Six decades of vitiligo genetics: genome-wide studies provide insights into autoimmune pathogenesis

Emerging therapies and innovations in vitiligo management: a comprehensive review

Vitiligo is a common skin disorder where melanocytes, the cells that produce skin pigment, are destroyed by the immune system, leading to white patches on the skin and mucous membranes. This condition affects 0.4% to 2.0% of the global population, with a higher prevalence in females and often beginning in childhood. In India, about 1% of the population is affected, particularly in northern regions, with a higher incidence in females and links to other autoimmune diseases. This review examines recent progress in understanding vitiligo and its treatment. It focuses on the genetic, autoimmune, and environmental factors involved in the disease and highlights new therapies, such as targeted molecular treatments and advanced repigmentation methods. Current research shows that oxidative stress and genetic predispositions contribute to the autoimmune destruction of melanocytes. Novel drug delivery systems, including liposomes, nanoemulsions, and nanostructured lipid carriers, have improved treatment effectiveness. Clinical trials are exploring new treatments like Ruxolitinib cream and melanocyte transplantation, while teledermatology is becoming useful for managing patients. Vitiligo also poses a significant economic burden due to its impact on patients' quality of life. Continued research is essential to develop better, more accessible treatments and reduce the economic impact of vitiligo.

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.

Vitiligo Treatments: Review of Current Therapeutic Modalities and JAK Inhibitors

Vitiligo is a chronic autoimmune disease characterized by loss of pigment of the skin, affecting 0.5-2% of the population worldwide. It can have a significant impact on patients' quality of life. In recent years, there has been significant progress in our understanding of the pathogenesis of vitiligo. It is believed that vitiligo develops due to a complex combination of genetics, oxidative stress, inflammation, and environmental triggers. Conventional treatments include camouflage, topical corticosteroids, topical calcineurin inhibitors, oral corticosteroids, phototherapy, and surgical procedures, with the treatment regimen dependent on the patient's preferences and characteristics. With increased understanding of the importance of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway in the pathogenesis of vitiligo, treatment has expanded to include the first US FDA-approved cream to repigment patients with vitiligo. This review summarizes our understanding of the major mechanisms involved in the pathogenesis of vitiligo and its most common available treatments.

Vitiligo and systemic sclerosis: Are they associated?- Lessons from a population-based study

BACKGROUND

The epidemiological relationship of vitiligo with systemic sclerosis (SSc) remains to be precisely evaluated.

OBJECTIVE

To investigate the bidirectional association between vitiligo and SSc.

METHODS

A population-based study was carried out to compare vitiligo patients (n = 20,851) with age-, sex- and ethnicity-matched control subjects (n = 102,475) regarding the incidence of new-onset and the prevalence of preexisting SSc. Adjusted hazard ratios (HRs) and adjusted odds ratios (ORs) were calculated by the Cox regression and logistic regression, respectively.

RESULTS

The incidence rate of new-onset SSc was calculated at 2.4 (95% CI, 1.6-3.4) and 0.4 (95% CI, 0.3-0.6) cases per 10,000 person-years among patients with vitiligo and controls, respectively. Patients with vitiligo had an increased risk of SSc (fully adjusted HR, 5.37; 95% CI, 3.03-9.54; p < 0.001). Correspondingly, a history of SSc predicted elevated odds of developing vitiligo (fully adjusted OR, 2.09; 95% CI, 1.23-3.55; p = 0.006). Relative to other patients with vitiligo, those with vitiligo and comorbid SSc were older and had a higher prevalence of ischaemic heart disease, hyperlipidaemia, and hypertension.

CONCLUSIONS

A robust bidirectional association exists between vitiligo and SSc. This knowledge is valuable for physicians managing patients with both conditions. Patients with vitiligo and comorbid SSc might be monitored for cardiovascular and metabolic comorbidities.

Comorbidities in Patients with Vitiligo: A Systematic Review and Meta-Analysis

Vitiligo has been reported to be associated with a variety of diseases, but it has not been systematically reviewed. Therefore, we aimed to identify prevalent diseases in patients with vitiligo and quantify their associations compared with those in healthy controls. A comprehensive search of MEDLINE and EMBASE from the inception to June 2022 was conducted. Observational studies on prevalent diseases in patients with vitiligo compared with those in healthy controls were included, whereas studies limited to pediatrics or providing only laboratory results were excluded. A total of 78 studies were eligible for analyses. Patients with vitiligo showed higher risks of having comorbid autoimmune and connective tissue diseases, including alopecia areata (OR = 2.63, 95% confidence interval [CI] = 2.50‒2.78), discoid lupus erythematosus (OR = 2.54, 95% CI = 1.74‒3.72), Sjogren's syndrome (OR = 2.50, 95% CI = 1.98‒3.16), myasthenia gravis (OR = 2.30, 95% CI = 1.74‒3.02), systemic lupus erythematosus (OR = 1.96, 95% CI = 1.52‒2.52), and rheumatoid arthritis (OR = 1.82, 95% CI = 1.55‒2.15). Thyroid diseases, diabetes mellitus, metabolic syndrome, sensorineural hypoacusis, and ophthalmic abnormalities were also more prevalent in patients with vitiligo. In conclusion, vitiligo is associated with various systemic diseases. Physicians should evaluate and manage potential comorbid conditions in patients with vitiligo.

Current Concepts of Vitiligo Immunopathogenesis

Vitiligo is an acquired immune-mediated disorder of pigmentation clinically characterized by well-defined depigmented or chalk-white macules and patches on the skin. The prevalence of vitiligo varies by geographical area, affecting 0.5% to 2% of the population. The disease imposes a significant psychological burden due to its major impact on patients’ social and emotional aspects of life. Given its autoimmune background, vitiligo is frequently associated with other autoimmune diseases or immune-mediated diseases. Vitiligo is a multifaceted disorder that involves both genetic predisposition and environmental triggers. In recent years, major predisposing genetic loci for the development of vitiligo have been discovered. The current findings emphasize the critical role of immune cells and their mediators in the immunopathogenesis of vitiligo. Oxidative-stress-mediated activation of innate immunity cells such as dendritic cells, natural killer, and ILC-1 cells is thought to be a key event in the early onset of vitiligo. Innate immunity cells serve as a bridge to adaptive immunity cells including T helper 1 cells, cytotoxic T cells and resident memory T cells. IFN-γ is the primary cytokine mediator that activates the JAK/STAT pathway, causing keratinocytes to produce the key chemokines CXCL9 and CXCL10. Complex interactions between immune and non-immune cells finally result in apoptosis of melanocytes. This paper summarizes current knowledge on the etiological and genetic factors that contribute to vitiligo, with a focus on immunopathogenesis and the key cellular and cytokine players in the disease’s inflammatory pathways.

