Vitiligo and alopecia areata: apples and oranges?

Pathogenesis of Alopecia Areata and Vitiligo: Commonalities and Differences

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

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

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

Biologic and targeted therapeutics in vitiligo

BACKGROUND

Vitiligo is a long-standing progressive autoimmune disease with depigmented macules/patches with significant psychological morbidity to the patients. From being one of the most poorly understood diseases in the past, there has been a rampant advance in determining the molecular and genetic factors influencing the disease process. More light has been shed on the complex intracellular environment and interplay between innate and adaptive immunity. Numerous cytokines and signaling pathways have been associated with disease pathogenesis in the recent past.

OBJECTIVE

The aim of this review the efficacy of biologic and targeted therapeutics in vitiligo.

METHODS

A detailed literature search was conducted on databases like PubMed, COCHRANE Central, EMBASE and Google Scholar using keywords-"biologics," "vitiligo," "treatment," "repigmentation," "JAK inhibitors,", "TNF-ꭤ inhibitors," and "IL17/23 inhibitors," Relevant studies and review articles in English were analyzed in detail and report was written. This article aimed at a comprehensive review of all the biologicals and newer targeted therapeutics tried in vitiligo and their efficacy with an insight into the potential complications arising as a result of the therapy.

RESULTS

Most conventional vitiligo treatment modalities are restricted to generalized nonspecific immunosuppressants like topical and oral corticosteroids, calcineurin inhibitors, phototherapy, and surgical modalities. There have been reports and studies on the usage of biologicals in treating vitiligo. JAK inhibitors have shown good efficacy in vitiligo; however, it lacks substantial evidence in the form of randomized control trials. Similarly, the use of targeted therapeutics in treating vitiligo is substantiated by limited evidence and requires more randomized trials for further evidence.

CONCLUSION

JAK inhibitors have shown promising results and good tolerability; Adjuvant phototherapy can achieve a superior response compared to monotherapy. Though TNF-ꭤ has been tried in a few cases, it is best used if vitiligo is present in association with other chronic autoimmune diseases for which it is indicated. More in vitro studies and clinical research are required to understand the pathogenesis clearly, and therapy has to be targeted at specific pathways for a better approach toward vitiligo. Treatment aimed at induction and differentiation of melanocytes may be added to achieve faster repigmentation.

Beyond skin white spots: Vitiligo and associated comorbidities

Vitiligo is a common depigmentation disorder of an unknown origin characterized by the selective loss of melanocytes, resulting in typical white macules and patches. However, vitiligo is now recognized as more than just a skin disease, what a dermatologist observes as a white spot of skin is just the "tip of the iceberg" of the condition. We attempt to clarify the classification of comorbidities associated with vitiligo from various reviews and reports, and describe their possible pathogenesis. In conclusion, the literature provides evidence of an association between vitiligo and ocular and auditory abnormalities, autoimmune disorders, other dermatological diseases, metabolic syndrome and related disorders, and psychological diseases. These associations highlight the importance of a multidisciplinary approach in managing vitiligo patients.

Videodermoscopic Changes of the Hair in Vitiligo Lesions in Relation to Disease Duration

INTRODUCTION

Vitiligo is an acquired disease of complex pathogenesis, in which the immunologic attack to the skin and hair follicle melanocytes leads to areas of depigmentation and leukotrichia, respectively.

OBJECTIVES

To study the dermoscopic features of the hair changes in vitiligo lesions in comparison to perilesional control areas and in relation to disease duration.

METHODS

Forty-seven patients with both old and recent vitiligo lesions were included. Dermoscopic features of hair within the lesions were examined and compared to those in perilesional non depigmented skin of the same patient.

RESULTS

Hair density (P < 0.001), terminal hair rate (P = 0.011), terminal to vellus hair ratio (P = 0.029) and mean hair shaft thickness (P = 0.031) were significantly decreased, whereas vellus hair rate (P = 0.011) was significantly increased in old vitiligo lesions compared to their respective control areas. The frequency of broken hair was significantly higher in old lesions (P < 0.001), while that of upright re-growing hair was significantly higher in recent lesions (P = 0.016).

CONCLUSIONS

Hair involvement in vitiligo lesions is not only limited to the development of leukotrichia. Other subtle changes in hair density, anagen and telogen hair rates, and mean hair thickness can be detected. These changes may serve as objective clues to the duration of the lesions.

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.

