Novel immunological and genetic factors associated with vitiligo: A review

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.