Immune mechanisms in vitiligo

Clinical profile of vitiligo patients and relationship with immuno-inflammatory markers

BACKGROUND

Vitiligo is the most common pigmentary disorder and is considered a chronic, cumulative, multifactorial disease. The crucial role of cytotoxic CD8+ T lymphocytes and the IFNγ/CXCL10 axis has been demonstrated in its pathogenesis.

OBJECTIVE

To evaluate the clinical profile and immuno-inflammatory markers in patients with vitiligo in a reference medical center.

METHODS

Cross-sectional study in which all patients with vitiligo seen at the medical center the from 2019 to 2022 were evaluated, to outline the clinical profile. Moreover, cardiovascular risk biomarkers (neutrophil/lymphocyte ratio and C-reactive protein levels) were measured, as well as cytokines and chemokines (TNFα, IFNγ, IL10, IL15 and CXCL10) in the serum of a subgroup of 30 patients.

RESULTS

There was a predominance of females, with a mean age of 43 years. Most were phototypes IV or V (71.3%), without comorbidities (77.55%), and without a family history of vitiligo (70.41%). Higher levels of neutrophil/lymphocyte ratio, C-reactive protein, and inflammatory cytokines/chemokines were documented in vitiligo patients when compared to the control group (non-significant). As relevant data, the highest values of CXCL10 were detected in patients with vitiligo versus controls, as well as in patients with disease of shorter duration (p<0.05).

STUDY LIMITATIONS

The number of assessed patients was small due to recruitment difficulties caused by the COVID-19 pandemic.

CONCLUSION

The present data contribute to confirming the relevant role of the IFNγ/CXCL10 axis in the pathogenesis of vitiligo, highlighting CXCL10 as a possible activity marker.

Immunomodulatory Effects of Medicinal Plants used for Vitiligo in Traditional Persian Medicine

BACKGROUND

Vitiligo is a hypopigmentation disorder that affects 1% of the world's population. Vitiligo causes white spots on the skin, mucous membranes, or white hair by destroying skin melanocytes. The pathogenesis of vitiligo is unknown but autoimmune, autocytotoxic, and neural mechanisms are suggested. According to the autoimmune theory, in people with vitiligo, immune cells invade and damage melanocytes. T cells are more commonly present in vitiligo patients' skin and remain in the lesion site, which is composed of CD8 and CD4 T cells. Many studies have been conducted on the presence and role of cytokines such as interleukins and interferongamma (IFN-γ) in the vitiligo process.

AIM

This study aimed to introduce herbs effective against vitiligo from the perspective of Persian medicine and to investigate their possible therapeutic mechanisms with the possible effects of herbs on autoimmune mechanisms.

METHODS

For this purpose, keywords were used to extract data from Persian medicine textbooks, and then relevant scientific databases, including Google Scholar, PubMed, Web of Science, and Scopus were examined.

RESULTS

It was found that Persian medicine scholars used 50 different medicinal plants to treat and reduce the complications of vitiligo, and recent scientific studies have proven immune-regulating properties and reducing the effect of many of them on cytokines.

CONCLUSION

According to scientific evidence on immunomodulatory effects, new research into the effects of these plants on vitiligo can lead to the discovery of new drugs and approaches for treating this disease.

The role of interleukins in vitiligo: a systematic review

Vitiligo is a disorder of the skin that causes depigmentation and asymptomatic macules whose exact cause is still unclear. Although its aetiology is not fully elucidated, the main theory of its pathomechanism is that it is associated with the autoimmune process. There is few summarized information about the role of inflammatory mediators, as interleukins, in vitiligo, so our aim was to present a systematic review of the role of interleukins in vitiligo, focusing on interleukins. In this review, we included all studies assessing interleukin levels in vitiligo patients conducted up to June 2017. Quality assessment of these studies was performed using the Newcastle-Ottawa Scale (NOS). The interleukins mainly involved were IL-2, IL-4, IL-6, IL-10 and IL-17. The studies highlight the crucial role of IL-17 in the onset and progression of the disease, and its synergistic action with IL-2, IL-6 and IL-33. Dysregulated levels of the interleukins were also correlated with the stage of disease, the affected skin surface area, and indicated as the main factor for lymphocyte infiltration found in depigmented regions. These findings illustrate the growing need for new therapies targeting vitiligo and further research into the role of interleukins as an area of particular interest.