Hair Follicle Melanogenesis Reflected in Hair Pigmentation as a Developmental Factor in Alopecia Areata

The mechanism of alopecia areata (AA) is not well-elucidated, and hair follicle melanogenesis pathways are implicated as possible sources for autoantigens. After a retrospective medical record review at a single tertiary medical center, the hair color of 112 AA patients were identified and compared to a control group of 104 androgenetic alopecia patients. There were no statistically significant differences in the natural hair color prevalence between the 2 groups (p = 0.164), and hair color was not a predictor of the alopecia type. Our results suggest hair pigmentation, determined by the eumelanin-to-pheomelanin ratio, is not a positive risk factor for AA development. We hope that our study will encourage multiple large-scale, collaborative, retrospective medical reviews to determine if our results are reproducible in diverse patient populations.

Nivolumab-Induced Alopecia Areata: A Case Report and Literature Review

Nivolumab (anti-PD-1) currently used in many cancers. With the usage of nivolumab increased, many cutaneous side effects were reported including maculopapular rash, lichenoid reactions, vitiligo, bullous disorders, psoriasis exacerbation, and alopecia areata (AA). Here, we report AA after nivolumab for treatment of hepatocellular carcinomas (HCC). A 55-year-old male presented with multiple hairless patch from 1 month ago. He suffered HCC and treated with nivolumab for 6 months after hepatectomy. He treated for hair loss with triamcinolone intra-lesional injection without improvement. We performed skin biopsy on the scalp. Histopathologic findings revealed decreased of hair follicles on the horizontal section with lymphocyte infiltration on the perifollicular area on the vertical section. Clinicopathologic findings were agreed with AA. Considering lack of previous history of AA and hairless patches with 6 months after nivolumab injection, we diagnosed him as nivolumab induced AA. Treatment included topical steroid, and minoxidil. No regrowth of hair was noted after 4 months of follow-up. Nivolimumab induced AA is rare side effect. Pathogenesis of nivolumab induced AA remain unclear. But our case is likely related to nivolumab, known to induce immune related adverse events, and given in the delay of a few months between introduction and the occurrence of the hair loss. Here, we reports nivolmumab induced AA; rare side effect.

Increased Circulatory Interleukin-17A Levels in Patients with Progressive and Leukotrichial Vitiligo

Background

Vitiligo is a chronic condition characterized by skin depigmentation. Although not life-threatening, it significantly impacts quality of life. The pathophysiology of vitiligo remains poorly understood, and treatment options are limited. Mounting evidence supports the importance of autoreactive T cells and, particularly interleukin-17A- (IL-17A-) secreting Th17 cells, in vitiligo. IL-17A targeting has been proven successful in various inflammatory dermatological conditions, including psoriasis and lupus erythematosus.

Objective

We evaluated the relationship between serum levels of IL-17A and the clinicopathological characteristics of Vietnamese vitiligo patients.

Methods

In this cross-sectional study, we analyzed data from 52 nonsegmental vitiligo patients and 50 age- and sex-matched healthy individuals. Serum levels of IL-17A were measured using an enzyme-linked immunosorbent assay. We evaluated the correlation between IL-17A levels and clinical characteristics including leukotrichia, disease duration, vitiligo activity, and body surface area involvement.

Results

Patients with progressive vitiligo had significantly higher IL-17A levels than patients with stable vitiligo (P = 0.014) or healthy individuals (P = 0.002). In addition, serum IL-17A levels were higher in vitiligo patients with leukotrichia than in patients without it (P = 0.04). Furthermore, serum IL-17A levels were negatively correlated with age (r = -0.39, P = 0.004) and age of onset (r = -0.33, P = 0.016) in vitiligo patients.

Conclusions

Higher serum levels of IL-17A in patients with progressive vitiligo and leukotrichia suggest a potential role of IL-17A in melanocyte destruction in the epidermis and the follicular matrix.

Alopecia areata: a review on diagnosis, immunological etiopathogenesis and treatment options

Patients suffering from alopecia areata (AA) can lose hair in focal regions, the complete scalp, including eyelashes and eyebrows, or even the entire body. The exact pathology is not yet known, but the most described theory is a collapse of the immune privilege system, which can be found in some specific regions of the body. Different treatment options, local and systemic, are available, but none of them have been proven to be effective in the long term as well for every treatment there should be considered for the possible side effects. In many cases, treated or non-treated, relapse often occurs. The prognosis is uncertain and is negatively influenced by the subtypes alopecia totalis and alopecia universalis and characteristics such as associated nail lesions, hair loss for more than 10 years and a positive familial history. The unpredictable course of the disease also makes it a mental struggle and AA patients are more often associated with depression and anxiety compared to the healthy population. Research into immunology and genetics, more particularly in the field of dendritic cells (DC), is recommended for AA as there is evidence of the possible role of DC in the treatment of other autoimmune diseases such as multiple Sclerosis and cancer. Promising therapies for the future treatment of AA are JAK-STAT inhibitors and PRP.

