The genetic concept of vitiligo

N-Acetyltransferase 2 gene polymorphism and its serum levels in vitiligo patients

BACKGROUND

Although numerous mechanisms are involved in vitiligo pathogenesis, few studies correlate N-acetyltransferase 2 to this disease.

AIM

To assess the N-acetyltransferase 2 (rs1799929) gene and its serum levels in vitiligo patients.

SUBJECTS AND METHODS

In this case-control study, 65 vitiligo cases were compared to 65 age- and sex-matched healthy controls. Serum NAT2 levels and the NAT2 gene polymorphism (rs1799929) were evaluated using ELISA and real-time PCR, respectively.

RESULTS

Serum N-acetyltransferase 2 levels were significantly lower in cases than in controls, 1.24 ± 0.31 vs. 2.01 ± 0.46 (p = 0.001). CC genotype was more dominant in controls (58.5%) than in cases (20%). TT and CT genotypes were more dominant in cases (30.8% and 49.2%) than in controls (13.8% and 27.7%), respectively (p = 0.001). The C allele was more prominent in controls (72.3%) than in cases (44.6%) while the T allele was more dominant in cases (55.4%) than in controls (27.7%) (p = 0.001). N-acetyltransferase 2 slow acetylator phenotype (TT genotype) was higher in cases (30.8%) than in controls (13.8%) and rapid acetylator phenotypes (CC and CT genotypes) were higher in controls (86.2%) than in cases (69.2%) (p = 0.035).

CONCLUSION

Slow acetylator genotype (TT) of NAT2 gene (rs1799929) and low serum levels of NAT2 enzyme might play a role in the susceptibility and pathogenesis of vitiligo.

Markers of Metabolic Abnormalities in Vitiligo Patients

While vitiligo is primarily caused by melanocyte deficiency or dysfunction, recent studies have revealed a notable prevalence of metabolic syndrome (MetS) among patients with vitiligo. This suggests shared pathogenic features between the two conditions. Individuals with vitiligo often exhibit variations in triglyceride levels, cholesterol, and blood pressure, which are also affected in MetS. Given the similarities in their underlying mechanisms, genetic factors, pro-inflammatory signalling pathways, and increased oxidative stress, this study aims to highlight the common traits between vitiligo and metabolic systemic disorders. Serum analyses confirmed increased low-density lipoprotein (LDL) levels in patients with vitiligo, compared to physiological values. In addition, we reported significant decreases in folate and vitamin D (Vit D) levels. Oxidative stress is one of the underlying causes of the development of metabolic syndromes and is related to the advancement of skin diseases. This study found high levels of inflammatory cytokines, such as interleukin-6 (IL-6) and chemokine 10 (CXCL10), which are markers of inflammation and disease progression. The accumulation of insulin growth factor binding proteins 5 (IGFBP5) and advanced glycation end products (AGEs) entailed in atherosclerosis and diabetes onset, respectively, were also disclosed in vitiligo. In addition, the blood-associated activity of the antioxidant enzymes catalase (Cat) and superoxide dismutase (SOD) was impaired. Moreover, the plasma fatty acid (FAs) profile analysis showed an alteration in composition and specific estimated activities of FAs biosynthetic enzymes resembling MetS development, resulting in an imbalance towards pro-inflammatory n6-series FAs. These results revealed a systemic metabolic alteration in vitiligo patients that could be considered a new target for developing a more effective therapeutic approach.

Target area treatment ratio of varied lesions in the cultured pure melanocyte transplantation repigmentation of vitiligo: A retrospective study

Autologous cultured pure melanocyte transplantation (CMT) can be utilized to treat stable vitiligo cases, but clinical data are insufficient to improve its efficacy. To evaluate the influence of various factors on the therapeutic effect of CMT, this single-center retrospective study enrolled stable vitiligo patients who underwent CMT between 2009 and 2020. Univariate and multivariable analysis were used to determine the factors affecting the outcome of repigmentation. The study included 491 patients with long-term follow-up data (6-120 months). It was found that 69.7% of patients achieved an excellent re-color effect and 18.4% achieved a good re-color effect. There were statistically significant differences in pigmentation between patients with stable disease course, vitiligo type, and lesion site. Overall, a significant positive correlation between the target area treatment ratio of varied lesions and the percentage of repigmentation was found. CMT is effective and well tolerated in the treatment of stable vitiligo. Various factors, especially the target area treatment ratio of varied lesions, should be carefully assessed before using CMT. As the target area treatment ratio of varied lesions could further improve the post-operative repigmentation other than type of vitiligo. This clinic trial was approved by Hangzhou Third People's Hospital (number 2023KA015, national clinical record number MR-33-23-034502).

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.

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.

An in-depth analysis reveals two new genetic variants on 22q11.2 associated with vitiligo in the Chinese Han population

BACKGROUND

Vitiligo is a complex disease in which patchy depigmentation is the result of an autoimmune-induced loss of melanocytes in affected regions. On the basis of a genome-wide linkage analysis of vitiligo in the Chinese Han population, we previously showed significant evidence of a linkage between 22q12 and vitiligo. Our aim in the current study was to identify vitiligo susceptibility variants within an expanded region of the 22q12 locus.

METHODS AND RESULTS

An in-depth analysis of the expanded region of the 22q12 locus was performed by imputation using a large GWAS dataset consisting of 1117 cases and 1701 controls. Eight nominal SNPs were selected and genotyped in an independent cohort of Chinese Han individuals (2069 patients and 1370 control individuals) by using the Sequenom MassArray iPLEX1 system. The data were analyzed with PLINK 1.07 software. The C allele of rs730669 located in ZDHHC8/RTN4R showed a strong association with vitiligo (P = 3.25 × 10^-8, OR = 0.81). The C allele of rs4820338 located in VPREB1 and the A allele of rs2051582 (a SNP reported in our previous study) located in IL2RB showed a suggestive association with vitiligo (P = 1.04 × 10^-5, OR = 0.86; P = 1.78 × 10^-6, OR = 1.27). The three identified SNPs showed independent associations with vitiligo in a conditional logistic regression analysis (all P < 1.0 × 10^-5; all D' < 0.05 and r² < 1.0 × 10^-4).

CONCLUSIONS

The study reveals that two novel variants rs730669 (ZDHHC8/RTN4R) and rs4820338 (VPREB1) on 22q11.2 might confer susceptibility to vitiligo and affect disease subphenotypes. The presence of multiple independent variants emphasizes their important roles in the genetic pathogenesis of disease.

Resident Memory T Cells in Autoimmune Skin Diseases

Tissue resident memory T cells (TRM) are a critical component of the immune system, providing the body with an immediate and highly specific response against pathogens re-infecting peripheral tissues. More recently, however, it has been demonstrated that TRM cells also form during autoimmunity. TRM mediated autoimmune diseases are particularly destructive, because unlike foreign antigens, the self-antigens are never cleared, continuously activating self-reactive TRM T cells. In this article, we will focus on how TRMs mediate disease in autoimmune skin conditions, specifically vitiligo, psoriasis, cutaneous lupus erythematosus, alopecia areata and frontal fibrosing alopecia.

