Breaking Tolerance—Another Piece Added to the Vitiligo Puzzle

Psoriasis and vitiligo are close relatives

BACKGROUND

Both vitiligo and psoriasis are chronic inflammatory autoimmune diseases with genetic elements.

OBJECTIVE

To estimate the frequencies of psoriasis in vitiligo patients and vice versa and to compare them with healthy controls.

PATIENTS AND METHODS

A total of 1000 subjects were included, 250 of them had vitiligo, 250 had psoriasis, and 500 were healthy controls. Measurement of the frequencies of vitiligo in psoriatic patients and psoriasis in vitiligo patients was carried out. Thereafter the frequencies of both diseases were assessed in healthy controls. The frequency of vitiligo among psoriatic patients was compared with that of vitiligo in healthy controls. A similar comparison was done between the frequency of psoriasis among vitiligo patients with that in healthy controls. Other comparisons were performed between the frequency of family history of psoriasis among vitiligo patients with that in healthy controls and between the frequency of family history of vitiligo in psoriatic patients with that in healthy controls.

RESULTS

The frequency of psoriasis among vitiligo patients was 15 (6%) and among healthy controls was 2 (0.4%); there is a statistically significant difference (P=0.001). The frequency of vitiligo among psoriatic patients was 5 (2%) and among healthy controls was 3 (0.6%); no statistically significant difference was found (P=0.16). The family history of psoriasis among vitiligo patients was 23 (9.2%) and among healthy controls was 20 (4%); there is a significant association (P=0.043). The family history of vitiligo among psoriatic patients was 24 (9.6%) and among healthy controls was 40 (8%); the difference is statistically significant (P=0.042).

CONCLUSION

The present work has confirmed the close relationship between vitiligo and psoriasis.

Plasma Levels of Interleukin-17, Interleukin-23, and Transforming Growth Factor-β in Sudanese Patients with Vitiligo: A Case-Control Study

Background:

Vitiligo is the most common pigmentary skin disorder. It is a multifactorial polygenic disease with epidermal melanocyte destruction. The cytokines profile found in vitiliginous patients was not fully elucidated.

Aims:

We sought to assess the autoimmune nature of vitiligo by comparing plasma levels of interleukin (IL)-17, IL-23, and transforming growth factor beta (TGF-β) in adult Sudanese vitiligo patients with matched control individuals.

Subjects and Methods:

Case-control study was conducted in Khartoum Dermatologic Teaching Hospital, in the period between July and December 2013. The cases were 42 adult Sudanese vitiligo patients matched with 43 control individuals. The cytokines were measured in the plasma by the quantitative “sandwich” ELISA.

Results:

Patients showed a significant lower median (25–75^th inter-quartile) of TGF-β than control (0.042 [0.041–0.044] vs. 0.047 [0.042–0.049]; P ≤ 0.001). Both IL-17 and IL-23 showed no significant difference between cases and controls. IL-17 showed a significant inverse relationship when correlated with TGF-β (r = −0.24; P = 0.026) while showing direct relationship when correlated with age (r = 0.28; P = 0.009).

Conclusion:

The positive findings detected in this study coincide with the important immunoregulatory role of the TGF-β, and support the autoimmune nature of the disease.

In vivo vitiligo induction and therapy model: double-blind, randomized clinical trial

In this study, we developed an in vivo vitiligo induction model to explore the underlying mechanisms leading to Koebner's phenomenon and to evaluate the efficacy of therapeutic strategies. The model consisted of 12 pigmented test regions on the back of generalized vitiligo patients that were exposed to three Koebner induction methods: cryotherapy, 755 nm laser therapy, and epidermal abrasion. In addition, four cream treatments (pimecrolimus, tacrolimus, steroid and placebo) were randomly applied. Koebnerization was efficiently induced by all three induction methods. In general, cryotherapy was the best method of Koebner induction, followed by 755 nm laser therapy and epidermal abrasion. Reproducible results were obtained, which showed enhanced depigmented surface areas and higher amounts of T lymphocytes in placebo-treated test zones compared to active treated areas. Tacrolimus and local steroids were better inhibitors of Koebner's process (P < 0.05) compared to pimecrolimus. Our in vivo vitiligo induction model is very informative to investigate vitiligo induction and to determine the efficacy of topical treatments in vitiligo. This proof of concept confirms the efficient comparison of head-to-head therapeutic strategies intra-individually in a standardized, specific and better timed way.

Expressional changes in the intracellular melanogenesis pathways and their possible role in the pathogenesis of vitiligo

BACKGROUND

Main pathway in human melanocytes through which signal from the melanocortin system reaches the melanogenesis enzymes is cAMP/PKA pathway and it is modulated by Wnt and MAPK pathways. In our previous study we established significant increase of melanocortin receptor expression in unaffected skin of vitiligo patients compared to healthy subjects.

OBJECTIVE

The aim of this study was to assess the gene expression profile of the intracellular signalling pathways linking melanocortin system with enzymes involved in melanogenesis.

METHODS

Using QRT-PCR method, mRNA expression levels of eight genes related to signal transduction from the melanocortin system to melanogenesis enzymes was measured in lesional and non-lesional skin of vitiligo patients and in the skin of healthy control subjects. Following genes were analyzed in the study: MITF, CREB1, p38, USF1, PIK3CB (PI3K), RPS6KB1, LEF1 and BCL2.

RESULTS

The mRNA levels of MITF, LEF1, p38, PIK3CB and RPS6KB1 were decreased in lesional skin of vitiligo patients compared to skin of healthy control subjects. We also found increased expression of USF1 and BCL2 in non-lesional skin of vitiligo patients compared to skin of healthy control subjects. mRNA levels of MITF and BCL2 were decreased in lesional skin of vitiligo patients compared to non-lesional skin of vitiligo patients.

CONCLUSIONS

Present study indicates increased expression of the genes of the intracellular melanogenesis pathway in the non-lesional skin of vitiligo patients. This finding suggests activation of melanogenesis pathway in the non-lesional skin of vitiligo.