Vitiligo is an acquired depigmenting disorder characterised by the loss of functional melanocytes from the cutaneous epidermis. A role for autoimmunity is supported by the presence of circulating antibodies and T lymphocytes which react against melanocyte antigens in patients with vitiligo. The identification and characterisation of these autoantigens will improve understanding of the immune response in vitiligo, and may allow development of better therapies and diagnostic tools. Candidate immunoregulatory genes may predispose to vitiligo. However, this study failed to find an association between vitiligo and a polymorphism of the cytotoxic T lymphocyte antigen-4 (CTLA-4), although the polymorphism increases the likelihood of autoimmune endocrinopathy patients developing vitiligo. The epitopes on melanocyte-specific antigens tyrosinase and Pmel17 which are recognised by antibodies in vitiligo patient sera were identified by molecular mapping. Multiple regions of tyrosinase and at least two domains on PmeI17 were identified as B cell epitopes. Sequence analysis revealed that the tyrosinase epitopes are likely to be cross-reactive with tyrosinase-related proteins but that the antibody response to Pmel17 is distinct. Antibody reactivity to a melanocyte protein, MelanA, targeted by a cellular immune response in vitiligo and melanoma was investigated by immunoblotting and radioimmunoassay. No MelanA-specific antibodies were isolated suggesting that either it is not a target of the humoral immune response in vitiligo, or that antibody reactivity was not detectable by the methods used. To identify novel vitiligo autoantigens, a melanoma cDNA expression library was constructed in a phage-display cloning system and immunoscreened with vitiligo patient IgG. Several possible autoantigens were enriched by this technique, including proteins previously characterised as autoantigens in other disorders. Additionally, humoral reactivity was identified to a protein with a possible role in pigmentation, the melanin-concentrating hormone receptor 1 (MCHR1). MCHR1-specific antibodies were detected in 16.4% (9/55) of vitiligo patients but not in other diseases or healthy control subjects. The study demonstrates the usefulness of phage-display for further autoantigen identification in vitiligo.

no / Background Generation and accumulation of reactive oxygen/nitrogen species in the epidermis of patients with vitiligo has been widely documented. Moreover, semiquinone radical-mediated sensitivity has been shown in blood lymphocytes of these patients. Objectives To determine the possible mechanism behind Q10-induced facial vitiligo. Methods This was a clinical assessment supported by in vivo Fourier transform–Raman spectroscopy and repigmentation. Results Topical Q10 application generated hydrogen peroxide (H2O2) leading in turn to facial vitiligo in susceptible individuals. Proof of the basic result stemmed from reduction of epidermal H2O2 by using narrowband ultraviolet B-activated propseudocatalase PC-KUS in association with cessation of depigmentation and repigmentation of the lost skin colour. Conclusions Over-the-counter availability of Q10-containing topical formulations can be harmful to individuals susceptible to vitiligo.

no / Background  Vitiligo is an acquired, idiopathic, and worldwide common depigmentation disorder with an estimated prevalence from 0.1 to 8%. These numbers are based on clinical population studies and field research examining inhabitants of geographically enclosed areas. Our aim was to collect all available data on the prevalence of vitiligo in the general population, paying particular attention to children/adolescent groups and adults. Materials and methods  Screening of available literature and online databases using several key words. Results  We found more than 50 studies that used several methods and subgroups of the general population. The prevalence of vitiligo ranges from 0.06 to 2.28%, whereas this was 0.0–2.16% in children/adolescents populations. Conclusions  The often cited prevalence of 8% could not be confirmed after excluding clinical patient populations. Accordingly, the worldwide prevalence of vitiligo ranges between 0.5 and 2%.

