlight the importance of shared decision-making. Dermatologists are encouraged to provide patients with detailed explanations of the prognosis and expected therapeutic outcomes based on clinical examination. The treatment goal should be discussed and clearly emphasized to patients given the different approaches for disease stabilization and repigmentation. The evaluation of disease activity remains a cornerstone in the tailor-made approach to vitiligo patients. CONCLUSIONS: These new treatment algorithms are intended to guide clinical decision-making in clinical practice. Promising novel therapies for vitiligo are on the horizon, further highlighting the need for reliable outcome measurement instruments and greater emphasis on shared decision-making.

Adolescent extra-truncal progressive macular hypomelanosis.

Two adolescent females presented to outpatient clinic with isolated, non-scaly, asymptomatic hypopigmented macules and patches on the arm(s). Both cases had Wood's lamp exams notable for extralesional punctiform coral-red perifollicular fluorescence on the back and faint intralesional enhancement. In one case, biopsy was performed and deemed consistent with progressive macular hypomelanosis. The patient had complete response to antimicrobial therapy and sun exposure.

T-cell positioning by chemokines in autoimmune skin diseases.

Autoimmune skin diseases are complex processes in which autoreactive cells must navigate through the skin tissue to find their targets. Regulatory T cells in the skin help to mitigate autoimmune inflammation and may in fact be responsible for the patchy nature of these conditions. In this review, we will discuss chemokines that are important for global recruitment of T cell populations to the skin during disease, as well as signals that fine-tune their localization and function. We will describe prototypical disease responses and chemokine families that mediate these responses. Lastly, we will include an overview of chemokine-targeting drugs that have been tested as new treatment strategies for autoimmune skin diseases.

A network of high-mobility group box transcription factors programs innate interleukin-17 production.

How innate lymphoid cells (ILCs) in the thymus and gut become specialized effectors is unclear. The prototypic innate-like γδ T cells (Tγδ17) are a major source of interleukin-17 (IL-17). We demonstrate that Tγδ17 cells are programmed by a gene regulatory network consisting of a quartet of high-mobility group (HMG) box transcription factors, SOX4, SOX13, TCF1, and LEF1, and not by conventional TCR signaling. SOX4 and SOX13 directly regulated the two requisite Tγδ17 cell-specific genes, Rorc and Blk, whereas TCF1 and LEF1 countered the SOX proteins and induced genes of alternate effector subsets. The T cell lineage specification factor TCF1 was also indispensable for the generation of IL-22 producing gut NKp46(+) ILCs and restrained cytokine production by lymphoid tissue inducer-like effectors. These results indicate that similar gene network architecture programs innate sources of IL-17, independent of anatomical origins.

Ruxolitinib cream for treatment of vitiligo: a randomised, controlled, phase 2 trial.

