Current Concepts of Vitiligo Immunopathogenesis

Beyond skin deep: exploring the complex molecular mechanisms and holistic management strategies of vitiligo

Vitiligo is a multifactorial skin disorder characterized by the progressive loss of pigmentation due to the destruction of melanocytes, affecting 0.5-2% of the global population. This condition not only impacts physical appearance but also has profound psychosocial effects on patients. In this review, various aspects of vitiligo are explored, including its clinical forms, epidemiology, and underlying mechanisms. Advances in research have identified key molecular pathways, such as Wnt/β-Catenin, JAK-STAT, and AhR signaling, which are essential for melanocyte survival and immune regulation. These pathways provide valuable insights into the disease's progression and potential treatment targets. Furthermore, the role of microbial imbalances in the gut and skin microbiomes, stress-related factors, and nutritional deficiencies in influencing the onset and progression of vitiligo is investigated. The potential of herbal treatments to stimulate repigmentation is also discussed. By presenting a comprehensive overview, this review aims to deepen the understanding of vitiligo's complex pathology and foster the development of effective therapeutic strategies to enhance patient care.

Non-coding RNAs (miRNAs - circRNAs - lncRNAs) and genes interact with the regulation of vitiligo

Vitiligo is a chronic skin disorder characterized by the loss of melanocytes, resulting in depigmented patches on the skin. The molecular mechanisms underlying vitiligo remain incompletely understood, with recent studies highlighting the role of non-coding RNAs in disease pathogenesis. To identify and analyze the roles of miRNAs, (circular RNAs) circRNAs, and (long non-coding RNAs) lncRNAs in the pathogenesis of vitiligo, focusing on their interactions with key coding genes and pathways. We utilized Microarray data from the GSE65127 and GSE75819 datasets in the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) related to Vitiligo. The analysis was conducted using GEO2R for identifying upregulated and downregulated genes. Protein-protein interaction (PPI) networks were constructed using STRING and further analyzed with Cytoscape and CytoHubba. Gene Ontology (GO), disease pathways, Disease gene associations, and phenotypes are determined by many online software. miRNAs and cirRNas, lncRNAs were predicted using bioinformatics tools. The constructed network identified AKT1 as a central hub, hsa-miR-140-3p assumes a critical role by interacting with both AKT1 and CTSD, while circRNAs such as hsa_circ_0020776, hsa_circ_0033552, and hsa_circ_0020773 significantly modulate these interactions. Also, hsa-miR-921 is highly effective in binding to AKT1, as well as to hsa_circ_0033546 and hsa_circ_0033547. lncRNAs, including AFAP1-AS1 and MALAT1, contribute to the network by establishing connections with the mRNA of target genes. we determined two genes, two miRNAs, and 5 circRNAs may serve as potential biomarkers or therapeutic targets for vitiligo.

Comparative study between combined follicular and epidermal cell suspension versus epidermal cell suspension in treatment of stable vitiligo

Recent developments in the treatment of vitiligo focus on minimizing adverse effects while also reducing the overall treatment duration. This work aimed to compare the advantages and limitations of epidermal cell transplantation versus combined epidermal and follicular cell transplantation in the treatment of stable vitiligo. This study was conducted on 20 vitiligo patients, aged between 15 and 50 years, all of whom presented with symmetrical lesions. The first lesion was treated with epidermal cell suspension (ECS), while the second lesion received a combined treatment of ECS and follicular cell suspension (FCS). The third lesion served as the control. A notable improvement in pigmentation was observed in the combined treatment group compared to the epidermal treatment group. Control patches exhibited resistance to NB-UVB therapy, showing minimal improvement and a slight reduction in depigmentation, in contrast to the treated patches. A significant correlation was found between the site of vitiligo, the tensity stages of the vitiligo extent tensity index (VETI) score after treatment, and the percentage of improvement (P < 0.05). Additionally, a significant relationship was observed between the vitiligo area severity index score and the tensity stages of the VETI score after treatment, as well as the percentage of improvement (P < 0.05). The combination of ECS and FCS as an innovative approach in vitiligo surgery, achieving good to excellent repigmentation within a short period. This method also ensures a favorable color match, even in cases of vitiligo that are typically resistant to treatment.

