Update on the pathogenesis of vitiligo

Effectiveness of fractional erbium-YAG laser, microneedling, platelet-rich plasma in localized stable vitiligo patients: randomized clinical trial

Vitiligo is considered an autoimmune disease, and its treatment is challenging. We assessed and compared the effect of fractional erbium:yttrium-aluminum-garnet (Er:YAG) laser-assisted delivery of platelet-rich plasma versus microneedling (Mn) with platelet-rich plasma (PRP) in enhancing skin repigmentation in localized stable vitiligo patients. In total, 40 patients with localized stable vitiligo were selected in a random manner into two similar groups (20 each). Group (A) was subjected to fractional Er:YAG laser combined with platelet-rich plasma and Group (B) was subjected to microneedling combined with platelet-rich plasma. The procedure was repeated every 2 weeks for up to 6 months. Each individual was assessed clinically utilizing Vitiligo Area Scoring Index (VASI). Fractional Er:YAG + PRP group achieved better pigmentation100% (excellent 30%, very good 15%, good 30% and satisfactory 25%) which is comparable to Mn + PRP where 80% of cases demonstrate repigmentation (20% very good, 10% good and 50% mild). When comparing the VASI scores for both groups after therapy to the baseline VASI, there was a statistically significant decrease [p = 0.001 for group(A) and 0.003 for group(B)]. Regarding the treatment side effects, there was significantly (p = 0.048) side effects among cases treated with microneedling group(B) (25%) than those fractional Er:Yag laser therapy group(A) (5%). Both forms of therapy demonstrated induction of repigmentation of vitiligo, but fractional Er:YAG laser efficacy is greater when combined with platelet-rich plasma.Clinical trials.gov identifier: NCT05511493.

Systems genetics uncover new loci containing functional gene candidates in Mycobacterium tuberculosis-infected Diversity Outbred mice

Mycobacterium tuberculosis infects two billion people across the globe, and results in 8-9 million new tuberculosis (TB) cases and 1-1.5 million deaths each year. Most patients have no known genetic basis that predisposes them to disease. Here, we investigate the complex genetic basis of pulmonary TB by modelling human genetic diversity with the Diversity Outbred mouse population. When infected with M. tuberculosis, one-third develop early onset, rapidly progressive, necrotizing granulomas and succumb within 60 days. The remaining develop non-necrotizing granulomas and survive longer than 60 days. Genetic mapping using immune and inflammatory mediators; and clinical, microbiological, and granuloma correlates of disease identified five new loci on mouse chromosomes 1, 2, 4, 16; and three known loci on chromosomes 3 and 17. Further, multiple positively correlated traits shared loci on chromosomes 1, 16, and 17 and had similar patterns of allele effects, suggesting these loci contain critical genetic regulators of inflammatory responses to M. tuberculosis. To narrow the list of candidate genes, we used a machine learning strategy that integrated gene expression signatures from lungs of M. tuberculosis-infected Diversity Outbred mice with gene interaction networks to generate scores representing functional relationships. The scores were used to rank candidates for each mapped trait, resulting in 11 candidate genes: Ncf2, Fam20b, S100a8, S100a9, Itgb5, Fstl1, Zbtb20, Ddr1, Ier3, Vegfa, and Zfp318. Although all candidates have roles in infection, inflammation, cell migration, extracellular matrix remodeling, or intracellular signaling, and all contain single nucleotide polymorphisms (SNPs), SNPs in only four genes (S100a8, Itgb5, Fstl1, Zfp318) are predicted to have deleterious effects on protein functions. We performed methodological and candidate validations to (i) assess biological relevance of predicted allele effects by showing that Diversity Outbred mice carrying PWH/PhJ alleles at the H-2 locus on chromosome 17 QTL have shorter survival; (ii) confirm accuracy of predicted allele effects by quantifying S100A8 protein in inbred founder strains; and (iii) infection of C57BL/6 mice deficient for the S100a8 gene. Overall, this body of work demonstrates that systems genetics using Diversity Outbred mice can identify new (and known) QTLs and functionally relevant gene candidates that may be major regulators of complex host-pathogens interactions contributing to granuloma necrosis and acute inflammation in pulmonary TB.

Implication of regulatory T cells' telomere shortening in pathogenesis of generalized vitiligo

Generalized vitiligo(GV) is a skin depigmenting condition due to loss of melanocytes. Regulatory T cells(Tregs), responsible for peripheral tolerance, show altered numbers and functions in GV patients, likely influenced by the aging process. Therefore, the present study was focused on measuring the relative telomere length of Tregs in 96 GV patients and 90 controls by qPCR, along with correlation of relative telomere length with in vitro Treg suppressive capacity. Interestingly, we found significantly decreased relative telomere length in Tregs of GV patients as compared to controls(p = 0.0001). Additionally, age based-analysis suggested significant decrease in relative telomere length in elderly GV patients(>40 years) in comparison to young GV patients(0-20 years; p = 0.0027). Furthermore, age of onset analysis suggested for reduced relative telomere length in early onset GV patients (0-20 years) in comparison to late onset GV patients(>40 years; p = 0.0036). The correlation analysis suggested positive correlation for relative telomere length with in vitro Tregs suppressive capacity(r = 0.68 & r = 0.45; p < 0.0001). Additionally, the in vitro Tregs suppressive capacity was significantly reduced in elderly GV patients(p = 0.003) and early onset GV patients(p = 0.0074). Overall, our study for the first time demonstrated that, the Tregs ageing due to telomere shortening may be responsible for altered Treg functions and number.