Lycium barbarum polysaccharide promotes proliferation of human melanocytes via activating the Nrf2/p62 signaling pathway by inducing autophagy in vitro

Vitiligo is a skin disease characterized by lack of functional melanocytes. Lycium barbarum polysaccharide (LBP) has been demonstrated to preserve keratinocytes and fibroblasts against oxidative stress. This study aimed to explore the efficacy and underlying mechanisms of LBP on autophagy in H₂ O₂ -damaged human melanocytes. Cellular viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and annexin V-fluorescein isothiocyanate/propidium iodide double staining. Reverse transcription-polymerase chain reaction, western blotting and electron microscopy were performed to detect autophagy. The protein expression level of Nrf2 and p62 were assessed by western blotting. Plasmid transfection and lentiviral infection were used to overexpress and silence Nrf2 in PIG1 cells. LBP promoted the proliferation and inhibited apoptosis of H₂ O₂ -damaged PIG1 cells. LBP increased the proliferation of H₂ O₂ -damaged PIG1 cells via induction of autophagy, and Nrf2 shRNA experiment confirmed that LBP activated the Nrf2/p62 signal pathway. These results suggest that LBP may be used for the treatment of vitiligo. PRACTICAL APPLICATIONS: Goji berry is the mature and dried fruit of Lycium barbarum L., which is a common food with a long history in China, as well as a Traditional Chinese Medicine. Our previous research found that LBP could activated the Nrf2/ARE pathway in an ultraviolet (UV)-induced photodamage model of keratinocytes, and increase the levels of phase II detoxification and antioxidant enzymes. We firstly confirmed the anti-vitiligo effects of L. barbarum polysaccharide (LBP) by inducing autophagy and promoted proliferation of human melanocytes, and LBP induced autophagy via activating the Nrf2/p62 signaling pathway in this study. These results proved that LBP can be an effective therapy for vitiligo treatment.

Association between exonic polymorphisms of human leukocyte antigen-G gene and non-segmental vitiligo in the Korean population

BACKGROUND

Vitiligo is a pigmentary skin disorder characterised by a chronic and progressive loss of melanocytes. Although several theories have been suggested to the pathogenesis of vitiligo, an autoimmune process leading to melanocyte destruction appears most likely. Human leukocyte antigen-G is a non-classic, major histocompatibility complex Class I molecule that plays an important role in the suppression of the immune response. Several recent studies have provided evidences that polymorphisms in the human leukocyte antigen-G gene might be related with autoimmune diseases.

OBJECTIVES

The aim of this study was to decide whether exonic single nucleotide polymorphisms in human leukocyte antigen-G contribute to the risk of developing non-segmental vitiligo in the Korean population.

METHODS

To evaluate the associations between exonic single nucleotide polymorphisms (rs1630223 [Ala5Ala] and rs12722477 [Leu134Ile]) of human leukocyte antigen-G and vitiligo, 244 patients with vitiligo and 398 healthy controls were recruited. Genotyping was performed using Fluidigm 192.24 Dynamic Array with EP1 (Fluidigm Corp., CA). The SNP type assay (Fluidigm Corp., CA), which employs allele-specifically designed fluorescences (FAM or VIC) primers and a common reverse primer was applied and the data were analysed using the EP1 single nucleotide polymorphisms genotyping analysis software to obtain genotype calls.

RESULTS

Two exonic single nucleotide polymorphisms (rs1630223 and rs12722477) exhibited significant associations with susceptibility and remained a statistically significant association following Bonferroni correction. These two single nucleotide polymorphisms were located within a block of linkage disequilibrium. Haplotypes G-C and A-A comprising rs1630223 and rs12722477 demonstrated a significant association with non-segmental vitiligo.

LIMITATIONS

The protein expression level of patients with vitiligo and controls was not studied and a replication study of the genetic association in an independent group was not managed.

CONCLUSION

Our results suggest that exonic human leukocyte antigen-G polymorphisms (rs1630223 and rs12722477) are associated with the development of non-segmental vitiligo.

The Current Status of Antioxidants in the Treatment of Vitiligo in China

Little is known about the use of antioxidants in the clinical treatment of vitiligo. To investigate the specific use of antioxidants in the treatment of vitiligo and the possible reasons behind its use in China, we conducted a prospective questionnaire-based study using an online questionnaire comprising 26 questions in 5 areas. A total of 323 clinical frontline dermatologists participated in this study. Differences among groups were compared using Pearson’s chi-square test. Ordinal logistic regression was used to develop knowledge–use multiple regression models. Among the 323 dermatologists, 293 (90.7%) approved the oxidative stress theory of vitiligo, and 182 (56.3%) encouraged the use of antioxidants for treating vitiligo; nonetheless, only 11.8% frequently treated vitiligo with antioxidants. Insufficient knowledge of antioxidants was a significant predictor of lower frequency of antioxidant usage (adjusted odds ratio, 0.401 [95% confidence interval, 0.256-0.629]; $P<.001$ ). The predictors associated with higher antioxidant efficacy included advanced or rapid progression, moderate or moderate-to-severe vitiligo, age of 0–2 years or 13–18 years, segmental vitiligo, oral and topical combination therapy, and course duration of <1 month. The use of antioxidants for treating vitiligo is highly encouraged; however, the rates of their clinical use are considerably low. Insufficient knowledge of antioxidants is associated with a lower frequency of antioxidant usage. The synergistic curative efficacy of antioxidants could be affected by the stage, type, severity, age of patients with vitiligo, and method of using antioxidants.

The Immunogenetics of Vitiligo: An Approach Toward Revealing the Secret of Depigmentation

Vitiligo is a hypomelanotic skin disease and considered to be of autoimmune origin due to breaching of immunological self-tolerance, resulting in inappropriate immune responses against melanocytes. The development of vitiligo includes a strong heritable component. Different strategies ranging from linkage studies to genome-wide association studies are used to explore the genetic factors responsible for the disease. Several vitiligo loci containing the respective genes have been identified which contribute to vitiligo and genetic variants for some of the genes are still unknown. These genes include mainly the proteins that play a role in immune regulation and a few other genes important for apoptosis and regulation of melanocyte functions. Despite the available data on genetic variants and risk alleles which influence the biological processes, only few immunological pathways have been found responsible for all ranges of severity and clinical manifestations of vitiligo. However, studies have concluded that vitiligo is of autoimmune origin and manifests due to complex interactions in immune components and their inappropriate response toward melanocytes. The genes involved in the immune regulation and processing the melanocytes antigen and its presentation can serve as effective immune-therapeutics that can target specific immunological pathways involved in vitiligo. This chapter highlights those immune-regulatory genes involved in vitiligo susceptibility and loci identified to date and their implications in vitiligo pathogenesis.

