A meta-analysis of chemokines in vitiligo: Recruiting immune cells towards melanocytes

Reproducibility of liver iron concentration measured by R2* method based on 1.5-T MRI: a meta-analysis

OBJECTIVES

To explore the reproducibility of the 1.5-T MR imaging (MRI)-based R2* method in measuring the liver iron concentration (LIC) across different MRI scanners, scan parameters, and postprocessing techniques.

MATERIALS AND METHODS

We performed a systematic search of the PubMed, Embase, Medline, Cochrane Library, and Web of Science databases and identified studies that used the 1.5-T MRI-based R2* method to measure the LIC. The original data were extracted from the selected studies. Reproducibility was assessed in terms of the ability to replicate the measured LIC with the 1.5-T MRI-based R2* method across different scanning instruments, scan parameters, and postprocessing techniques. We used the scanner equipment, scan parameters, and postprocessing technique as random effects to determine whether the R2* values obtained in the different studies were significantly different after the effects of the measured LIC were excluded. The calibration curve that best fit the R2* value to the LIC was estimated via univariate regression.

RESULTS

Twenty-one studies (1147 participants) were included. The seven studies (435 participants) in which the initial TE was ≤ 1.0 ms and the TE spacing was ≤ 1.4 ms did not have significant differences in the measured R2* value in pairwise comparisons (p > 0.05). Calibration of R2* to LIC was as follows: LIC (mg/g) = 0.042 + 2.85 × 10-2 R2* (s-1) (R2 = 0.79).

CONCLUSION

The 1.5-T MRI-based R2* method in estimating LIC was reproducible across different MRI scanners, scan parameters, and postprocessing techniques.

KEY POINTS

Question The R2* method is widely used to quantify LIC, but the reproducibility of R2*-based LIC estimation remains unknown. Findings In scan sequences with an initial echo time (TE) ≤ 1.0 ms and a TE spacing ≤ 1.4 ms, the R2*-based LIC quantification at 1.5 T achieved good reproducibility. Clinical relevance The 1.5-T MRI-based R2* method enables reproducible quantification of the LIC; its reproducibility spares patients from unnecessary trauma and economic burdens while promoting the extensive clinical dissemination of R2*-based LIC quantification methods.

Involvement of interferon γ-producing mast cells in immune responses against melanocytes in vitiligo requires Mas-related G protein-coupled receptor X2 activation

BACKGROUND

Increasing evidence indicates that oxidative stress and interferon γ (IFNγ)-driven cellular immune responses are responsible for the pathogenesis of vitiligo. However, the connection between oxidative stress and the local production of IFNγ in early vitiligo remains unexplored. The aim of this study was to identify the mechanism underlying the production of IFNγ by mast cells and its impact on vitiligo pathogenesis.

METHODS

Skin specimens from the central, marginal, and perilesional skin areas of active vitiligo lesions were collected to characterize changes of mast cells, CD8 + T cells, and IFNγ-producing cells. Cell supernatants from hydrogen peroxide (H 2 O 2 )-treated keratinocytes (KCs) were harvested to measure levels of soluble stem cell factor (sSCF) and matrix metalloproteinase (MMP)-9. A murine vitiligo model was established using Mas-related G protein-coupled receptor-B2 (MrgB2, mouse ortholog of human MrgX2) conditional knockout (MrgB2 -/- ) mice to investigate IFNγ production and inflammatory cell infiltrations in tail skin following the challenge with tyrosinase-related protein (Tyrp)-2 180 peptide. Potential interactions between the Tyrp-2 180 peptide and MrgX2 were predicted using molecular docking. The siRNAs targeting MrgX2 and the calcineurin inhibitor FK506 were also used to examine the signaling pathways involved in mast cell activation.