Sirtuin1 Deficiency Could Exacerbate Melanocyte Apoptosis Under Endoplasmic Reticulum Stress

Vitiligo is a depigmentation disease caused by the targeted destruction of melanocytes, resulting in skin and hair depigmentation and significant psychological stress. However, the mechanisms underlying its onset and progression remain unclear. Endoplasmic reticulum (ER) stress, which is linked with oxidative stress and autoimmunity, is involved in the development of vitiligo, and prolonged ER stress induces apoptosis. Sirtuin 1 (Sirt1) might be a key regulator of ER stress. Thus, we explored how Sirt1 modulates ER stress-induced melanocyte apoptosis in vitro and in vivo. Our results showed that Sirt1 affected ER stress-induced apoptosis of melanocyte apoptosis when upon to ER stress in vitro. Sirt1 inhibition aggravated the vitiligo phenotype in mice; thereby protecting against the stress response, and abating the unfolded protein response. These results suggest that Sirt1 impairment could accelerate melanocyte apoptosis in vitiligo.

Efficacy of CLT4A variants as immunoregulatory molecules among Vitiligo patients in Saudi Arabia

Vitiligo is a skin depigmentation condition caused by the immune-mediated perdition of melanocytes. In vitiligo, cytotoxic T-lymphocytes damage melanocytes, causing skin depigmentation. The Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) gene has been reported to be related to vitiligo and other autoimmune diseases. The purpose of this study was to explore the molecular involvement of rs231775 and rs3087243 SNPs in the CTLA4 gene in vitiligo patients. The recruitment was based on the sample size calculation and based on it, we have recruited 300 Saudi individuals who were evenly divided into vitiligo cases and controls. Extracted genomic DNA was utilized to amplify rs231775 and rs3087243 SNPs in the CTLA4 gene, which were subsequently digested and verified using Sanger sequencing. The polymerase chain reaction and restriction fragment length polymorphism analysis laboratory data were stored in Excel and used for further statistical analysis. Although baseline details had no correlation (p > 0.05) between the two groups, Hardy-Weinberg Equilibrium analysis was in agreement with the vitiligo patients (p > 0.05). The genotype and allele frequencies were frequently associated (p < 0.05) with rs3087243, and rs231775 SNP showed a nominal association with GG genotype and G allele (p < 0.05). The specific relationship in vitiligo cases was revealed by MDR, GDMR, and linkage disequilibrium (p < 0.05), but not with haplotype analysis (p > 0.05). Thus, the study concluded that rs3087243 SNP was associated and rs231775 SNP showed a nominal association with vitiligo in the Saudi population.

Dietary Interventions, Supplements, and Plant-Derived Compounds for Adjunct Vitiligo Management: A Review of the Literature

Vitiligo is a chronic autoimmune pigmentation disorder shaped by a complex interplay of genetic predispositions and environmental triggers. While conventional therapies-phototherapy, corticosteroids, and immunosuppressants-can be effective, their benefits are often partial and temporary, with recurrence common once treatment stops. As such, there is increasing interest in exploring complementary approaches that may offer a more sustainable impact. Emerging evidence suggests that macronutrient and micronutrient-level changes could be beneficial for managing progression and, in some cases, facilitating repigmentation. Antioxidant-rich foods, such as apples, green tea, Indian gooseberry, onions, and peppers, may help mitigate oxidative stress, while inflammatory foods, such as gluten and high-phenol nuts and berries, may exacerbate the condition. Certain supplements, including high-dose vitamin D, vitamin C, vitamin E, and selenium, may enhance phototherapy outcomes. Omega-3 and other unsaturated fatty acids, in addition to prebiotics and probiotics, are under active investigation for their roles in gut health and immune regulation. Notably, plant-derived compounds, i.e., Ginkgo biloba, have demonstrated promise in promoting repigmentation and managing disease progression. However, it must be emphasized that these nutritional interventions remain exploratory, and more research is needed to establish their efficacy, safety, and optimal usage before they can be recommended as part of a standard treatment regimen.