Topical Tofacitinib: A Janus Kinase Inhibitor for the Treatment of Vitiligo in an Adolescent Patient

Vitiligo is an autoimmune skin disease presenting with areas of depigmentation. Recent reports suggest that Janus kinase (JAK) inhibitors may be an effective therapy. In this case report, we show our experience with an adolescent patient with a long history of generalized and refractory vitiligo, for which treatment with topical tofacitinib, a JAK inhibitor, associated with phototherapy for 9 months, resulted in near complete repigmentation.

Autoimmunity in vitiligo: Therapeutic implications and opportunities

Vitiligo is an acquired chronic pigmentary disorder affecting the melanocytes, mainly in the skin and mucosae. It occurs due to the dynamic interaction between genetic and environmental factors leading to autoimmune destruction of melanocytes. Defects in melanocyte adhesion and increased oxidative stress further augment the immune response in vitiligo. It is a cosmetically disfiguring condition with a substantial psychological burden. Its autoimmune nature with resultant chronicity, variable responses to therapeutic modalities, and frequent recurrences have further diminished the quality of life. Hence, treatment should aim to provide more extended remission periods, prevent recurrences, provide good cosmetic outcomes and ensure patient satisfaction. These treatment goals seem plausible with the recent progress in our understanding of the complex pathogenic mechanisms underlying vitiligo at a molecular and genetic level. We provide a literature review of the pathogenic mechanisms and the therapies targeting these mechanisms.

TLR4 gene polymorphisms in Egyptian vitiligo patients: insights into emerging association with clinical activity, family history, and response to therapy

BACKGROUND

Vitiligo is a common pigmentary disorder in which autoimmunity has been suggested to play an important role. Toll-like receptor (TLR) family are recognized different molecular structures expressed on immune cells and have been implicated in a number of autoimmune diseases (AIDs) such as vitiligo. The purpose of this study was to investigate the possible association between TLR4 gene polymorphisms: rs11536858, rs1927911, rs1927914 in Egyptian vitiligo patients and their clinical data, their response to therapy. Using PCR-RFLP for TLR4 gene polymorphisms (rs11536858, rs1927911, and rs1927914), both alleles and genotypes were determined after extraction of DNA in a case-control study of 100 vitiligo Egyptian patients and 100 matched age and sex controls.

RESULTS

The distribution of the protective CT genotype of rs1927914 was higher in the control group. After dividing both patients and controls into 2 age groups (below 18 and above 18 years), no significant associations between the genotypes of the selected TLR4 SNPs and the demographic and clinical data of the vitiligo patients in group 1 (below 18 years) were observed. For group 2 (above 18 years), also no significant associations were found except for the association between the CC genotype of rs1927914 and psychiatric trauma, from one side, and between the CT genotype of rs1927911 and alopecia, from the other side. The association between combined genotypes and the risk of vitiligo showed either higher frequency in patients (risky), or controls (protective), and some equal frequencies (non-significant). The association between haplotypes and risk of vitiligo in patients' group revealed the highest frequency for the risky ATT and the least frequency for ATC haplotypes. In control group, the protective GCT haplotype showed the highest frequency while the GTC and GCC showed the least frequency. No significant correlations of haplotypes with clinical and demographic data of selected patients' group were observed apart from that between ACC haplotype and family history of AIDs and between ATT haplotype and remission after phototherapy.

CONCLUSIONS

The significant relationship between TLR4 gene polymorphisms and vitiligo patients charcteristics clarify the role of innate immunity in pathogensis of vitiligo and its effect on the used therapies.

Vulvar Lichen Sclerosus from Pathophysiology to Therapeutic Approaches: Evidence and Prospects

Vulvar lichen sclerosus (VLS) is a chronic, distressing, inflammatory disease with an enormous impact on quality of life. Treatment goals are relieving symptoms, reversing signs and preventing anatomical changes. Despite the availability of numerous therapeutic options, treatment outcome may not be entirely satisfactory and a definitive cure does not exist. This may be due to the fact that the exact VLS etiopathogenesis remains unknown. The objectives of this paper were to review the most up-to-date knowledge on VLS etiopathogenesis and to consider the available therapies through the lens of a plausible pathogenetic model. An electronic search on both VLS etiopathogenesis and its treatment was performed using the National Library of Medicine PubMed database. Based on current knowledge, it is conceivable that various, heterogeneous environmental factors acting on a genetic background trigger an autoimmune, Th-1 response, which leads to a chronic inflammatory state. This, in turn, can determine both tissue and micro-vascular injury and activation of signaling pathways involved in fibroblast and collagen metabolism. This pathogenetic sequence may explain the effectiveness of anti-inflammatory treatments, mostly topical corticosteroids, in improving VLS clinical-pathological changes. Further deepening of the disease pathways will presumably allow key mediators to become new therapeutic targets and optimize the available treatments.

Mechanisms of melanocyte death in vitiligo

Vitiligo is an autoimmune depigment disease results from extensive melanocytes destruction. The destruction of melanocyte is thought to be of multifactorial causation. Genome-wide associated studies have identified single-nucleotide polymorphisms in a panel of susceptible loci as risk factors in melanocyte death. But vitiligo onset can't be solely attributed to a susceptive genetic background. Oxidative stress triggered by elevated levels of reactive oxygen species accounts for melanocytic molecular and organelle dysfunction, a minority of melanocyte demise, and melanocyte-specific antigens exposure. Of note, the self-responsive immune function directly contributes to the bulk of melanocyte deaths in vitiligo. The aberrantly heightened innate immunity, type-1-skewed T helper, and incompetent regulatory T cells tip the balance toward autoreaction and CD8+ cytotoxic T lymphocytes finally execute the killing of melanocytes, possibly alarmed by resident memory T cells. In addition to the well-established apoptosis and necrosis, we discuss several death modalities like oxeiptosis, ferroptosis, and necroptosis that are probably employed in melanocyte destruction. This review focuses on the various mechanisms of melanocytic death in vitiligo pathogenesis to demonstrate a panorama of that. We hope to provide new insights into vitiligo pathogenesis and treatment strategies by the review.

A retrospective study of long term follow-up of 2283 vitiligo patients treated by autologous, non-cultured melanocyte-keratinocyte transplantation

Background: Autologous non-cultured melanocyte-keratinocyte transplantation (MKTP) can be used to treat stable vitiligo cases, but there were insufficient clinical data to evaluate its safety and efficacy.

Objective: To assess the influence of various factors on the therapeutic outcome of MKTP.

