Immunological Parameters Associated With Vitiligo Treatments: A Literature Review Based on Clinical Studies

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.

Serum Zinc Level in Vitiligo: A Case-control Study

Background:

Vitiligo is characterized by the idiopathic destruction of melanocytes, probably of autoimmune etiology, that results in depigmented patches of skin and mucosal surfaces. Oxidative stress may contribute to the pathogenesis of vitiligo. Zinc, a trace element with antiapoptotic properties, plays a major role in the process of melanogenesis and elimination of free radicals. The present study was conducted with the aim of comparing serum zinc levels in patients with vitiligo and in normal controls.

Materials and Methods:

In this case–control study, we studied 103 patients with vitiligo and 103 healthy sex-and age-matched controls. Serum zinc levels were measured in these two groups using atomic absorption spectrophotometry and compared with each other.

Results:

The mean serum zinc level was 92.1 mcg/dl in the focal vitiligo, 81.3 mcg/dl in the generalized vitiligo, and 91.8 mcg/dl in the control group. A significant difference in serum zinc levels was observed between the patients with generalized vitiligo and the controls. Lower serum zinc levels were also correlated with longer duration of the disease. Furthermore, a negative relationship was found between serum zinc level and age of patients with vitiligo.

Conclusion:

Serum zinc level is low in patients with generalized vitiligo. In these patients, serum zinc level is in negative correlation with patient's age and disease duration.

Topical mycophenolate mofetil in the treatment of vitiligo: a pilot study

BACKGROUND

Vitiligo is a multifactorial disease that is characterized by circumscribed depigmented macules and patches. Autoimmune reactions may play an important role in the pathogenesis of the disease. Mycophenolate mofetil is a drug that inhibits DNA synthesis in lymphocytes and has been used in autoimmune diseases such as immunobullous skin diseases, lupus erythematosus, and autoimmune hepatitis.

OBJECTIVES

The objective of this study was to show the efficacy of topical mycophenolate mofetil in the treatment of vitiligo.

METHODS

Thirty patients with limited vitiligo were enrolled in this study. The patients applied a topical preparation of mycophenolate mofetil 15% twice daily for three months and at the end of every month, repigmentation was assessed using the Vitiligo Area Scoring Index (VASI).

RESULTS

At the end of the third month, 36.6 % (n=11) of the patients showed about 25% repigmentation of the lesions. No side effects were observed throughout the study.

CONCLUSION

This study showed that topical mycophenolate mofetil can be somewhat effective in the treatment of vitiligo; however, it seems to be inferior to potent topical steroids in inducing repigmentation.

Decreased Circulating T Regulatory Cells in Egyptian Patients with Nonsegmental Vitiligo: Correlation with Disease Activity

Background. Vitiligo is an acquired depigmentary skin disorder resulting from autoimmune destruction of melanocytes. Regulatory T cells (Tregs), specifically CD4⁺CD25⁺ and Forkhead box P3⁺ (FoxP3⁺) Tregs, acquired notable attention because of their role in a variety of autoimmune pathologies. Dysregulation of Tregs may be one of the factors that can break tolerance to melanocyte self-antigens and contribute to vitiligo pathogenesis. Methods. In order to sustain the role of Tregs in pathogenesis and disease activity of vitiligo, surface markers for CD4⁺CD25⁺ and FoxP3⁺ peripheral Tregs were evaluated by flow cytometry in 80 Egyptian patients with nonsegmental vitiligo in addition to 60 healthy control subjects and correlated with clinical findings. Results. Vitiligo patients had significantly decreased numbers of both peripheral CD4⁺CD25⁺ and FoxP3⁺ T cells compared to control subjects (11.49%  ± 8.58% of CD4⁺ T cells versus 21.20%  ± 3.08%, and 1.09%  ± 0.96% versus 1.44%  ± 0.24%, resp., P < 0.05 for both). Peripheral numbers of CD4⁺CD25⁺ and FoxP3⁺ Tregs correlated negatively with VIDA score. Conclusion. Treg depletion with impaired immune downregulatory function might play a key role in the autoimmune conditions beyond nonsegmental vitiligo particularly in active cases. Effective Treg cell-based immunotherapies might be a future hope for patients with progressive vitiligo.