Deleterious effect of angiotensin-converting enzyme gene polymorphism in vitiligo patients

Vitiligo is a rare skin condition caused by an immune reaction. Vitiligo can occur anywhere on the body. This proposed explanation of vitiligo makes it clear that vitiligo is not linked to any other autoimmune diseases. The polymorphisms of some genes present in the immune system play a major function in susceptibility of vitiligo. Meta-analysis studies have shown that the Angiotensin converting enzyme (ACE) gene insertion and deletion polymorphism is closely associated with vitiligo in many ethnicities. The connection between ACE gene and vitiligo is connected through the auto immune diseases and there are no genetic polymorphism studies have been carried out with ACE gene with vitiligo in the Saudi population. Previous studies show that vitiligo patients are more likely to also have an autoimmune disorder. The current study aims to investigate the I/D polymorphism in the ACE gene with diagnosed patients with vitiligo subjects. This is a case-control study carried out in the Saudi population with 100 vitiligo cases and 100 healthy controls. Genotyping was performed through polymerase chain reaction followed by 3% agarose gel electrophoresis. Genotype and allele frequencies were carried out with genetic mode of inheritances. Statistical analysis was performed considering p < 0.05 as significant association. There was a substantial difference in allele frequency distribution between vitiligo patients and healthy controls (OR-1.70 (95%CI: 1.14-2.53); p = 0.008). Additionally, DD genotype (OR-4.71 (95%CI: 1.42-15.61); p = 0.008) and recessive model (OR-2.66 (95%CI: 1.41-5.02); p = 0.002) was strongly associated. Both dominant and co-dominant showed the negative association (p > 0.05) when compared between the vitiligo cases and controls. The correlation between age and genotyping was performed with Anova analysis and current study results confirmed the substantial link between 11 and 20 years (p = 0.01) and 31-40 years (p = 0.04) with the defined age groups. In conclusion, in Saudi populations, the ACE gene I/D polymorphism was identified as being correlated with vitiligo. This is the first study in Saudi Arabia to report the risk factors of vitiligo with the ACE gene polymorphism.

Novel immunological and genetic factors associated with vitiligo: A review

Vitiligo is a skin disorder characterized by depigmentation of the skin due to a lack of melanin. This condition affects men and woman of all ages and its incidence is not restricted by ethnicity or region. Vitiligo is a multifactorial disease, in which melanocytes, which serve important functions in skin pigmentation and immune processes, are impaired. There is sufficient evidence that immunological and genetic factors are primarily responsible for the destruction and dysfunction of melanocytes. Therefore, genetic DNA sequence variants that participate in skin homeostasis, pigmentation and immune response regulation, as well as altered expression patterns, may contribute to the risk of developing vitiligo. The current review presented an overview of the mechanism of pigmentation and of currently known factors involved in depigmentation, as well as the classification, epidemiology, associated comorbidities, risk factors, immunopathogenesis and several genetic and molecular changes associated with vitiligo.

A Concise Review on the Role of Endoplasmic Reticulum Stress in the Development of Autoimmunity in Vitiligo Pathogenesis

Vitiligo is characterized by circumscribed depigmented macules in the skin resulting due to the autoimmune destruction of melanocytes from the epidermis. Both humoral as well as cell-mediated autoimmune responses are involved in melanocyte destruction. Several studies including ours have established that oxidative stress is involved in vitiligo onset, while autoimmunity contributes to the disease progression. However, the underlying mechanism involved in programing the onset and progression of the disease remains a conundrum. Based on several direct and indirect evidences, we suggested that endoplasmic reticulum (ER) stress might act as a connecting link between oxidative stress and autoimmunity in vitiligo pathogenesis. Oxidative stress disrupts cellular redox potential that extends to the ER causing the accumulation of misfolded proteins, which activates the unfolded protein response (UPR). The primary aim of UPR is to resolve the stress and restore cellular homeostasis for cell survival. Growing evidences suggest a vital role of UPR in immune regulation. Moreover, defective UPR has been implicated in the development of autoimmunity in several autoimmune disorders. ER stress-activated UPR plays an essential role in the regulation and maintenance of innate as well as adaptive immunity, and a defective UPR may result in systemic/tissue level/organ-specific autoimmunity. This review emphasizes on understanding the role of ER stress-induced UPR in the development of systemic and tissue level autoimmunity in vitiligo pathogenesis and its therapeutics.

Investigation of the Role of Interleukin 6 in Vitiligo Pathogenesis

Interleukin-6 (IL6) is involved in pathogenesis of several autoimmune disorders including vitiligo. Hence, we aimed to investigate the association of IL6 -174 G/C and -572 G/C polymorphisms and its transcript levels with vitiligo; to evaluate the effect of IL-6 on normal human melanocyte (NHM) viability and expression of IL6R, MITF and TYR. IL6 -174 G/C and -572 G/C polymorphisms were genotyped by ARMS-PCR and PCR-RFLP respectively in 343 controls and 322 vitiligo patients. IL6 transcript levels were estimated from PBMCs (96 controls and 77 patients) and skin samples (15 controls and 15 patients) by qPCR. NHM viability was assessed by MTT; IL6R, MITF and TYR transcript and protein levels were monitored by qPCR and ICC respectively. Genetic analyses revealed no association of IL6 -174 G/C polymorphism (p> .05) with vitiligo. Analysis of IL6 -572 G/C revealed reduced risk of vitiligo in individuals with GC/CC genotypes compared to GG genotype (p = .010). IL6 expression was significantly increased (p = .0197) in PBMCs of patients. Further, IL6 expression was significantly higher in non-lesional skin compared to controls (p = .009). In-vitro NHM viability was decreased upon IL-6 exposure (10-50 ng/ml; p< .05), with significantly increased IL6R transcript (p = .042) and protein levels (p = .003) however, MITF transcript (p = .0003) and protein levels (p = .016), and TYR transcript levels (p = .001) were significantly decreased. The results suggest that IL6 -572 G/C polymorphism might be associated with vitiligo susceptibility in Gujarat population. Moreover, increased IL6 expression in vitiligo patients and its effect on NHM suggest a potential role in melanocyte biology.

CONCLUSION

The results suggest that IL6 - 572 G/C polymorphism might be associated with vitiligo susceptibility in Gujarat population. Moreover, increased IL6 expression in vitiligo patients and its effect on NHM suggest a potential role in melanocyte biology.

Is NAT2 Gene Polymorphism Associated with Vitiligo?

Background:

N-acetyltransferase-2 (NAT2) is a phase II xenobiotic enzyme that plays an important role against oxidative stress-mediated reactive oxygen species protection. Polymorphism in specific genotypes of NAT2 may lead to increase an imbalance in antioxidant systems and may influence the pathogenesis of vitiligo. We conducted this study to see the association between NAT2 gene polymorphism and risk of vitiligo. We looked into whether single-nucleotide polymorphisms (SNP) at positions 857, 481 and 590 of the coding region of the NAT2 gene play as a risk factor for vitiligo among north Indian people.

