Novel immunological and genetic factors associated with vitiligo: A review

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

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

Evaluation of the clinical and sociodemographic features of patients with vitiligo from the central region of Romania

Background

In this study, we aimed to investigate and analyze the clinical and sociodemographic features and possible correlation with factors associated with the development of vitiligo in a cohort of patients suffering from this disease in the central region of Romania.

Methods

Patients diagnosed with vitiligo from private outpatient clinics in the region and from the outpatient clinic of the Dermatology Clinic in Târgu Mureş participated in the study. The study period was between March 2021 and March 2022. Both sets of patients adhered to the same specified inclusion and exclusion criteria. Included just patients who received a complete dermatological clinical examination. They were asked by experienced physicians about epidemiological and clinical data of the disease, using the questions about vitiligo from the validated questionnaire edited by the Vitiligo Research Foundation from the United States of America. The patients who were given incomplete responses were excluded. This questionnaire contains 30 questions with multiple answers, about the patients with vitiligo, divided into seven subgroups as follows: group 1. Origins (demographic data), 2. History of vitiligo, 3. Vitiligo description, 4. Vitiligo treatments, 5. Skin condition, 6. Other conditions (comorbidities), 7. Impact (cost of treatments). Our study consisted of 114 patients, all of whom were Caucasians with Fitzpatrick skin types ranging from I-III.

Results

We have analyzed the found data and compared the result with the data found in the literature. Most of the clinical and epidemiological characteristics of vitiligo in our patients were similar to those in other studies. A few of the characteristics linked to the possible appearance of the disease were present in higher percentages like the presence of the disease in the family, lighter color of the eyes, gray colored hair, the presence of the halo naevus, the predisposition to sunburn, the skin trauma as starting cause and the presence of increased level of thyroid disease.

Conclusion

Based on our results, we can conclude a profile of a potential patient who can develop vitiligo. To our knowledge, this study is the first of its kind from our country, however, our inferences remain limited by the single center, a relatively small sample size, recall bias, and a self-decided classification of some clinical aspects, which are potential limitations of this study.

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

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

Impact of Consanguinity and Familial Aggregation on Vitiligo Epidemiology in Saudi Arabia: A Case-Control Study

Background Vitiligo, characterized by depigmented patches due to melanocyte loss, involves genetic, autoimmune, and environmental factors. Recent studies suggest a link between family history, consanguinity, and vitiligo prevalence, particularly in regions with prevalent consanguineous marriages. This study explored the relationship between consanguinity and familial vitiligo prevalence in Saudi Arabia. Methods A case-control study enrolled 792 participants from Saudi dermatology clinics (382 vitiligo cases, 408 controls). Family histories and consanguinity levels were assessed. Logistic regression analysis, adjusting for relevant variables, evaluated associations. Results Significant associations were found between vitiligo and both parental consanguinity and family history. Cases had higher consanguinity rates, with 246 out of 382 (64.4%), compared to controls, with 161 out of 408 (39.5%). A positive family history of vitiligo was more common in cases, with 184 out of 382 (48.2%) than in controls, with 90 out of 408 (22.1%). Logistic regression identified parental consanguinity and positive family history as significant risk factors for vitiligo, with adjusted odds ratios (aOR) of 2.39 and 2.92, respectively. Their synergistic effect notably amplified the risk (aOR = 7.58), indicating a complex genetic and familial influence on vitiligo in Saudi Arabia. Conclusions Consanguinity showed a significant association with vitiligo prevalence, highlighting genetic factors' role. Further genetic research is needed to identify specific mutations in vitiligo among consanguineous populations. Genetic counseling and awareness programs are crucial in regions with high consanguinity rates to mitigate vitiligo and other genetic disorders' risks.

First Cousin Marriages and the Risk of Childhood-Onset Vitiligo: Exploring the Genetic Background: A Cross-Sectional Study

Background

Vitiligo, a condition characterized by depigmented skin, has been observed to have a higher incidence in patients with a family history of the disease. This study investigates the relationship between parental consanguinity, family medical history, and the onset of childhood vitiligo, hypothesizing that genetic factors play a significant role.

Methods

A cross-sectional study was conducted involving 382 people diagnosed with vitiligo in Saudi Arabia. The study assessed the prevalence of parental consanguinity and its correlation with the disease's onset, employing statistical analysis to evaluate the data collected through medical records and family history questionnaires.

Results

The findings reveal a significant association between parental consanguinity, particularly among first cousins, and the incidence of childhood-onset vitiligo. Additionally, a notable correlation was found between family medical history and the onset of the condition, with familial vitiligo being more prevalent in patients with adult-onset vitiligo.