Mechanistic Insights into the Stimulatory Effect of Melanogenesis of 4-Methylcoumarin Derivatives in B16F10 Melanoma Cells

Vitiligo is a skin condition characterized by the loss of pigment, resulting in white patches on various parts of the body. It occurs when melanocytes, the cells that are responsible for producing skin pigment, are destroyed or stop functioning. This study aimed to investigate the melanogenic potential of various 4-methylcoumarin (4MC) derivatives, including 6-methoxy-4-methylcoumarin (6M-4MC), 7-methoxy-4-methylcoumarin (7M-4MC), 7-amino-4-methylcoumarin (7A-4MC), 6,7-dihydroxy-4-methylcoumarin (6,7DH-4MC), 7,8-dihydroxy-4-methylcoumarin (7,8DH-4MC), and 6,7-dimethoxy-4-methylcoumarin (6,7DM-4MC), in B16F10 melanoma cells. Our findings revealed that, while 4MC, 7A-4MC, 6,7DH-4MC, and 7,8DH-4MC did not exhibit any effect on melanin production, significant stimulation of melanogenesis was observed with 6M-4MC, 7M-4MC, and 6,7DM-4MC, with 6M-4MC demonstrating the most pronounced effect. 6M-4MC significantly stimulated melanin production and tyrosinase activity in a concentration-dependent manner in B16F10 cells. A Western blot analysis revealed that 6M-4MC increased the expression levels of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2). Further mechanistic studies showed that 6M-4MC inhibited extracellular signal-regulated kinase (ERK) and protein kinase B (AKT), which led to the upregulation of MITF and TRP proteins and subsequent activation of melanin synthesis. Additionally, 6M-4MC activated GSK3β phosphorylation, reduced β-catenin phosphorylation, and stimulated melanogenesis via the GSK3β/β-catenin pathway. Moreover, a primary skin irritation test was conducted on the upper backs of 32 healthy female volunteers to assess the potential irritation or sensitization from 6M-4MC when applied topically at concentrations of 50 µM and 100 µM. The test results showed no adverse effects on the skin. Collectively, these findings suggest that 6M-4MC may be a promising pigmentation stimulator for use in cosmetics and in the medical treatment of hypopigmentation disorders, particularly in the treatment of skin conditions such as vitiligo.

Vitiligo is associated with an increased risk of cardiovascular diseases: a large-scale, propensity-matched, US-based retrospective study

BACKGROUND

Vitiligo is an autoimmune disease, characterized by specific destruction of melanocytes. While associations with numerous comorbid conditions, which potentially increase the risk of cardiovascular diseases have been described, data on the risk for cardiovascular disease is inconclusive. To address this relevant knowledge gap, this study aims to identify the risk of cardiovascular disease in vitiligo.

METHODS

The US Collaborative Network was accessed using the TriNetX platform, allowing retrospective data retrieval from electronic health records (EHRs) from 57 US based health care organizations (HCOs). Patients with vitiligo and controls were identified by their respective ICD10 codes. Risk of onset of several cardiovascular diseases was determined in patients within 15 years after diagnoses.

FINDINGS

A total of 94 diagnoses with a prevalence of ≥1% in both cohorts, which consisted of 96,581 individuals per group after propensity-score-matching, were identified. Of those, 54 displayed an increased risk in vitiligo. None of the cardiovascular diseases investigated were associated with a decreased risk in patients with vitiligo. Specifically, cerebral infarction occurred in 1.3% of patients with vitiligo, and 1.0% in controls. This difference translated into a hazard ratio (HR) of 1.21 (95% confidence interval [CI] 1.11-1.32, padj < 0.001). Venous thromboembolism was recorded in 1.34% of cases and 1.02% of controls without vitiligo, resulting in an increased HR of 1.27 (95% CI 1.171-1.38, padj < 0.001). Further, major adverse cardiovascular events (MACE) as a composite endpoint was evaluated. The risk for MACE was increased following a vitiligo diagnosis (HR 1.28, 95% CI 1.22-1.35, padj < 0.001), which persisted in both sensitivity analyses.