Method: The single-center retrospective study included stable vitiligo patients who underwent MKTP between June 2009 and June 2018. Univariate and/or multivariable analysis were used to determine the factors affecting the outcome of repigmentation.

Result: The study comprised 2283 patients who had long-term follow-up data (12-108months). Excellent repigmentation was achieved in 400/606 (66%),788/1341 (58.8%),437/684 (63.9%),18/24 (75%) patients with segmental vitiligo, pre-MKTP phototherapy, younger than 24 years, the lesion on the perineum and scrotum, respectively. However, the patients with a positive family history, Koebner phenomenon responded worse(χ²=29.417, P<0.001; χ²=107.397, P<0.001; respectively). Overall, a significant positive correlation between duration of stability and percentage of repigmentation was found (χ²=42.053, P<0. 001).

Conclusion: MKTP is efficient and well tolerated for stable vitiligo treatment. Various factors such as duration of disease stability, vitiligo type, family history, site of lesion should be carefully assessed before using MKTP, as it would further improve the post-operative repigmentation.

Association of GZMB polymorphisms and susceptibility to non-segmental vitiligo in a Korean population

Non-segmental vitiligo (NSV) is the most common type of vitiligo, which is characterized by chronic and progressive loss of melanocytes. Genetic factors have been shown to play a key role in NSV in association and family studies. Granzyme B is a serine protease found in the cytoplasmic granules of cytotoxic T lymphocytes and natural killer cells that play an important role in inducing apoptotic changes of target cells. Several recent studies have provided evidence that polymorphism in the GZMB gene might be associated with autoimmune disease. A total of 249 NSV patients and 455 healthy controls were recruited to determine whether single nucleotide polymorphisms (SNPs) [rs2236337 (3′ untranslated region, UTR), rs2236338 (Tyr247His), rs11539752 (Pro94Ala), rs10909625 (Lys80Lys), rs8192917 (Arg55Gln), and rs7144366 (5′ near gene)] in GZMB gene contribute to the risk of developing NSV. Genotyping was performed using a single 192.24 Dynamic Array IFC. Data were analyzed using EP1 SNP Genotyping Analysis software to obtain genotype calls. Among the six SNPs tested, five SNPs (rs2236337, rs2236338, rs11539752, rs10909625, and rs8192917) showed significant association with NSV susceptibility. Among them, rs2236338, rs11539752, rs10909625, and rs8192917 remained a statistically significant association following multiple correction test. The five SNPs were located within a block of linkage disequilibrium. Haplotypes T–A–G–T–T and C–G–C–C–C consisting of rs2236337, rs2236338, rs11539752, rs10909625, and rs8192917 demonstrated significant association with NSV. Our results suggest that GZMB polymorphisms are associated with the development of NSV.

Validation of Susceptibility Loci for Vitiligo Identified by GWAS in the Chinese Han Population

Forty-nine susceptible loci have been reported to be significantly associated with vitiligo by genome-wide association studies (GWASs) in European-derived whites. To date, some of these reported susceptibility loci have not yet been validated in the Chinese Han population. The purpose of this study was to examine whether the 16 reported susceptible loci in European-derived whites were associated with vitiligo in the Chinese Han population. Imputation was performed using our previous GWAS dataset by IMPUTE v2.2.2. The 16 imputed top single-nucleotide polymorphisms (SNPs) with suggestive signals, together with the reported SNPs, were genotyped in a total of 2581 patients and 2579 controls by the Sequenom MassARRAY system. PLINK 2.0 software was used to perform association analysis. The dbSNP database, HaploReg, and eQTL data were adopted to annotate the biological function of the SNPs. Finally, four SNPs from three loci were significantly associated with vitiligo, including rs3747517 (P = 1.29 × 10^–3, OR = 0.87) in 2q24.2, rs4807000 (P = 7.78 × 10^–24, OR = 0.66) and rs6510827 (P = 3.65 × 10^–5, OR = 1.19) in 19p13.3, and rs4822024 (P = 6.37 × 10^–10, OR = 0.67) in 22q13.2. According to the dbSNP database, rs3747517 is a missense variant of IFIH1, rs4807000 and rs6510827 are located in TICAM1, and rs4822024 is located 6 kb upstream of TEF. Further bioinformatics analysis by HaploReg and eQTL found that rs4807000, rs6510827, and rs4822024 are involved in regulating gene expression. Our study revealed the strong association of 2q24.2 (rs3747517), 19p13.3 (rs4807000, rs6510827), and 22q13.2 (rs4822024) with the risk of vitiligo in the Chinese Han population, which implicates common factors for vitiligo across different ethnicities, and helps expand the understanding of the genetic basis of this disease.

Association of multiple sclerosis with vitiligo: a systematic review and meta-analysis

Polyautoimmunity implicates that some autoimmune diseases share common etiopathogenesis. Some studies have reported an association between multiple sclerosis (MS) and vitiligo; meanwhile, other studies have failed to confirm this association. We performed a systemic review and meta-analysis to examine the association of MS with vitiligo. We searched the MEDLINE and Embase databases on March 8, 2020 for relevant case–control, cross-sectional, and cohort studies. The Newcastle–Ottawa Scale was used to evaluate the risk of bias of the included studies. Where applicable, we performed a meta-analysis to calculate the pooled odds ratio (OR) for case–control/cross-sectional studies and risk ratio for cohort studies with 95% confidence interval (CI). Our search identified 285 citations after removing duplicates. Six case–control studies with 12,930 study subjects met our inclusion criteria. Our meta-analysis found no significant association of MS with prevalent vitiligo (pooled OR 1.33; 95% CI 0.80‒2.22). Analysis of the pooled data failed to display any increase of prevalent vitiligo in MS patients compared with controls. Ethnic and genetic factors may play an important role for sporadically observed associations between MS and vitiligo. Future studies of this association should therefore consider stratification by ethnic or genetic factors.

Can monocyte to HDL cholesterol ratio and monocyte to lymphocyte ratio be markers for inflammation and oxidative stress in patients with vitiligo? A preliminary study

Both systemic inflammation and oxidative stress play crucial roles in the pathogenesis of vitiligo. In recent studies, monocyte to high-density lipoprotein cholesterol ratio (MHR), monocyte to lymphocyte ratio (MLR), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), mean platelet volume (MPV) and plateletcrit (PCT) have been shown to reflect inflammation and oxidative stress in chronic inflammatory and autoimmune diseases. In this study, we aimed to investigate the hematological and inflammatory parameters in patients with vitiligo and to evaluate their possible relationship with disease severity. The parameters including MHR, MLR, NLR, PLR, MPV, and PCT were retrospectively investigated in patients with vitiligo and healthy controls. Disease severity was evaluated using the vitiligo extent tensity index (VETI) score. A total of 180 patients with vitiligo, and age-gender-matched 180 healthy controls were enrolled in the study. MHR, MLR, PLR, PCT values were found to be significantly higher in patients with vitiligo (p < 0.05). MPV and NLR values showed no statistically significant difference between the two groups. A positive correlation was also detected between MHR and MLR values, disease duration, and VETI score (p < 0.05). We suggest that MHR and MLR can be used as markers of inflammation and oxidative stress in patients with vitiligo. Both markers may also reflect disease severity.