Epigallocatechin-3-gallate (EGCG) Suppresses the Trafficking of Lymphocytes to Epidermal Melanocytes via Inhibition of JAK2: Its Implication for Vitiligo Treatment

Vitiligo is an inflammatory skin disorder in which activated T cells play an important role in its onset and progression. Epigallocatechin-3-gallate (EGCG), the major chemical constituent of green tea, exhibits remarkable anti-oxidative and anti-inflammatory properties. EGCG administration has been confirmed to decrease the risk of vitiligo; however, the underlying mechanism is undetermined. In this study, we proved that EGCG directly inhibited the kinase activity of Janus kinase 2 (JAK2). In primary cultured human melanocytes, EGCG pre-treatment attenuated interferon (IFN)-γ-induced phosphorylation of JAK2 and its downstream signal transducer and activator of transcription (STAT)1 and STAT3 in a dose-dependent manner. We further examined the chemoattractant expression in melanocytes and demonstrated that EGCG significantly inhibited IFN-γ-induced expression of intracellular adhesion molecule (ICAM)-1, CXCL10, and monocyte chemotactic protein (MCP)-1 in human melanocytes. In addition, EGCG reduced the protein levels of the corresponding receptors including CD11a, CXCR3, and CCR2 in human T lymphocytes. As a consequence, adhesion of human T cells to melanocytes induced by IFN-γ was effectively suppressed by EGCG. Taken together, our results provided new evidence for the effectiveness of EGCG in vitiligo treatment and supported JAK2 as a molecular target for vitiligo medicine development.

On the role of dendritic cells in the pathogenesis of vitiligo

The authors give the results of immunohistochemistry studies of the skin of 16 healthy volunteers and 16 patients suffering from vulgar vitiligo with the determination of the contents of immature (CD1a+) and mature (CD83+) subpopulations of dendritic cells (DCs) as well as CD4+ and CD8+ lymphocytes in the epidermis and perivascular infiltrates of the derma. They revealed an increased quantity of CD1a+ and CD83+ DCs in areas of depigmented, peripheral and perifocal normally pigmented skin of vitiligo foci. DCs with the CD1a+ phenotype were revealed both in the epidermis and in the derma while DCs with the CD83+ phenotype were revealed in the derma only. A higher quantity of CD4+ and CD8+ lymphocytes than in healthy volunteers was also revealed along with the increased contents of DCs in all three areas of vitiligo foci. The authors established a strong correlation between the quantity of CD83+ DCs and CD4+ lymphocytes in the depigmentation zone (r=0.84; Р

Current remedies for vitiligo

Vitiligo is a disorder with complex causes and is a type of autoimmune disease in which the immune system targets the body's own pigment cells and tissues. Our aim is to present an overall view of the current remedies widely adopted for the treatment of vitiligo. Medical treatments target the immune system, and try to reverse the destruction. The goal is to restore the skin's color by restoring healthy melanocytes to the affected area. Apart from melanocytes, vitiligo autoantigens appear also on other cells. Even though antibodies to pigment cells are not an agent of vitiligo, the most valuable contribution is that anti-melanocyte antibody reactivity can help in identifying relevant antigens. T cells from vitiligo skin are highly reactive towards melanoma cells and serve as an effective source to treat melanoma and stays as a solution for vitiligo. There have been many treatments to cure vitiligo such as use of steroid creams, PUVA (psoralen and ultraviolet A light), narrow band UVB (ultraviolet B), various surgical techniques, vitamin D analogues and pseudocatalase. These treatments are subjected for undesired side effects whereas some herbal and natural treatments act against the immune system with no side effects.

Vitiligo update

Vitiligo is an acquired dyschromia of the skin in which there is a loss of epidermal melanocytes. The prevalence of vitiligo is approximately 1% in the United States and 0.1-2% worldwide. The exact pathogenesis of vitiligo remains elusive and is likely multifactorial. After completing this update, participants should be able to discuss the epidemiology of vitiligo and summarize the proposed mechanisms for development of this disease. In addition, they should be able to discuss physical findings, approach to the patient, and some of the therapeutic modalities for this disorder.