no / Vitiligo is an acquired, idiopathic skin disease characterized by the mostly progressive loss of the inherited skin color leading to white patches and in some cases to total depigmentation. The course of this ancient disease is still unknown. The worldwide prevalence range is 0.5-1%. The disease burden includes stigmatization, depression, impaired quality of life, lack of self-confidence, embarrassment and self-consciousness. To the best of our knowledge, the extent to which this chronic disease may exert an influence upon the life course of affected individuals has, to date, not been investigated. The material presented herein is the result of an accurate analysis of published literature. Moreover, we included our own data collected in two studies. To apply the concept of cumulative life course impairment in vitiligo, we looked at possible trigger factors, role of patient's age and the age at disease onset, disease duration and stigmatization. Stigmatization had the strongest impact. It is common in patients with an early disease onset, often leading to other disturbances. Our data revealed that older patients or those with a disease onset later in life adjust better to this chronic skin disorder and that they are less socially avoidant. However, long disease duration can also lead to impaired quality of life and obsession, while this group seems to be less depressed or embarrassed. Results from our own work with peer groups of these patients strongly support a positive long-lasting effect of treatment on quality of life of children, adolescents and adults. To which extent vitiligo may contribute to a cumulative life course impairment remains to be shown.

No / Background  Vitiligo is an acquired, non-contagious depigmentation disorder involving a patchy loss of skin color. It often leads to stigmatization, embarrassment, and reduced quality of life (QoL) in adult patients. Little is known about children’s reactions. Objectives  This study aimed to explore disease-related QoL and experiences in a multinational group of children and adolescents. Methods  Quality of life, disease-related experiences and behavior, and sociodemographic data were examined in 24 boys and 50 girls (age range: 7–17 years) using the Children’s Dermatology Life Quality Index (CDLQI) and additional questions. Eighteen children without skin disorders served as age-, sex- and skin color-matched controls. Results  The mean disease duration was 3.5 years. The most common sites of onset were the trunk, legs, and head and neck. Overall, 35.1% of the 74 subjects reported a positive family history, 91.9% had visited a doctor, and 75.7% had received treatment. Two-thirds (66.2%) were distressed by their vitiligo, and 93.2% had experienced low-key stigmatization, 44.6% nasty comments, and 21.7% bullying. A total of 24.4% had concealed their disease, and 29.7% had avoided situations because of vitiligo. Frequency of stigmatization influenced avoidant behavior. Parents, particularly mothers, and friends were important sources of support. Patients and controls had similar numbers of friends and leisure time activities. The mean CDLQI score of the group was low (2.8). Higher CDLQI scores were related to stigmatization, hiding of white spots, facial depigmentation, avoidance of situations, and a vitiligo-negative family history. Conclusions  Disease-related stigmatization, negative experiences, and avoidant behavior affect QoL. Therefore, the CDLQI should be combined with other instruments to screen for disease burden. These results call for the careful evaluation of young patients with vitiligo.