Identification of key genes and pathways involved in vitiligo development based on integrated analysis

Vitiligo is a chronic skin condition lack of melanocytes. However, researches on the aetiology and pathogenesis of vitiligo are still under debate. This study aimed to explore the key genes and pathways associated with occurrence and development of vitiligo.Weighted gene coexpression network analysis (WGCNA) was applied to reanalyze the gene expression dataset GSE65127 systematically. Functional enrichments of these modules were carried out at gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set variation analysis (GSVA), and gene set enrichment analysis (GSEA). Then, a map of regulatory network was delineated according to pivot analysis and drug prediction. In addition, hub genes and crucial pathways were validated by an independent dataset GSE75819. The expressions of hub genes in modules were also tested by quantitative real-time polymerase chain reaction (qRT-PCR).Eight coexpressed modules were identified by WGCNA based on 5794 differentially expressed genes of vitiligo. Three modules were found to be significantly correlated with Lesional, Peri-Lesional, and Non-Lesional, respectively. The persistent maladjusted genes included 269 upregulated genes and 82 downregulated genes. The enrichments showed module genes were implicated in immune response, p53 signaling pathway, etc. According to GSEA and GSVA, dysregulated pathways were activated incessantly from Non-Lesional to Peri-Lesional and then to Lesional, 4 of which were verified by an independent dataset GSE75819. Finally, 42 transcription factors and 228 drugs were spotted. Focusing on the persistent maladjusted genes, a map of regulatory network was delineated. Hub genes (CACTIN, DCTN1, GPR143, HADH, MRPL47, NKTR, NUF2) and transcription factors (ITGAV, SYK, PDPK1) were validated by an independent dataset GSE75819. In addition, hub genes (CACTIN, DCTN1, GPR143, MRPL47, NKTR) were also confirmed by qRT-PCR.The present study, at least, might provide an integrated and in-depth insight for exploring the underlying mechanism of vitiligo and predicting potential diagnostic biomarkers and therapeutic targets.

Genome-wide association study identifies CDH13 as a susceptibility gene for rhododendrol-induced leukoderma

Racemic RS-4-(4-hydroxyphenyl)-2-butanol (rhododendrol; trade name: Rhododenol [RD]), which is used in topical skin-lightening cosmetics, was unexpectedly reported in Japan to induce leukoderma or vitiligo called RD-induced leukoderma (RIL) after repeated application. To our knowledge, no studies have investigated chemical-induced vitiligo pathogenesis on a genome-wide scale. Here, we conducted a genome-wide association study (GWAS) for 147 cases and 112 controls. CDH13, encoding a glycosylphosphatidylinositol-anchored protein called T-cadherin (T-cad), was identified as the strongest RIL susceptibility gene. RD sensitivity was remarkably increased by T-cad knockdown in cultured normal human melanocytes. Furthermore, we confirmed tyrosinase upregulation and downregulation of the anti-apoptotic molecules (BCL-2 and BCL-XL), suggesting that T-cad is associated with RD via tyrosinase or apoptotic pathway regulation. Finally, monobenzyl ether of hydroquinone sensitivity also tended to increase with T-cad knockdown, suggesting that the T-cad could be a candidate susceptibility gene for RIL and other chemical-induced vitiligo forms. This is the first GWAS for chemical-induced vitiligo, and it could be a useful model for studying the disease's genetic aspects.

Vitiligo: A Review

Vitiligo, a common depigmenting skin disorder, has an estimated prevalence of 0.5–2% of the population worldwide. The disease is characterized by the selective loss of melanocytes which results in typical nonscaly, chalky-white macules. In recent years, considerable progress has been made in our understanding of the pathogenesis of vitiligo which is now clearly classified as an autoimmune disease. Vitiligo is often dismissed as a cosmetic problem, although its effects can be psychologically devastating, often with a considerable burden on daily life. In 2011, an international consensus classified segmental vitiligo separately from all other forms of vitiligo, and the term vitiligo was defined to designate all forms of nonsegmental vitiligo. This review summarizes the current knowledge on vitiligo and attempts to give an overview of the future in vitiligo treatment.

Premature cell senescence in human skin: Dual face in chronic acquired pigmentary disorders

Although senescence was originally described as an in vitro acquired cellular characteristic, it was recently recognized that senescence is physiologically and pathologically involved in aging and age-related diseases in vivo. The definition of cellular senescence has expanded to include the growth arrest caused by various cellular stresses, including DNA damage, inadequate mitochondria function, activated oncogene or tumor suppressor genes and oxidative stress. While senescence in normal aging involves various tissues over time and contributes to a decline in tissue function even with healthy aging, disease-induced premature senescence may be restricted to one or a few organs triggering a prolonged and more intense rate of accumulation of senescent cells than in normal aging. Organ-specific high senescence rate could lead to chronic diseases, especially in post-mitotic rich tissue. Recently, two opposite acquired pathological conditions related to skin pigmentation were described to be associated with premature senescence: vitiligo and melasma. In both cases, it was demonstrated that pathological dysfunctions are not restricted to melanocytes, the cell type responsible for melanin production and transport to surrounding keratinocytes. Similar to physiological melanogenesis, dermal and epidermal cells contribute directly and indirectly to deregulate skin pigmentation as a result of complex intercellular communication. Thus, despite senescence usually being reported as a uniform phenotype sharing the expression of characteristic markers, skin senescence involving mainly the dermal compartment and its paracrine function could be associated with the disappearance of melanocytes in vitiligo lesions and with the exacerbated activity of melanocytes in the hyperpigmentation spots of melasma. This suggests that the difference may arise in melanocyte intrinsic differences and/or in highly defined microenvironment peculiarities poorly explored at the current state of the art. A similar dualistic phenotype has been attributed to intratumoral stromal cells as cancer-associated fibroblasts presenting a senescent-like phenotype which influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. Here, we present a framework dissecting senescent-related molecular alterations shared by vitiligo and melasma patients and we also discuss disease-specific differences representing new challenges for treatment.

