Pathogenesis of vitiligo: An update

The Pathogenesis and Management of Vitiligo

Vitiligo is a common autoimmune disease that progressively destroys melanocytes in the skin, resulting in the appearance of patchy depigmentation. The aim of this review is to increase awareness towards vitiligo by providing insight on the pathogenesis and management options. Vitiligo is an acquired pigmentary skin disease, which can appear with one or a few macules. Based on the distribution pattern, vitiligo is classified into three different types: segmental, non-segmental, and unclassified. Oxidative stress, autoimmunity, and genetic factors are the main theories contributing to the cause of vitiligo, although the exact cause remains unknown. Various management methods depend on the type, severity, and progression of the disease. This dermatological condition is prevalent globally and shows a slightly higher incidence in females. Multiple hypotheses explain the complex mechanisms of vitiligo, with current research focusing on the roles of oxidative stress, genetic predisposition, and autoimmune responses in its development. Effective treatments include topical corticosteroids and phototherapy.

A randomized clinical trial of Shaman chikitsa versus Shaman chikitsa with vamana in vitiligo (Shwitra)

Vitiligo is a chronic skin disorder due to melanocyte destruction in the epidermis. It is a social stigma. Therefore, it affects the patient psychologically as well. Various therapies have been evaluated in the management of vitiligo. Vamana is a helpful panchakarma to treat skin diseases, but it has still not been studied. To study the efficacy of Vamana, we randomly selected 30 patients with vitiligo and divided them into two groups of 15 patients in each group. For Group A, Vamana was administered, and oral Swayambhu Guggul was administered at 500 mg/day with cow urine and Savarnakar Lepa for local application. This treatment was given for six weeks. In Group -B, the same treatment was given without Vamana. The Vitiligo Area Severity Index (VASI) and overall assessment were used to assess the results. Group A decreased the score from 59.67 to 27.20 ± 18.28, and Group B decreased the score from 42.6 to 36.2 ± 7.58. The P value was statistically significant in Group A and nonsignificant in Group B. In the overall assessment, Group A showed statistically significant results. We concluded that Vamana with Shaman Chikitsa is more efficacious than Shaman Chikitsa alone, but more studies are required to ascertain whether vitiligo can be reversed completely by the combined treatment of Vamana and Shaman Chikitsa.  

Biologic and targeted therapeutics in vitiligo

BACKGROUND

Vitiligo is a long-standing progressive autoimmune disease with depigmented macules/patches with significant psychological morbidity to the patients. From being one of the most poorly understood diseases in the past, there has been a rampant advance in determining the molecular and genetic factors influencing the disease process. More light has been shed on the complex intracellular environment and interplay between innate and adaptive immunity. Numerous cytokines and signaling pathways have been associated with disease pathogenesis in the recent past.

OBJECTIVE

The aim of this review the efficacy of biologic and targeted therapeutics in vitiligo.

METHODS

A detailed literature search was conducted on databases like PubMed, COCHRANE Central, EMBASE and Google Scholar using keywords-"biologics," "vitiligo," "treatment," "repigmentation," "JAK inhibitors,", "TNF-ꭤ inhibitors," and "IL17/23 inhibitors," Relevant studies and review articles in English were analyzed in detail and report was written. This article aimed at a comprehensive review of all the biologicals and newer targeted therapeutics tried in vitiligo and their efficacy with an insight into the potential complications arising as a result of the therapy.

RESULTS

Most conventional vitiligo treatment modalities are restricted to generalized nonspecific immunosuppressants like topical and oral corticosteroids, calcineurin inhibitors, phototherapy, and surgical modalities. There have been reports and studies on the usage of biologicals in treating vitiligo. JAK inhibitors have shown good efficacy in vitiligo; however, it lacks substantial evidence in the form of randomized control trials. Similarly, the use of targeted therapeutics in treating vitiligo is substantiated by limited evidence and requires more randomized trials for further evidence.

CONCLUSION

JAK inhibitors have shown promising results and good tolerability; Adjuvant phototherapy can achieve a superior response compared to monotherapy. Though TNF-ꭤ has been tried in a few cases, it is best used if vitiligo is present in association with other chronic autoimmune diseases for which it is indicated. More in vitro studies and clinical research are required to understand the pathogenesis clearly, and therapy has to be targeted at specific pathways for a better approach toward vitiligo. Treatment aimed at induction and differentiation of melanocytes may be added to achieve faster repigmentation.