The Double Strike Hypothesis of the vitiligo pathomechanism: new approaches to vitiligo and melanoma

Based on current research, we present a consolidated set of theses which explain the pathomechanisms of vitiligo- and melanoma-associated hypopigmentation. The main thesis is the Double Strike Hypothesis, i.e. vitiligo is caused by at least two different major pathomechanisms: an antibody-based pathomechanism and a T-cell-based pathomechanism. The antibody-based pathomechanism is dominant in diffuse vitiligo, while the T-cell based pathomechanism is dominant in localised vitiligo. Based on this main thesis we derive new therapeutical approaches to vitiligo and melanoma by using the different pathomechanisms. Finally we explain why melanoma-associated hypopigmentation as a natural immunotherapy is still in statu nascendi.

Development of vitiligo during melanoma treatment with a novel survivin inhibitor: a case report and review of the literature

BACKGROUND

The development of vitiligo has been associated with an improved clinical response in melanoma patients.

METHODS

We report a case of vitiligo associated with a novel antisurvivin drug and review the literature to determine the pathogenesis of vitiligo occurring during melanoma treatment.

RESULTS

A 78-year-old man with stage IV malignant melanoma developed vitiligo after the first therapeutic cycle of a novel antisurvivin drug. Although his vitiligo remained static, his melanoma continued to progress and he died in 8 months. A review of the literature demonstrates a relationship between vitiligo development and improved clinical response in many melanoma cases treated with immunotherapy; however, the relationship may depend on the type of treatment.

CONCLUSIONS

Understanding complex immune responses in vitiliginous skin and melanoma sites is important in order to interpret the development of vitiligo occurring during melanoma treatment.

Halo congenital nevocellular nevi associated with extralesional vitiligo: a case series with review of the literature

Halo formation in association with congenital nevi is uncommon and is postulated to have an immunologic etiology. In this report, we present nine cases of patients with congenital nevi and vitiligo who uniquely developed both halo formation around the nevi in addition to vitiligo formation in distinctly separate locations. While the precise etiology of halo formation and vitiligo remains uncertain, several theories suggest that both phenomena result from an immunologic response to pigment cells, whether in the "normal" skin of vitiligo or in the excessively pigmented congenital nevus.

Proteomic Scan for Tyrosinase Peptide Antigenic Pattern in Vitiligo and Melanoma: Role of Sequence Similarity and HLA-DR1 Affinity

Immune responses contribute to the pathogenesis of vitiligo and target melanoma sometimes associated with vitiligo-like depigmentation in some melanoma patients. We analyzed the sera from patients with vitiligo and cutaneous melanoma for reactivity toward tyrosinase peptide sequences 1) endowed with low level of similarity to human proteome, and 2) potentially able to bind HLA-DR1 Ags. We report that the tyrosinase autoantigen was immunorecognized with the same molecular pattern by sera from vitiligo and melanoma patients. Five autoantigen peptides composed the immunodominant anti-tyrosinase response: aa95-104FMGFNCGNCK; aa175-182 LFVWMHYY; aa176-190FVWMHYYVSMDALLG; aa222-236IQKLTGDENFTIPYW, and aa233-247 IPYWDWRDAEKCDIC. All of the five antigenic peptides were characterized by being (or containing) a sequence with low similarity level to the self proteome. Sera from healthy subjects were responsive to aa95-104FMGFNCGNCK, aa222-236IQKLTGDENFTIPYW, and aa233-247 IPYWDWRDAEKCDIC, but did not react with the aa175-182LFVWMHYY and aa176-190FVWMHYYVSMDALLG peptide sequences containing the copper-binding His180 and the oculocutaneous albinism I-A variant position F176. Our results indicate a clear-cut link between peptide immunogenicity and low similarity level of the corresponding amino acid sequence, and are an example of a comparative analysis that might allow to comprehensively distinguish the epitopic peptide sequences within a disease from those associated to natural autoantibodies. In particular, these data, for the first time, delineate the linear B epitope pattern on tyrosinase autoantigen and provide definitive evidence of humoral immune responses against tyrosinase.