Association Study Reveals One Susceptibility Locus with Vitiligo in the Chinese Han Population

Objective: The purpose of this study was to investigate associations between the 14 reported loci (from a meta-analysis of genome-wide association studies [GWAS] in the Caucasian population) and vitiligo in the Chinese Han population. Materials and Methods: In this study 14 single nucleotide polymorphisms (SNPs) at 14 different genetic loci were evaluated for their association with viteligo in a Chinese Han cohort, including 1472 cases and 1472 controls of by using the Sequenom MassArray iPLEX1 system. A Bonferroni adjustment was used for multiple comparisons and p_Bonferroni <0.0056 was considered statistically significant. Results: The T allele of the locus within the FBXO45-NRROS gene (3q29) was significantly associated with vitiligo (odds ratio = 1.22, 95% confidence interval: 1.10-1.36, p = 0.0001). Association at the genotype level was strong (p = 0.0007). The other SNPs were not associated with vitiligo (p_Bonferroni >0.0056). Conclusion: A SNP at the rs6583331 locus 3q29 is associated with the susceptibility of vitiligo in the Chinese Han population, which suggests that there is a common genetic factor predisposing to the development of vitiligo in the Chinese and Caucasian populations.

Predominant role of innate pro-inflammatory cytokines in vitiligo disease

Vitiligo is a skin disorder with melanocyte destruction and an autoimmune basis. Given the importance of cytokines in autoimmunity, we aimed to find the cytokine profile of innate and adaptive immunity in vitiligo patients, and correlate them with clinical parameters. The serum levels of innate immunity [interleukin(IL)-1α, IL-1β, IL-6, IL-8, IL-12, IL-15 and tumor necrosis factor (TNF)-α] and T helper(Th)1 [IL-2, interferon (IFN)-γ, TNF-β], Th2 (IL-4, IL-5, IL-10, IL-13) and Th17 (IL-17, IL-23) cytokines in 44 vitiligo patients were measured by multiplex cytokine assay and compared with 44 healthy subjects. All innate immunity (p < 0.04), Th1 (p < 0.01), Th2 (p < 0.05) and Th17 (p < 0.001) cytokines were higher in patients than controls. Total summation levels of innate immunity and adaptive immunity cytokines showed a remarkable up-regulation in the patients (p < 0.0001). The ratio of innate immunity to Th1 (p = 0.03), Th2 (p = 0.01) and Th17 (p = 0.03) cytokines was significantly higher in patients vs. controls. We found significant higher ratio of Th1 to Th2 cytokines and TNF-β elevated levels in patients with a family history of autoimmunity (p < 0.05). IL-4 and IL-13 (p < 0.04) levels were lower in patients with amelanotic hair. Increased IL-10 level was observed in patients with stable disease (p = 0.02).In conclusion, the profile of cytokines in patients showed a dominant role of innate immunity pro-inflammatory cytokines in vitiligo, which suggests the potential of targeting these cytokines for vitiligo treatment. While a higher ratio of Th1/Th2 cytokines was observed in the patients, association of decreased Th2 cytokines with disease complications suggests a protective role for Th2 pathway.

Skin-resident memory T cells as a potential new therapeutic target in vitiligo and melanoma

Tissue-resident memory T (T_RM ) cells are abundant in the memory T cell pool and remain resident in peripheral tissues, such as the skin, where they act as alarm sensors or cytotoxic killers. T_RM cells persist long after the pathogen is eliminated and can respond rapidly upon reinfection with the same antigen. When aberrantly activated, skin-located T_RM cells have a profound role in various skin disorders, including vitiligo and melanoma. Autoreactive T_RM cells are present in human lesional vitiligo skin and mouse models of vitiligo, which suggests that targeting these cells could be effective as a durable treatment strategy for vitiligo. Furthermore, emerging evidence indicates that induction of melanoma-reactive T_RM cells is needed to achieve effective protection against tumor growth. This review highlights seminal reports about skin-resident T cells, focusing mainly on their role in the context of vitiligo and melanoma, as well as their potential as therapeutic targets in both diseases.

Innate lymphocyte-induced CXCR3B-mediated melanocyte apoptosis is a potential initiator of T-cell autoreactivity in vitiligo

T-cells play a crucial role in progression of autoimmunity, including vitiligo, yet the initial steps triggering their activation and tissue damage remain unknown. Here we demonstrate increased presence of type-1 innate lymphoid cells (NK and ILC1)-producing interferon gamma (IFNγ) in the blood and in non-lesional skin of vitiligo patients. Melanocytes of vitiligo patients have strong basal expression of chemokine-receptor-3 (CXCR3) isoform B which is directly regulated by IFNγ. CXCR3B activation by CXCL10 at the surface of cultured human melanocytes induces their apoptosis. The remaining melanocytes, activated by the IFNγ production, express co-stimulatory markers which trigger T-cell proliferation and subsequent anti-melanocytic immunity. Inhibiting the CXCR3B activation prevents this apoptosis and the further activation of T cells. Our results emphasize the key role of CXCR3B in apoptosis of melanocytes and identify CXCR3B as a potential target to prevent and to treat vitiligo by acting at the early stages of melanocyte destruction.

Tissue signals that prime autoreactive T cells at the onset of autoimmunity remain enigmatic. Here the authors show NK and ILC1 cells are increased in vitiligo patients, and induce melanocyte apoptosis via CXCR3B, which in turn leads to increased priming of T cell responses in cell culture.

The Use of Janus Kinase Inhibitors in Vitiligo: A Review of the Literature

Vitiligo is a common acquired depigmenting disorder characterized by the development of white macules and patches due to the loss of melanocytes. Patients with vitiligo can be stigmatized by society, making the disease a source of psychological stress that can considerably affect quality of life. The goal of vitiligo treatment is to obtain skin repigmentation in the majority of cases, and less commonly to depigment the remaining normal skin. There is no consistent, long-term, durable therapy for vitiligo for all patients, highlighting the unmet need for new safe and effective therapies to control this disease. Recently, JAK inhibitors have been explored as a promising novel treatment option in vitiligo. The JAK and signal transducers and activators of transcription (STAT) pathway is an attractive therapeutic target because IFN-γ-dependent cytokines produced through this pathway have been implicated in the pathogenesis of disease. This literature review describes vitiligo pathophysiology, explains the usefulness of the JAK inhibitors for treatment, and summarizes published case reports, case series, and open-label studies. Research outlined here shows JAK inhibitors in patients with vitiligo have a favorable safety profile and effectively produce repigmentation of lesions, especially with concomitant ultraviolet exposure. Additional studies are required to confirm efficacy, establish safety, and investigate durability of repigmentation.