Increased Serum Levels of IFN-γ, IL-1β, and IL-6 in Patients with Alopecia Areata and Nonsegmental Vitiligo

Alopecia areata (AA) and vitiligo are both common skin diseases of autoimmune origin. Both alopecia areata and vitiligo have shown to be affected by oxidative stress. The present work is aimed at evaluating and comparing the serum proinflammatory cytokine levels in AA and nonsegmental vitiligo (NSV). A cross-sectional study was conducted of 33 patients with AA, 30 patients with NSV, and 30 healthy controls. Serum levels of interferon γ (IFN-γ), interleukin- (IL-) 1β, and IL-6 were determined quantitatively by ELISA method. Our analysis identified a signature of oxidative stress associated with AA and NSV, characterized by elevated levels of IFN-γ (AA: p = 0.007283; NSV: p = 0.038467), IL-1β (AA; NSV: p ≤ 0.001), and IL-6 (AA; NSV: p ≤ 0.001). IL-6 was also significantly increased in NSV patients in comparison with AA patients (p = 0.004485). Our results supported the hypothesis that oxidative stress may play a significant role in promoting and amplifying the inflammatory process both in AA and vitiligo. The complex understanding of both disease etiopathogenesis involves interrelationships between oxidative stress and autoimmunity. The clinical study registration number is RNN/266/16/KE.

Cutaneous polyautoimmunity in two unrelated dogs: pemphigus foliaceus and generalized discoid lupus erythematosus

BACKGROUND

Polyautoimmunity, the concurrent expression of two or more distinct autoimmune diseases (ADs) in a single individual, is a known phenomenon in humans and has been rarely reported in dogs. To the best of the authors' knowledge, comorbid pemphigus foliaceus (PF) and generalized discoid lupus erythematosus (GDLE) has not been reported in dogs.

HYPOTHESIS/OBJECTIVES

To describe the clinical, histological and immunological features and treatment outcome of two unrelated dogs with comorbid PF and GDLE.

ANIMALS

One 10-year-old, spayed German shepherd dog and one 8-year-old, castrated American Staffordshire terrier presented for evaluation of a symmetrical, facial- and/or pedal-dominant pustular dermatitis with concurrent, truncal scaly plaques.

METHODS

For each dog, clinicopathological characterization included physical examination, lesion cytological evaluation, bacterial culture and sensitivity testing, skin histopathological investigation and direct and indirect immunofluorescence testing. Additional diagnostic imaging and haematological testing was performed to exclude extracutaneous disease.

RESULTS

Both dogs exhibited lesions clinically and histologically compatible with PF and GDLE. Moreover, one dog exhibited generalized leucotrichia and chronic superficial keratitis. Remission was achieved with immunosuppressive dosages of prednisolone [high-dose pulse (Case 1) or standard immunosuppressive dosage (Case 2)] and ciclosporin (5-6 mg/kg/day). Tissue-bound antikeratinocyte immunoglobulin (Ig)G and IgM were detected in both dogs. A weak basement membrane zone deposit of C3 was seen in one dog. Circulating antikeratinocyte and anti-desmocollin-1 IgG were detected in one dog.

CONCLUSIONS AND CLINICAL IMPORTANCE

Cutaneous polyautoimmunity can occur in the dog. Depending on the specific disease combinations, overlapping clinical features may present diagnostic and/or therapeutic challenges. Moreover, these cases should be monitored for development of additional cutaneous or extra-cutaneous AD(s).

Hair(y) Matters in Melanoma Biology

Melanocyte stem cells (MeSCs), one candidate for the cellular origin of melanoma, reside in the bulge region of the hair follicle (HF), an immune-privileged tissue niche with impaired tumor immunosurveillance. Surprisingly, however, primary melanoma is only very rarely associated with HFs. Here, we explore the hypothesis that this profoundly immunoinhibitory signaling environment deprives both MeSCs and melanocytes of the anagen hair matrix of proinflammatory signals required for full oncogenic transformation. Understanding the cellular and molecular mechanisms for generating a putative antimelanoma tissue habitat, namely in the bulge, could help to recreate a similar melanoma-suppressive signaling environment in melanoma high-risk individuals. We further discuss how mimicking the bulge immune privilege may be an effective melanoma prevention strategy.