Role of Dermal Factors Involved in Regulating the Melanin and Melanogenesis of Mammalian Melanocytes in Normal and Abnormal Skin

Mammalian melanin is produced in melanocytes and accumulated in melanosomes. Melanogenesis is supported by many factors derived from the surrounding tissue environment, such as the epidermis, dermis, and subcutaneous tissue, in addition to numerous melanogenesis-related genes. The roles of these genes have been fully investigated and the molecular analysis has been performed. Moreover, the role of paracrine factors derived from epidermis has also been studied. However, the role of dermis has not been fully studied. Thus, in this review, dermis-derived factors including soluble and insoluble components were overviewed and discussed in normal and abnormal circumstances. Dermal factors play an important role in the regulation of melanogenesis in the normal and abnormal mammalian skin.

Janus kinase inhibitors and the changing landscape of vitiligo management: a scoping review

Vitiligo is a chronic skin condition caused by an autoimmune response that results in the progressive loss of melanocytes and recent studies have suggested that Janus kinase inhibitors (JAKi) are emerging as a promising new treatment modality. Therefore, to assess and understand the extent of knowledge in the emerging field of JAKi use in vitiligo, a scoping review of the literature was undertaken. The reviewed articles explored a wide variety of JAKi administered either orally or topically for vitiligo. There were no injectable JAKi studied. Tofacitinib was the most commonly studied oral JAKi in 16 of the 35 studies selected for review, followed by baricitinib (n = 3), and one study each with ritlecitinib, ruxolitinib, and upadacitinib. Ruxolitinib (n = 6) and tofacitinib (n = 6) were the most often studied topical JAKi, followed by delgocitinib (n = 1). Potential benefits may vary between JAKi based on their receptor selectivity profile and coexistent autoimmune diseases. A topical JAKi would be advantageous in limited body area involvement and in adolescents. Concurrent use of JAKi with phototherapy or sun exposure appears beneficial. Most studies permitted the use of other topical agents. Acne-related events, though frequent yet mild, were reported with both oral and topical JAKi. Nasopharyngitis, upper respiratory tract infections, and headaches were the most common adverse effects seen in the larger trials with JAKi. No serious or clinically meaningful hematology or thromboembolic events were detected. Treatment of vitiligo with oral or topical JAKi seems to be promising and the growing evidence shows a favorable risk-benefit profile.

Association between miR-202, miR-211, and miR-1238 gene polymorphisms and risk of vitiligo

Vitiligo, as a common pigment defect in the skin, hair, and mucous membranes, results from the destruction of melanocytes. Recent investigations have shown that miRNA dysregulation contributes in the pathogenesis of vitiligo. Therefore, in this research, our aim is to explore the relationship between miR-202 rs12355840, miR-211 rs8039189, and miR-1238 rs12973308 polymorphisms and susceptibility to vitiligo. A total number of 136 vitiligo patients and 129 healthy individuals as a control group were included in this research. The salting out approach was implemented to extraction genomic DNA. The genetic polymorphisms of miR-202 rs12355840, miR-211 rs8039189, and miR-1238 rs12973308 were determined using PCR-RFLP approach. The findings revealed that miR-202 rs12355840 polymorphism under codominant (CT and TT genotypes), dominant, recessive, overdominant, and also allelic models is correlated with increased risk of vitiligo. In addition, codominant, dominant, overdominant, as well as allelic models of miR-211 rs8039189 polymorphism decrease risk of vitiligo. No significant relationship was observed between the miR-1238 rs12973308 polymorphism and susceptibility to vitiligo. The miR-211 rs8039189 polymorphism may serve a protective effect on vitiligo development and miR-202 rs12355840 polymorphism may act as a risk factor for vitiligo susceptibility.

Expert Recommendations on Use of Topical Therapeutics for Vitiligo in Pediatric, Adolescent, and Young Adult Patients

Importance

Evidence-based recommendations for the treatment of vitiligo in pediatric, adolescent, and young adult patients in the US are needed.

Objective

To develop evidence- and consensus-based expert recommendations on the diagnosis and treatment of vitiligo in young patients.

Evidence Review

A process was developed to produce consensus recommendations addressing questions regarding pediatric vitiligo. A librarian-conducted literature review was performed using articles that met the inclusion criteria: published in English, containing primary data (including meta-analysis) and pediatric-specific data, and analysis of 6 or more patients. Included articles were graded by the Strength of Recommendation Taxonomy criteria and Oxford Centre for Evidence-based Medicine's Levels of Evidence and Grades of Recommendation. Research questions were reviewed on May 9, 2022, through a video conference. One month after the conference, participants participated in an online survey documenting their level of agreement with the generated statements, using a 5-point Likert scale.