RESULTS

IFNγ-producing mast cells were closely aligned with the recruitment of CD8 + T cells in the early phase of vitiligo skin. sSCF released by KCs through stress-enhanced MMP9-dependent proteolytic cleavage recruited mast cells into sites of inflamed skin (Perilesion vs . lesion, 13.00 ± 4.00/high-power fields [HPF] vs . 26.60 ± 5.72/HPF, P <0.05). Moreover, IFNγ-producing mast cells were also observed in mouse tail skin following challenge with Tyrp-2 180 (0 h vs . 48 h post-recall, 0/HPF vs . 3.80 ± 1.92/HPF, P <0.05). The IFNγ + mast cell and CD8 + T cell counts were lower in the skin of MrgB2 -/- mice than in those of wild-type mice (WT vs . KO 48 h post-recall, 4.20 ± 0.84/HPF vs . 0.80 ± 0.84/HPF, P <0.05).

CONCLUSION

Mast cells activated by MrgX2 serve as a local IFNγ producer that bridges between innate and adaptive immune responses against MCs in early vitiligo. Targeting MrgX2-mediated mast cell activation may represent a new strategy for treating vitiligo.

Accuracy of MRI R2* Mapping in Diagnosis of Liver Iron Concentration: A Meta-Analysis

While current guidelines recommend R2* method as the first-line method for liver iron concentration (LIC) measurement, its diagnostic accuracy is debatable. A prior meta-analysis suggested limited accuracy of R2* method for identifying patients with iron overload. However, substantial advances in R2* method over the past decade may have improved its diagnostic performance. The purpose of this study is to explore the accuracy of the R2* method in identifying patients at clinically relevant LIC thresholds (1.8, 3.2, 7.0, and 15.0 mg/g). This is a meta-analysis. On February 16, 2024, databases including PubMed, Medline, Embase, Web of Science, and the Cochrane Library were searched for studies using the R2* method to quantify LIC. R2* values were derived from gradient echo sequence, with LIC from the FerriScan® (R2) or biopsy as reference standard. The true positive, false positive, true negative, and false negative at each LIC threshold (1.8, 3.2, 7.0, and 15.0 mg/g) were extracted from each study by two reviewers. Summary receiver operating characteristic (SROC) curves were generated using the hierarchical SROC (HSROC) model. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Twenty-six studies with 1687 patients were included. In identifying patients at each LIC threshold (1.8, 3.2, 7.0, and 15.0 mg/g), the area under the SROC curves (AUCs) were 0.96 or higher, with pooled sensitivities of 0.95 or higher. Pooled specificities were 0.93 or higher; however, studies using biopsy as a reference showed a wide range 95% confidence interval (CI) (0.51-0.99) for identifying patients at the 1.8 mg/g threshold. The R2* method accurately identified patients at different clinically relevant LIC thresholds (1.8, 3.2, 7.0, and 15.0 mg/g). However, when biopsy is used as a reference, the method may be unstable for the 1.8 mg/g threshold (95% CI for pooled specificity, 0.51-0.99). LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 2.

ACKR3 in Skin Homeostasis, an Overlooked Player in the CXCR4/CXCL12 Axis

CXCL12 and its receptor CXCR4 emerge as critical regulators within the intricate network of processes ensuring skin homeostasis. In this review, we discuss their spatial distribution and function in steady-state skin; delve into their role in acute wound healing, with emphasis on fibrotic and regenerative responses; and explore their relevance in skin responses to commensals and pathogens. Given the lack of knowledge surrounding ACKR3, the atypical receptor of CXCL12, we speculate whether and how it might be involved in the processes mentioned earlier. Is ACKR3 the (a)typical friend who enjoys missing the party, or do we need to take a closer look?

Comprehensive Overview of Cytokine Interplay in Vitiligo: A Decade of Meta-Analyses Systematically Reviewed