Conclusion

This study underscores the critical role of genetic predispositions in the development of childhood-onset vitiligo, highlighting the influence of parental consanguinity. The results advocate for increased awareness and screening in populations with high rates of consanguinity to facilitate early detection and management of vitiligo. Future research should focus on exploring the genetic mechanisms underlying this association to develop targeted interventions.

Macrophage inhibitory factor alters the functionality of macrophages and their involvement in disease pathogenesis of active generalized vitiligo patients

INTRODUCTION

In autoimmune dermatitis patients, a macrophage migration inhibitory factor (MIF) is widely used to determine the severity of the diseases with other clinical parameters. Moreover, in vitiligo, MIF has shown significant positive correlation with the VASI (Vitiligo Area Scoring Index) score of both generalized and localized vitiligo patients. MIF function as pro-inflammatory cytokine and inhibited random migration of macrophages from inflammation loci. Hence, activated macrophage infiltrates promote the diseases pathogenesis. Till date, macrophages and involvement of their secreted MIF in disease severity of vitiligo patients remains undetermined.

MATERIAL AND METHOD

The frequency of both M1 and M2 macrophages was evaluated in active GV patients (n = 20) using flow cytometry in blood and in tissues by confocal microscopy (n = 10). Relative m-RNA expression and cytokine profiling of pro and anti-inflammatory mediators were estimated in PBMCs and in serum of patients. Lastly, concentration of nitric oxide and phagocytic activity from macrophages of active patients were calculated to understand the diseases pathology in detail.

RESULT

Both in circulation as well as in tissues, the infiltration of M1 macrophages was increased in active GV patients, while the percentage of M2 macrophages was comparable to healthy tissues. Aberrant expression of pro and anti-inflammatory molecules including IL-1β, IL-6, TNF-α, IL-12 and MIF impair the cellular hemostasis and induce systematic inflammation. Elevated nitric oxide and higher phagocytic activity of macrophages enhanced the destruction and/or depigmentation of melanocytes causing vitiligo.

CONCLUSION

Elevated macrophages in both tissue and blood enhanced the secretion of MIF and other inflammatory mediators that further enforce the production of nitric oxide, activation and phagocytic activity of macrophages against melanocytes and melanocytes antigens. As a result, destruction of melanocytes and melanin production occurred and caused the depigmentation and/or white macules on the skin.

A novel hybrid model to predict concomitant diseases for Hashimoto's thyroiditis

Hashimoto's thyroiditis is an autoimmune disorder characterized by the destruction of thyroid cells through immune-mediated mechanisms involving cells and antibodies. The condition can trigger disturbances in metabolism, leading to the development of other autoimmune diseases, known as concomitant diseases. Multiple concomitant diseases may coexist in a single individual, making it challenging to diagnose and manage them effectively. This study aims to propose a novel hybrid algorithm that classifies concomitant diseases associated with Hashimoto's thyroiditis based on sequences. The approach involves building distinct prediction models for each class and using the output of one model as input for the subsequent one, resulting in a dynamic decision-making process. Genes associated with concomitant diseases were collected alongside those related to Hashimoto's thyroiditis, and their sequences were obtained from the NCBI site in fasta format. The hybrid algorithm was evaluated against common machine learning algorithms and their various combinations. The experimental results demonstrate that the proposed hybrid model outperforms existing classification methods in terms of performance metrics. The significance of this study lies in its two distinctive aspects. Firstly, it presents a new benchmarking dataset that has not been previously developed in this field, using diverse methods. Secondly, it proposes a more effective and efficient solution that accounts for the dynamic nature of the dataset. The hybrid approach holds promise in investigating the genetic heterogeneity of complex diseases such as Hashimoto's thyroiditis and identifying new autoimmune disease genes. Additionally, the results of this study may aid in the development of genetic screening tools and laboratory experiments targeting Hashimoto's thyroiditis genetic risk factors. New software, models, and techniques for computing, including systems biology, machine learning, and artificial intelligence, are used in our study.