Findings

Articles on topical corticosteroids and/or topical calcineurin inhibitors (n = 50), topical Janus kinase inhibitors (n = 5), pseudocatalase (n = 2), and microdermabrasion (n = 2) met inclusion criteria. Forty-two recommendations were made on the diagnosis of vitiligo and optimal topical therapeutics, with 33 recommendations obtaining a 70% or greater composite agreement and strong agreement. Topical calcineurin inhibitors twice daily, topical corticosteroids with time limitation due to atrophy risk, and topical ruxolitinib, 1.5%, cream-used off-label for patients younger than 12 years and limited to nonsegmental vitiligo-were identified as evidence-based first-line therapies in the management of pediatric and adolescent patients, with specific guidance on age-based data, minimum therapeutic trial of 6 months or greater, prolonged therapy to prevent recurrence, and the positive benefit of coordinated use of UV therapeutic sources.

Conclusions and Relevance

Evidence supports the use of topical calcineurin inhibitors, topical corticosteroids, and topical Janus kinase inhibitors as effective therapeutics for vitiligo in pediatric, adolescent, and young adult patients, with specific decisions on choice of agent based on factors such as site location, body surface area, and age.

Thyroid autoimmunity in relation to HLA-DRB1 and HLA-DQB1 polymorphism in nonsegmental vitiligo: a cross-sectional-study

OBJECTIVES

Nonsegmental vitiligo (NSV) is frequently associated with thyroid autoimmunity (TAI), however, the immunopathogenic mechanisms of such association remain to be investigated. The aims of this work were to estimate the frequency of TAI and to describe the genetic polymorphism in the human leukocyte antigen (HLA)-DRB1 and -DQB1 loci in TAI susceptibility among patients with NSV.

PATIENTS AND METHODS

In this cross-sectional study, screening for TAI was performed in 97 Moroccan patients with NSV by measuring antibodies against thyroid peroxidase (TPOAb) and thyroglobulin (TGAb). HLA-DRB1 and -DQB1 were determined with single specific primer-polymerase chain reaction (PCR-SSP) typing methods.

RESULTS

TAI was diagnosed in 20 patients with NSV (20.6%). The phenotypic frequency of DQB1*05 (OR = 5.04; P = 0.006; pc = 0.036) was significantly higher in NSV patients with TAI. Genotype DQB1*05/DQB1*06 (OR = 25.33; P = 0.001; pc = 0.003) confer susceptibility to TAI in NSV patients. NSV patients with TAI and early onset vitiligo have an extremely high phenotype frequency of DQB1*05 allele (OR = 14.67; P = 0.001; pc = 0.048) and DQB1*05/DQB1*06 genotype (OR = 26.55; P = 0.01; pc = 0.03). TAI in patients with NSV was (6.2%) associated with onset of clinical thyroid disease based on TSH and free T4.

CONCLUSION

Our findings suggest that HLA-DQ polymorphisms influence TAI risk in subjects with NSV, although HLA does not completely explain the co-occurrence of these two diseases.

Mannose-binding lectin gene polymorphism in psoriasis and vitiligo: an observational study and computational analysis

Introduction

Psoriasis and vitiligo are inflammatory autoimmune skin disorders with remarkable genetic involvement. Mannose-binding lectin (MBL) represents a significant immune molecule with one of its gene variants strongly linked to autoimmune diseases. Therefore, in this study, we investigated the role of the MBL variant, rs1800450, in psoriasis and vitiligo disease susceptibility.

Methods

The study comprised performing in silico analysis, performing an observational study regarding psoriasis patients, and performing an observational study regarding vitiligo patients. Various in silico tools were used to investigate the impact of the selected mutation on the function, stability, post-translational modifications (PTMs), and secondary structures of the protein. In addition, a total of 489 subjects were enrolled in this study, including their demographic and clinicopathological data. Genotyping analysis was performed using real-time PCR for the single nucleotide polymorphism (SNP) rs1800450 on codon 54 of the MBL gene, utilizing TaqMan genotyping technology. In addition, implications of the studied variant on disease susceptibility and various clinicopathological data were analyzed.

Results

Computational analysis demonstrated the anticipated effects of the mutation on MBL protein. Furthermore, regarding the observational studies, rs1800450 SNP on codon 54 displayed comparable results in our population relative to global frequencies reported via the 1,000 Genomes Project. This SNP showed no significant association with either psoriasis or vitiligo disease risk in all genetic association models. Furthermore, rs1800450 SNP did not significantly correlate with any of the demographic or clinicopathological features of both psoriasis and vitiligo.

Discussion

Our findings highlighted that the rs1800450 SNP on the MBL2 gene has no role in the disease susceptibility to autoimmune skin diseases, such as psoriasis and vitiligo, among Egyptian patients. In addition, our analysis advocated the notion of the redundancy of MBL and revealed the lack of significant impact on both psoriasis and vitiligo disorders.