SIRT3-Dependent Mitochondrial Dynamics Remodeling Contributes to Oxidative Stress-Induced Melanocyte Degeneration in Vitiligo

Mitochondrial dysregulation has been implicated in oxidative stress-induced melanocyte destruction in vitiligo. However, the molecular mechanism underlying this process is merely investigated. Given the prominent role of nicotinamide adenine dinucleotide (NAD⁺)-dependent deacetylase Sirtuin3 (SIRT3) in sustaining mitochondrial dynamics and homeostasis and that SIRT3 expression and activity can be influenced by oxidative stress-related signaling, we wondered whether SIRT3 could play an important role in vitiligo melanocyte degeneration by regulating mitochondrial dynamics.

Methods: We initially testified SIRT3 expression and activity in normal and vitiligo melanocytes via PCR, immunoblotting and immunofluorescence assays. Then, cell apoptosis, mitochondrial function and mitochondrial dynamics after SIRT3 intervention were analyzed by flow cytometry, immunoblotting, confocal laser microscopy, transmission electron microscopy and oxphos activity assays. Chromatin immunoprecipitation (ChIP), co-immunoprecipitation (Co-IP), immunoblotting and immunofluorescence assays were performed to clarify the upstream regulatory mechanism of SIRT3. Finally, the effect of honokiol on protecting melanocytes and the underlying mechanism were investigated via flow cytometry and immunoblotting analysis.

Results: We first found that the expression and the activity of SIRT3 were significantly impaired in vitiligo melanocytes both in vitro and in vivo. Then, SIRT3 deficiency led to more melanocyte apoptosis by inducing severe mitochondrial dysfunction and cytochrome c release to cytoplasm, with Optic atrophy 1 (OPA1)-mediated mitochondrial dynamics remodeling involved in. Moreover, potentiated carbonylation and dampened peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) activation accounted for SIRT3 dysregulation in vitiligo melanocytes. Finally, we proved that honokiol could prevent melanocyte apoptosis under oxidative stress by activating SIRT3-OPA1 axis.

Conclusions: Overall, we demonstrate that SIRT3-dependent mitochondrial dynamics remodeling contributes to oxidative stress-induced melanocyte degeneration in vitiligo, and honokiol is promising in preventing oxidative stress-induced vitiligo melanocyte apoptosis.

Markedly Reduced Risk of Internal Malignancies in Patients With Vitiligo: A Nationwide Population-Based Cohort Study

PURPOSE

Recent studies indicated that the autoimmunity of vitiligo exerts effects on cells other than melanocytes, which confer reduced risks of both melanoma and nonmelanoma skin cancers in patients with vitiligo. However, the risk of internal malignancy in patients with vitiligo has not been elucidated.

PATIENTS AND METHODS

We conducted a population-based retrospective cohort study using data from the Korean National Health Insurance claims database obtained from January 2007 to December 2016. All patients age 20 years or older with vitiligo who had at least two contacts with a physician from 2009 to 2016, during which a principal diagnosis was made, were identified (vitiligo group). Controls were randomly selected (two per patient with vitiligo) after frequency matching with the vitiligo group for age and sex during the same period (control group).

RESULTS

A total of 101,078 patients with vitiligo and 202,156 controls without vitiligo were included. The incidence rates of internal malignancies were 612.9 and 708.9 per 100,000 person-years in the vitiligo and control groups, respectively. Patients with vitiligo showed a significantly reduced risk of overall internal malignancies (hazard ratio [HR], 0.86; 95% CI, 0.82 to 0.89; P < .001) compared with controls without vitiligo after adjustments for age, sex, and comorbidities. With regard to organ-specific malignancies, patients with vitiligo showed a remarkably decreased risk of cancer in the colon and rectum (HR, 0.62; 95% CI, 0.55 to 0.69; P < .001), ovary (HR, 0.62; 95% CI, 0.46 to 0.83; P < .001), and lung (HR, 0.75; 95% CI, 0.65 to 0.86; P < .001).

CONCLUSION

Vitiligo was associated with a reduced risk of overall internal malignancies. These findings suggest that autoimmune diseases, including vitiligo, may provide immune surveillance for the development of cancer beyond the targeted organ.

Imbalance of peripheral follicular helper T lymphocyte subsets in active vitiligo

Vitiligo is an autoimmune disease characterized by the presence of several autoantibodies, some of which are directed against melanocyte components and have been shown to be associated with the progression of the disease. However, the mechanism involved in the production of autoantibodies remains unclear. Follicular helper CD4⁺ T cells (TFH) are specialized in B-cell activation and antibody production, especially the TFH cell subsets type 2 and type 17. To date, TFH cell subsets have not been studied in human vitiligo. This study in 44 vitiligo patients and 19 healthy controls showed an increase in circulating TFH cells associated with disease clinical progression. A more precise analysis of TFH cell phenotype demonstrated that vitiligo is characterized by populations of peripheral TFH cells responsible for helping B-cell function, such as TFH type 2 and type 17 which produce Th2- and TH17-related cytokines, respectively. These findings suggest a new mechanism involving TFH cell subsets in the pathogenesis of human vitiligo and leading to the production of autoantibodies and disease.

Inhibitory Receptors and Pathways of Lymphocytes: The Role of PD-1 in Treg Development and Their Involvement in Autoimmunity Onset and Cancer Progression

Regulatory T (Treg) cells represent a subpopulation of suppressor CD4⁺ T cells critically involved in the establishment of peripheral tolerance through the inhibition of effector T (Teff) cells and the suppression of the immune-mediated tissue destruction toward self-antigens. Treg generation, their suppressive properties and also Treg-Teff cell interactions could be modulated at least in part by programmed cell death-1 (PD-1) expression on their surface and through binding between PD-1 and programmed cell death ligand-1 (PD-L1). Defects involving PD-1 and Tregs can lead to the development of pathological conditions, including autoimmune disorders or promote cancer progression by favoring tumor evasion from the host immune response. At the same time, PD-1 and Tregs could represent attractive targets for treatment, as demonstrated by the therapeutic blockade of PD-L1 applied for the management of different cancer conditions in humans. In the present Review, we focus specifically the role of PD-1/PD-L1 on Treg development and activity.