BACKGROUND: Vitiligo is a chronic autoimmune disease resulting in skin depigmentation and reduced quality of life. There is no approved treatment for vitiligo repigmentation and current off-label therapies have limited efficacy, emphasising the need for improved treatment options. We investigated the therapeutic potential of ruxolitinib cream in patients with vitiligo and report the efficacy and safety results up to 52 weeks of double-blind treatment. METHODS: We did a multicentre, randomised, double-blind, phase 2 study for adult patients with vitiligo in 26 US hospitals and medical centres in 18 states. Patients with depigmentation of 0·5% or more of their facial body surface area (BSA) and 3% or more of their non-facial BSA were randomly assigned (1:1:1:1:1) by use of an interactive response technology system to receive ruxolitinib cream (1·5% twice daily, 1·5% once daily, 0·5% once daily, or 0·15% once daily) or vehicle (control group) twice daily on lesions constituting 20% or less of their total BSA for 24 weeks. Patients in the control group in addition to patients in the 0·15% once daily group who did not show a 25% or higher improvement from baseline in facial Vitiligo Area Scoring Index (F-VASI) at week 24 were re-randomised to one of three higher ruxolitinib cream doses (0·5% once daily, 1·5% once daily, 1·5% twice daily). Patients in the 0·5% once daily, 1·5% once daily, or 1·5% twice daily groups remained at their original dose up to week 52. Patients, investigators, and the study sponsor (except members of the interim analysis and primary endpoint analysis data monitoring teams) remained masked to treatment assignment throughout the study. The primary endpoint was the proportion of patients achieving a 50% or higher improvement from baseline in F-VASI (F-VASI50) at week 24, assessed in the intention-to-treat population. The study is registered with ClinicalTrials.gov, NCT03099304. FINDINGS: Between June 7, 2017, and March 21, 2018, 205 patients were screened for eligibility, 48 were excluded and 157 patients (mean age, 48·3 years [SD 12·9]; 73 [46%] male and 84 [54%] female) were randomly assigned to either an intervention group or the control group. 32 (20%) of 157 were assigned to the control group, 31 (20%) to the 0·15% once daily group, 31 (20%) to the 0·5% once daily group, 30 (19%) to the 1·5% once daily group, and 33 (21%) to the 1·5% twice daily group. F-VASI50 at week 24 was reached by significantly more patients given ruxolitinib cream at 1·5% twice daily (15 [45%] of 33) and 1·5% once daily (15 [50%] of 30) than were treated with vehicle (one [3%] of 32). Four patients had serious treatment-emergent adverse events (one patient in the 1·5% twice daily group developed subdural haematoma; one patient in the 1·5% once daily group had a seizure; one patient in the 0·5% once daily group had coronary artery occlusion; and one patient in the 0·5% once daily group had oesophageal achalasia), all of which were unrelated to study treatment. Application site pruritus was the most common treatment-related adverse event among patients given ruxolitinib cream (one [3%] of 33 in the 1·5% twice daily group; three [10%] of 30 in the 1·5% once daily group; three [10%] of 31 in the 0·5% once daily group; and six [19%] of 31 in the 0·15% once daily group)with three [9%] of 32 patients showing application site pruritis in the control group. Acne was noted as a treatment-related adverse event in 13 (10%) of 125 patients who received ruxolitinib cream and one (3%) of 32 patients who received vehicle cream. All treatment-related adverse events were mild or moderate in severity and similar across treatment groups. INTERPRETATION: Treatment with ruxolitinib cream was associated with substantial repigmentation of vitiligo lesions up to 52 weeks of treatment, and all doses were well tolerated. These data suggest that ruxolitinib cream might be an effective treatment option for patients with vitiligo. FUNDING: Incyte.

The Role of Memory CD8+ T Cells in Vitiligo.

Vitiligo is an autoimmune skin disease mediated by autoreactive CD8+ T cells that destroy the pigment-producing cells of the epidermis, melanocytes, leading to areas of depigmentation. Patients with vitiligo require lifelong treatment to regain and maintain their pigment. Clinical observations uncovered the importance of autoimmune memory in vitiligo because cessation of treatment frequently led to relapse of disease at the site of previous lesions. A subset of memory T cells known as CD8+ resident memory T cells (TRM) are long-lived, nonmigratory memory cells that persist in most nonlymphoid tissues, including the skin. Recent reports describe the presence of CD8+ TRM in lesional vitiligo patient skin and suggest their role as active players in disease maintenance. In this review, we will discuss the role of skin CD8+ TRM in maintaining disease in vitiligo and the opportunity to target this population to induce a long-lasting reversal of disease.

Standardizing serial photography for assessing and monitoring vitiligo: A core set of international recommendations for essential clinical and technical specifications.