Repigmentation in vitiligo using janus kinase (JAK) inhibitors with phototherapy: systematic review and Meta-analysis

Introduction: Vitiligo is an autoimmune disorder characterized by progressive loss of melanocytes, leading to cutaneous depigmentation. Vitiligo has significant psychosocial impacts on patients and is challenging to manage with limited treatment options. Recent studies have suggested promising results for JAK1/3 inhibitors including tofacitinib and ruxolitinib.Objective: To determine the expected response of vitiligo to JAK inhibitor therapy and factors which influence response rates.Methods: A systematic review and meta-analysis was performed according to PRISMA guidelines. Good response was defined as repigmentation >50% or a 'good' or 'excellent' outcome as described by authors. Partial response was defined as some repigmentation <50%.Results: From the 9 eligible studies, individual patient data from 45 cases were pooled. Good response was achieved in 57.8%, partial response in 22.2%, and none or minimal response in 20% of cases. When subgrouped according to site, facial vitiligo had the highest good response rate (70%), compared to extremities (27.3%) and torso/non-sun exposed areas (13.6%). Concurrent phototherapy was significant associated with higher rates of good overall response (p < .001) and good facial response (p < .001).Conclusions: There is promising low-quality evidence regarding the effectiveness of JAK inhibitors in vitiligo. Concurrent UVB phototherapy appears to improve efficacy of JAK inhibitors for vitiligo.

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

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

Emerging drugs for the treatment of vitiligo

Introduction: Vitiligo is a relatively common autoimmune depigmenting disorder of the skin. There has been a great advance in understanding the pathological basis, which has led to the development and utilization of various new molecules in treating vitiligo. This review aims at a comprehensively describing the treatments available and the emerging treatment aspects and the scope for future developments.Areas covered: This study comprehensively summarizes the current concepts in the pathogenesis of vitiligo with special focus on the cytokine and signaling pathways, which are the targets for newer drugs. JAK kinase signaling pathways and the cytokines involved are the focus of vitiligo treatment in current research, followed by antioxidant mechanisms and repigmenting mechanisms. Topical immunosuppressants may be an alternative to steroids in localized vitiligo. Newer repigmenting agents like basic fibroblast growth factors, afamelanotide have been included and a special emphasis is laid on the upcoming targeted immunotherapy.Expert opinion: The treatment of vitiligo needs to be multimodal with emphasis on targeting different limbs of the pathogenesis. Topical and oral JAK inhibitors are the most promising new class of drugs currently available for treating vitiligo and acts best in conjunction with NB-UVB.

Harnessing the Power of Regenerative Therapy for Vitiligo and Alopecia Areata

Vitiligo and alopecia areata (AA) are common autoimmune conditions characterized by white spots on the skin (vitiligo) and bald spots on the scalp (AA), which significantly impact patients' lives by damaging their appearance and function. Melanocytes are the target of immune destruction in vitiligo and are hypothesized to be the site of immune attack in AA. This inflammatory process can be partially reversed by immunosuppressive drugs. Both conditions demonstrate regenerative components that are just now being identified. In this review, we focus on the regenerative medicine aspects of vitiligo and AA, using experimental data from human, mouse, and in vitro models, summarizing the key pathways involved in repopulation of the epidermis with melanocytes in vitiligo and in regrowth of hair follicles in AA. We also discuss treatments that may activate these pathways. Of the regenerative treatments, JAK inhibitors and bimatoprost stimulate repopulation of depleted cells in both diseases, intralesional injections of autologous concentrated platelet-rich plasma and minoxidil showed some benefit in AA, and phototherapy with narrowband UVB was shown to be effective especially in vitiligo. Finally, we discuss future treatments based on the mobilization of stem cells to regenerate anagen hair follicles in AA and intraepidermal melanocytes in vitiligo.

The Use of Janus Kinase Inhibitors in Vitiligo: A Review of the Literature

Vitiligo is a common acquired depigmenting disorder characterized by the development of white macules and patches due to the loss of melanocytes. Patients with vitiligo can be stigmatized by society, making the disease a source of psychological stress that can considerably affect quality of life. The goal of vitiligo treatment is to obtain skin repigmentation in the majority of cases, and less commonly to depigment the remaining normal skin. There is no consistent, long-term, durable therapy for vitiligo for all patients, highlighting the unmet need for new safe and effective therapies to control this disease. Recently, JAK inhibitors have been explored as a promising novel treatment option in vitiligo. The JAK and signal transducers and activators of transcription (STAT) pathway is an attractive therapeutic target because IFN-γ-dependent cytokines produced through this pathway have been implicated in the pathogenesis of disease. This literature review describes vitiligo pathophysiology, explains the usefulness of the JAK inhibitors for treatment, and summarizes published case reports, case series, and open-label studies. Research outlined here shows JAK inhibitors in patients with vitiligo have a favorable safety profile and effectively produce repigmentation of lesions, especially with concomitant ultraviolet exposure. Additional studies are required to confirm efficacy, establish safety, and investigate durability of repigmentation.

