CXCL9 as a key biomarker of vitiligo activity and prediction of the success of cultured melanocyte transplantation

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.

Ritlecitinib, a JAK3/TEC family kinase inhibitor, stabilizes active lesions and repigments stable lesions in vitiligo

The efficacy of ritlecitinib, an oral JAK3/TEC family kinase inhibitor, on active and stable lesions was evaluated in patients with active non-segmental vitiligo in a phase 2b trial (NCT03715829). Patients were randomized to placebo or daily ritlecitinib 50 mg (with or without 4-week 100-mg or 200-mg loading dose), 30 mg, or 10 mg for 24 weeks. Active lesions showed greater baseline expression of inflammatory/immune markers IFNG and CCL5, levels of CD103, and T-cell infiltrates than stable lesions. Patients with more active than stable vitiligo lesions showed higher baseline serum levels of CXCL9 and PD-L1, while patients with more stable than active lesions showed higher baseline serum levels of HO-1. At Week 24, ritlecitinib 50 mg significantly stabilized mean percent change from baseline in depigmentation extent in both active lesions and stable lesions vs. placebo-response, with stable lesions showing greater repigmentation. After 24 weeks of treatment, ritlecitinib 50 mg increased expression of melanocyte markers in stable lesions, while Th1/Th2-related and co-stimulatory molecules decreased significantly in both stable and active lesions. Serum from patients with more active than stable lesions showed decreased levels of ICOS and NK cell activation markers. These data, confirmed at transcription/protein levels, indicate that stable lesion repigmentation occurs early with ritlecitinib, while active lesions require stabilization of inflammation first. ClinicalTrials.gov: NCT03715829.

The IFN-γ-CXCL9/CXCL10-CXCR3 axis in vitiligo: Pathological mechanism and treatment

Vitiligo is a disease featuring distinct white patches that result from melanocyte destruction. The overall pathogenesis of vitiligo remains to be elucidated. Nevertheless, considerable research indicates that adaptive immune activation plays a key role in this process. Specifically, the interferon-gamma (IFN-γ), C-X-C motif chemokine ligands (CXCL9/10), and C-X-C motif chemokine receptor (CXCR3) signaling axis, collectively referred to as IFN-γ-CXCL9/10-CXCR3 or ICC axis, has emerged as a key mediator responsible for the recruitment of autoimmune CXCR3+ CD8+ T cells. These cells serve as executioners of melanocytes by promoting their detachment and apoptosis. Moreover, IFN-γ is generated by activated T cells to create a positive feedback loop, exacerbating the autoimmune response. This review not only delves into the mechanistic insights of the ICC axis but also explores the significant immunological effects of associated cytokines and their receptors. Additionally, the review provides a thorough comparison of existing and emerging treatment options that target the ICC axis for managing vitiligo. This review aims to foster further advancements in basic research within related fields and facilitate a deeper understanding of alternative treatment strategies targeting different elements of the axis.

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.

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

Chemokine research offers insightful information on the pathogenesis of cutaneous immune disorders, such as vitiligo. Compared to cytokines, the higher detectable levels of chemokines display promising potential as future disease biomarkers. Nonetheless, some published study results are contradictory, which can be attributed to patient characteristics and methodological differences. In this study, a meta-analysis was performed to compare chemokine expression in blood and skin samples from vitiligo patients versus healthy controls. Furthermore, the relationship between chemokine expression and disease activity was evaluated. Chemokine levels were investigated in 15 articles in the circulation and in 9 articles in vitiligo skin. Overall, some clear trends were observed. CXCR3 signaling by CXCL10 and CXCL9 has been confirmed by several reports, although CXCL10 showed more robust findings in blood samples. In this meta-analysis, CCL5, CXCL8, CXCL12, and CXCL16 levels were also significantly elevated. This indicates a complex immune pathway activation in vitiligo that overall supports a Th1-dominant response. Chemokines linked to the Th2 and Th17 pathways were less prevalent. Despite these findings, study protocols that examine a broader range of chemokines are encouraged, because current research is mostly focused on a small number of chemokines that were differentially expressed in previous studies.

Skin Interstitial Fluid and Plasma Multiplex Cytokine Analysis Reveals IFN-γ Signatures and Granzyme B as Useful Biomarker for Activity, Severity and Prognosis Assessment in Vitiligo

Background

The course of vitiligo is unpredictable, with periods of disease flare-ups and prolonged recovery periods. It is essential to establish a biomarker profile as a substitute marker for disease activity to predict disease activity, severity, and prognosis prediction. The use of localized skin interstitial fluid as biomarkers has recently gained interest, but extensive studies of the association between skin interstitial fluid, plasma, and the disease course is lacking. This study aims to evaluate the cytokine expression profiles in the skin and plasma and the utility of the biomarker panel in assessing disease activity, severity, and prognosis in patients with vitiligo.