Association of rs4711998 of IL-17A, rs2275913 of IL-17A and rs763780 IL-17F gene polymorphisms with non-segmental vitiligo in a Mexican population

Vitiligo is the most common depigmenting disease characterized by achromic macules due to selective loss of melanocytes. The pathogenesis remains poorly elucidated, and multiple hypotheses exist regarding its pathogenesis. Evidence suggests that stress on melanocytes can result in activation of the immune system, and involvement of both activated cluster of differentiation (CD8+) cytotoxic and CD4+ T cells in the dysfunction, depigmentation, and apoptosis of melanocytes. Recent studies show that the interleukin 17 (IL-17) axis plays a central role in the pathogenesis of the disease. IL-17 is an important regulatory effector cytokine in this pathway. The aim of this study was to evaluate the association of IL-17A rs4711998 (-832A/G), IL-17A rs2275913 (-197G/A), and IL-17F rs763780 (7488A/G) with vitiligo in a Northeastern Mexican population. This was a case-control study and included 116 patients with vitiligo and 116 control subjects. Genotype characterization of IL-17A rs4711998 (-832A/G), IL-17A rs2275913 (-197G/A), and IL-17F rs763780 (7488A/G) was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. A p ≤ 0.05 was considered significant. It was observed that the combination of the genotypes GG/GA for IL-17F rs763780 (7488A/G) was associated with an increased risk for the development of vitiligo (OR 2.0943, 95% Cl 1.2375-3.5445, p = 0.0056). Regarding IL-17A rs4711998 (-832A/G) and IL-17A rs2275913 (-197G/A) genotyping, no association with vitiligo development was found. In conclusion, the SNP rs763780 in the IL-17F gene appears to be a risk factor for vitiligo development in this Mexican population and it may be useful in future studies, especially for the development of new therapies.

The Use of Herbal Medicine in the Treatment of Vitiligo: An Updated Review

Vitiligo is a chronic disease of unknown etiology that causes progressive cutaneous depigmentation. Current pharmacological treatments have limited success and present significant risks. Many efforts have been made in recent years to explore new anti-vitiligo therapeutic strategies, including herbal-based therapies. The objective of the present review is to provide an updated overview on the most frequently used medicinal plants in the treatment of vitiligo. A bibliographical search was carried out in scientific databases Pubmed, Scifinder, Scopus, Google Scholar, and Medline up to October 2021 using the descriptors vitiligo, herbal, medicinal plants, and alternative therapies. In our search, the highest number of published studies comprise plants commonly used in traditional herbal medicine, highlighting the usefulness of ethnopharmacology in the discovery of new therapeutic agents. The review outlines current understanding and provides an insight into the role of psoralens and khellin (photosensitizing agents obtained from plants such as Cullen corylifolium or Ammi visnaga). The paper also describes other traditional herbs such as Ginkgo biloba, Phlebodium aureum, Piper nigrum, Picrorhiza kurroa, and Baccharoides anthelmintica that can likewise act as potential therapeutical agents. Based on our findings, photosensitizing agents in combination with phototherapy, the association of oral Phebodium aureum with phototherapies as well as oral G. biloba in monotherapy showed greater scientific evidence as therapeutic options. The research results emphasize that further investigation in this area is merited. More long-term follow up clinical trials and higher quality randomized trials are needed.

Genetically predicted levels of folate, vitamin B12, and risk of autoimmune diseases: A Mendelian randomization study

Background

Evidence from observational studies on the association of folate and vitamin B12 with autoimmune diseases are conflicting.

Objective

We aimed to investigate the relationship of folate and vitamin B12 with autoimmune diseases using Mendelian randomization (MR).

Materials and methods

We selected single-nucleotide polymorphisms associated with folate and vitamin B12 at the genome-wide significance level. Summary-level data for four common autoimmune diseases (vitiligo, inflammatory bowel disease, rheumatoid arthritis, and systemic lupus erythematosus) were obtained from large-scale genome-wide association studies, with a sample size of 44,266, 86,640, 58,284, and 23,210, respectively. MR analyses were conducted using the inverse variance weighted (IVW) approach, and sensitivity analyses were further performed to test the robustness.

Results

We found that a higher genetically determined serum folate level per one standard deviation (SD) was associated with a decreased risk of vitiligo by the IVW method [odds ratios (OR) = 0.47; 95% confidence interval (CI): 0.32–0.69; P = 1.33 × 10-4]. Sensitivity analyses using alternative methods showed similar associations, and no evidence of pleiotropy was detected by MR-Egger regression (P = 0.919). In addition, we observed that vitamin B12 per one SD was positively associated with IBD (IVW: OR = 1.14, 95% CI: 1.03–1.26, P = 0.010; maximum likelihood: OR = 1.14, 95% CI: 1.01–1.29, P = 0.035; MR-PRESSO: OR = 1.14, 95% CI:1.01–1.28, P =0.037), while the association was not significant after Bonferroni correction.

Conclusion

The study provides convincing evidence for an inverse association between serum folate level and risk of vitiligo. Further studies are warranted to elucidate the possible association between vitamin B12 and risk of IBD.