(1) Background: Vitiligo is an autoimmune skin disorder characterized by melanocyte destruction. Despite metabolic disturbances and oxidative stress also playing a key role in its pathogenesis, accumulating evidence highlights a prominent role for cytokine dysregulation. (2) Methods: A systematic search was conducted to identify meta-analyses published in the last decade that investigated cytokine involvement in vitiligo. (3) Results: Based on predefined inclusion criteria, nine meta-analyses were retrieved and reviewed. The findings confirm a central role for interferon-gamma (IFN-γ) in vitiligo pathogenesis, although recent meta-analyses suggest that IFN-γ gene polymorphisms are more broadly associated with autoimmunity rather than being vitiligo-specific. Elevated interleukin-17 (IL-17) levels have been consistently reported in vitiligo patients, supporting its contribution to immune-mediated melanocyte destruction. Regulatory T cell dysfunction appears to play a crucial role in disease progression. Additionally, TNF-α-308 G/A polymorphism has been linked to a genetic susceptibility to vitiligo, particularly in specific populations, reinforcing the role of TNF-α in immune dysregulation. Lastly, chemokines involved in immune cell recruitment to melanocytes further illustrate the complex inflammatory network underlying the disease. (4) Conclusions: This systematic review consolidates evidence from a decade of meta-analyses, underscoring the significance of cytokine dysregulation in vitiligo and highlighting potential therapeutic targets.

Candidate approaches for predicting vitiligo recurrence: an effective model and biomarkers

Background

Vitiligo is a challenging chronic condition with unpredictable disease course and high propensity for relapse post-treatment. Recent studies have reported the biomarkers for disease activity, severity, and therapeutic response of vitiligo, yet very few have investigated cytokines as predictive biomarkers for disease recurrence in vitiligo. This study aims to explore cytokines that serve as biomarkers for disease recurrence and extend research on factors related to the disease's activity.

Methods

92 patients and 40 healthy controls were recruited at the Air Force Medical Center from September 20, 2023, to November 30, 2023. Ultrasensitive multiplex cytokine array was used to measure plasma concentrations of cytokines, including IFN-γ, CXCL9, CXCL10, CXCL11, IL-6, and IL-15.

Results

IFN-γ, CXCL9, CXCL10, CXCL11, IL-6, and IL-15 were expressed at higher levels in the circulation of patients with both segmental and non-segmental vitiligo compared to healthy controls (p < 0.001). There were no significant differences in these cytokine levels between the two types of vitiligo. CXCL9 was associated with the activity of vitiligo (p = 0.027). Correlation analysis showed a positive relationship between IFN-γ, CXCL9, CXCL10, CXCL11, IL-6, and IL-15 in the plasma of patients with recurrent vitiligo. The expression of IFN-γ, CXCL9, CXCL10, CXCL11, and IL-6 was significantly higher in recurrent vitiligo than in cases of persistent stable vitiligo (p = 0.001, p = 0.003, p < 0.001, p = 0.002, p = 0.026, respectively), with ROC analysis demonstrating their predictive capability for vitiligo recurrence, with AUC values of 0.806, 0.773, 0.896, 0.785, and 0.709, respectively. Multivariate logistic regression model showed IFN-γ is an independent predictor for vitiligo recurrence [OR (95%CI) =1.051 (1.012~1.116)], with a prediction accuracy of 90.5% (38/42) on the training dataset and 88.9% (16/18) on the testing dataset.

Conclusion

Plasma IFN-γ, CXCL9, CXCL10, CXCL11 and IL-6 might be potential biomarkers for vitiligo recurrence, with CXCL9 also associated with disease activity. Additionally, multivariate logistic regression model demonstrated that IFN-γ is an independent predictor of vitiligo recurrence and the model could be a candidate approach for predicting vitiligo recurrence.

Short-term efficacy and safety of upadacitinib combined with 308 excimer light versus upadacitinib alone and 308 excimer light alone in patients with progressing facial vitiligo