Transfer of efficient anti-melanocyte T cells from vitiligo donors to melanoma patients as a novel immunotherapeutical strategy

BACKGROUND

Vitiligo is a relatively common progressive depigmentary condition that is believed to be due to the autoimmune-mediated loss of epidermal melanocytes. High frequencies of self-reactive T lymphocytes directed toward melanocyte differentiation antigens are found in vitiligo patients and might be directly responsible for the pathogenesis of the disease. An interesting aspect of vitiligo is its relation to melanoma: cytotoxic T lymphocytes directed to self antigens shared by normal melanocytes and melanoma cells are found in both conditions, but the resulting immune reactions are completely different. From this standpoint, the selective destruction of pigment cells that occurs in cases of vitiligo is the therapeutic goal sought in melanoma research.

PRESENTATION OF THE HYPOTHESIS

Our working hypothesis is that vitiligo patients might represent a unique source of therapeutic cells to be used in allo-transfer for HLA-matched melanoma patients. The adoptive transfer of ex-vivo generated autologous tumor-specific T cells is a therapy that has met with only limited success, essentially because of inability to isolate therapeutically valuable T cells from the majority of tumor patients. Ideally, model systems where strong and efficient responses against the same (tumor) antigens are achieved would represent a better source of therapeutic cells. We believe it is possible to identify one such model in the melanoma-vitiligo dichotomy: T lymphocytes specific for different melanocyte differentiation antigens are found in vitiligo and represent the effective anti-melanocyte reactivity that is often ineffective in melanoma.

TESTING THE HYPOTHESIS

Melanocyte-specific T cell clones can be isolated from the peripheral blood of vitiligo patients and tested for their capacity to efficiently expand in vitro without loosing their cytotoxic activity and to migrate to the skin. Cytotoxicity against melanoma patients' non-tumor cells can also be tested. In addition, it would be interesting to attempt an in vivo animal model. If the results obtained from these validation steps will be satisfactory, it might be possible to plan the clinical grade preparation of relevant clones for transfer.

IMPLICATIONS OF THE HYPOTHESIS

When translated into a clinical trial, the possibility of in vitro selecting few effective tumor-specific T cell clones for infusion, inherent with this approach, could enhance the therapeutic graft-versus-tumor effect while possibly decreasing the risk of graft-versus-host disease.

Melanocyte-specific, cytotoxic T cell responses in vitiligo: the effective variant of melanoma immunity?

Vitiligo is a relatively common progressive depigmentary condition that is believed to be due to the autoimmune-mediated loss of epidermal melanocytes. An interesting aspect of vitiligo is its relation to melanoma: cytotoxic T lymphocytes directed to self-antigens shared by normal melanocytes and melanoma cells are found in both conditions and might prove important in melanocyte destruction, yet the resulting immune reactions are completely different. From this standpoint, the selective destruction of pigment cells that occurs in cases of vitiligo is the therapeutic goal sought in melanoma research. In the present article, we will address these issues by reviewing current literature on the subject as well as by posing some speculations.

Topical tacrolimus therapy for vitiligo: therapeutic responses and skin messenger RNA expression of proinflammatory cytokines

BACKGROUND

Previous studies have documented humoral and cell-mediated immunologic defects in patients with vitiligo.

OBJECTIVE

This 24-week study assessed the efficacy and safety of tacrolimus 0.1% ointment in patients with generalized vitiligo as well as the pretreatment and post-treatment expression of cytokines in the depigmented and normal skin of patients compared with controls.

METHODS

Twenty-three patients were enrolled in this investigation, and 19 patients completed the study; 8 were male and 11 were female. Fifteen age-, race-, and sex-matched control subjects were also included. Patients were treated with tacrolimus 0.1% ointment applied twice daily. Repeat evaluations were performed at 4, 8, 12, 16, 20, and 24 weeks. Three-millimeter punch biopsy specimens were taken from the depigmented, non-sun-exposed skin and adjacent normal skin of patients at baseline and 24 weeks, and from normal, non-sun-exposed skin of controls. Cellular messenger RNA expression for interleukin 2 (IL-2), IL-4, IL-10, tumor necrosis factor alfa (TFN-alpha), and interferon gamma (IFN-gamma) were determined by real-time quantitative polymerase chain reaction.