The role of aryl hydrocarbon receptor in vitiligo: a review

Vitiligo is an acquired autoimmune dermatosis characterized by patchy skin depigmentation, causing significant psychological distress to the patients. Genetic susceptibility, environmental triggers, oxidative stress, and autoimmunity contribute to melanocyte destruction in vitiligo. Due to the diversity and complexity of pathogenesis, the combination of inhibiting melanocyte destruction and stimulating melanogenesis gives the best results in treating vitiligo. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that can regulate the expression of various downstream genes and play roles in cell differentiation, immune response, and physiological homeostasis maintenance. Recent studies suggested that AhR signaling pathway was downregulated in vitiligo. Activation of AhR pathway helps to activate antioxidant pathways, inhibit abnormal immunity response, and upregulate the melanogenesis gene, thereby protecting melanocytes from oxidative stress damage, controlling disease progression, and promoting lesion repigmentation. Here, we review the relevant literature and summarize the possible roles of the AhR signaling pathway in vitiligo pathogenesis and treatment, to further understand the links between the AhR and vitiligo, and provide new potential therapeutic strategies.

The Assessment of Infection Risk in Patients with Vitiligo Undergoing Dialysis for End-Stage Renal Disease: A Retrospective Cohort Study

Vitiligo is an autoimmune condition that causes patchy skin depigmentation. Although the mechanism by which vitiligo induces immunocompromise is unclear, other related autoimmune diseases are known to predispose those affected to infection. Individuals with vitiligo exhibit epidermal barrier disruption, which could potentially increase their susceptibility to systemic infections; patients with renal disease also show a predisposition to infection. Nevertheless, there is little research addressing the risk of infection in dialysis patients with vitiligo in comparison to those without it. A retrospective analysis was performed on patients with end-stage renal disease (ESRD) in the United States Renal Data System who started dialysis between 2004 and 2019 to determine if ESRD patients with vitiligo are at an increased risk of bacteremia, cellulitis, conjunctivitis, herpes zoster, or septicemia. Multivariable logistic regression modeling indicated that female sex, black compared to white race, Hispanic ethnicity, hepatitis C infection, and tobacco use were associated with an enhanced risk of vitiligo, whereas increasing age and catheter, versus arteriovenous fistula, and access type were associated with a decreased risk. After controlling for demographics and clinical covariates, vitiligo was found to be significantly associated with an increased risk of bacteremia, cellulitis, and herpes zoster but not with conjunctivitis and septicemia.

Systems genetics uncover new loci containing functional gene candidates in Mycobacterium tuberculosis-infected Diversity Outbred mice

Mycobacterium tuberculosis, the bacillus that causes tuberculosis (TB), infects 2 billion people across the globe, and results in 8-9 million new TB cases and 1-1.5 million deaths each year. Most patients have no known genetic basis that predisposes them to disease. We investigated the complex genetic basis of pulmonary TB by modelling human genetic diversity with the Diversity Outbred mouse population. When infected with M. tuberculosis, one-third develop early onset, rapidly progressive, necrotizing granulomas and succumb within 60 days. The remaining develop non-necrotizing granulomas and survive longer than 60 days. Genetic mapping using clinical indicators of disease, granuloma histopathological features, and immune response traits identified five new loci on mouse chromosomes 1, 2, 4, 16 and three previously identified loci on chromosomes 3 and 17. Quantitative trait loci (QTLs) on chromosomes 1, 16, and 17, associated with multiple correlated traits and had similar patterns of allele effects, suggesting these QTLs contain important genetic regulators of responses to M. tuberculosis. To narrow the list of candidate genes in QTLs, we used a machine learning strategy that integrated gene expression signatures from lungs of M. tuberculosis-infected Diversity Outbred mice with gene interaction networks, generating functional scores. The scores were then used to rank candidates for each mapped trait in each locus, resulting in 11 candidates: Ncf2, Fam20b, S100a8, S100a9, Itgb5, Fstl1, Zbtb20, Ddr1, Ier3, Vegfa, and Zfp318. Importantly, all 11 candidates have roles in infection, inflammation, cell migration, extracellular matrix remodeling, or intracellular signaling. Further, all candidates contain single nucleotide polymorphisms (SNPs), and some but not all SNPs were predicted to have deleterious consequences on protein functions. Multiple methods were used for validation including (i) a statistical method that showed Diversity Outbred mice carrying PWH/PhJ alleles on chromosome 17 QTL have shorter survival; (ii) quantification of S100A8 protein levels, confirming predicted allele effects; and (iii) infection of C57BL/6 mice deficient for the S100a8 gene. Overall, this work demonstrates that systems genetics using Diversity Outbred mice can identify new (and known) QTLs and new functionally relevant gene candidates that may be major regulators of granuloma necrosis and acute inflammation in pulmonary TB.