Patients with progressing facial vitiligo who had been treated with upadacitinib, 308 nm excimer light and upadacitinib combined with 308 nm excimer light were selected for retrospective analysis and comparison of their efficacy and safety. Efficacy was evaluated using the Vitiligo Area Severity Index (VASI) and Dermatology Life Quality Index (DLQI) at baseline, after 8 weeks, and after 20 weeks. The progression of skin lesions was monitored through reflectance confocal microscopy (RCM), while adverse reactions were documented. In the combination treatment group, the average VASI at baseline was 0.875 ± 0.4111, which decreased to 0.56 ± 0.32 at week 8 and 0.23 ± 0.218 at week 20 of follow-up (F = 9.918, p = 0.001). RCM analysis indicated that cases achieving VASI100 showed restoration to normalcy regarding loss of integrity within the pigment ring in lesion areas. Although one patient experienced exacerbation of acne, this condition was manageable with topical medication. In contrast, the average VASI score in the 308 nm excimer light group prior to treatment was recorded at 0.908 ± 0.334; by week twenty, it further declined to an average of 0.495 ± 0.4196. The differences observed were statistically significant (F = 28.644, p < 0.001). For patients in the upadacitinib group, the initial average VASI score was noted as being 0.825 ± 0.34; by twenty weeks it averaged approximately 0.53 ± 0.33; however, these differences did not reach statistical significance (F = 2.87, p = 0.14). The efficacy of the combined treatment group was significantly superior compared to both other groups (F = 3.927, p = 0.026). In conclusion, upadacitinib combined with308nm excimer light represents an effective therapeutic option for progressive facial vitiligo and is associated with fewer adverse reactions as well as improved quality of life for patients.

An Overview of the Biological Complexity of Vitiligo

Vitiligo is a skin disease that affects all ethnicities and genders and is characterized by the loss of pigment essentially due to the selective loss of melanocytes. Although it is generally considered a systemic disease associated with polymorphisms in genes involved in the immune response, vitiligo is also considered an oxidative imbalance-associated disease. It represents a multifactorial pathology in which some genetic predisposition and epigenetic factors coupled with some critical biochemical and molecular pathways could play a pivotal role. The aim of this work was thus to review some of the fine cellular mechanisms involved in the etiopathogenesis of vitiligo, mainly focusing on the nonimmunological ones, extensively highlighted elsewhere. We took into consideration, in addition to oxidative stress, both the cause and the hallmark of the pathology, some less investigated aspects such as the role of epigenetic factors, e.g., microRNAs, of receptors of catecholamines, and the more recently recognized role of the mitochondria. Sex differences associated with vitiligo have also been investigated starting from sex hormones and the receptors through which they exert their influence. From literature analysis, a picture seems to emerge in which vitiligo can be considered not just a melanocyte-affecting disease but a systemic pathology that compromises the homeostasis of a complex tissue such as the skin, in which different cell types reside playing multifaceted physiological roles for the entire organism. The exact sequence of cellular and subcellular events associated with vitiligo is still a matter of debate. However, the knowledge of the individual biological factors implicated in vitiligo could help physicians to highlight useful innovative markers of progression and provide, in the long run, new targets for more tailored treatments based on individual manifestations of the disease.

Concurrent Refractory Atopic Dermatitis and Generalized Vitiligo Successfully Treated with Abrocitinib: A Case Report

Atopic dermatitis (AD) may sometimes be comorbid with vitiligo. However, these therapeutic agents are often slow acting and lead to various adverse effects, resulting in poor patient compliance. This report describes a 65-year-old male patient with refractory moderate-to-severe atopic dermatitis (AD) and generalized vitiligo. The patient was treated with repeated antihistamine and dupilumab injections; however, erythema and pruritus did not improve. Consequently, oral abrocitinib was administered to treat AD and vitiligo, and the patient's generalized erythema, papules, and pruritus ameliorated with the repigmentation of vitiligo lesions. This case provided evidence of the efficacy and safety of oral abrocitinib for patients with concurrent refractory AD and vitiligo.

Evaluation of neutrophil activation marker in patients with vitiligo

BACKGROUND

Vitiligo is an inflammatory, autoimmune disorder. Its pathogenesis is unclear. A neutrophil activation marker (calprotectin) is a protein complex present in many different types of cells and may be used as an indicator of inflammation.

AIMS

This study is to assess calprotectin levels in non-segmental vitiligo patients and compare them to the severity of the illness to identify potential associations.

METHODS

The present inquiry was conducted on thirty non-segmental vitiligo patients and thirty healthy volunteers matched in terms of age and gender. The Vitiligo Area Scoring Index was used to assess the vitiligo severity. Calprotectin levels were measured in serum samples obtained from all participants by Enzyme Linked Immunosorbent Assay.

RESULTS

Compared to controls, non-segmental vitiligo patients had considerably elevated serum calprotectin levels. Additionally, calprotectin levels were shown to have a significant positive association with disease severity (r = 0.833, P = 0.000).