Stimulatory effects of Lycium shawii on human melanocyte proliferation, migration, and melanogenesis: In vitro and in silico studies

There is no first-line treatment for vitiligo, a skin disease characterized by a lack of melanin produced by the melanocytes, resulting in an urgent demand for new therapeutic drugs capable of stimulating melanocyte functions, including melanogenesis. In this study, traditional medicinal plant extracts were tested for cultured human melanocyte proliferation, migration, and melanogenesis using MTT, scratch wound-healing assays, transmission electron microscopy, immunofluorescence staining, and Western blot technology. Of the methanolic extracts, Lycium shawii L. (L. shawii) extract increased melanocyte proliferation at low concentrations and modulated melanocyte migration. At the lowest tested concentration (i.e., 7.8 μg/mL), the L. shawii methanolic extract promoted melanosome formation, maturation, and enhanced melanin production, which was associated with the upregulation of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein (TRP)-1 and TRP-2 melanogenesis-related proteins, and melanogenesis-related proteins. After the chemical analysis and L. shawii extract-derived metabolite identification, the in silico studies revealed the molecular interactions between Metabolite 5, identified as apigenin (4,5,6-trihydroxyflavone), and the copper active site of tyrosinase, predicting enhanced tyrosinase activity and subsequent melanin formation. In conclusion, L. shawii methanolic extract stimulates melanocyte functions, including melanin production, and its derivative Metabolite 5 enhances tyrosinase activity, suggesting further investigation of the L. shawii extract-derived Metabolite 5 as a potential natural drug for vitiligo treatment.

Association between the CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants with vitiligo: Study on a Mexican population

Background

Vitiligo is characterized by an autoimmune response targeting melanocytes, thus resulting in skin depigmentation. There are several genetic components involved in the development of vitiligo, of which various gene polymorphisms are currently considered as risk factors. For example, the CTLA4 (T-lymphocyte antigen 4) +49A/G (rs231775) and CT60 (rs3087243) gene variants have been associated with a predisposition for autoimmune diseases in different populations; however, their involvement in the development of vitiligo remains controversial.

Objective

We evaluated the association between vitiligo and the CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants in a Mexican population.

Methods

A total of 116 vitiligo patients and 117 control subjects from northeast Mexico were included in the study and analyzed through PCR-RFLP to determine whether there is an association between vitiligo and CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants.

Results

No statistical difference was observed for both gene polymorphisms between vitiligo patients and controls (p > 0.05). Otherwise, vitiligo activity, family history of vitiligo, personal history of autoimmune diseases, or sex did not show any difference (p > 0.05).

Conclusion

As suggested by the analysis of a northeastern Mexican population, the CTLA4 +49A/G (rs231775) and CT60 (rs3087243) gene variants do not constitute a risk factor in the development of vitiligo.

Contribution of HLA class II genes, DRB4*01:01, DRB1*07:01, and DQB1*03:03:2 to clinical features of Vitiligo disease in Iranian population

BACKGROUND

Vitiligo is a multifactorial depigmentation condition, which is due to skin melanocyte destruction. Increased expression of HLA class II genes in patients with pre-lesions of Vitiligo suggests a crucial role for the participation of immune response in Vitiligo development. Recent studies progressively focused on HLA-DRB1 and DQB1 genes. In this study, we have evaluated the association and role of HLA-DRB4*01:01, -DRB1*07:01, and -DQB1*03:03:2 genes in different clinical subtypes of Vitiligo in the Iranian population.

METHODS

First, Genomic DNA from peripheral blood of 125 unrelated Vitiligo patients and 100 unrelated healthy controls were extracted through the salting-out method. Then, HLA class II genotyping was performed using the sequence-specific primer PCR method. Finally, the clinical relevance of the testing for these genotypes was evaluated by applying the PcPPV (prevalence-corrected positive predictive value) formula.

RESULTS

Our results indicated the positive associations of DRB4*01:01 and DRB1*07:01 allelic genes with early-onset Vitiligo (p = 0.024 and 0.022, respectively). DRB4*01:01 also showed strong protection against late-onset Vitiligo (p = 0.0016, RR = 0.360). Moreover, our data revealed that the DRB1*07:01 increases the susceptibility to Sporadic Vitiligo (p = 0.030, RR = 1.702). Furthermore, our findings proposed that elevated vulnerability of Vitiligo patients due to DRB4*01:01 and DRB1*07:01 alleles maybe is correlated with the presence of amino acid Arginine at position 71 at pocket 4 on the antigen-binding site of the HLA-DRB1 receptor.

CONCLUSION

Our findings on different subtypes of Vitiligo suggest that, despite a more apparent autoimmune involvement, a non-autoimmune nature for the etiology of Vitiligo should also be considered.