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Segmental vitiligo and generalized vitiligo are in general considered to be separate entities. The aetiopathogenesis of segmental vitiligo remains unclear, although several hypotheses have been put forward including mainly neuronal mechanisms. The typical association with other autoimmune diseases, as seen in generalized vitiligo, seems to be significantly less in segmental vitiligo, although recent insights point towards a possible immune-mediated overlap between the two subtypes. In this article, we describe a case with simultaneous presence of segmental vitiligo, alopecia areata, psoriasis and a halo naevus. To our knowledge, this is the first case with this exceptional combination. This concomitant presence could support the involvement of a shared autoimmune-mediated process, and may provide new insights into the pathogenesis of segmental vitiligo and direct future research. In the light of this remarkable case, different possible aetiopathogenetic mechanisms leading to the clinical presentation of segmental vitiligo are discussed and a new three-step theory is proposed.

Summary 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

Background : In analogy with melanoma-associated leucoderma, halo naevi may trigger in some patients the development of additional depigmentations which are in distribution, extent and prognosis not in accordance with classic vitiligo. Objective : The aim of this study was to support the hypothesis that in a subset of halo naevi patients vitiligo-like lesions develop directly linked to the halo phenomenon. Methods : Forty-one patients with halo naevi were examined for the development of depigmentations not corresponding to typical vitiligo lesions. Results : We identified a subset of five halo naevi patients with additional subtle depigmentations. After the occurrence of multiple halo naevi, they developed leucoderma that showed a different disease pattern than vitiligo (variable asymmetric distribution, limited extent and lack of progression). Moreover, the characteristics of these halo naevi patients with associated leucoderma were different from classic vitiligo patients (high number of halo naevi, absence of family history for vitiligo and absence of autoimmune diseases) and the timing of occurrence of the leucoderma suggested a direct relation with the halo phenomenon. Conclusions : In this article, we describe in a limited subset of patients with multiple halo naevi discrete depigmentations at distance from halo naevi which may result from a temporary autoimmune process directly linked to the halo phenomenon. This finding illustrates the collateral damage resulting from skin immunosurveillance and may have clinical consequences as the evolution pattern in this subset of patients is less progressive compared with vitiligo. We present clinical data that support this hypothesis and suggest to call it halo naevi-associated leucoderma.

Summary Background Vitiligo and halo naevi can present together or separately. Whether they are different entities remains unclear. Objectives To assess the clinical significance of halo naevi, both with respect to the future development of vitiligo, and to the clinical profile and course of vitiligo. Methods In total, 291 patients were included in this study: patients with only halo naevi (group 1; n = 40), patients with generalized vitiligo without halo naevi (group 2; n = 173) and patients with generalized vitiligo with halo naevi (group 3; n = 78). Results Patients with only halo naevi (group 1) reported significantly less associated autoimmune disease (P = 0·001), were less likely to have a family history of vitiligo (P = 0·013) and were less likely to have presence of Koebner phenomenon (P

Background Segmental vitiligo and generalized vitiligo are in general considered separate entities. However, clinico-epidemiological data on segmental vitiligo are scarce compared with those of generalized vitiligo. Objective To analyse the clinical profile and distribution pattern of lesions in segmental vitiligo patients. Methods Segmental vitiligo patients were examined and questioned in a prospective and retrospective setting. The distribution and extent of the lesions were evaluated using clinical photographs. Results Different phenotypes of segmental vitiligo were found, including the unilateral segmental type (124 patients; group 1), the bilateral segmental type (three patients; group 2) and the mixed segmental and generalized type (14 patients; group 3). Furthermore, lesions were present with (10%) or without associated halo naevi. The age of onset of segmental vitiligo (median 14 years) was significantly different between the three subgroups (P = 0.028). Extensive involvement of segmental vitiligo lesions on trunk and extremities was significantly (P = 0.031) more observed in patients with a lower age of onset, while the generalized vitiligo lesions in the mixed vitiligo group were mostly very mild. Associated autoimmune diseases were reported in 11%, whereas a positive family history for vitiligo was present in 14.9% of patients. Lesions were not strictly dermatomal nor Blaschkolinear, although a typical recurring pattern could be observed. Conclusion Our data provide clinical evidence that segmental vitiligo and generalized vitiligo are parts of the same disease spectrum and that segmental vitiligo could have a polygenetic background as well. Whether different aetiopathological mechanisms underlie the different clinical phenotypes of segmental vitiligo remain to be elucidated.