INTERPRETATION

Patients with vitiligo display an increased risk of onset of cardiovascular diseases as compared to healthy individuals. Thus, vitiligo might require more precise monitoring and systemic treatment.

FUNDING

This research was supported by the Schleswig-Holstein Excellence-Chair Program from the State of Schleswig Holstein, by the Excellence Cluster Precision Medicine in Chronic Inflammation (DFG, EXC 2167), and by DFG Individual Grant LU 877/25-1.

The Anti-Vitiligo Effects of Feshurin In Vitro from Ferula samarcandica and the Mechanism of Action

BACKGROUND

Vitiligo is a complex disorder characterized by skin depigmentation; the canonical Wnt signaling pathway that involves β-catenin plays a crucial role in promoting the melanin production in melanocytes. Targeted inhibition of the Janus kinase JAK-STAT pathway can effectively diminish the secretion of the chemokine C-X-C motif ligand CXCL10, thereby safeguarding melanocytes. Ferula has been applied as a treatment regimen for a long period; however, its use for the treatment of vitiligo has not been previously documented.

METHODS

CCK-8 assay, Intracellular melanin content assay, Tyrosinase activity assay, Western blotting, qRT-PCR, and ELISA methods were employed. Using molecular docking verified the inhibitory effects of feshurin on the JAK1.

RESULTS

The sesquiterpene coumarin feshurin was separated from Ferula samarcandica. Feshurin was shown to induce GSK-3β phosphorylation, resulting in the translocation of β-catenin into the nucleus. This translocation subsequently upregulated the transcription of microphthalmia-associated transcription factor (MITF), leading to increased tyrosinase activity and melanin production. In addition, feshurin inhibited the production of chemokine CXCL10 via the JAK-STAT signaling pathway, which was verified by molecular docking.

CONCLUSIONS

Based on these findings, it can be concluded that feshurin exhibits significant potential for the development of novel anti-vitiligo therapeutics.

IL-17 family cytokines in inflammatory or autoimmune skin diseases

As potent pro-inflammatory mediators, IL-17 family cytokines play crucial roles in the pathogenesis of various inflammatory and autoimmune skin disorders. Although substantial progress has been achieved in understanding the pivotal role of IL-17A signaling in psoriasis, leading to the development of highly effective biologics, the functions of other IL-17 family members in inflammatory or autoimmune skin diseases remain less explored. In this review, we provide a comprehensive overview of IL-17 family cytokines and their receptors, with a particular focus on the recent advancements in identifying cellular sources, receptors and signaling pathways regulated by these cytokines. At the end, we discuss how the aberrant functions of IL-17 family cytokines contribute to the pathogenesis of diverse inflammatory or autoimmune skin diseases.

Analysis of granulysin expression in vitiligo and halo-nevus

Vitiligo and halo nevus are immune-mediated skin diseases that have a similar pathogenesis and involve cellular cytotoxicity mechanisms that are not yet fully understood. In this study, we investigated the expression patterns of the cytolytic molecule granulysin (GNLY) in different cytotoxic cells in skin samples of vitiligo and halo nevus. Skin biopsies were taken from perilesional and lesional skin of ten vitiligo patients, eight patients with halo nevus and ten healthy controls. We analysed the expression of GNLY by immunohistochemistry in CD8+ and CD56+ NK cells. A significantly higher accumulation of GNLY+, CD8+ GNLY+ and fewer CD56+ GNLY+ cells was found in the lesional skin of vitiligo and halo nevus than in the healthy skin. These cells were localised in the basal epidermis and papillary dermis, suggesting that GNLY may be involved in the immune response against melanocytes. Similarly, but to a lesser extent, upregulation of GNLY+ and CD8+ GNLY+ cells was observed in the perilesional skin of vitiligo and halo nevus compared to healthy controls. In this study, we demonstrated for the first time an increased expression of CD8+ GNLY+ T lymphocytes and CD56+ GNLY+ NK cells in lesions of vitiligo and halo nevus, indicating the role of GNLY in the pathogenesis of both diseases.