RESULTS

At 24 weeks, 17 of 19 patients (89%) achieved varying levels of repigmentation. There was a statistically significant decrease in overall disease severity scores at 24 weeks. Thirteen patients (68%) had greater than 75% repigmentation of face and/or neck lesions. Signs and symptoms of irritation were minimal. At baseline, compared with healthy controls, vitiligo patients demonstrated a statistically significant increase in the expression of IFN-gamma in involved and adjacent uninvolved skin (P=.05 and P=.02, respectively); significantly increased TNF-alpha expression in involved and uninvolved skin (P=.01 and P=0.02, respectively); and significantly increased IL-10 expression in involved and uninvolved skin (P=.01 and P=.04, respectively). Posttreatment, TNF-alpha expression decreased in the depigmented and adjacent uninvolved skin (P <.001). There was no statistically significant change in IL-10 or IFN-gamma posttreatment. These data suggest that tacrolimus 0.1% ointment is a safe and effective therapy for patients with vitiligo. It further suggests that an imbalance in local cytokine expression may play a role in the pathogenesis of vitiligo. Suppression of TNF-alpha after topical tacrolimus application may be associated with repigmentation of vitiligo.

Psicodermatologia: uma interface entre psicologia e dermatologia

O objetivo deste artigo é apresentar alguns resultados importantes provenientes da tese de doutorado da primeira autora, orientado pela segunda. O tema da tese foi um estudo com pacientes de vitiligo, através da abordagem analítica, buscando compreender o vitiligo como possibilidade de manifestação simbólica da relação psique/corpo. Treze mulheres fizeram parte do estudo, sendo que dez receberam acompanhamento médico e psicológico por seis meses. Destas, cinco receberam acompanhamento psicológico grupal e cinco, acompanhamento psicológico individual. Três pacientes receberam só acompanhamento médico por igual período. Buscou-se, com esse atendimento diferenciado, avaliar se haveria diferença à resposta clínica (condição de repigmentação) das pacientes. Os resultados indicam que o modelo analítico permitiu a compreensão simbólica da doença vitiligo como manifestação de conteúdos inconscientes que necessitavam ser integrados à consciência. As pacientes que receberam tratamento conjunto médico e psicológico apresentaram um percentual de repigmentação de até 80%, enquanto as que receberam exclusivamente tratamento médico obtiveram um percentual de repigmentação de até 20%. Esse dado demonstra a importância de um trabalho integrado no tratamento das doenças de manifestação psicossomática.

Vitiligo

O vitiligo é doença de pele de causa desconhecida que acomete cerca de 1% da população, comprometendo de modo semelhante homens e mulheres, preferencialmente entre 10 e 30 anos de idade. Alguns fatores precipitantes para essa doença são: estresse físico e emocional, traumas mecânicos e substâncias químicas, como derivados do fenol. Doenças auto-imunes, principalmente as tireoidianas, podem estar associadas ao vitiligo. Novas terapias têm sido propostas, como o uso de imunomoduladores tópicos, aliadas àquelas já consolidadas, como os psoralenos e os corticosteróides; o sucesso terapêutico, entretanto, está estritamente relacionado à qualidade da relação médico/paciente.