Ischemic modified albumin as a new biomarker in predicting oxidative stress in alopecia areata

Background/aim

Results show that oxidative stress is a pathophysiologic factor for alopecia areata (AA); however, the markers used can be confounding. Thus, we aimed to investigate the role of oxidative stress in the pathogenesis of AA through an evaluation of ischemia-modified albumin (IMA); other markers of the oxidant/antioxidant system, such as SOD, CAT, GSH-ST, and MDA; and contributing clinical risk factors.

Materials and methods

The usefulness of IMA as a new marker for oxidative stress was compared with that of other markers and evaluated in patients with AA.

Results

The mean serum level of IMA was of higher statistical significance in AA patients than in the control group (IMA: 0.57 ± 0.01 vs. 0.52 ± 0.02 ΔABSU, P < 0.0001). IMA (P = 0.03, OR = 25.8, 95% CI = 1.4–482.7) was found to be an independent predictor of oxidative stress in patients with AA. Increased severity of AA was found as an independent risk factor for IMA.

Conclusion

Long-lasting disease, male sex, >1 site of involvement of disease, and increased severity of disease were correlated with increased oxidation. Presence of AA, male sex, and severe disease were determined to be independent risk factors for antioxidant and oxidant systems. IMA has great potential as a biomarker of oxidative stress in AA when compared to other studied biomarkers.

Recalcitrant alopecia areata responsive to leflunomide and anthralin-Potentially undiscovered JAK/STAT inhibitors?

Several treatment modalities are available for the management of alopecia areata (AA); however, no therapy is universally effective and treatment can be frustrating in severe cases, with low response and high recurrence rates. Recent studies show that the JAK/STAT pathway plays a central role in the pathogenesis of this disease by determining the crosstalk between the infiltrating CD8+ T cells and the hair follicles, suggesting a role of JAK inhibitors in the treatment of AA. However, reports on the off-label use of these more expensive targeted agents have shown variable results. We present a case of a child with recalcitrant ophiasis-pattern AA who had failed steroid therapy and was treated successfully with leflunomide and anthralin, possibly by the synergistic effect on the JAK/STAT pathway inhibition, and we propose this combination could be a cost-effective therapeutic option for recalcitrant AA.

Quality of Life, Burden of Disease, Co-morbidities, and Systemic Effects in Vitiligo Patients

Vitiligo is a complex, systemic disease associated with many autoimmune and autoinflammatory conditions. Additionally, the cutaneous changes of vitiligo have significant effects on quality of life and self-esteem. Further efforts are needed to increase our understanding of vitiligo comorbidities as well as to increase awareness of the psychological effects of vitiligo.

Alopecia and the metabolic syndrome

Hair loss is a common condition that affects most people at some point in their lives. It can exist as an isolated problem or with other diseases and conditions. Androgenetic alopecia (AGA) and its association with the metabolic syndrome (MetS) have received increasing interest since 1972, when the first link between cardiovascular risk factors and hair loss was raised. We have reviewed studies concerning the relationship between alopecia and MetS. Many studies have investigated the relationship among AGA and MetS and its individual components, particularly in men, where a disproportionately large number of these studies supports this association. AGA has also been associated with other metabolic-related conditions, including coronary artery disease, polycystic ovary syndrome, and Cushing syndrome, as well as several nutritional deficiencies, all of which have led to many clinicians advocating for the screening of MetS and cardiovascular risk factors in patients who present with AGA.

Repigmentation in vitiligo using the Janus kinase inhibitor tofacitinib may require concomitant light exposure

BACKGROUND

Vitiligo is an autoimmune disease in which cutaneous depigmentation occurs. Existing therapies are often inadequate. Prior reports have shown benefit of the Janus kinase (JAK) inhibitors.

OBJECTIVE

To evaluate the efficacy of the JAK 1/3 inhibitor tofacitinib in the treatment of vitiligo.

METHOD

This is a retrospective case series of 10 consecutive patients with vitiligo treated with tofacitinib. Severity of disease was assessed by body surface area of depigmentation.