Methods:

In this study, we assessed 100 patients with vitiligo and 160 healthy individuals as controls. Genomic DNA was extracted from human peripheral blood and polymerase chain reaction–restricted fragment length polymorphism was done to identify the single nucleotide polymorphism at positions 857, 481, and 590 of the coding region of the NAT2 gene.

Results:

In this study, we observed a significant higher risk with slow acetylator genotypes of NAT2 (OR = 2.85; 95% CI = 1.68-4.84, P value < 0.001) for the vitiligo. Furthermore, in the association between NAT2 acetylator genotypes with percentage of body surface area (BSA) of disease, we observed that slow acetylator genotypes of NAT2 has significant higher risk with low grade of disease (1%–10% >11%–30% >30% of BSA).

Limitations:

A major limitation of this study was the small sample size and warrants further investigation on a large epidemiological study to confirm these findings.

Conclusions:

Our preliminary data indicate that NAT2 slow acetylator genotype exhibits significant association for the risk of vitiligo, especially in disease predisposition and initiation.

A case series pilot study on the combination of 5-aminolevulinic acid and photodynamic therapy (ALA-PDT) for treatment of vitiligo

BACKGROUND

To study the effective therapeutic concentration, drug application duration, irradiation duration and irradiation dosage of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) for treating vitiligo and observe its clinical efficacy.

OBJECTIVE

To assess the clinical efficacy of ALA-PDT for treating vitiligo.

METHODS

ALA with different drug concentrations, drug application durations, irradiation durations and irradiation dosages were adopted to treat skin lesions caused by vitiligo to determine the effective drug concentration, drug application duration, irradiation duration and irradiation dosage for treating three vitiligo volunteers and observe the therapeutic results.

RESULTS

The clinical trial suggested that ALA at a drug concentration of 1.5%, drug application duration for 3 hours, irradiation dosage of 80mw/cm2 and irradiation duration for 20 min was effective in treating vitiligo. Under these parameters, ALA-PDT was effective to the three vitiligo volunteers, with mild pain and feeling of burning but no other adverse reaction during treatment.

STUDY LIMITATIONS

Due to the small sample size in this study for the effectiveness of PDT in treating vitiligo and the potential variations in the efficacy for treating the disease at different areas, further studies shall be conducted for confirmation.

CONCLUSIONS

ALA with a drug concentration at 1.5%, drug application duration for 3 hours, irradiation dosage of 80 mw/cm2 and irradiation duration for 20 min is effective in treating vitiligo. Therefore, ALA-PDT is safe and effective in treating the disease, with minor adverse events, providing a new method for treating vitiligo in the future.

Vitiligo in Children: A Better Understanding of the Disease

Vitiligo is an important skin disease of childhood. The authors briefly discuss the etiopathobiology, clinics and comorbidities of the disease.

Differential Expression of Nitric Oxide Synthase Isoforms nNOS and iNOS in Patients with Non-Segmental Generalized Vitiligo

Nitric oxide (NO) is involved in several biological processes, but its role in human melanogenesis is still not well understood. Exposure to UVA and UVB induces nitric oxide production in keratinocytes and melanocytes through the activation of constitutive nitric oxide synthase, increasing tyrosinase activity and melanin synthesis, whereas inducible nitric oxide synthase over expression might be involved in hypopigmentary disorders. The aim of this study was to evaluate whether inducible nitric oxide synthase and neuronal nitric oxide synthase expression were modified in vitiligo skin compared to healthy controls. Skin biopsies were obtained from inflammatory/lesional and white/lesional skin in 12 patients with active, non-segmental vitiligo; site-matched biopsies of normal skin from eight patients were used as controls. Nitric oxide synthase isoforms expression was evaluated by confocal laser scanning microscopy and Western Blot analysis. Inducible nitric oxide synthase expression was significantly increased in inflammatory/lesional skin compared to healthy skin; melanocytes showed a moderate neuronal nitric oxide synthase expression in white/lesional skin, demonstrating that metabolic function still goes on. The obtained data demonstrated that vitiligo lesions were characterized by modifications of nitric oxide synthase isoforms, thus confirming the hypothesis that nitric oxide imbalance is involved in vitiligo and supporting the idea that nitric oxide synthase inhibitors might be used as a possible therapeutic approach for the management of vitiligo.

Genetic variants of interferon-gamma and its mRNA expression and inflammatory parameters in the pathogenesis of vitiligo

Although genetics plays an essential role in the pathogenesis of vitiligo, vitiligo pathogenesis is still unclear. Our aim was to investigate the role of IFN-γ expression and polymorphism in vitiligo susceptibility and whether intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor (TNF)-α, and TNF-β play a role in vitiligo pathogenesis as important inflammatory parameters. Eighty-five patients with vitiligo and 90 controls were investigated for IFN-γ gene expression by quantitative real-time PCR and genotyped for IFN-γ +874T/A (rs2430561) and IFN-γ +2109A/G (rs1861494) gene polymorphisms by sequence-specific primer (SSP)-PCR and PCR-restriction fragment length polymorphism (RFLP), respectively. Serum levels of inflammatory parameters were measured using ELISA. Frequencies of the +874 TT genotype and T allele were significantly higher in patients with active vitiligo than in stable patients (P = 0.01 and 0.03, respectively). Calculation of odds ratio suggested a 1.7-fold increased risk of vitiligo in individuals having the TA haplotype. We observed overexpression of IFN-γ mRNA with elevated serum levels of IFN-γ, ICAM-1, TNF-α, and TNF-β in patients with vitiligo when compared with the control group (P = 0.001, for all). In addition, these levels were elevated in patients with active vitiligo compared with stable patients with vitiligo (P = 0.008, 0.006, 0.01, 0.01, and 0.03, respectively), which suggests the involvement of these cytokines in disease activity. In conclusion, IFN-γ is a promising immunological marker in vitiligo pathogenesis.

Aquaporin 3 and E-Cadherin Expression in Perilesional Vitiligo Skin

INTRODUCTION

Vitiligo is a common dermatologic disorder with debated aetiology. Most studies focused on role of melanocytes and few investigated the role of keratinocytes in pathogenesis of the disease.

AIM

To investigate the keratinocyte adhesion in perilesional vitiligo skin through the immunolocalization of Aquaporin-3 (AQP3) and E-cadherin.

SETTING AND DESIGN

Sixty five subjects were selected. These included 40 cases with vitiligo and 25 age and gender-matched healthy subjects as a control group.

MATERIALS AND METHODS

Skin biopsies were taken from perilesional skin of cases and from site-matched areas of control subjects. The expression of AQP3 and E-cadherin was evaluated by immunohistochemical techniques.

STATISTICAL ANALYSIS

Results were statistically analysed using IBM personal computer and the statistical package SPSS version 11. Fisher-exact and Chi-square tests were used to study the association between two qualitative variables. Mann-Whitney test was used for comparison between quantitative variables not normally distributed. Spearman's correlation coefficient was used to assess correlation between two quantitative variables. The p≤0.05 was considered significant.