Identifying the genetic association between common rheumatic diseases and vitiligo

BACKGROUND

Although observational studies have suggested a correlation between vitiligo and rheumatic diseases, conclusive evidence supporting a causal relationship is still lacking. Therefore, this study aims to explore the potential causal relationship between vitiligo and rheumatic diseases.

METHODS

Using genome-wide association studies, we performed a two-sample Mendelian randomization (MR) analysis. In our analysis, the random-effects inverse variance weighted (IVW) method was predominantly employed, followed by several sensitivity analyses, which include heterogeneity, horizontal pleiotropy, outliers, and "leave-one-out" analyses.

RESULTS

The genetically predicted vitiligo was associated with an increased risk of rheumatoid arthritis (RA) (OR, 1.47; 95% confidence interval [CI], 1.29-1.68; p < 0.001), and systemic lupus erythematosus (SLE) (OR, 1.22; 95% CI, 1.06-1.39; p = 0.005). The causal associations were supported by sensitivity analyses. In Sjögren's syndrome and ankylosing spondylitis, no causal relationship with vitiligo was found in the study.

CONCLUSION

Our MR results support the causal effect that vitiligo leads to a higher risk of RA and SLE. Individuals with vitiligo should be vigilant for the potential development of RA and SLE. Managing and addressing this potential requires regular monitoring.

Long-Term Effects and Prognosis Following Suction Blister Epidermal Grafting in Vitiligo Patients

BACKGROUND

Suction blister epidermal grafting (SBEG) is currently one of the most prevalent surgical methods for stable vitiligo.

OBJECTIVE

To investigate the long-term outcomes of vitiligo patients who underwent SBEG and to explore risk factors associated with postoperative relapse.

METHODS

A retrospective cohort study was conducted in patients who underwent SBEG in our department between January 2016 and December 2022. Treatment outcomes, including repigmentation rate, adverse events, and postoperative relapse, were surveyed via telephone interview or out-=patient visit. Multivariate logistic regression models were used to assess the potential risk factors for postoperative relapse. Statistical significance was assumed at P < .05.

RESULTS

A total of 253 patients were included with a repigmentation rate of 96% (243/253) after grafting. Common adverse events included cobblestone-like appearance (73.1%, 185/253) in the donor site, perigraft halo (46.2%, 117/253), and cobblestone-like appearance (26.1%, 66/253) in the recipient site. Postoperative relapse occurred in 20.1% of patients over a mean time of 29.7 months after grafting. Nonsegmental type of vitiligo and coexistence of autoimmune diseases were risk factors for postoperative relapse.

CONCLUSION

SBEG is an effective surgical treatment for vitiligo with high repigmentation rate and good safety profile. Nonsegmental vitiligo and comorbid autoimmune diseases may increase the risk of postoperative relapse.

Exploring the roles and potential therapeutic strategies of inflammation and metabolism in the pathogenesis of vitiligo: a mendelian randomization and bioinformatics-based investigation

Introduction

Vitiligo, a common autoimmune acquired pigmentary skin disorder, poses challenges due to its unclear pathogenesis. Evidence suggests inflammation and metabolism's pivotal roles in its onset and progression. This study aims to elucidate the causal relationships between vitiligo and inflammatory proteins, immune cells, and metabolites, exploring bidirectional associations and potential drug targets.

Methods

Mendelian Randomization (MR) analysis encompassed 4,907 plasma proteins, 91 inflammatory proteins, 731 immune cell features, and 1400 metabolites. Bioinformatics analysis included Protein-Protein Interaction (PPI) network construction, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Subnetwork discovery and hub protein identification utilized the Molecular Complex Detection (MCODE) plugin. Colocalization analysis and drug target exploration, including molecular docking validation, were performed.

Results

MR analysis identified 49 proteins, 39 immune cell features, and 59 metabolites causally related to vitiligo. Bioinformatics analysis revealed significant involvement in PPI, GO enrichment, and KEGG pathways. Subnetwork analysis identified six central proteins, with Interferon Regulatory Factor 3 (IRF3) exhibiting strong colocalization evidence. Molecular docking validated Piceatannol's binding to IRF3, indicating a stable interaction.