Le vitiligo est une dermatose inflammatoire caractérisée par une perte progressive des mélanocytes de la lame basale de l’épiderme. Cette pathologie reste à ce jour orpheline de traitement efficace. Toutefois, les mécanismes qui sont liés à la perte des mélanocytes restent débattus et impliquent un détachement des mélanocytes de la lame basale ou leur mort cellulaire par apoptose. Nous avons montré au sein de notre équipe l’implication des lymphocytes T CD8+ effecteurs mémoires dans la pathogénie du vitiligo. Ces populations produisent des niveaux élevés de deux cytokines inflammatoires qui sont, le TNF-α (tumor necrosis factor) et l’IFN-γ (interféron γ), suggérant ainsi un rôle majeur de ces deux cytokines dans la pathogénie du vitiligo. L’objectif de mon projet de thèse est d’étudier les mécanismes immunologiques impliqués dans la perte du mélanocyte au cours du vitiligo. Ainsi, nous avons observé dans les zones péri-lésionnelles de vitiligo ou lésionnelles de psoriasis, une localisation suprabasale des mélanocytes et une anomalie de l’expression de la E-cadhérine dans l’épiderme, protéine majeure impliquée dans l’attachement des mélanocytes. Nous avons également montré l’absence de la mort cellulaire par apoptose des mélanocytes au niveau cutané chez les patients atteints de vitiligo et/ou de psoriasis. En se basant sur ces observations, nous nous sommes donc intéressés à évaluer les effets combinés du TNF-α et de l’IFN-γ sur l’adhésion des mélanocytes. Nos résultats ont montré que les deux cytokines combinés diminuent l’expression du gène codant la Ecadhérine et entrainent probablement la redistribution de cette protéine. De plus, nous avons observé que ces deux cytokines en combinaison altèrent l’expression de la E-cadhérine dans un modèle d’épidermes reconstruits pigmentés in vitro. Cette altération était associée à une augmentation des niveaux de la E-cadhérine soluble (sE-cad) au niveau des surnageants de culture. D’une manière intéressante, nous avons montré que ces deux cytokines induisent l’expression kératinocytaire de la métalloprotéase 9 (MMP9) dont l’action est connue pour cliver la E-cadhérine sous sa forme soluble, participant ainsi au détachement des mélanocytes. Des taux élevés de MMP9, mais également de la sE-cad sont retrouvés dans le sérum des patients atteints de vitiligo. L’inhibition de la MMP9 dans des modèles in vitro et in vivo empêche les effets combinés du TNF- α et de l’IFN-γ sur le détachement des mélanocytes permettant leur stabilisation à la lame basale. Par ailleurs, comme nous avons montré que la survie des mélanocytes n’était pas altérée dans le vitiligo, nous nous sommes intéressés à évaluer l’action combinée du TNF-α et de l’IFN-γ sur la fonction, le phénotype des mélanocytes et leur production des médiateurs inflammatoires. Nous avons montré que ces deux cytokines en combinaison inhibent l’expression des gènes mélanocytaires (MITF, TYR, DCT) et favorisent l’induction des chimiokines CXCL9 et CXCL10, de la cytokine inflammatoire TNF-α et de la molécule d’adhésion ICAM-1, suggérant un rôle majeur des mélanocytes dans la promotion de l’inflammation. Enfin, considérant que la voie de signalisation du récepteur de l’IFN-γ est dépendante de la voie JAK/STAT, nous avons étudié l’impact de l’inhibition de cette voie dans les effets induits dans nos modèles, et avons montré au niveau de l’expression des gènes, une amélioration des gènes associés à la fonction mélanocytaire et une inhibition de ceux associés à l’inflammation. L’ensemble de nos résultats mettent en évidence un nouveau mécanisme pour expliquer la perte des mélanocytes et identifie MMP9 ainsi que les inhibiteurs de JAK comme des cibles thérapeutiques prometteuses permettant ainsi de mieux comprendre les mécanismes physiopathologiques au cours du vitiligo et d’établir un lien direct entre immunité, facteurs solubles inflammatoires et perte des mélanocytes au cours du vitiligo. / Vitiligo is a chronic inflammatory skin disorder characterized by a progressive loss of melanocytes. This stigmatizing disease has a major social impact and no real effective therapies have been reported so far. However, the mechanisms leading to melanocyte disappearance remain debated and include melanocyte detachment and/or death. The role of the immune response has now been well described, implying CD8+ effector memory T cells that produce high levels of inflammatory cytokines as TNF-α (tumor necrosis factor) and IFN-γ(interferon γ), suggesting the involvement of these two cytokines in the pathogenesis of vitiligo. Thus, the aim of this project is to study the interplay between the inflammatory response characterizing vitiligo disease and melanocyte loss. We first observed that melanocytes are located in suprabasal layers of the epidermis in perilesional skin of vitiligo and lesional skin of psoriasis patients, which was associated with an altered expression of E-cadherin, a major protein involved in melanocyte attachment to the basal membrane. Such suprabasal melanocytes did not undergo apoptosis. Based on these observations, we next investigated the combined effects of TNF-α and IFN-γ on melanocyte adhesion. We showed that these two cytokines decrease E cadherin gene expression and probably induce a redistribution of E-cadherin. In addition, these two cytokines in combination altered the expression of E-cadherin in reconstructed human pigmented epidermis in vitro. This finding was associated with increased levels of soluble E-cadherin in culture supernatants. Furthermore, TNF-α and IFN-γ induced the production of matrix metalloproteinase 9 (MMP9) by keratinocytes, leading to the cleavage of the E-cadherin. Inhibition of MMP9 prevents the combined effects of TNF-α and IFN-γ on melanocyte detachment and led to their stabilization to the basal membrane of epidermis in vitro and in vivo models. Since we demonstrated that melanocyte survival is not impaired in vitiligo, we assessed the impact of these two cytokines on melanocyte function, phenotype and inflammation. We demonstrate that the combination of TNF-α and IFN-γ inhibits the expression of genes involved in melanocyte function (MITF, TYR, DCT) and promote the induction of the chemokine ligands CXCL9 and CXCL10, the inflammatory cytokine TNF-α and adhesion molecule ICAM-1, suggesting an important role of melanocytes in the promotion of inflammation. Lastly, considering that the signaling pathway of IFN-γ involves activation of the JAK / STAT pathway, we studied the impact of the inhibition of that pathway in our models. Our results show that the JAK inhibition suppressed the effects of TNF-α and IFN-γ on melanocyte function, on the release of pro-inflammatory mediators and led to the melanocyte stabilization to the basal membrane of epidermis. All of our results highlight a new mechanism to explain the loss of melanocytes and identify MMP9 and JAKs as promising therapeutic targets to better understand the physiopathological mechanisms during vitiligo and establish a direct link between immunity, soluble factors. Inflammation and loss of melanocytes during vitiligo.