Patient-reported outcomes: A 5-year long study reveals previously unreported therapeutic, demographic, socio-economic, and other correlations in vitiligo

Vitiligo is a non-lethal, non-communicable, immune-mediated, and generally progressive skin disease, with poorly understood etiopathogenesis and weak evidence base. The aim of the study is to contribute to the scant research on the patient-reported outcomes in vitiligo, and to examine the presence of associations between various inputs for possible use in clinical practice. The study was designed as a web-based questionnaire with 40 inputs across seven dimensions. The questions include demographics, skin type, eye and natural hair color, age of respondent and age of onset, possible triggers, disease extent, localization, progression and activity, the efficacy of most common treatment modalities, medication side-effects, heredity and diseases among parents, and out-of-pocket expenses for treatments to date. The analysis presented with this work contributes to the discussion about the relation between therapies, socio-economic factors, and treatment outcomes in vitiligo. All physicians should adequately manage patient expectations in terms of overall treatment duration and expected out-of-pocket expenses, and actively evaluate patients at shorter intervals. A more aggressive therapeutic approach using telehealth devices should be considered to supplement therapy, monitor treatment progress, and protocol compliance.

The convergence theory for vitiligo: A reappraisal

Vitiligo is characterized by progressive loss of skin pigmentation. The search for aetiologic factors has led to the biochemical, the neurologic and the autoimmune theory. The convergence theory was then proposed several years ago to incorporate existing theories of vitiligo development into a single overview of vitiligo aetiology. The viewpoint that vitiligo is not caused only by predisposing mutations, or only by melanocytes responding to chemical/radiation exposure, or only by hyperreactive T cells, but rather results from a combination of aetiologic factors that impact melanocyte viability, has certainly stood the test of time. New findings have since informed the description of progressive depigmentation. Understanding the relative importance of such aetiologic factors combined with a careful selection of the most targetable pathways will continue to drive the next phase in vitiligo research: the development of effective therapeutics. In that arena, it is likewise important to acknowledge that pathways affected in some patients may not be altered in others. Taken together, the convergence theory continues to provide a comprehensive viewpoint of vitiligo aetiology. The theory serves to intertwine aetiologic pathways and will help to define pathways amenable to disease intervention in individual patients.

Vitiligo: An Update on Pathophysiology and Treatment Options

The pathophysiology of vitiligo is becoming increasingly clarified. In non-segmental vitiligo, early factors include activation of innate immunity, inflammasome activation, oxidative stress, and loss of melanocyte adhesion. Nonetheless, the main mechanism leading to non-segmental vitiligo involves an immune-mediated destruction of melanocytes. Anti-melanocyte-specific cytotoxic T cells exert a central role in the final effector stage. Genetic research revealed a multi-genetic inheritance displaying an overlap with other autoimmune disorders. However, some melanocyte-specific genes were also affected. Segmental vitiligo carries a different pathogenesis with most evidence indicating a mosaic skin disorder. Current management includes topical corticosteroids and immunomodulators. Narrow-band ultraviolet B can be used in patients not responding to topical treatment or in patients with extensive disease. Pigment cell transplantation offers an alternative for the treatment of segmental vitiligo or stable non-segmental lesions. Recent findings have revealed new targets for treatment that could lead to more efficient therapies. Targeted immunotherapy may halt the active immune pathways, although combination therapy may still be required to induce satisfying repigmentation. A recently established core set of outcome measures, new measurement instruments, and biomarker research pave the way for future standardized clinical trials.

Meta-analysis of the association between NLRP1 polymorphisms and the susceptibility to vitiligo and associated autoimmune diseases

Genetic variants are linked to vitiligo and associated autoimmune diseases. We performed a meta-analysis to evaluate the effects of the rs12150220, rs2670660, and rs6502867 polymorphisms within the human NLR Family Pyrin Domain Containing 1 (NLRP1) gene. We initially identified 1,306 candidate articles through literature searches of Pubmed, WOS, Embase, CNKI, WANFANGI, Ovid, Scopus, and Cochrane in July 2017. After strict screening, we included 19 eligible case-control studies, and analyzed the data using Stata/SE 12.0 software. No difference between vitiligo cases and controls was detected for NLRP1 rs12150220, rs2670660, or rs6502867 under most genetic models [P_association (P value of association test) > 0.05). With regard to vitiligo-associated autoimmune diseases, like Addison's disease, type 1 diabetes, or systemic lupus erythematosus, a decreased risk was detected for rs12150220 in the Caucasian subgroup under all models [P_association < 0.05, odds ratio (OR) < 1]. No relationships were observed for other polymorphisms, including rs2670660, rs6502867, and the “A-A, G-T, G-A, A-T” haplotypes of rs2670660/rs12150220 (P_association > 0.05). This meta-analysis demonstrates that within the Caucasian population, the NLRP1 rs12150220 polymorphism may correlate with a decreased risk of vitiligo-associated autoimmune diseases, especially autoimmune Addison's disease, type 1 diabetes, or systemic lupus erythematosus.

Repigmentation in vitiligo using the Janus kinase inhibitor tofacitinib may require concomitant light exposure

BACKGROUND

Vitiligo is an autoimmune disease in which cutaneous depigmentation occurs. Existing therapies are often inadequate. Prior reports have shown benefit of the Janus kinase (JAK) inhibitors.

OBJECTIVE

To evaluate the efficacy of the JAK 1/3 inhibitor tofacitinib in the treatment of vitiligo.

METHOD

This is a retrospective case series of 10 consecutive patients with vitiligo treated with tofacitinib. Severity of disease was assessed by body surface area of depigmentation.

RESULTS

Ten consecutive patients were treated with tofacitinib. Five patients achieved some repigmentation at sites of either sunlight exposure or low-dose narrowband ultraviolet B phototherapy. Suction blister sampling revealed that the autoimmune response was inhibited during treatment in both responding and nonresponding lesions, suggesting that light rather than immunosuppression was primarily required for melanocyte regeneration.

LIMITATIONS

Limitations include the small size of the study population, retrospective nature of the study, and lack of a control group.

CONCLUSION

Treatment of vitiligo with JAK inhibitors appears to require light exposure. In contrast to treatment with phototherapy alone, repigmentation during treatment with JAK inhibitors may require only low-level light. Maintenance of repigmentation may be achieved with JAK inhibitor monotherapy. These results support a model wherein JAK inhibitors suppress T cell mediators of vitiligo and light exposure is necessary for stimulation of melanocyte regeneration.

Vitiligo Pathogenesis and Emerging Treatments

The pathogenesis of vitiligo involves interplay between intrinsic and extrinsic melanocyte defects, innate immune inflammation, and T-cell-mediated melanocyte destruction. The goal of treatment is to not only halt disease progression but also promote repigmentation through melanocyte regeneration, proliferation, and migration. Treatment strategies that address all aspects of disease pathogenesis and repigmentation are likely to have greatest efficacy, a strategy that may require combination therapies. Current treatments generally involve nontargeted suppression of autoimmunity, whereas emerging treatments are likely to use a more targeted approach based on in-depth understanding of disease pathogenesis, which may provide higher efficacy with a good safety profile.