Methods

In this prospective cohort study, 86 patients and 34 healthy controls were recruited from the outpatient department of a tertiary medical center from March 2019 to September 2021. All patients were of Asian ethnicity. Two independent investigators evaluated disease activity and severity with longitudinal follow-ups for treatment response for a-12 month period. Ultrasensitive multiplex cytokine panel and single-molecule counting technology immunoassays were used to study the cytokine expression in skin interstitial fluid and plasma.

Results

IFN-γ and its’ signature cytokines, including CXCL9, CXCL10, and GzmB, are most highly expressed in the vitiligo patients’ lesion skin interstitial fluid and plasma compared to healthy control. By way of comparison, no significant changes in IL-1β, IL-13, IL-15, IL-17A, IL-18 were observed. Receiver operating characteristic analysis revealed that IFN-γ is the most sensitive and specific marker in predicting disease activity, followed by CXCL10 and GzmB. CXCL-9 was sensitive and specific in diagnosing vitiligo disease severity. The decrease in IFN-γ expression level is positively correlated with the treatment response.

Conclusion

IFN-γ, CXCL9, CXCL10, and GzmB are highly expressed in vitiligo patients’ lesion skin and plasma and may serve as biomarkers for the clinical activity, severity, and prognosis prediction in vitiligo patients. Among all, IFN-γ exerts the highest predictive value in disease activity and treatment response, supporting the critical role of IFN-γ in the pathogenesis of vitiligo.

Identification and Validation of Autophagy-Related Genes in Vitiligo

Vitiligo is a common depigmented disease with unclear pathogenesis. Autophagy is crucial for maintaining cellular homeostasis and has been linked to a variety of autoimmune disorders; however, there have been no reports exploring the involvement of autophagy-related genes (ARGs) in vitiligo using bioinformatics methodologies. In this study, RNA-sequencing technology was used to identify the differentially expressed genes (DEGs) and the Human Autophagy Database (HADb) was overlapped to identify differentially expressed autophagy-related genes (DEARGs) in stable non-segmental vitiligo (NSV). Bioinformatics analyses were conducted with R packages and Ingenuity Pathways Analysis (IPA). DEARGs were further confirmed with qRT-PCR. Critical autophagy markers were detected with Western blotting analysis. We identified a total of 39 DEARGs in vitiligo lesions. DEARGs-enriched canonical pathways, diseases and bio functions, upstream regulators, and networks were discovered. qRT-PCR confirmed the significant increases in FOS and RGS19 in vitiligo lesions. Lower microtubule-associated protein 1 light chain (LC3) II/LC3I ratio and higher sequestosome 1 (SQSTM1, p62) expression were found in vitiligo lesions. In conclusion, this study provided a new insight that autophagy dysregulation appeared in stable vitiligo lesions and might be involved in the etiology of vitiligo by taking part in multiple pathways and bio functions.

Differentiating active from stable vitiligo: the role of dermoscopic findings and their relation to CXCL-10

BACKGROUND

Distinguishing vitiligo activity/stability status is pivotal in the management of patients with vitiligo. CXCL10 is a chemokine released in the tissues and sera of patients with vitiligo and an indicator of disease activity.

AIM

This study aimed to assess the role of dermoscopy in detecting active and stable vitiligo by comparing the dermoscopic signs in vitiligo with Vitiligo Disease Activity Score (VIDA) score, clinical activity, and CXCL10 activity.

METHODS

Ninety-seven patients with vitiligo were enrolled in this cross-sectional study. Vitiligo activity/stability was assessed using VIDA scores, clinical examination, dermoscopy, and serum CXCL10 levels measured by enzyme-linked immunosorbent assay technique. Dermoscopic scores were calculated using BPLeFoSK score.

RESULTS

The dermoscopic score was concordant with the VIDA score in 83.5% of patients (n = 81), clinical assessment in 97.9% (n = 95), and serum CXCL10 level in 70.1% (n = 68). Dermoscopic signs of ill-defined border, satellite lesions, and micro-Koebner and starburst appearance were more common in active vitiligo, while a well-defined border was more common in stable lesions.

CONCLUSION

Dermoscopic examination is a practical, reliable, noninvasive, semi-objective tool in the assessment of vitiligo activity/stability that helps reach an informed decision on the disease status to choose the appropriate therapeutic modality.