Vitiligo: Pathogenesis and New and Emerging Treatments

Vitiligo is a complex disease with a multifactorial nature and a high impact on the quality of life of patients. Although there are multiple therapeutic alternatives, there is currently no fully effective treatment for this disease. In the current era, multiple drugs are being developed for the treatment of autoimmune diseases. This review assesses the available evidence on the pathogenesis of vitiligo, and a comprehensive review of treatments available for vitiligo now and in the near future is provided. This qualitative analysis spans 116 articles. We reviewed the mechanism of action, efficacy and safety data of phototherapy, afamelanotide, cyclosporine, phosphodiesterase 4 inhibitors, trichloroacetic acid, basic fibroblast growth factor, tumor necrosis factor (TNF) inhibitors, secukinumab, pseudocatalase and janus kinase (JAK) inhibitors. At the moment, there is no clearly outstanding option or fully satisfactory treatment for vitiligo, so it is necessary to keep up the development of new drugs as well as the publication of long-term effectiveness and safety data for existing treatments.

Serum Inflammatory and Oxidative Stress Markers in Patients with Vitiligo

BACKGROUND

Vitiligo is a common chronic hypomelanotic skin disorder. An intricate pool of markers associated with a complex combination of biological and environmental factors is thought to be implicated in etiology. This study aims to investigate the most important markers associated with vitiligo pathogenesis, including redox status, inflammation, and immune profile, in patients with vitiligo.

MATERIALS AND METHODS

The study included a total of 96 subjects: 30 patients with active non-segmental vitiligo, 30 patients with stable non-segmental vitiligo, and 36 controls. The vitiligo area severity index (VASI) and vitiligo disease activity score (VIDA) were determined. The following serum parameters were assessed: antioxidant status (TAS), superoxide dismutase activity (SOD), catalase activity (CAT), glutathione peroxidase activity (GPx), glutathione-S-transferase activity (GST), malondialdehyde (MDA), advanced oxidation protein products (AOPP), C reactive protein (CRP), interleukin-15 (IL-15), and chemokines (CXCL9, CXCL10).

RESULTS

The VASI score was not significantly different between active and stable vitiligo patients, as it was approximately 0.1. TAS, CAT, GPx, and GST were significantly lower in vitiligo patients compared to controls (p < 0.05). They were also significantly lower in active vitiligo when compared to stable vitiligo (p < 0.05). However, SOD levels were significantly higher in vitiligo patients than in controls and in the active vitiligo group than in the stable vitiligo group (p < 0.05). MDA and AOPP levels were significantly higher in patients with active and stable vitiligo compared to controls (p < 0.05). However, they did not significantly differ between active and stable vitiligo patients (p < 0.05). In both active and stable vitiligo, CRP and IL-15 were significantly higher than controls (p < 0.05). Whereas CRP was significantly higher in active (range = 2.0-7.2, mean = 4.46 ± 1.09) than in stable vitiligo (range = 1.6-6.7, mean = 3.75 ± 1.08) (p < 0.05). There was no significant difference in IL-15 levels between active and stable vitiligo. In both active and stable vitiligo, CXCL9 and CXCL10 were significantly higher than controls (p < 0.05), and they were significantly higher in active than stable vitiligo (p < 0.05).

CONCLUSIONS

In vitiligo, oxidative damage induces an increase in pro-inflammatory IL-15, which in turn promotes IFN-γ-inducible chemokines such as CXCL9 and CXCL10. Further, there seems to be a link between the VASI score and IL-15 levels. These data imply that inhibiting IL-15 could be a promising method for developing a potentially targeted treatment that suppresses the early interplay between oxidant stress and IL-15 keratinocyte production, as well as between resident and recirculating memory T cells.

JAK-STAT pathway inhibitors in dermatology

The JAK-STAT signaling pathway mediates important cellular processes such as immune response, carcinogenesis, cell differentiation, division and death. Therefore, drugs that interfere with different JAK-STAT signaling patterns have potential indications for various medical conditions. The main dermatological targets of JAK-STAT pathway inhibitors are inflammatory or autoimmune diseases such as psoriasis, vitiligo, atopic dermatitis and alopecia areata; however, several dermatoses are under investigation to expand this list of indications. As JAK-STAT pathway inhibitors should gradually occupy a relevant space in dermatological prescriptions, this review presents the main available drugs, their immunological effects, and their pharmacological characteristics, related to clinical efficacy and safety, aiming to validate the best dermatological practice.

Unveiling the Unseen Struggles: A Comprehensive Review of Vitiligo's Psychological, Social, and Quality of Life Impacts

This review explores the psychosocial impact of vitiligo on patients, its consequences for their quality of life, and the need for holistic support. Vitiligo's psychosocial burden, driven by the need to conceal lesions and societal beauty ideals, leads to stress, sadness, and low self-esteem. Social stigma affects self-esteem, especially in cultural contexts, exacerbating the need for culturally sensitive support. Anxiety and depression are common due to visible differences and societal pressures. Vitiligo significantly reduces the quality of life, especially in younger patients, impacting daily activities, careers, and relationships. Disease severity worsens these effects, particularly in visible areas and among individuals with darker skin tones. Long-term disease activity may improve acceptance and quality of life. Psychological support and counseling are crucial, as many patients don't seek medical help. Education plays a key role, improving understanding and reducing anxiety. Raising awareness about the impact of vitiligo can challenge perceptions and contribute to enhancing patients' well-being. In conclusion, this review highlights the interplay between psychosocial factors, quality of life, and the importance of addressing social stigma, providing psychological support, and advancing education and awareness for those with vitiligo.