>Magister Scientiae - MSc / Tyrosinase is an enzyme widely distributed in the biosphere and is found in many species of bacteria, fungi, animals, and plants; it is associated with melanin production. Even though it possesses many beneficial properties such as photoprotection, but overproduction causes undesirable effects such melasma, solar lentigines etc. Therefore, tyrosinase enzyme inhibitors are of far-ranging importance in cosmetics, medicinal products, and food industries. This study is aimed to test anti-tyrosinase activity in 37 plants from 20 families using mushroom tyrosinase inhibition method; each plant was extracted with methanol. The results showed that 17 plant extracts, exerted a considerable level of in vitro tyrosinase inhibition comparable to positive controls of kojic acid in the same solvent systems when evaluated spectrophotometrically. Among plant extracts, those that showed an inhibition rate >50 % at 50 μg/ml and ˃60 % at 200 μg/ml were A. karroo (Hayne.), A. afra Jacq. Ex Willd, C. geifolia (L.), E. racemosa (L.), H. petiolare Hilliard & B.L.Burt, M. quercifolia (L.), M. communis (L.), P. rigida (Wikstr.), P. ecklonii (Benth.), P. ericoides (L.), S. Africanacaerulea (L.), S. Africana-lutea (L.), S. antarcticus (Willd.), S. lucida (L.) F.A.Barkley, S. hamilifolius (L.), S. furcellata R.Br and T riparia which exhibited great anti-tyrosinase activity.