Conclusion

This study comprehensively elucidates inflammation, immune response, and metabolism's intricate involvement in vitiligo pathogenesis. Identified proteins and pathways offer potential therapeutic targets, with IRF3 emerging as a promising candidate. These findings deepen our understanding of vitiligo's etiology, informing future research and drug development endeavors.

Vitiligo and Prostate Cancer Correlation

A 72-year-old male with a history of systemic hypertension, asthma, chronic obstructive pulmonary disease (COPD), and hyperlipidemia presents with diffuse patches of cutaneous depigmentation. A shave biopsy of different regions of depigmented skin indicated vitiligo. The patient was prescribed Opzelura (ruxolitinib) 1.5% topical cream as well as tacrolimus 0.1% topical ointment for vitiligo. He also had a history of prostate cancer. A prostate biopsy revealed three sites of prostatic adenocarcinoma with a Gleason score of 6 and a Prostate Imaging-Reporting and Data System (PI-RADS) score of 2. The patient remained in active surveillance for prostate cancer without treatment, due to its low severity. A subsequent biopsy five years later revealed a decrease in prostate cancer prevalence, with cancer present in only one core and at a lower severity. The purpose of this case presentation is to discuss possible links between vitiligo and prostate cancer, as well as their shared mechanisms and pathways.

Human Mesenchymal Stem Cell-Derived Exosomes Promote the Proliferation and Melanogenesis of Primary Melanocytes by Attenuating the H2O2-Related Cytotoxicity in vitro

Background

Mesenchymal stem cell-derived exosomes (MSC-Exo) have therapeutic potential. However, the impact of MSC-Exo on the survival and melanogenesis of human primary melanocytes following H2O2-induced damage has not been clarified. We therefore investigated the effects of MSC-Exo on the H2O2-affected survival of human primary melanocytes and their proliferation, apoptosis, senescence, and melanogenesis in vitro.

Methods

MSC-Exo were prepared from human MSCs by sequential centrifugations and characterized by Transmission Electron Microscopy, Western blot and Nanoparticle Tracking Analysis. Human primary melanocytes were isolated and treated with different concentrations of MSC-Exo, followed by exposing to H2O2. Furthermore, the impact of pretreatment with MSC-Exo on the proliferation, apoptosis, senescence and melanogenesis of melanocytes were tested by CCK-8, flow cytometry, Western blot, L-Dopa staining, tyrosinase activity and RT-qPCR.

Results

Pretreatment with lower doses of MSC-Exo protected human primary melanocytes from the H2O2-triggered apoptosis, while pretreatment with higher doses of MSC-Exo enhanced the H2O2-induced melanocyte apoptosis. Compared with the untreated control, pretreatment with a lower dose (1 µg/mL) of MSC-Exo enhanced the proliferation of melanocytes, abrogated the H2O2-increased p53, p21, IL-1β, IL-6 and IL-8 expression and partially rescued the H2O2-decreased L-dopa staining reaction, tyrosinase activity, MITF and TRP1 expression in melanocytes.

Conclusion

Our findings indicate that treatment with a low dose of MSC-Exo promotes the proliferation and melanogenesis of human primary melanocytes by ameliorating the H2O2-induced apoptosis and senescence of melanocytes. MSC-Exo may be a promising therapeutic strategy of vitiligo.

Interactions between CNS and immune cells in tuberculous meningitis

The central nervous system (CNS) harbors its own special immune system composed of microglia in the parenchyma, CNS-associated macrophages (CAMs), dendritic cells, monocytes, and the barrier systems within the brain. Recently, advances in the immune cells in the CNS provided new insights to understand the development of tuberculous meningitis (TBM), which is the predominant form of Mycobacterium tuberculosis (M.tb) infection in the CNS and accompanied with high mortality and disability. The development of the CNS requires the protection of immune cells, including macrophages and microglia, during embryogenesis to ensure the accurate development of the CNS and immune response following pathogenic invasion. In this review, we summarize the current understanding on the CNS immune cells during the initiation and development of the TBM. We also explore the interactions of immune cells with the CNS in TBM. In the future, the combination of modern techniques should be applied to explore the role of immune cells of CNS in TBM.