RESULTS

Regarding AQP3 expression, strong intensity, diffuse distribution, higher percent of expression and higher H-score (p<0.001 for all) were significantly associated with control skin compared with perilesional skin in follicular and inter-follicular epidermis. Regarding E-cadherin expression, moderate intensity, higher percent of expression and higher H- score (p<0.001 for all) were significantly associated with control skin compared with perilesional skin in follicular and inter-follicular epidermis. No significant association was found between E-cadherin and AQP3 H-scores or percent of expression and clinical data of selected cases. No significant correlation was detected between E-cadherin and AQP3 H-scores or percent of expression and age of cases, disease duration or Vitiligo Disease Activity (VIDA) score.

CONCLUSION

The following sequence of events can be suggested for vitiligo pathogenesis, based on findings in perilesional skin: AQP3 is downregulated by a primary unknown factor and this will lead to down regulation of its downstream molecules, mainly phosphatidylinositol 3-kinase, E-cadherin and catenins, which is followed by defective keratinocyte adhesion and decreased release of keratinocyte-derived growth factors. Subsequently a secondary event, physical trauma, oxidative stress or autoantibodies, may lead to exfoliation of keratinocytes and pigmented cells.

Spontaneous Coronary Artery Dissection: Report of 3 Cases and Literature Review Hormonal, Autoimmune, Morphological Factors

The number of cases with spontaneous coronary artery dissection (SCAD) is considered to be being underestimated because of a large amount of SCAD leading to sudden death without previous diagnosis. Besides, not only in clinics but also in autopsy practice, correct diagnosis of SCAD is important to prevent forensic malpractice.The article is intended to discuss the pathological findings through the forensic point of view for improving the malpractice expertise in scope of clinicians' timely antemortem diagnosis according to risk factors and in scope of forensic pathologists' the cause of death determination ability according to macroscopical and microscopical findings of the autopsy.In 3 cases reported, the main characteristics were the female sex, pregnancy history and a sudden death without any trauma. However, although there are many women giving birth or using oral contraceptives, only some of them are facing with SCAD. This suggests the possibility of some hereditary factors, whereas hereditary characteristics may be understood in many different ways like hormone-releasing regulating mechanisms as well as immunity, morphology, or any other mechanism. For instance, autoimmunity has been also a hereditary underlying factor for vessel injury considered in presented cases.

Association of ApaI and BsmI polymorphisms with vitiligo risk: a meta-analysis

BACKGROUND

It has been reported that polymorphisms of the vitamin D receptor gene (VDR) such as ApaI or BsmI may affect the risk of vitiligo. However, the results have been inconsistent.

AIM

To evaluate the association between two common polymorphisms (ApaI and BsmI) in the VDR gene and the susceptibility to vitiligo.

METHODS

The PubMed, Cochrane Library and China National Knowledge Infrastructure (CNKI) databases were searched, and OR with 95% CI was calculated. The strength of association and vitiligo risk was assessed under five genetic models: allele, dominant, recessive, homozygous and heterozygous.

RESULTS

Six relevant studies were identified, including five studies that assessed the ApaI polymorphism and four the BsmI polymorphism (some overlapped). The meta-analysis results indicated that either the ApaI or the BsmI gene polymorphism may increase the risk of vitiligo in East Asian populations (aa + Aa vs. AA: OR = 1.40, 95% CI 1.01-1.96, P < 0.05; bb vs. Bb + BB: OR = 1.32, 95% CI 1.09-1.59, P < 0.01). No publication bias was detected in this meta-analysis.

CONCLUSION

The current meta-analysis suggests that the ApaI a allele or BsmI bb genotype are associated with the risk of vitiligo in East Asian populations. Thus, these polymorphisms could be potential biomarkers for early detection of vitiligo.

Inducible nitric oxide synthase promoter polymorphism: a molecular susceptibility marker for vitiligo in Egyptians

BACKGROUND

Vitiligo is a depigmentary disease characterized by loss of melanocytes from the skin and mucous membranes. The pathomechanism of vitiligo is still obscure. Inducible nitric oxide synthase (iNOS) produces very large amounts of nitric oxide (NO). Promotor polymorphisms within iNOS gene have been reported to be associated with overproduction of NO, which may induce melanocyte destruction.

AIM

The current study aimed at investigating the possible association between iNOS gene polymorphism (-954 G/C and Ex 16+14 C/T) and susceptibility to non-segmental vitiligo in a cohort of Egyptians.

METHODS

The study was conducted on 200 participants: 100 patients with vitiligo and 100 aged matched healthy controls. Polymerase chain reaction using restriction fragment length polymorphism method (PCR-RFLP) was used to identify the genotypes.

RESULTS

Our results showed that iNOS -954 G/C heteromutant genotype (GC) was associated with increased risk of vitiligo (OR = 3.35, 95% CI = 1.77-6.33), and the risk increased when confined to females (OR = 7.4, 95% CI = 2.80-19.40). iNOS Ex 16 + 14 C/T heteromutant genotype (CT) conferred two folds increased risk of vitiligo (OR = 2.47, 95% CI = 1.39-4.37). Furthermore, the risk of vitiligo increased when the heteromutant genotype of iNOS -954 G/C (GC) was co-inherited with the wild genotype of iNOS Ex16+14 C/T (CC) (OR = 23.2, 95% CI = 3.04-177.21).

CONCLUSIONS

Inducible nitric oxide synthase -954 G/C and Ex 16+14 C/T might be considered as genetic susceptibility markers for non-segmental vitiligo among Egyptians.

Protein tyrosine phosphatase PTPN22 +1858C/T polymorphism is associated with active vitiligo

Vitiligo is characterized by a skin depigmentation disorder resulting from an autoimmune response targeting melanocytes. Within the genetic factors involved in the development of the vitiligo immune response, various genes in the major histocompatibility complex (MHC) and non-MHC loci have been considered to be risk factors. The PTPN22 gene encodes for a lymphoid protein tyrosine phosphatase, a regulator of the activation and development of T-cells. The +1858C/T polymorphism has been associated to autoimmune disease susceptibility in different populations and could be implicated in the onset of vitiligo. To assess the possible association between the presence of PTPN22 +1858C/T and vitiligo, 187 patients with vitiligo and 223 control subjects were analyzed in the study. Genomic DNA was isolated using the salting-out method and samples were subjected to polymerase chain reaction-restriction fragment length polymorphism in order to detect the PTPN22 +1858C/T polymorphism. Causal associations were determined by χ² test and their respective odds ratio (OR) was assessed in a 2×2 contingency table. The results showed an association between active vitiligo and the allele T load [P=0.0418; OR, 2.5706; 95% confidence interval (CI), 1.0040-6.5816], and active vitiligo-CT genotype (P=0.0389, OR, 2.6548; 95% CI, 1.0191-6.9156). In conclusion, the present data indicates a possible association between the PTPN22 +1858C/T genotype and a significant susceptibility of developing an active form of vitiligo.