Vitiligo is an idiopathic, non-contagious and often familial depigmentation disorder affecting both sexes equally. The mostly progressive and patchy loss of the inherited skin colour is not only a cosmetical problem, it has a profound impact on the patient's well-being. Stigmatisation and rejection often causes depression, self-consciousness, sexual problems and an impaired quality of life. To further substantiate earlier investigations and to introduce new aspects, we utilised the Dermatology Life Quality Index (DLQI), the Beck Depression Inventory (BDI) and the Adjustment to Chronic Skin Disorders Questionnaire (ACS) with its sub-scales on Social anxiety/avoidance, Helplessness and Anxious-depressive Mood in 422 patients and 55 healthy controls. We also included 103 children, their parents and 18 controls by using the Children's Dermatology Life Quality Index (CDLQI) and an adapted version of the ACS. We found that patients with vitiligo experience high levels of stigmatisation. They have an impaired quality of life and are more socially anxious/avoidant, helpless and (anxious-) depressive compared to healthy controls. The results correlate with disease severity, avoidant behaviour/hiding of vitiligo and the belief that psychological stress influences the disease. Female patients are generally more affected. Treatment with pseudocatalase PC-KUS improves quality of life and reduces anxious-depressive mood. Children also suffer from stigmatisation and an impaired quality of life. Parents are more socially anxious and helpless compared to the control group.

no / Nonsegmental vitiligo (NSV) is characterized by loss of inherited skin color. The cause of the disease is still unknown despite accumulating in vivo and in vitro evidence of massive epidermal oxidative stress via H2O2 and peroxynitrite (ONOO−) in affected individuals. The most favored hypothesis is based on autoimmune mechanisms. Strictly segmental vitiligo (SSV) with dermatomal distribution is a rare entity, often associated with stable outcome. Recently, it was documented that this form can be associated with NSV (mixed vitiligo). We here asked the question whether ROS and possibly ONOO− could be players in the pathogenesis of SSV. Our in situ results demonstrate for the first time epidermal biopterin accumulation together with significantly decreased epidermal catalase, thioredoxin/thioreoxin reductase, and MSRA/MSRB expression. Moreover, we show epidermal ONOO− accumulation. In vivo FT-Raman spectroscopy reveals the presence of H2O2, methionine sulfoxide, and tryptophan metabolites; i.e., N-formylkynurenine and kynurenine, implying Fenton chemistry in the cascade (n=10). Validation of the basic data stems from successful repigmentation of skin and eyelashes in affected individuals, regardless of SSV or segmental vitiligo in association with NSV after reduction of epidermal H2O2 (n=5). Taken together, our contribution strongly supports H2O2/ONOO-mediated stress in the pathogenesis of SSV. Our findings offer new treatment intervention for lost skin and hair color.—Schallreuter, K. U., Salem, M. A. E. L., Holtz, S., Panske, A. Basic evidence for epidermal H2O2/ONOO−-mediated oxidation/nitration in segmental vitiligo is supported by repigmentation of skin and eyelashes after reduction of epidermal H2O2 with topical NB-UVB-activated pseudocatalase PC-KUS.

Vitiligo is an idiopathic, non-contagious and often familial depigmentation disorder affecting both sexes equally. The mostly progressive and patchy loss of the inherited skin colour is not only a cosmetical problem, it has a profound impact on the patient¿s well-being. Stigmatisation and rejection often causes depression, self-consciousness, sexual problems and an impaired quality of life. To further substantiate earlier investigations and to introduce new aspects, we utilised the Dermatology Life Quality Index (DLQI), the Beck Depression Inventory (BDI) and the Adjustment to Chronic Skin Disorders Questionnaire (ACS) with its sub-scales on Social anxiety / avoidance, Helplessness and Anxious-depressive Mood in 422 patients and 55 healthy controls. We also included 103 children, their parents and 18 controls by using the Children¿s Dermatology Life Quality Index (CDLQI) and an adapted version of the ACS. We found that patients with vitiligo experience high levels of stigmatisation. They have an impaired quality of life and are more socially anxious / avoidant, helpless and (anxious-) depressive compared to healthy controls. The results correlate with disease severity, avoidant behaviour / hiding of vitiligo and the belief that psychological stress influences the disease. Female patients are generally more affected. Treatment with pseudocatalase PC-KUS improves quality of life and reduces anxious-depressive mood. Children also suffer from stigmatisation and an impaired quality of life. Parents are more socially anxious and helpless compared to the control group. / German Vitiligo Association (Deutscher Vitiligo Verein)