Trained immunity in the pathogenesis of vitiligo

Vitiligo is caused by an autoimmune reaction against melanocytes leading to melanocyte loss. The cause of vitiligo is an interaction between genetic susceptibility and environmental factors. Both the adaptive immune system-through cytotoxic CD8+ T cells and melanocyte specific antibodies-and the innate immune system are involved in these immune processes in vitiligo. While recent data stressed the importance of innate immunity in vitiligo, the question remains why vitiligo patients' immune response becomes overly activated. Could a long-term increase in innate memory function, described as trained immunity after vaccination and in other inflammatory diseases, play a role as an enhancer and continuous trigger in the pathogenesis of vitiligo? After exposure to certain stimuli, innate immune system is able to show an enhanced immunological response to a secondary trigger, indicating a memory function of the innate immune system, a concept termed trained immunity. Trained immunity is regulated by epigenetic reprogramming, including histone chemical modifications and changes in chromatin accessibility that cause sustained changes in the transcription of specific genes. In responses to an infection, trained immunity is beneficial. However, there are indications of a pathogenic role of trained immunity in inflammatory and autoimmune diseases, with monocytes presenting features of a trained phenotype, resulting in increased cytokine production, altered cell metabolism through mTOR signaling, and epigenetic modifications. This hypothesis paper focusses on vitiligo studies that have shown these indications, suggesting the involvement of trained immunity in vitiligo. Future studies focusing on metabolic and epigenetic changes in innate immune cell populations in vitiligo could help in elucidating the potential role of trained immunity in vitiligo pathogenesis.

Efficacy and safety of compound glycyrrhizin in the patients with vitiligo: a systematic review and meta-analysis

OBJECTIVE

Compound glycyrrhizin (CG) is widely used to treat vitiligo in China, and the efficacy and adverse events (AEs) of CG for vitiligo need further analysis. This study aimed to systematically reevaluate the efficacy and safety of CG in the patients with vitiligo.

RESEARCH DESIGN AND METHODS

Eight literature databases were searched up to 31 December 2022, and randomized controlled trials which compared CG plus conventional treatments with conventional treatments alone were included.

RESULTS

17 studies with 1492 patients were included. The pooled results showed that the combination of CG and conventional treatments was superior to conventional treatments alone in the total efficacy rate (risk ratio (RR) = 1.54, 95% confidence interval (CI) = 1.40 to 1.69, P < 0.00001), cure rate (RR = 1.62, 95%CI = 1.32 to 1.99, P < 0.00001), the levels of serum IL-6, TNF-α, IL-17, and TGF-ß, and the ratio of CD4⁺/CD8⁺ T cell in blood. Moreover, few patients suffered from the mild and tolerable AEs of CG.

CONCLUSIONS

CG plus conventional treatments is an effective treatment for vitiligo with mild and tolerable AEs. More high-quality and large-sample studies are required in the future to provide more evidence of CG for vitiligo.

PROSPERO REGISTRATION

CRD42023401166.

The Essential Role of microRNAs in Inflammatory and Autoimmune Skin Diseases-A Review

The etiopathogenesis of autoimmune skin diseases is complex and still not fully understood. The role of epigenetic factors is emphasized in the development of such diseases. MicroRNAs (miRNAs), a group of non-coding RNAs (ncRNAs-non-coding RNAs), are one of the important post-transcriptional epigenetic factors. miRNAs have a significant role in the regulation of the immune response by participating in the process of the differentiation and activation of B and T lymphocytes, macrophages, and dendritic cells. Recent advances in research on epigenetic factors have provided new insights into the pathogenesis and potential diagnostic and therapeutic targets of many pathologies. Numerous studies revealed a change in the expression of some microRNAs in inflammatory skin disorders, and the regulation of miRNA expression is a promising therapeutic goal. This review presents the state of the art regarding changes in the expression and role of miRNAs in inflammatory and autoimmune skin diseases, including psoriasis, atopic dermatitis, vitiligo, lichen planus, hidradenitis suppurativa, and autoimmune blistering diseases.

Expression Signature of Immune-Related MicroRNAs in Autoimmune Skin Disease: Psoriasis and Vitiligo Insights

BACKGROUND

Psoriasis and vitiligo are both chronic, skin-specific diseases classified as autoimmune diseases due to the involvement of several biochemical pathways in their pathogenesis, similar to those altered in other autoimmune diseases. The role of miRNAs in regulating skin autoimmune function has yet to be fully characterized.

AIM

The aim of this study was to assess the expression profile of a panel of 11 circulating immune-related miRNAs in patients with autoimmune skin diseases, specifically psoriasis and vitiligo, and correlate their expression signature with the clinicopathological features of the diseases.