Exosomal miRNAs in autoimmune skin diseases

Exosomes, bilaterally phospholipid-coated small vesicles, are produced and released by nearly all cells, which comprise diverse biological macromolecules, including proteins, DNA, RNA, and others, that participate in the regulation of their biological functions. An increasing number of studies have revealed that the contents of exosomes, particularly microRNA(miRNA), play a significant role in the pathogenesis of various diseases, including autoimmune skin diseases. MiRNA is a class of single-stranded non-coding RNA molecules that possess approximately 22 nucleotides in length with the capability of binding to the untranslated as well as coding regions of target mRNA to regulate gene expression precisely at the post-transcriptional level. Various exosomal miRNAs have been found to be significantly expressed in some autoimmune skin diseases and involved in the pathogenesis of conditions via regulating the secretion of crucial pathogenic cytokines and the direction of immune cell differentiation. Thus, exosomal miRNAs might be promising biomarkers for monitoring disease progression, relapse and reflection to treatment based on their functions and changes. This review summarized the current studies on exosomal miRNAs in several common autoimmune skin diseases, aiming to dissect the underlying mechanism from a new perspective, seek novel biomarkers for disease monitoring and lay the foundation for developing innovative target therapy in the future.

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.

Insight into immune profile associated with vitiligo onset and anti-tumoral response in melanoma patients receiving anti-PD-1 immunotherapy

Introduction

Immunotherapy with checkpoint inhibitors is an efficient treatment for metastatic melanoma. Development of vitiligo upon immunotherapy represents a specific immune-related adverse event (irAE) diagnosed in 15% of patients and associated with a positive clinical response. Therefore, a detailed characterization of immune cells during vitiligo onset in melanoma patients would give insight into the immune mechanisms mediating both the irAE and the anti-tumor response.

Methods

To better understand these aspects, we analyzed T cell subsets from peripheral blood of metastatic melanoma patients undergoing treatment with anti-programmed cell death protein (PD)-1 antibodies. To deeply characterize the antitumoral T cell response concomitant to vitiligo onset, we analyzed T cell content in skin biopsies collected from melanoma patients who developed vitiligo. Moreover, to further characterize T cells in vitiligo skin lesion of melanoma patients, we sequenced T cell receptor (TCR) of cells derived from biopsies of vitiligo and primary melanoma of the same patient.

Results and discussion

Stratification of patients for developing or not developing vitiligo during anti-PD-1 therapy revealed an association between blood reduction of CD8-mucosal associated invariant T (MAIT), T helper (h) 17, natural killer (NK) CD56bright, and T regulatory (T-reg) cells and vitiligo onset. Consistently with the observed blood reduction of Th17 cells in melanoma patients developing vitiligo during immunotherapy, we found high amount of IL-17A expressing cells in the vitiligo skin biopsy, suggesting a possible migration of Th17 cells from the blood into the autoimmune lesion. Interestingly, except for a few cases, we found different TCR sequences between vitiligo and primary melanoma lesions. In contrast, shared TCR sequences were identified between vitiligo and metastatic tissues of the same patient. These data indicate that T cell response against normal melanocytes, which is involved in vitiligo onset, is not typically mediated by reactivation of specific T cell clones infiltrating primary melanoma but may be elicited by T cell clones targeting metastatic tissues. Altogether, our data indicate that anti-PD-1 therapy induces a de novo immune response, stimulated by the presence of metastatic cells, and composed of different T cell subtypes, which may trigger the development of vitiligo and the response against metastatic tumor.

Ubiquitin-specific protease 34 in macrophages limits CD8 T cell-mediated onset of vitiligo in mice