RESULTS

Ten consecutive patients were treated with tofacitinib. Five patients achieved some repigmentation at sites of either sunlight exposure or low-dose narrowband ultraviolet B phototherapy. Suction blister sampling revealed that the autoimmune response was inhibited during treatment in both responding and nonresponding lesions, suggesting that light rather than immunosuppression was primarily required for melanocyte regeneration.

LIMITATIONS

Limitations include the small size of the study population, retrospective nature of the study, and lack of a control group.

CONCLUSION

Treatment of vitiligo with JAK inhibitors appears to require light exposure. In contrast to treatment with phototherapy alone, repigmentation during treatment with JAK inhibitors may require only low-level light. Maintenance of repigmentation may be achieved with JAK inhibitor monotherapy. These results support a model wherein JAK inhibitors suppress T cell mediators of vitiligo and light exposure is necessary for stimulation of melanocyte regeneration.

Next generation human skin constructs as advanced tools for drug development

Many diseases, as well as side effects of drugs, manifest themselves through skin symptoms. Skin is a complex tissue that hosts various specialized cell types and performs many roles including physical barrier, immune and sensory functions. Therefore, modeling skin in vitro presents technical challenges for tissue engineering. Since the first attempts at engineering human epidermis in 1970s, there has been a growing interest in generating full-thickness skin constructs mimicking physiological functions by incorporating various skin components, such as vasculature and melanocytes for pigmentation. Development of biomimetic in vitro human skin models with these physiological functions provides a new tool for drug discovery, disease modeling, regenerative medicine and basic research for skin biology. This goal, however, has long been delayed by the limited availability of different cell types, the challenges in establishing co-culture conditions, and the ability to recapitulate the 3D anatomy of the skin. Recent breakthroughs in induced pluripotent stem cell (iPSC) technology and microfabrication techniques such as 3D-printing have allowed for building more reliable and complex in vitro skin models for pharmaceutical screening. In this review, we focus on the current developments and prevailing challenges in generating skin constructs with vasculature, skin appendages such as hair follicles, pigmentation, immune response, innervation, and hypodermis. Furthermore, we discuss the promising advances that iPSC technology offers in order to generate in vitro models of genetic skin diseases, such as epidermolysis bullosa and psoriasis. We also discuss how future integration of the next generation human skin constructs onto microfluidic platforms along with other tissues could revolutionize the early stages of drug development by creating reliable evaluation of patient-specific effects of pharmaceutical agents. Impact statement Skin is a complex tissue that hosts various specialized cell types and performs many roles including barrier, immune, and sensory functions. For human-relevant drug testing, there has been a growing interest in building more physiological skin constructs by incorporating different skin components, such as vasculature, appendages, pigment, innervation, and adipose tissue. This paper provides an overview of the strategies to build complex human skin constructs that can faithfully recapitulate human skin and thus can be used in drug development targeting skin diseases. In particular, we discuss recent developments and remaining challenges in incorporating various skin components, availability of iPSC-derived skin cell types and in vitro skin disease models. In addition, we provide insights on the future integration of these complex skin models with other organs on microfluidic platforms as well as potential readout technologies for high-throughput drug screening.

A case-control study on association of proteasome subunit beta 8 (PSMB8) and transporter associated with antigen processing 1 (TAP1) polymorphisms and their transcript levels in vitiligo from Gujarat

BACKGROUND

Autoimmunity has been implicated in the destruction of melanocytes from vitiligo skin. Major histocompatibility complex (MHC) class-II linked genes proteasome subunit beta 8 (PSMB8) and transporter associated with antigen processing 1 (TAP1), involved in antigen processing and presentation have been reported to be associated with several autoimmune diseases including vitiligo.

OBJECTIVES

To explore PSMB8 rs2071464 and TAP1 rs1135216 single nucleotide polymorphisms and to estimate the expression of PSMB8 and TAP1 in patients with vitiligo and unaffected controls from Gujarat.

METHODS

PSMB8 rs2071464 polymorphism was genotyped using polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) and TAP1 rs1135216 polymorphism was genotyped by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) in 378 patients with vitiligo and 509 controls. Transcript levels of PSMB8 and TAP1 were measured in the PBMCs of 91 patients and 96 controls by using qPCR. Protein levels of PSMB8 were also determined by Western blot analysis.

RESULTS

The frequency of 'TT' genotype of PSMB8 polymorphism was significantly lowered in patients with generalized and active vitiligo (p = 0.019 and p = 0.005) as compared to controls suggesting its association with the activity of the disease. However, TAP1 polymorphism was not associated with vitiligo susceptibility. A significant decrease in expression of PSMB8 at both transcript level (p = 0.002) as well as protein level (p = 0.0460) was observed in vitiligo patients as compared to controls. No significant difference was observed between patients and controls for TAP1 transcripts (p = 0.553). Interestingly, individuals with the susceptible CC genotype of PSMB8 polymorphism showed significantly reduced PSMB8 transcript level as compared to that of CT and TT genotypes (p = 0.009 and p = 0.003 respectively).