SUBJECTS AND METHODS

Relative gene expression quantification for 11 immune-related circulating miRNAs in plasma was done for 300 subjects-100 patients with psoriasis, 100 patients with vitiligo and 100 normal healthy volunteers-followed by different modalities of bioinformatics analysis for the results.

RESULTS

The expression levels of all the studied immune-related miRNAs were elevated in both autoimmune skin disorders, with much higher levels of expression in psoriasis than in vitiligo patients. There was a significant correlation between most of the studied miRNAs, suggesting shared target genes and/or pathways. Moreover, all the studied miRNAs showed significant results as biomarkers for autoimmune skin disease, with miRNA-145 being the best candidate. Regarding the clinicopathological data, miRNA-7, miRNA-9, miRNA-145, miRNA-148a, and miRNA-148b were positively correlated with age. All the miRNAs were inversely correlated with obesity and disease duration.

CONCLUSION

This study highlights the critical role of miRNAs in skin-specific autoimmune diseases that proved to be potential biomarkers for autoimmune skin disorders, warranting their exploration as therapeutic targets.

Prevalence of immune-mediated inner ear disease in non-segmental vitiligo: A cross-sectional study

BACKGROUND

Sensorineural hearing loss (SNHL) is associated with non-segmental vitiligo (NSV); however, the aetiology of SNHL has not been explored. The concomitance of autoimmune disease in vitiligo patients demands the investigation of immune-mediated inner ear disease (IMIED) as a cause of SNHL in NSV. The anti-Hsp70 antibody is a serological marker of IMIED, which may help in the early diagnosis of this disease.

OBJECTIVE

To evaluate the prevalence of IMIED in NSV patients.

METHODS

Cross-sectional study involving NSV adult patients and a control group, evaluated through audiometry and serological dosage of the anti-Hsp70 antibody.

RESULTS

In total, 112 cases and 23 controls were evaluated. Bilateral SNHL was found in 28 (25.0%; 95%CI 17.9%-32.1%) patients and in 1 (4.3%) control (p = 0.019). Six cases (5.4%; 95%CI 2.7%-8.0%) presented bilateral SNHL of unexplained aetiology, and anti-Hsp70 antibody positivity, fulfilling the diagnostic criteria for IMIED. No controls met the diagnostic criteria for IMIED. Serum anti-Hsp70 antibodies were higher in cases with IMIED: median 220.9 vs. 85.1 ng/ml (p = 0.001).

CONCLUSION

The prevalence of IMIED is remarkable in NSV adult patients.

Treatment update for vitiligo based on autoimmune inhibition and melanocyte protection

INTRODUCTION

The treatment of vitiligo remains challenging due to the complexity of its pathogenesis, influenced by genetic factors, oxidative stress and abnormal cell adhesion that collectively impact melanocyte survival and trigger immune system attacks, resulting in melanocyte death. Melanocytes in vitiligo are believed to exhibit genetic susceptibility and defects in cellular mechanisms, such as defects in autophagy, that reduce their ability to resist oxidative stress, leading to increased expression of the pro-inflammatory protein HSP70. The low expression of adhesion molecules, such as DDR1 and E-cadherin, accelerates melanocyte damage and antigen exposure. Consequently, autoimmune attacks centered on IFN-γ-CXCR9/10-CXCR3-CD8⁺ T cells are initiated, causing vitiligo.

AREAS COVERED

This review discusses the latest knowledge on the pathogenesis of vitiligo and potential therapeutic targets from the perspective of suppressing autoimmune attacks and activating melanocytes functions.

EXPERT OPINION

Vitiligo is one of the most challenging dermatological diseases due to its complex pathogenesis with diverse therapeutic targets. Immune suppression, such as corticosteroids and emerging JAK inhibitors, has proven effective in disease progression. However, during the early stages of the disease, it is also important to optimize therapeutic strategies to activate melanocytes for alleviating oxidative stress and improving treatment outcomes.

The Role of Oxidative Stress in Vitiligo: An Update on Its Pathogenesis and Therapeutic Implications

Vitiligo is an autoimmune skin disorder caused by dysfunctional pigment-producing melanocytes which are attacked by immune cells. Oxidative stress is considered to play a crucial role in activating consequent autoimmune responses related to vitiligo. Melanin synthesis by melanocytes is the main intracellular stressor, producing reactive oxygen species (ROS). Under normal physiological conditions, the antioxidative nuclear factor erythroid 2-related factor 2 (Nrf2) pathway functions as a crucial mediator for cells to resist oxidative stress. In pathological situations, such as with antioxidant defects or under inflammation, ROS accumulate and cause cell damage. Herein, we summarize events at the cellular level under excessive ROS in vitiligo and highlight exposure to melanocyte-specific antigens that trigger immune responses. Such responses lead to functional impairment and the death of melanocytes, which sequentially increase melanocyte cytotoxicity through both innate and adaptive immunity. This report provides new perspectives and advances our understanding of interrelationships between oxidative stress and autoimmunity in the pathogenesis of vitiligo. We describe progress with targeted antioxidant therapy, with the aim of providing potential therapeutic approaches.