As an autoimmune disorder, vitiligo is characterized by depigmented skin macules. CD8⁺T cells and macrophages enrichment promote the onset of vitiligo, while the role of macrophages to CD8⁺T is not well deciphered. To develop a mouse model of vitiligo with prominent epidermal depigmentation, Krt14-Kitl* transgenic mice containing an elevated number of melanocytes in the epidermis with membrane-bound Kit ligand (Kitl*) were adoptively transferred with premelanosome protein (PMEL) CD8⁺ T cells. On the other hand, Krt14-Kitl* mice were mated with ubiquitin-specific protease 34 (USP34)^MKO mice to decipher the role of USP34 in vitiligo. Vitiligo scores and PMEL CD8⁺ T cell enrichment were detected with flow cytometry. Human peripheral blood mononuclear cells (PBMCs) or mice bone marrow-derived macrophages (BMDMs) were incubated with lipopolysaccharide (LPS), CpG, or co-incubated with KU-55933, an ataxia telangiectasia-mutated (ATM) inhibitor. Chemokine (C-C motif) ligand 2 (CCL2), Ccl5, and interleukin (Il)-12α expression was assayed with real-time PCR, and p-IKKα/β was assayed with Western blots. USP34 was up-regulated in the PBMCs of vitiligo patients and LPS-stimulated BMDMs. USP34 deficiency did not affect the differentiation of CD11b⁺F4/80⁺ macrophages in the bone marrow. Immunoprecipitation demonstrated the interaction between USP34 and ATM. USP34 deficiency or KU-55933 administration promoted the induction of Ccl2, Ccl5, Il12α, and p-IKKα/β in LPS or CpG stimulated BMDMs; KU-55933 administration could not affect the expression of the above molecules in USP34 deficient BMDMs. It further revealed that USP34 deficiency promoted the development of vitiligo with increased PMEL CD8⁺ T cell enrichment, which was not affected by KU-55933 administration. USP34 deficiency in macrophages promotes the onset of vitiligo with increased PMEL CD8⁺ T cell enrichment, and USP34/ATM complex can be considered as a therapy target.

Portable paper-based electrochemiluminescence test incorporating lateral-flow immunosensors for detection of interferon-γ levels

Tuberculosis (TB) poses a serious threat to human health and social development. Accurate diagnosis of mycobacterium tuberculosis infection plays a critical role in the prevention and treatment of tuberculosis. Interferon-γ (INF-γ) release assay (IGRA) is currently the only quantitative tuberculosis infection diagnosis method. An accurate, fast, and easily handled INF-γ detection method is the key to obtaining accurate results. Herein, we report a novel paper-based electrochemiluminescence (ECL) method based on lateral flow immunosensors that combines the easy handling characteristics of immunochromatography and the high sensitivity of electrochemiluminescence to detect IFN-γ. To our knowledge this is the first INF-γ detection method that combines immunochromatography with electrochemiluminescence. The paper-based ECL-LFI test consists of a sample pad, conjugation pad (with binding antibody IFN-γ-Ab1 conjugated with ruthenium tripyridine), detection pad (with capture antibody IFN-γ-Ab2 immobilized on nanospheres), absorbent pad, and electrode for signal activation. The ECL signal is obtained by cyclic voltammetry scanning at a speed of 0.1 V/s in the detection area of the paper-based ECL-LFI test. In our experiments, the paper-based ECL-LFI test exhibited a minimum detection limit of 2.57 pg/mL within 12 min, and a broad detection range of 2.57-5,000 pg/mL, with repeatability of 8.10% and stability of 4.97%. With the advantage of high accuracy and sensitivity, easy handling, and low user training requirements, this ECL-LFI test might be used as point-of-care testing (POCT) in the IGRA for tuberculosis diagnosis.

Regenerative Medicine-Based Treatment for Vitiligo: An Overview

Vitiligo is a complex disorder with an important effect on the self-esteem and social life of patients. It is the commonest acquired depigmentation disorder characterized by the development of white macules resulting from the selective loss of epidermal melanocytes. The pathophysiology is complex and involves genetic predisposition, environmental factors, oxidative stress, intrinsic metabolic dysfunctions, and abnormal inflammatory/immune responses. Although several therapeutic options have been proposed to stabilize the disease by stopping the depigmentation process and inducing durable repigmentation, no specific cure has yet been defined, and the long-term persistence of repigmentation is unpredictable. Recently, due to the progressive loss of functional melanocytes associated with failure to spontaneously recover pigmentation, several different cell-based and cell-free regenerative approaches have been suggested to treat vitiligo. This review gives an overview of clinical and preclinical evidence for innovative regenerative approaches for vitiligo patients.