CONCLUSIONS

PSMB8 rs2071464 was associated with generalized and active vitiligo from Gujarat whereas TAP1 rs1135216 showed no association. The down-regulation of PSMB8 in patients with risk genotype 'CC' advocates the vital role of PSMB8 in the autoimmune basis of vitiligo.

Targeting CTLA-4, PD-L1 and IDO to modulate immune responses in vitiligo

For decades, an extensive debate is continued on the pathophysiology of vitiligo. Numerous hypotheses have been put forward, and many supported by well-documented arguments. Regardless of the initiating steps, most experts agree that an immune-based melanocyte destruction is responsible for the final steps leading to epidermal depigmentation. It is remarkable that currently the only therapeutic approach to counter this phenomenon consists of non-specific local and systemic immunosuppressants. Immunotherapy for melanoma reveals that targeting factors involved in peripheral tolerance are sufficient to break the natural defense mechanisms to develop skin depigmentations. Therapeutically enhancing these immune checkpoints seems therefore a promising long-term therapy for vitiligo. In this viewpoint, we propose this strategy as a promising therapeutic option for vitiligo. Several approaches are proposed with a focus on cytotoxic T-lymphocyte-associated protein 4, programmed death ligand-1 and indoleamine 2,3-dioxygenase.

Understanding autoimmunity of vitiligo and alopecia areata

PURPOSE OF REVIEW

Vitiligo and alopecia areata are common, disfiguring skin diseases. Treatment options are limited and include nontargeted approaches, such as corticosteroids, topical calcineurin inhibitors, narrow band ultraviolet B phototherapy, and other immune-modifying agents. The purpose of this article is to review shared, novel mechanisms between vitiligo and alopecia areata, as well as discuss how they inform the development of future targeted treatments.

RECENT FINDINGS

Vitiligo and alopecia areata are both autoimmune diseases, and striking similarities in pathogenesis have been identified at the level of both the innate and adaptive immune system. Increased reactive oxygen species and high cellular stress level have been suggested as the initiating trigger of the innate immune system in both diseases, and genome-wide association studies have implicated risk alleles that influence both innate and adaptive immunity. Most importantly, mechanistic studies in mouse models of vitiligo and alopecia areata have specifically implicated an interferon (IFN)γ-driven immune response, including IFNγ, IFNγ-induced chemokines, and cytotoxic CD8 T cells as the main drivers of disease pathogenesis. These recent discoveries may reveal an effective strategy to develop new treatments, and several proof-of-concept clinical studies support this hypothesis.

SUMMARY

The identification of IFNγ-driven immune signaling pathways has enabled discoveries of potential new treatments for vitiligo and alopecia areata, and supports initiation of larger clinical trials.

Follicular vitiligo: A report of 8 cases

BACKGROUND

Follicular vitiligo, a recently proposed new subtype of vitiligo, has primary involvement of the hair follicle melanocytic reservoir.

OBJECTIVE

We sought to characterize follicular vitiligo through a case series of 8 patients.

METHODS

Patients with features of follicular vitiligo who were seen at the vitiligo clinic in the National Center for Rare Skin Disorders in Bordeaux, France, were recruited. A retrospective review of case records and clinical photographs was carried out.

RESULTS

There were 8 male patients with a mean age of 48 years. All patients reported significant whitening of their body and, in some, scalp hairs before cutaneous depigmentation. Examination revealed classic generalized depigmented lesions of vitiligo and an impressive presence of leukotrichia, not only in the vitiliginous areas, but also in areas with clinically normal-appearing skin. Punch biopsy specimen of the leukotrichia and vitiligo lesions demonstrated loss of melanocytes and precursors in the basal epidermis and hair follicle.

LIMITATIONS

This was a cross-sectional study based on a single-center experience.

CONCLUSION

Follicular vitiligo is a distinct entity within the spectrum of vitiligo. This entity may serve as the missing link between alopecia areata and vitiligo, with probable physiopathological similarities between these conditions.

Risk factors and characterization of vitiligo and alopecia areata in patients with chronic graft-vs-host disease

IMPORTANCE

Cutaneous manifestations of chronic graft-vs-host disease (GvHD) are highly variable and may recapitulate well-characterized autoimmune diseases, including systemic sclerosis and Sjögren syndrome. However, vitiligo and alopecia areata (AA) have not been well characterized in the chronic GvHD setting.