Current aspects of vitiligo genetics

Vitiligo is a common acquired depigmentation disorder of the skin manifested by the presence of white macules. The disease occurs at a frequency of approximately 1–4% of the world population. Currently, the most popular theory of vitiligo development is a multifactorial hypothesis according to which genetic conditions predispose vitiligo macules to occur as a result of specific environmental factors. According to the genetic hypothesis, vitiligo inheritance is multigenic. Genetic studies conducted so far concern patients with non-segmental vitiligo. There are three basic techniques of genetic studies: candidate gene association studies, genomewide linkage studies and genome-wide association studies (GWAS). The GWAS are the “gold standard” for detecting susceptibility genes. Up to now, approximately 36 convincing non-segmental vitiligo susceptibility loci have been identified. Approximately 90% of them encode immunoregulatory proteins, while approximately 10% encode melanocyte proteins. The existence of various associations between vitiligo and other autoimmune diseases may provide new knowledge on the causes of many disorders. Examples include the inverse relationship between vitiligo and melanoma and association of vitiligo with other autoimmune diseases. The main goal of all researches is to find new, optimal therapeutic strategies for vitiligo and other autoimmune diseases.

Analysis of oxidative stress status, catalase and catechol-O-methyltransferase polymorphisms in Egyptian vitiligo patients

Vitiligo is the most common depigmentation disorder of the skin. Oxidative stress is implicated as one of the probable events involved in vitiligo pathogenesis possibly contributing to melanocyte destruction. Evidence indicates that certain genes including those involved in oxidative stress and melanin synthesis are crucial for development of vitiligo. This study evaluates the oxidative stress status, the role of catalase (CAT) and catechol-O-Methyltransferase (COMT) gene polymorphisms in the etiology of generalized vitiligo in Egyptians. Total antioxidant capacity (TAC) and malondialdehyde (MDA) levels as well as CAT exon 9 T/C and COMT 158 G/A polymorphisms were determined in 89 patients and 90 age and sex-matched controls. Our results showed significantly lower TAC along with higher MDA levels in vitiligo patients compared with controls. Meanwhile, genotype and allele distributions of CAT and COMT polymorphisms in cases were not significantly different from those of controls. Moreover, we found no association between both polymorphisms and vitiligo susceptibility. In conclusion, the enhanced oxidative stress with the lack of association between CAT and COMT polymorphisms and susceptibility to vitiligo in our patients suggest that mutations in other genes related to the oxidative pathway might contribute to the etiology of generalized vitiligo in Egyptian population.

Association of the 389 C/T polymorphism of the catalase gene with susceptibility to vitiligo: a meta-analysis

BACKGROUND

The 389 C/T polymorphism in the catalase gene, CAT, has been reported to be associated with the risk of vitiligo.

AIM

To evaluate the association of the CAT 389 C/T polymorphism with susceptibility to vitiligo.

METHODS

We undertook a literature search and included the relevant studies passing the selection criteria. After the relevant data were extracted from each study, we statistically analysed the strength of association between the CAT gene and vitiligo risk.

RESULTS

In total, 7 relevant studies were identified, comprising 1531 patients with vitiligo and 1608 controls. The genotype distribution in the controls of all studies complied with Hardy-Weinberg equilibrium. After pooling all studies, the results indicated that the 389 C/T polymorphisms in CAT were not associated with the risk of vitiligo in Asians and Turks; however the CT genotype might be a genetic risk factor for susceptibility to vitiligo (OR = 1.77, 95% CI 1.30-2.43, P < 0.001) and the CC genotype might decrease the risk of vitiligo (OR = 0.63, 95% CI 0.47-0.86, P < 0.01) in western Europeans.

CONCLUSIONS

The 389 C/T polymorphisms in the CAT gene may be associated with vitiligo in western Europeans. Further studies with larger sample sizes are warranted to confirm our findings.

Correlation of Vitamin D Levels with Pigmentation in Vitiligo Patients Treated with NBUVB Therapy

Cholecalciferol (vitamin D) might play a physiological role in photo-induced melanogenesis in human skin. We estimated the levels of 25-hydroxy vitamin D [25(OH)D] before, during, and after Narrow Band Ultraviolet B (NBUVB) radiation in patients of vitiligo and their correlation with NBUVB induced pigmentation. Thirty patients of vitiligo and equal number of age and sex matched controls were recruited for the study. Vitiligo patients were treated with NBUVB thrice weekly for 12 weeks. [25(OH)D] levels and Vitiligo Area and Severity Index (VASI) were calculated at 0 (baseline), 6, and 12 weeks. Baseline [25(OH)D] levels were measured in controls. Significant reduction in VASI score was observed after 12 weeks of therapy. Comparison and correlation between mean improvement in VASI and [25(OH)D] levels at 12 weeks showed moderate correlation, and the results were statistically insignificant. Mean reduction in VASI and increase in [25(OH)D] levels after 12 weeks of NBUVB showed moderate correlation. Thus, vitamin D might play a significant role in photo-induced melanogenesis. However, there might be additional effects of the phototherapy on melanogenesis. The complete mechanism of NBUVB induced pigmentation in vitiligo needs to be elucidated.

Tumor necrosis factor B (TNFB) genetic variants and its increased expression are associated with vitiligo susceptibility

Genetic polymorphisms in TNFB are involved in the regulation of its expression and are found to be associated with various autoimmune diseases. The aim of the present study was to determine whether TNFB +252A/G (rs909253) and exon 3 C/A (rs1041981) polymorphisms are associated with vitiligo susceptibility, and expression of TNFB and ICAM1 affects the disease onset and progression. We have earlier reported the role of TNFA in autoimmune pathogenesis of vitiligo, and we now show the involvement of TNFB in vitiligo pathogenesis. The two polymorphisms investigated in the TNFB were in strong linkage disequilibrium and significantly associated with vitiligo. TNFB and ICAM1 transcripts were significantly increased in patients compared to controls. Active vitiligo patients showed significant increase in TNFB transcripts compared to stable vitiligo. The genotype-phenotype analysis revealed that TNFB expression levels were higher in patients with GG and AA genotypes as compared to controls. Patients with the early age of onset and female patients showed higher TNFB and ICAM1 expression. Overall, our findings suggest that the increased TNFB transcript levels in vitiligo patients could result, at least in part, from variations at the genetic level which in turn leads to increased ICAM1 expression. For the first time, we show that TNFB +252A/G and exon 3 C/A polymorphisms are associated with vitiligo susceptibility and influence the TNFB and ICAM1 expression. Moreover, the study also emphasizes influence of TNFB and ICAM1 on the disease progression, onset and gender bias for developing vitiligo.

Involvement of interferon-gamma genetic variants and intercellular adhesion molecule-1 in onset and progression of generalized vitiligo

Interferon-gamma (IFN-γ) is a paracrine inhibitor of melanocytes and genetic variability due to intron 1 polymorphisms in IFNG has been reported to be associated with increased risk for several autoimmune diseases. The aim of present study was to determine whether intron 1 +874A/T (rs2430561) and CA microsatellite (rs3138557) polymorphisms in IFNG are associated with generalized vitiligo (GV) susceptibility and expression of IFNG and intercellular adhesion molecule-1 (ICAM1) affects the disease onset and progression. Here we report that IFNG CA microsatellite but not +874A/T may be a genetic risk factor for GV; however, +874T allele plays a crucial role in increased expression of IFNG mRNA and protein levels which could affect the onset and progression of the disease. Active GV patients showed increased IFNG levels compared to stable GV patients. The genotype-phenotype analysis revealed that IFNG expression levels were higher in patients with +874 TT genotypes and 12 CA repeats. Patients with the early age of onset showed higher IFNG expression and female GV patients showed higher IFNG and ICAM1 expression implicating gender biasness and involvement of IFN-γ in early onset of the disease. Moreover, the increased IFN-γ levels in patients lead to increased ICAM1 expression, which could be a probable link between cytokines and T-cell involvement in pathogenesis of GV.