The role of cytokines and vitamin D in vitiligo pathogenesis

Vitiligo is a pigment-related disease with a global prevalence of 0.2% to 1.8% associated with considerable burden on quality of life. The treatment is still a challenge because of relapses and/or incomplete re-pigmentation. Although the exact cause is still unclear, its pathogenesis seems to be justifiable with the autoimmune theory, supported by the results of clinical research. In this narrative review, we aimed to summarize the evidence related to cytokines and vitiligo development. This review is consisted of English articles published in PubMed and Google Scholar concerning levels of inflammatory mediators, especially interleukins, in vitiligo patients over the last 20 years. References of relevant articles were also considered for review. Crucial role of dysregulated levels of interleukins and their synergistic function to each other, in the onset or progression of the disease is evident. The theory of autoimmune vitiligo is reinforced by the results of the studies in the literature, due to the association of pathogenesis with increased secretion of pro-inflammatory mediators and reduction of anti-inflammatory mediators. Decreased vitamin D levels may have a considerable role in vitiligo development by affecting Th1- and Th17-related immune responses. Cytokines play an important role in the pathogenesis or progression of the disease. Moreover, we believe that decreased vitamin D level has a considerable role in vitiligo development by affecting Th1- and Th17-related immune responses.

Efficacy of Topical 5% 5-Fluorouracil with Needling versus 5% 5-Fluorouracil Alone in Stable Vitiligo: A Randomized Controlled Study

Background:

Vitiligo is a chronic disease of great cosmetic concern presenting with depigmented macules and patches. It is often recalcitrant to medical treatment.

Aim:

The aim of the study was to study the efficacy and safety of topical 5% 5-fluorouracil with needling versus topical 5% 5-fluorouracil alone in stable vitiligo.

Materials and Methods:

This interventional prospective study was conducted from July 2018 to June 2019. Total of 60 patients, with stable vitiligo of age older than 10 years, were randomly assigned into two groups of 30 patients each. Group A was treated with needling followed by topical 5% 5-fluorouracil over vitiligo patches. The procedure was performed every 2 weeks for 3 months. Group B was treated with topical 5% 5-fluorouracil alone. Clinical improvement was assessed monthly till 6 months by serial clinical photographs and grading score.

Results:

Initiation of repigmentation started at 1 month in 76 patches (65%) in Group A, whereas in group B, it was seen in 45 patches (38.7%), which was statistically significant (P = 0.0001). Excellent improvement (>75% repigmentation) was noted in 55 patches (47%) in Group A as compared to 5 patches (4.3%) in group B at the end of 6 months (P = 0.03).

Conclusion:

Needling with 5% 5-fluorouracil appears to be simple, safe, and effective treatment in vitiligo. It can be used in poor responders to conventional therapy.

Emerging drugs for the treatment of vitiligo

Introduction: Vitiligo is a relatively common autoimmune depigmenting disorder of the skin. There has been a great advance in understanding the pathological basis, which has led to the development and utilization of various new molecules in treating vitiligo. This review aims at a comprehensively describing the treatments available and the emerging treatment aspects and the scope for future developments.Areas covered: This study comprehensively summarizes the current concepts in the pathogenesis of vitiligo with special focus on the cytokine and signaling pathways, which are the targets for newer drugs. JAK kinase signaling pathways and the cytokines involved are the focus of vitiligo treatment in current research, followed by antioxidant mechanisms and repigmenting mechanisms. Topical immunosuppressants may be an alternative to steroids in localized vitiligo. Newer repigmenting agents like basic fibroblast growth factors, afamelanotide have been included and a special emphasis is laid on the upcoming targeted immunotherapy.Expert opinion: The treatment of vitiligo needs to be multimodal with emphasis on targeting different limbs of the pathogenesis. Topical and oral JAK inhibitors are the most promising new class of drugs currently available for treating vitiligo and acts best in conjunction with NB-UVB.

Predominant role of innate pro-inflammatory cytokines in vitiligo disease

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