Segmental vitiligo is often ascribed to the neurogenic theory of melanocyte destruction, although data about the initial etiopathological events are scarce. Clinical, histopathological and T-cell phenotypic analyses were performed during the early onset of a segmental vitiligo lesion in a patient with associated halo nevi. Histopathological analysis revealed a lymphocytic infiltrate, mainly composed of CD8+ T-cells and some CD4(+) T-cells around the dermo-epidermal junction. Flow cytometry analysis of resident T-cells revealed a clear enrichment of pro-inflammatory IFN-gamma producing CD8+ T-cells in lesional skin compared to the non-lesional skin. Using human leukocyte antigen-peptide tetramers (MART-1, tyrosinase, gp100), increased numbers of T cells, recognizing melanocyte antigens were found in segmental vitiligo lesional skin, as compared with the non-lesional skin and the blood. Our findings indicate that a CD8+ melanocyte specific T cell-mediated immune response, as observed in generalized vitiligo, also plays a role in segmental vitiligo with associated halo nevi.

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 (P0.05) 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.

An in-depth look at cutting-edge research on the body's innate immune systemInnate immunity is the body's first line of protection against potential microbial, viral, and environmental attacks, and the skin and oral mucosa are two of the most powerful barriers that which we rely on to stay well. The definitive book on the subject, Innate Immune System of Skin and Oral Mucosa: Properties and Impact in Pharmaceutics, Cosmetics, and Personal Care Products provides a comprehensive overview of these systems, including coverage of antimicrobial peptides and lipids and microbial challenges and stressors that can influence innate immunity.Designed to help experts and newcomers alike in fields like dermatology, oral pathology, cosmetics, personal care, and pharmaceuticals, the book is filled with suggestions to assist research and development. Looking at the many challenges facing the innate immune system, including the impact of topically applied skin products and medications, Innate Immune System of Skin and Oral Mucosa paves the way for next generation treatment avenues, preventative approaches, and drug development.

Although the exact aetiology of vitiligo remains unclear, vitiligo is widely considered to have an autoimmune component in its pathogenesis based on disease associations. According to ethnic background, large variations exist in association with autoinflamma-tory/autoimmune disorders. Some reported associations may reflect a simple coexistence of two disorders, and the repertoire of associations may help to detect shared heritable predispositions for inflamma-tion and autoimmunity. Thyroid disorders are the most commonly associated to vitiligo in Caucasian populations, alopecia areata in Chinese populations, rheumatoid arthritis (RA) being more rarely associated in both.

Squamous cell carcinomas (SCCs) of the skin are sun-induced skin cancers that are particularly numerous in patients on T cell immunosuppression. We found that blood vessels in SCCs did not express E-selectin, and tumors contained few cutaneous lymphocyte antigen (CLA)+ T cells, the cell type thought to provide cutaneous immunosurveillance. Tumors treated with the Toll-like receptor (TLR)7 agonist imiquimod before excision showed induction of E-selectin on tumor vessels, recruitment of CLA+ CD8+ T cells, and histological evidence of tumor regression. SCCs treated in vitro with imiquimod also expressed vascular E-selectin. Approximately 50% of the T cells infiltrating untreated SCCs were FOXP3+ regulatory T (T reg) cells. Imiquimod-treated tumors contained a decreased percentage of T reg cells, and these cells produced less FOXP3, interleukin (IL)-10, and transforming growth factor (TGF)-β. Treatment of T reg cells in vitro with imiquimod inhibited their suppressive activity and reduced FOXP3, CD39, CD73, IL-10, and TGF-β by indirect mechanisms. In vivo and in vitro treatment with imiquimod also induced IL-6 production by effector T cells. In summary, we find that SCCs evade the immune response at least in part by down-regulating vascular E-selectin and recruiting T reg cells. TLR7 agonists neutralized both of these strategies, supporting their use in SCCs and other tumors with similar immune defects.

Squamous cell carcinomas (SCCs) are sun-induced skin cancers that are particularly numerous and aggressive in patients taking T-cell immunosuppressant medications. Imiquimod is a topical immune response modifier and Toll-like receptor 7 (TLR7) agonist that induces the immunological destruction of SCC and other skin cancers. TLR7 activation by imiquimod has pleiotropic effects on innate immune cells, but its effects on T cells remain largely uncharacterized. Because tumor destruction and formation of immunological memory are ultimately T-cell-mediated effects, we studied the effects of imiquimod therapy on effector T cells infiltrating human SCC. SCC treated with imiquimod before excision contained dense T-cell infiltrates associated with tumor cell apoptosis and histological evidence of tumor regression. Effector T cells from treated SCC produced more IFN-gamma, granzyme, and perforin and less IL-10 and transforming growth factor-beta (TGF-beta) than T cells from untreated tumors. Treatment of normal human skin with imiquimod induced activation of resident T cells and reduced IL-10 production but had no effect on IFN-gamma, perforin, or granzyme, suggesting that these latter effects arise from the recruitment of distinct populations of T cells into tumors. Thus, imiquimod stimulates tumor destruction by recruiting cutaneous effector T cells from blood and by inhibiting tonic anti-inflammatory signals within the tumor. PMID: 19516264 [PubMed - indexed for MEDLINE]