Correlation of increased MYG1 expression and its promoter polymorphism with disease progression and higher susceptibility in vitiligo patients

BACKGROUND

MYG1 (Melanocyte proliferating gene 1 or C12orf10) -119C/G promoter and Arg4Gln structural polymorphisms have a functional impact on its regulation. The promoter polymorphism was shown to be associated with vitiligo in Caucasian population.

OBJECTIVE

The present study explores MYG1 polymorphisms and correlates them with MYG1 mRNA expression, disease onset and progression in vitiligo patients.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used for genotyping of MYG1 -119C/G promoter (rs1465073) and 11-12AA/GC structural polymorphisms (rs1534284-rs1534283; Arg4Gln) in 846 vitiligo patients and 726 age-matched unaffected controls. MYG1 mRNA levels were assessed in whole blood of 166 patients and 175 controls by Real-time PCR.

RESULTS

The MYG1 -119C/G promoter polymorphism was found to be in significant association with vitiligo being 'G' allele prevalent in patients. However, 11-12AA/GC structural polymorphism was prevalently monogenic in patients and controls with only MYG1 GC (4Arg) allele being present. Significant increase in MYG1 mRNA expression was observed in vitiligo patients compared to controls. The MYG1 mRNA expression was increased in patients with active and generalized vitiligo as compared to stable and localized vitiligo. MYG1 mRNA expression was increased in patients with susceptible -119 GG genotype compared to controls. Also, patients with susceptible -119 GG genotype had early age of onset of vitiligo. Moreover, patients with age groups 1-20 years and 21-40 years showed increased expression of MYG1 mRNA compared to those of controls. Female patients showed significant increase in MYG1 mRNA and early age of onset of vitiligo compared to male patients.

CONCLUSION

The present study suggests that MYG1 -119C/G promoter polymorphism may be a genetic risk factor for susceptibility and progression of vitiligo. The up-regulation of MYG1 transcript in patients with susceptible -119GG genotype advocates the crucial role of MYG1 in autoimmune pathogenesis of vitiligo.

T helper and regulatory T cell cytokine profile in active, stable and narrow band ultraviolet B treated generalized vitiligo

BACKGROUND

Vitiligo is a T cell mediated autoimmune depigmenting disease. Altered cytokine concentrations have been suggested in the pathogenesis of vitiligo.

METHODS

T helper and regulatory T cell cytokines (IL-2, IFN-γ, IL-10, IL-13, IL-17 and TGF-β) have been estimated by ELISA and their clinical correlation was determined. The study had 3 groups: group I with 80 vitiligo patients (60 active and 20 stable), group II with 25 narrow band ultraviolet B treated vitiligo and group III with 70 healthy controls.

RESULTS

Significant difference was found in the serum interleukin (IL)-10, IL-13, IL-17A and TGF-β1 concentrations among 3 groups (P<0.05). In group I, serum IL-2, IL-17A concentrations were significantly increased and TGF-β1 concentrations were decreased in active vitiligo compared to stable vitiligo (P<0.05). Concentrations of IL-2, IL-10 and IL-13 (rho=-0.307, rho=-0.407, rho=-0.351 and P<0.05; respectively) were negatively- and TGF-β1 concentrations were positively-correlated (rho=0.799, P=0.001) with disease duration. Interleukin-13 concentrations were negatively- and serum TGF-β1 concentrations were positively-correlated (rho=-0.326, rho=0.244 and P<0.05; respectively) with percentage of body surface area involvement.

CONCLUSIONS

Increased concentrations of serum IL-10, IL-13, and IL-17A and decreased concentrations of TGF-β1 suggested altered cell-mediated immunity that may facilitate the melanocyte cytotoxicity in vitiligo.

Vitiligo road map

Vitiligo is a depigmenting disorder stemming from melanocyte loss or dysfunction. It has a complex, multifaceted etiology. We constructed a "vitiligo road map," consisting of basic science, clinical, and treatment components, in order to better portray our current understanding of vitiligo pathogenesis and reflect upon novel biomarkers and therapeutic targets for future research. The melanocyte map elaborates on the molecular processes and intracellular signaling pathways initiated by various external autocrine/paracrine factors in representing normal melanocyte homeostatic functions modulating its viability, proliferation, differentiation, dendricity, migration, and melanogenic processes. This vitiligo map identifies known inducers/triggers of vitiligo onset and progression that cultivate a microenvironment for melanocyte disappearance, real or functional. This map describes the molecular mechanisms of currently utilized clinical and experimental treatments of vitiligo that facilitate repigmentation.

Complex inheritance of melanoma and pigmentation of coat and skin in Grey horses

The dominant phenotype of greying with age in horses, caused by a 4.6-kb duplication in intron 6 of STX17, is associated with a high incidence of melanoma and vitiligo-like skin depigmentation. However, the progressive greying and the incidence of melanoma, vitiligo-like depigmentation, and amount of speckling in these horses do not follow a simple inheritance pattern. To understand their inheritance, we analysed the melanoma grade, grey level, vitiligo grade, and speckling grade of 1,119 Grey horses (7,146 measurements) measured in six countries over a 9-year period. We estimated narrow sense heritability (h²), and we decomposed this parameter into polygenic heritability (h²_POLY), heritability due to the Grey (STX17) mutation (h²_STX17), and heritability due to agouti (ASIP) locus (h²_ASIP). A high heritability was found for greying (h² = 0.79), vitiligo (h² = 0.63), and speckling (h² = 0.66), while a moderate heritability was estimated for melanoma (h² = 0.37). The additive component of ASIP was significantly different from zero only for melanoma (h²_ASIP = 0.02). STX17 controlled large proportions of phenotypic variance (h²_STX17 = 0.18–0.55) and overall heritability (h²_STX17/h² = 0.28–0.83) for all traits. Genetic correlations among traits were estimated as moderate to high, primarily due to the effects of the STX17 locus. Nevertheless, the correlation between progressive greying and vitiligo-like depigmentation remained large even after taking into account the effects of STX17. We presented a model where four traits with complex inheritance patterns are strongly influenced by a single mutation. This is in line with evidence of recent studies in domestic animals indicating that some complex traits are, in addition to the large number of genes with small additive effects, influenced by genes of moderate-to-large effect. Furthermore, we demonstrated that the STX17 mutation explains to a large extent the moderate to high genetic correlations among traits, providing an example of strong pleiotropic effects caused by a single gene.