OBJECTIVE

To determine laboratory markers, transplant-related factors, and other systemic manifestations associated with vitiligo and/or AA in patients with chronic GvHD.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional, retrospective study conducted by the National Institutes of Health (NIH) of 282 adult and pediatric patients with chronic GvHD seen under the NIH natural history protocol between 2004 and 2013.

MAIN OUTCOMES AND MEASURES

Demographic, clinical, and laboratory data, including measures of 11 antibodies, were included in the analysis. Patients with vitiligo and/or AA were identified from dermatologist documentation and photographic evidence. Univariate and multivariable logistic regression analyses were used to determine risk factors for vitiligo and AA development.

RESULTS

Fifteen (5.3%) of 282 patients demonstrated vitiligo (14 of 282; 4.9%) and/or AA (2 of 282; 0.7%) (1 patient had both vitiligo and AA). Univariate analysis identified female donor to male recipient sex mismatch (P = .003), positive test results for anticardiolipin (ACA) IgG (P = .03) or antiparietal antibody (P = .049), elevated CD19 level (P = .045), and normal or elevated IgG level (P = .02) as risk factors for vitiligo or AA. Female donor to male recipient sex mismatch (P = .003) and positive findings for ACA-IgG (P = .01) retained significance in the multivariable analysis.

CONCLUSIONS AND RELEVANCE

Female donor and female donor to male recipient sex mismatch, in particular, are significantly associated with the development of vitiligo and/or AA. Further studies are needed to explore transplant-related risk factors that may lead to better understanding of the pathomechanisms of chronic GvHD.

Colocalization of vitiligo and alopecia areata presenting as poliosis

Vitiligo and alopecia areata are two cutaneous diseases believed to be primarily autoimmune in pathogenesis. While the coexistence of the two conditions in the same patient has been well-described, reports of the two disease processes occurring in the same location are rare. We report the case of a 10-year-old male with an unremarkable past medical history who presented with a single localized area of poliosis with depigmented underlying skin on the frontal scalp. The hair in the affected area was relatively decreased in density. A punch biopsy of the depigmented patch demonstrated features consistent with both vitiligo and alopecia areata. The decreased number of large hair follicles and a focal peribulbar lymphocytic infiltrate around an anagen follicle were suggestive of alopecia areata. A panel of melanocyte-specific stains revealed absent melanocytes in the epidermis, consistent with vitiligo. Loss of microphthalmia-associated transcription factor-positive root sheath cells was seen, suggestive of loss of melanocyte stem cells. The combination of clinical and histopathologic findings supports the theory of a common pathogenesis of alopecia areata and vitiligo.

Accelerating bleaching in vitiligo: balancing benefits versus risks

While the goal of available treatment in vitiligo is to regain pigmentation, some patients affected by extensive and treatment-resistant vitiligo, with a major social and emotional impact, may benefit from depigmentation therapy. However, results from such therapy may not always be satisfactory. So to achieve better, faster and complete bleaching, Webb et al. propose a synergistic approach that combines topical application of bleaching phenols which targets melanocytes and initiate local inflammation with immune adjuvants so as to obtain an enhanced immune response against remaining melanocytes. This strategy could be reliable, but should be evaluated cautiously in future studies, in terms of potential side effects and induction of undesired autoimmunity.

T helper 17 and Tregs: a novel proposed mechanism for NB-UVB in vitiligo

Narrowband ultraviolet (NB-UV)B is accepted as corner stone therapy for vitiligo. Its influence on the expression of IL-17, IL- 22 and FoxP3 as markers for the Th17 and Tregs lineages has not been studied before in the context of non-segmental vitiligo (NSV). The study included 20 active NSV patients who received 36 NB-UVB sessions and 20 controls. Clinical evaluation Vitiligo Area Scoring Index (VASI) and determination of tissue expression of IL-17, IL-22 and FoxP3 by qRT-PCR (lesional, perilesional) were carried out before and after therapy. Baseline levels of IL-17 and IL-22 were significantly higher in patients, whereas FoxP3 was significantly lower. After therapy, IL-17 and IL-22 significantly dropped, whereas FoxP3 significantly increased (lesional, perilesional). Baseline and post-treatment VASI showed significant positive correlations with IL-17 and IL-22 and significant negative correlation with FoxP3 expression. Restoration of the balance between Th17 and Tregs might represent a novel pathway for the improvement that NB-UVB exerts in vitiligo patients.