CONCLUSIONS

Elevated levels of serum calprotectin in non-segmental vitiligo patients relative to healthy individuals with high sensitivity indicated that it may have a role in the vitiligo pathophysiology and can act as a marker for disease monitoring.

Immunohistochemical Expression of CXCL 10 in Vitiligo

BACKGROUND

Vitiligo is a skin disorder characterized by the loss of melanocytes from the epidermis. Cysteine x cysteine motif chemokine ligand 10 (CXCL10) is linked to the Th1 pattern and has been suggested as one of the most relevant chemokine axes that promote T-cell migration in different autoimmune and inflammatory processes. The aim of this study was to assess the immunohistochemical (IHC) expression of CXCL 10 in skin lesions of patients with vitiligo to explore its possible role in the pathogenesis of the disease.

METHODS

In this prospective, case-control study, we examined biopsies from the lesional skin of 20 patients with vitiligo for IHC expression of CXCL 10: 10 patients presented with stable nonsegmental vitiligo (group A), 10 patients presented with active nonsegmental vitiligo (group B), and 10 apparently healthy volunteers were examined as controls (group C).

RESULTS

Nine patients in group A had mild IHC expression of CXCL 10 (+1) and 1 patient had moderate expression (+2). In group B, 8 patients had strong expression of CXCL 10 (+3), and the remaining patients had moderate expression (+2). However, there was no expression of CXCL 10 in all skin specimens in the control group.

CONCLUSIONS

CXCL10 IHC expression was increased in vitiligo lesions indicating a possible role in the pathogenesis of disease. The expression was significantly increased in active vitiligo compared with stable vitiligo.

Insights into the gut microbiome of vitiligo patients from India

BACKGROUND

Vitiligo is an autoimmune disease characterized by loss of pigmentation in the skin. It affects 0.4 to 2% of the global population, but the factors that trigger autoimmunity remain elusive. Previous work on several immune-mediated dermatological disorders has illuminated the substantial roles of the gut microbiome in disease pathogenesis. Here, we examined the gut microbiome composition in a cohort of vitiligo patients and healthy controls from India, including patients with a family history of the disease.

RESULTS

Our results show significant alterations in the gut microbiome of vitiligo patients compared to healthy controls, affecting taxonomic and functional profiles as well as community structure. We observed a reduction in the abundance of several bacterial taxa commonly associated with a healthy gut microbiome and noted a decrease in the abundance of SCFA (Short Chain Fatty Acids) producing taxa in the vitiligo group. Observation of a higher abundance of genes linked to bacteria-mediated degradation of intestinal mucus suggested a potential compromise of the gut mucus barrier in vitiligo. Functional analysis also revealed a higher abundance of fatty acid and lipid metabolism-related genes in the vitiligo group. Combined analysis with data from a French cohort of vitiligo also led to the identification of common genera differentiating healthy and gut microbiome across populations.

CONCLUSION

Our observations, together with available data, strengthen the role of gut microbiome dysbiosis in symptom exacerbation and possibly pathogenesis in vitiligo. The reported microbiome changes also showed similarities with other autoimmune disorders, suggesting common gut microbiome-mediated mechanisms in autoimmune diseases. Further investigation can lead to the exploration of dietary interventions and probiotics for the management of these conditions.

Th Pathways in Immune-Mediated Skin Disorders: A Guide for Strategic Treatment Decisions

In recent years, there have been significant breakthroughs in the identification of immunological components of skin diseases and in the development of immunomodulatory drugs. Novel therapies create exciting prospects for personalized care. This article provides an overview of the role played by Th1, Th2, Th17, and follicular Th pathways in the most common skin diseases. Additionally, it elucidates the impact of current and upcoming treatments on each of these signaling cascades. Skin diseases predominantly influenced by a single dominant Th pathway such as psoriasis and atopic dermatitis are well-suited for biologics. However, in many other disorders a complex interplay between different immune pathways exists. This can lead to inconsistent efficacy of biologics based on individual patient profiles. In case of activation of several Th pathways, it may be more suitable to consider conventional therapies or JAK inhibitors. Increasing immunological insights have transitioned from laboratory research to practical applications, a trend that is expected to continue growing in the future.