Clarifying the genetic architecture of complex traits is a problem with profound implications for agriculture, biology, and medicine. Using data from Lipizzan horses with the grey coat phenotype, we present an example of a single mutation (intronic duplication in STX17) that explains 18%–55% of phenotypic variation in four complex traits, while polygenic background additive effects also explain 11%–57% of phenotypic variation. This study provides a prime example of complex traits being influenced by genes of moderate-to-large effect and supports further the evidence of recent studies in domestic animals that some complex traits are, in addition to the large number of genes with small additive effects, influenced by genes of moderate-to-large effect. We further show that the STX17 mutation accounts for a large proportion of the estimated genetic correlations between the traits. This case of strong pleiotropic effects of a single mutation on complex traits makes this work of significant general interest for biology and medicine.

Niosomes as a propitious carrier for topical drug delivery

INTRODUCTION

Topical delivery is defined as drug targeting to the pathologic sites of skin with the least systemic absorption. Drug localization in this case is a crucial issue. For these purposes vesicular drug delivery systems including niosomes, proniosomes, liposomes and transferosomes have been developed.

AREAS COVERED

This review first highlights the role of niosome in dermatology focusing on localized skin delivery and then reviews the most recent literatures regarding specific applications of niosomal drug delivery systems in clinics.

EXPERT OPINION

Niosomes are becoming popular in the field of topical drug delivery due to their outstanding characteristics like enhancing the penetration of drugs, providing a sustained pattern of drug release, increasing drug stability and ability to carry both hydrophilic and lipophilic drugs.

Transcriptome analysis reveals markers of aberrantly activated innate immunity in vitiligo lesional and non-lesional skin

BACKGROUND

Vitiligo is characterized by the death of melanocytes in the skin. This is associated with the presence of T cell infiltrates in the lesional borders. However, at present, there is no detailed and systematic characterization on whether additional cellular or molecular changes are present inside vitiligo lesions. Further, it is unknown if the normal appearing non-lesional skin of vitiligo patients is in fact normal. The purpose of this study is to systematically characterize the molecular and cellular characteristics of the lesional and non-lesional skin of vitiligo patients.

METHODS AND MATERIALS

Paired lesional and non-lesional skin biopsies from twenty-three vitiligo patients and normal skin biopsies from sixteen healthy volunteers were obtained with informed consent. The following aspects were analyzed: (1) transcriptome changes present in vitiligo skin using DNA microarrays and qRT-PCR; (2) abnormal cellular infiltrates in vitiligo skin explant cultures using flow cytometry; and (3) distribution of the abnormal cellular infiltrates in vitiligo skin using immunofluorescence microscopy.

RESULTS

Compared with normal skin, vitiligo lesional skin contained 17 genes (mostly melanocyte-specific genes) whose expression was decreased or absent. In contrast, the relative expression of 13 genes was up-regulated. The up-regulated genes point to aberrant activity of the innate immune system, especially natural killer cells in vitiligo. Strikingly, the markers of heightened innate immune responses were also found to be up-regulated in the non-lesional skin of vitiligo patients.

CONCLUSIONS AND CLINICAL IMPLICATIONS

As the first systematic transcriptome characterization of the skin in vitiligo patients, this study revealed previously unknown molecular markers that strongly suggest aberrant innate immune activation in the microenvironment of vitiligo skin. Since these changes involve both lesional and non-lesional skin, our results suggest that therapies targeting the entire skin surface may improve treatment outcomes. Finally, this study revealed novel mediators that may facilitate future development of vitiligo therapies.

Immunohistochemical detection of P53 and Mdm2 in vitiligo

Background:

Vitiligo is a common depigmented skin disorder that is caused by selective destruction of melanocytes. It is generally accepted that the main function of melanin resides in the protection of skin cells against the deleterious effect of ultraviolet rays (UVRs). Association of vitiligo and skin cancer has been a subject of controversy. Occurrence of skin cancer in long-lasting vitiligo is rare despite multiple evidences of DNA damage in vitiliginous skin.

Aim:

To detect the expression of P53 and Mdm2 proteins in both depigmented and normally pigmented skin of vitiligo patients and to compare it to control subjects suffering from nonmelanoma skin cancer (NMSC).

Materials and Methods:

Thirty-four patients with vitiligo and 30 age and sex-matched patients with nodulo-ulcerative basal cell carcinoma (BCC) as a control group were selected. Both patients and control subjects had outdoor occupations. Skin biopsies were taken from each case and control subjects. Histopathological examination of Hematoxylin and eosin-stained sections was done. Expression of P53 and Mdm2 proteins were examined immunohistochemically.

Results:

Both P53 and Mdm2 were strongly expressed in depigmented as well as normally pigmented skin of vitiligo patients. This expression involved the epidermis, skin adnexa and blood vessels with significant differences between cases and controls.

Conclusions:

The overexpression of P53 and Mdm2 proteins in both normally pigmented and depigmented skin of patients with vitiligo could contribute to the decreased occurrence of actinic damage and NMSC in these patients.

Comparisons of clinical features of HLA-DRB1*07 positive and negative vitiligo patients in Chinese Han population

BACKGROUND

Human leucocyte antigen (HLA)-II alleles have been found to be associated with vitiligo in different populations, and several studies also suggested that HLA class II alleles/haplotypes were associated with a different type vitiligo. Of HLA class II alleles, DRB1*07 has consistently shown a positive association with vitiligo in Chinese Han population.

OBJECTIVE

To further explore the relationship between DRB1*07 and vitiligo and to evaluate the DRB1*07 effect on the clinical features of vitiligo in Chinese Han population.

METHODS

This study investigated DRB1*07 allele distribution in 1178 unrelated Chinese vitiligo patients and 1743 healthy controls using polymerase chain reaction/sequence specific primer method and observed clinical differences between DRB1*07 positive and DRB1*07 negative patients.

RESULTS

The analysis of the 1178 cases and 1743 controls revealed a highly association between DRB1*07 allele and vitiligo [odds ratio (OR) = 1.97, P = 2.13 × 10(-17) ]. DRB1*07 positive patients had early disease onset (OR = 1.49, P = 0.001), higher frequency of family history (OR = 1.44, P = 0.006) compared with DRB1*07 negative patients.

CONCLUSIONS

The DRB1*07 showed significant association with vitiligo in the study population. This study confirmed that DRB1*07 positive patients had some obvious clinical differences from DRB1*07 negative patients in the Chinese Han population.

Association of UVRAG polymorphisms with susceptibility to non-segmental vitiligo in a Korean sample

Autoimmune, self-destructive, oxidative stress and genetic theories have been proposed for the pathogenesis of vitiligo. Autophagy is essential for cellular homeostasis and is implicated in many pathophysiological conditions such as cancer, response to oxidative stress and autoimmunity. The ultraviolet (UV) radiation resistance-associated gene (UVRAG) activates the Beclin1-PI(3)KC3 complex, promoting autophagy. To evaluate whether UVRAG polymorphisms are associated with non-segmental vitiligo (NSV) patients in a Korean sample, we conducted a case-control association study of 225 NSV patients and 439 matched healthy controls. A total of five single nucleotide polymorphisms (SNPs) of UVRAG were selected for analysis. Among these, two SNPs (rs1458836, rs7933235) showed significant genotypic differences between the NSV patient group and the control group. These two SNPs were located within a strong linkage disequilibrium (LD) block. In addition, the haplotype of the UVRAG polymorphism was associated with NSV. This study suggests a possible association between UVRAG and NSV susceptibility.