BACKGROUND: Clinical photography is an important component of the initial assessment and follow-up of patients with vitiligo in clinical practice and research settings. Standardization of this photographic process is essential to achieve useful, high-quality, and comparable photographs over time. OBJECTIVE: The aim is to develop an international consensus for a core set of recommendations for standardized vitiligo clinical photography. METHODS: Based an international meeting of vitiligo experts, a standard operating procedure was developed for vitiligo photography in daily practice and research settings. This protocol was subsequently reviewed by 20 vitiligo experts until agreement was reached. RESULTS: The resulting protocol includes a set of 10 and 15 photographs for clinical practice and research purposes, respectively. The photographic series are based on anatomic units included in the Vitiligo Extent Score. Furthermore, graphic representations of standardized positioning and suggestions for guidelines to standardize the process (background color, lighting, position marking, scales, materials, instruments) for both color and ultraviolet photographs are described. CONCLUSIONS: This consensus-based protocol for vitiligo photography will harmonize imaging for both clinical practice, translational research, and clinical trials. It can improve outcome assessment, foster multicenter collaboration, and promote better communication with patients regarding outcomes of treatment.

Cellular stress and innate inflammation in organ-specific autoimmunity: lessons learned from vitiligo.

For decades, research in autoimmunity has focused primarily on immune contributions to disease. Yet recent studies report elevated levels of reactive oxygen species and abnormal activation of the unfolded protein response in cells targeted by autoimmunity, implicating cellular stress originating from the target tissue as a contributing factor. A better understanding of this contribution may help to answer important lingering questions in organ-specific autoimmunity, as to what factors initiate disease and what directs its tissue specificity. Vitiligo, an autoimmune disease of the skin, has been the focus of translational research for over 30 years, and both melanocyte stress and immune mechanisms have been thought to be mutually exclusive explanations for pathogenesis. Chemical-induced vitiligo is a unique clinical presentation that reflects the importance of environmental influences on autoimmunity, provides insight into a new paradigm linking cell stress to the immune response, and serves as a template for other autoimmune diseases. In this review, I will discuss the evidence for cell stress contributions to a number of autoimmune diseases, the questions that remain, and how vitiligo, an underappreciated example of organ-specific autoimmunity, helps to answer them.

Patient satisfaction and physician productivity in shared medical appointments for vitiligo.

BACKGROUND: The shared medical appointment (SMA) allows patients with a similar diagnosis to be simultaneously cared for and educated by 1 provider, which has had success in dermatology and other fields of specialty. The SMA provides a potential solution to improve patient access to dermatologists. OBJECTIVE: The purpose of this study was to implement the SMA for patients with vitiligo and compare it to traditional appointments with regard to patient satisfaction, time to appointment, number of new patients seen per month, and generated revenue. METHODS: A vitiligo SMA was implemented, and a 12-question survey was used to assess satisfaction in both SMA and traditional appointment settings. Satisfaction, revenue, and appointment logistic data for SMAs were compared with those for traditional appointments for new patients. RESULTS: Patients were highly satisfied with both SMAs and traditional appointments (P > .05). Time to appointment was faster for the SMA, and significantly more new patients were seen monthly with the SMA (P = .009). LIMITATIONS: Limitations include small sample size, inability to correlate responder characteristics with survey responses, potential response bias, and selection bias due to absence of randomization. CONCLUSION: SMAs were successful in a vitiligo clinic for both patient and provider. The SMA is a solution to improve access to dermatologists without compromising patient benefit, experience, or satisfaction.

Building and Crossing the Translational Bridge: 2016 Alopecia Areata Research Summit Highlights.

Alopecia areata (AA) is a common autoimmune skin disease that results in the loss of hair on the scalp and elsewhere on the body and affects over 146 million people worldwide at some point in their lives. Founded in 1981, the National Alopecia Areata Foundation is a nonprofit organization that supports research to find a cure or acceptable treatment for AA, supports those with the disease, and educates the public about AA. The National Alopecia Areata Foundation conducts research summits every 2 years to review progress and create new directions in its funded and promoted research. The Foundation brings together scientists from all disciplines to get a broad and varied perspective. These AA research summits are part of the Foundation's main strategic initiative, the AA Treatment Development Program, to enhance the understanding of AA and accelerate progress toward a viable treatment.