Vitiligo: From Pathogenesis to Treatment

Recent advances in vitiligo have provided promising treatment options, particularly through understanding the immune-mediated mechanisms leading to depigmentation. The inflammatory components in both vitiligo (non-segmental) and segmental vitiligo have similarities. Both are believed to result from an immune-based destruction of melanocytes by anti-melanocyte-specific cytotoxic T cells. The JAK-STAT pathway is activated with IFN-γ as the crucial cytokine and Th1-associated chemokines such as CXCL9 and CXCL10 recruit immune cells towards vitiligo skin. Nonetheless, clear differences are also present, such as the localized nature of segmental vitiligo, likely due to somatic mosaicism and increased presence of poliosis. The differing prevalence of poliosis suggests that the follicular immune privilege, which is known to involve immune checkpoints, may be more important in vitiligo (non-segmental). Immunomodulatory therapies, especially those targeting the JAK-IFNγ pathway, are currently at the forefront, offering effective inhibition of melanocyte destruction by cytotoxic T cells. Although Janus Kinase (JAK) inhibitors demonstrate high repigmentation rates, optimal results can take several months to years. The influence of environmental UV exposure on repigmentation in patients receiving immunomodulating drugs remains largely underexplored. Nonetheless, the combined effect of phototherapy with JAK inhibitors is impressive and suggests a targeted immune-based treatment may still require additional stimulation of melanocytes for repigmentation. Identifying alternative melanocyte stimulants beyond UV light remains crucial for the future management of vitiligo.

Vogt-Koyanagi-Harada Syndrome Following COVID-19 mRNA Vaccination: Th2 to Th1 Transition-related Molecular Machinery

Abstract is missing (Short communication)

Immune cell trafficking: a novel perspective on the gut-skin axis

Immune cell trafficking, an essential mechanism for maintaining immunological homeostasis and mounting effective responses to infections, operates under a stringent regulatory framework. Recent advances have shed light on the perturbation of cell migration patterns, highlighting how such disturbances can propagate inflammatory diseases from their origin to distal organs. This review collates and discusses current evidence that demonstrates atypical communication between the gut and skin, which are conventionally viewed as distinct immunological spheres, in the milieu of inflammation. We focus on the aberrant, reciprocal translocation of immune cells along the gut-skin axis as a pivotal factor linking intestinal and dermatological inflammatory conditions. Recognizing that the translation of these findings into clinical practices is nascent, we suggest that therapeutic strategies aimed at modulating the axis may offer substantial benefits in mitigating the widespread impact of inflammatory diseases.

Proteomics data in vitiligo: a scoping review

An unbiased screening of which proteins are deregulated in vitiligo using proteomics can offer an enormous value. It could not only reveal robust biomarkers for detecting disease activity but can also identify which patients are most likely to respond to treatments. We performed a scoping review searching for all articles using proteomics in vitiligo. Eight manuscripts could be identified. Unfortunately, very limited overlap was found in the differentially expressed proteins between studies (15 out of 272; 5,51%) with variable degrees of the type of proteins and a substantial variety in the prevalence of acute phase proteins (range: 6-65%). Proteomics research has therefore brought little corroborating evidence on which proteins are differentially regulated between vitiligo patients and healthy controls or between active and stable vitiligo patients. While a limited patient size is an obvious weakness for several studies, an incomplete description of patient characteristics is an unfortunate and avoidable shortcoming. Additionally, the variations in the used methodology and analyses may further contribute to the overall observed variability. Nonetheless, more recent studies investigating the response to treatment seem to be more robust, as more differentially expressed proteins that have previously been confirmed to be involved in vitiligo were found. The further inclusion of proteomics analyses in clinical trials is recommended to increase insights into the pathogenic mechanisms in vitiligo and identify reliable biomarkers or promising drug targets. A harmonization in the study design, reporting and proteomics methodology could vastly improve the value of vitiligo proteomics research.

Pathogenesis of Alopecia Areata and Vitiligo: Commonalities and Differences

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

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.