Apoptosis in feathers of Smyth line chickens with autoimmune vitiligo

Vitiligo is an acquired dermatological disorder characterized by a loss of epidermal melanocytes resulting in depigmentation of the skin. Mechanisms underlying the destruction of melanocytes in vitiligo remain unclear. An animal model to study spontaneously occurring autoimmune vitiligo is the mutant Smyth line (SL) of chickens. This investigation was designed to determine whether the pathogenesis of depigmentation in Smyth line chicken vitiligo (SLV) involves an apoptotic mechanism. Terminal deoxynucleotide transferase-mediated fluorescein-dUTP nick end labeling (TUNEL) was used to detect in situ cell apoptosis in cryostat sections of 2-week-old regenerating feathers. Two-week-old regenerating feathers were obtained from SL chickens and their normally pigmented controls including the parental Brown line (BL) and Light Brown Leghorn (LBL) chickens at 6, 8, 10 and 12 weeks of age. In feathers from vitiliginous SL chickens, the number of TUNEL+ cells was significantly (P<or=0.05) higher than that in the feathers of non-vitiliginous SL, BL or LBL chickens. These TUNEL+ cells were primarily located in the epithelial barb ridge where melanocyte cell bodies are located. The extent of this apoptosis in the feathers of SLV chickens varied with the severity of depigmentation of the feathers (i.e., highest in active depigmentation), suggesting a close association between apoptosis and the disappearance of melanocytes. In addition to TUNEL staining, most sections were double-stained with monoclonal antibodies specific to either CD8 or MHC class II molecules to further explore the relationship between CD8+ feather-infiltrating lymphocytes and this increase in apoptotic cells. Compared to normally pigmented controls, the number of CD8+ and MHC class II+ cells in the feather pulp and the barb ridge increased 2-4 weeks before the visible onset of SLV, and was directly related to the changes in the number of TUNEL+ cells prior to, at onset and during depigmentation. Moreover, some of these infiltrating CD8+ cells were localized next to or near the TUNEL+ cells. These observations suggest that enhanced apoptosis in the feather of SLV chickens is a pathogenic mechanism involved in the death of melanocytes and appears to be induced by infiltrating cytotoxic T lymphocytes (CD8+).

A case of giant congenital nevocytic nevus with neurotization and onset of vitiligo

The authors report the case of a 21-year-old woman with a giant congenital nevocytic nevus (GCNN) who developed vitiligo at the age of 16 years on skin areas remote from the GCNN. This is the first reported case of GCNN developing neurotization combined with vitiliginous changes within the GCNN lesion. Treatment with PUVA achieved repigmentation of the vitiligo lesions, except for the hypochromic areas within the area of the nevus that were shielded from UVA radiation.

Autoimmune aspects of vitiligo

Vitiligo is a depigmenting disorder characterised by the loss of melanocytes from the cutaneous epidermis. Although the exact cause of the condition remains to be established, an autoimmune aetiology has been suggested and several observations support this theory. These will be the topic of discussion in this review. In brief, the disease is frequently associated with other disorders which have an autoimmune origin such as autoimmune thyroiditis and insulin-dependent diabetes mellitus. Furthermore, circulating antibodies and T lymphocytes which react against melanocyte antigens are present in the sera of a significant proportion of vitiligo patients compared with healthy individuals. Immunosuppressive therapies which are reasonably effective in treating the condition, well-studied animal models of the disease as well as the association of vitiligo with MHC antigens, all add credence to the hypothesis that immune mechanisms play a role in the development of vitiligo.

Specific cytotoxic T lymphocyte responses against Melan-A/MART1, tyrosinase and gp100 in vitiligo by the use of major histocompatibility complex/peptide tetramers: the role of cellular immunity in the etiopathogenesis of vitiligo

Vitiligo is a common skin disease characterized by the presence of well circumscribed, depigmented, milky white macules devoid of identifiable melanocytes. Although the detection of circulating anti-melanocytic antibodies and of infiltrating lymphocytes at the margin of lesions supports the view that vitiligo is an autoimmune disorder, its etiology remains unknown. In particular, it is still a matter of debate whether the primary pathogenic role is exerted by humoral or cellular abnormal immune responses. In this study, the presence of specific cytotoxic T lymphocyte responses against the melanocyte differentiation antigens Melan-A/MART1, tyrosinase, and gp100 in vitiligo patients have been investigated by the use of major histocompatibility complex/peptide tetramers. High frequencies of circulating melanocyte-specific CD8+ T cells were found in all vitiligo patients analyzed. These cells exerted anti-melanocytic cytotoxic activity in vitro and expressed skin-homing capacity. In one patient melanocyte-specific cells were characterized by an exceptionally high avidity for their peptide/major histocompatibility complex ligand. These findings strongly suggest a role for cellular immunity in the pathogenesis of vitiligo and impact on the common mechanisms of self tolerance.