Abnormal DNA methylation in peripheral blood mononuclear cells from patients with vitiligo

BACKGROUND

Vitiligo is a skin disorder characterized by the destruction of melanocytes by autoreactive lymphocytes. The genetic and environmental factors that trigger the autoimmune response are poorly understood. However, alterations to epigenetic DNA methylation patterns contribute to many other autoimmune diseases.

OBJECTIVES

To investigate genomic and gene-specific DNA methylation levels in peripheral blood mononuclear cells (PBMCs) of patients with vitiligo and to relate any changes to the expression of genes that regulate methylation, as well as the autoimmune-related gene IL10.

METHODS

We quantified global methylcytosine levels in PBMCs from 20 patients with vitiligo and 20 healthy controls. mRNA levels of DNA methyltransferases (DNMTs), methyl-DNA binding domain proteins (MBDs) and interleukin (IL)-10 were measured by real-time reverse transcriptase-polymerase chain reaction. Methylation of an IL10 regulatory element domain was determined by bisulphite genomic sequencing.

RESULTS

Genomic DNA methylation in PBMCs of patients with vitiligo was increased relative to healthy controls (P = 0·012). DNMT1, MBD1, MBD3, MBD4 and MeCP2 expression was significantly higher than in control PBMCs (P = 0·013, 0·001, 0·005, 0·001 and 0·001, respectively). MBD1 and MBD3 expression correlated positively with global DNA methylation in vitiligo PBMCs (MBD1: r = 0·519, P = 0·019; MBD3: r = 0·529, P = 0·016). IL10 expression was significantly decreased (P = 0·030), and an IL-10 enhancer region was hypermethylated in vitiligo PBMCs compared with controls (P = 0·014).

CONCLUSIONS

These data show that levels of DNA methylation are altered in PBMCs of patients with vitiligo, and this may contribute to disease activity by affecting the expression of autoimmunity-related genes.

CTLA-4 A49G gene polymorphism is not associated with vitiligo in South Indian population

Background:

Vitiligo or leukoderma is a chronic skin condition that causes loss of pigment due to destruction of melanocytes, resulting in irregular pale patches of skin. Vitiligo is a polygenic disease and is associated with autoimmunity with an unknown etiology.

Aims:

One of the candidate genes which has a strong association with several autoimmune diseases is CTLA-4 gene located in chromosome 2q33 region. We investigated the possible association between CTLA-4 gene polymorphism in exon 1 (A49G) and vitiligo in patients from South India and compared the distribution of this polymorphism to matched control groups.

Patients and Methods:

The polymorphism was detected by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method in 175 patients and 180 normal, age/ethnicity matched individuals. Consistency of genotype frequencies with the Hardy-Weinberg equilibrium was tested using a χ² test.

Results:

There was no significant difference between the genotype (P = 0.93) and allele (P = 0.615) frequencies of CTLA-4 A49G polymorphism in patients and normal healthy individuals. However there was significant association of the CTLA-4 genotype (P = 0.02) and allelic frequency (P = 0.008) between the segmental and non-segmental sub groups within vitiligo.

Conclusion:

Our results indicate that there is no association between CTLA-4 A49G gene polymorphism and vitiligo in southern Indian population.

Promoter polymorphism -119C/G in MYG1 (C12orf10) gene is related to vitiligo susceptibility and Arg4Gln affects mitochondrial entrance of Myg1

Background

MYG1 (Melanocyte proliferating gene 1, also C12orf10 in human) is a ubiquitous nucleo-mitochondrial protein, involved in early developmental processes and in adult stress/illness conditions. We recently showed that MYG1 mRNA expression is elevated in the skin of vitiligo patients. Our aim was to examine nine known polymorphisms in the MYG1 gene, to investigate their functionality, and to study their association with vitiligo susceptibility.

Methods

Nine single nucleotide polymorphisms (SNPs) in the MYG1 locus were investigated by SNPlex assay and/or sequencing in vitiligo patients (n = 124) and controls (n = 325). MYG1 expression in skin biopsies was detected by quantitative-real time PCR (Q-RT-PCR) and polymorphisms were further analysed using luciferase and YFP reporters in the cell culture.

Results

Control subjects with -119G promoter allele (rs1465073) exhibited significantly higher MYG1 mRNA levels than controls with -119C allele (P = 0.01). Higher activity of -119G promoter was confirmed by luciferase assay. Single marker association analysis showed that the -119G allele was more frequent in vitiligo patients (47.1%) compared to controls (39.3%, P < 0.05, OR 1.37, 95%CI 1.02-1.85). Analysis based on the stage of progression of the vitiligo revealed that the increased frequency of -119G allele occurred prevalently in the group of patients with active vitiligo (n = 86) compared to the control group (48.2% versus 39.3%, P < 0.05; OR 1.44, 95%CI 1.02-2.03). Additionally, we showed that glutamine in the fourth position (in Arg4Gln polymorphism) completely eliminated mitochondrial entrance of YFP-tagged Myg1 protein in cell culture. The analysis of available EST, cDNA and genomic DNA sequences revealed that Myg1 4Gln allele is remarkably present in human populations but is never detected in homozygous state according to the HapMap database.

Conclusions

Our study demonstrated that both MYG1 promoter polymorphism -119C/G and Arg4Gln polymorphism in the mitochondrial signal of Myg1 have a functional impact on the regulation of the MYG1 gene and promoter polymorphism (-119C/G) is related with suspectibility for actively progressing vitiligo.

Intraepidermal injection of dissociated epidermal cell suspension improves vitiligo

This study was initiated to evaluate the safety and effectiveness of intraepidermal injection of dissociated epidermal cells into the lesions of stable vitiligo patients. Autologous dissociated epidermal cell suspensions were injected intraepidermally into 10 stable vitiligo patients. None of the patients received adjuvant therapy. The response was evaluated as: marked (76-100%), moderate (51-75%), mild (26-50%) and minimal repigmentation (0-25%). Transmission electron microscopy was used to evaluate the transplanted cells and immunohistochemical staining with HMB-45 was performed to assess the repigmentation in vivo. In all cases, repigmentation started during the 4-week period after transplantation. Six months after transplantation, a marked repigmentation in four (40%), moderate repigmentation in two (20%) and mild repigmentation in two (20%) patients were observed. Two (20%) patients with white patches on their lids showed minimal repigmentation. No side effects were observed in any patients. Interestingly, repigmentation of gray hair in one patient, 4 months post transplantation was observed. Analysis of the ultrastructure of transplanted cells showed 1.5% of the cells had melanocyte morphology. HMB-45 positive cells were observed after cell transplantation. This method is an effective, simple and safe therapeutic option for stable vitiligo lesions.