Vitiligo, from Pathogenesis to Therapeutic Advances: State of the Art

Vitiligo is an acquired hypopigmentation of the skin due to a progressive selective loss of melanocytes; it has a prevalence of 1-2% and appears as rounded, well-demarcated white macules. The etiopathology of the disease has not been well defined, but multiple factors contribute to melanocyte loss: metabolic abnormalities, oxidative stress, inflammation, and autoimmunity. Therefore, a convergence theory was proposed that combines all existing theories into a comprehensive one in which several mechanisms contribute to the reduction of melanocyte viability. In addition, increasingly in-depth knowledge about the disease's pathogenetic processes has enabled the development of increasingly targeted therapeutic strategies with high efficacy and fewer side effects. The aim of this paper is, by conducting a narrative review of the literature, to analyze the pathogenesis of vitiligo and the most recent treatments available for this condition.

Management of Stable Vitiligo-A Review of the Surgical Approach

At present, vitiligo is the most common depigmenting skin disorder, characterized by clearly demarcated discolored patches of various shapes and sizes. Depigmentation results from the initial dysfunction and subsequent destruction of melanin-producing cells, called melanocytes, which are located in the basal layer of the epidermis and in hair follicles. This review concludes that the extent of repigmentation, regardless of the treatment method, is greatest in stable localized vitiligo patients. The aim of this review is to provide an overview of the clinical evidence for which the vitiligo treatment method (cellular or tissue) is more effective. The treatment relies on multiple factors, ranging from patient skin predisposition for repigmentation to the experience of the facility performing the procedure. Vitiligo is a significant problem in modern society. Although it is a typically asymptomatic and not life-threatening disease, it may have significant psychological and emotional impacts. Standard treatment relies on pharmacotherapy and phototherapy; however, the treatment of patients with stable vitiligo varies. The stability of vitiligo more than often implies the exhaustion of the potential for skin self-repigmentation. Thus, the surgical methods that distribute normal melanocytes into the skin are crucial elements of these patients' therapy. The most commonly used methods are described in the literature, with an indication of their recent progress and changes. In addition, information on the efficiency of the individual methods at specific locations is compiled in this study, and the prognostic factors indicating repigmentation are presented. Cellular methods are the best therapeutic option for large-sized lesions; although they are more exorbitant than tissue methods, they benefit from more rapid healing times and presenting fewer side effects. Dermoscopy is a valuable tool used to assess the further course of repigmentation, where it is of great value to evaluate the patient prior to and following an operation.

Vitiligo: An immune disease and its emerging mesenchymal stem cell therapy paradigm

Melanocyte damage, innate immune response, adaptive immune response, and immune inflammatory microenvironment disorders are involved in the development of the immunological pathogenic mechanism of vitiligo. Mesenchymal stem cells are considered an ideal type of cells for the treatment of vitiligo owing to their low immunogenicity, lower rates of transplant rejection, and ability to secrete numerous growth factors, exosomes, and cytokines in vivo. The regulation of signaling pathways related to oxidative stress and immune imbalance in the immunological pathogenesis of vitiligo can improve the immune microenvironment of tissue injury sites. In addition, co-transplantation with melanocytes can reverse the progression of vitiligo. Therefore, continuous in-depth research on the immunopathogenic mechanism involved in this disease and mesenchymal stem cell-based therapy is warranted for the treatment of vitiligo in the future.

Review of Ruxolitinib for Treatment of Non-Segmental Vitiligo

OBJECTIVE

To review the pharmacokinetics, efficacy, and safety of topical ruxolitinib for treatment of nonsegmental vitiligo.

DATA SOURCES

Literature published between January 1983 and October 2022 was reviewed from MEDLINE and ClinicalTrials.gov.

STUDY SELECTION AND DATA EXTRACTION

Relevant articles in English and data from clinical trials were included.

DATA SYNTHESIS

In 2 phase II trials, treatment with ruxolitinib cream showed significant improvements in Vitiligo Area Scoring Index (VASI) scores compared with controls. The 1.5% concentration applied twice daily showed the best results after 52 weeks, with 50% VASI improvement in 58% of patients, 75% VASI improvement in 52% of patients, and 90% VASI improvement in 33% of patients. In 2 phase III trials, more patients achieved at least 75% improvement in facial VASI at 24 weeks (primary endpoint; trial 1: 29.9%, trial 2: 29.9%) than controls (trial 1: 7.5% [P < 0.0001], trial 2: 12.9% [P < 0.01]). Common adverse effects were erythema, pruritus, and acne; all events were mild.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON TO EXISTING DRUGS

This review summarizes the pharmacokinetics, efficacy, and safety data regarding topical ruxolitinib for vitiligo. Ruxolitinib is associated with significant clinical improvements with low bioavailability and minimal adverse effects compared with conventional topical steroids, calcineurin inhibitors, phototherapy, and depigmentation agents.

CONCLUSIONS

Ruxolitinib cream is the first therapy approved by the Food and Drug Administration for repigmentation of nonsegmental vitiligo. Clinicians should consider these benefits when recommending treatment as conventional therapies may be time-intensive and carry greater risks of adverse effects.