Vitiligo at Injection Site of PEG-IFN-α 2a in Two Patients with Chronic Hepatitis C: Case Report and Literature Review

IFN‑γ induces apoptosis in human melanocytes by activating the JAK1/STAT1 signaling pathway

The present study aimed to investigate the role of janus kinase (JAK)1/STAT1 in interferon (IFN)-γ-induced apoptosis in human melanocytes. Following IFN-γ treatment, the viability of human melanocytes were analyzed using a Cell Counting Kit-8 assay and the apoptotic rate was determined using flow cytometry. Western blotting was also performed to analyze the phosphorylation levels of JAK1, JAK2 and the transcriptional factor STAT1, as well as the expression levels of Bcl-2, Bax, Bcl-2 homologous antagonist killer (Bak) and cleaved caspase-3. Finally, following the pretreatment with the STAT1 inhibitor fludarabine, human melanocytes were treated with IFN-γ and flow cytometry was used to detect the apoptotic rate. The results revealed that IFN-γ reduced the proliferation and induced the apoptosis of human melanocytes. In addition, IFN-γ treatment led to decreased expression levels of Bcl-2 and increased expression levels of Bax, Bak and cleaved caspase-3, alongside the activation of the JAK1/STAT1 signaling pathway. Conversely, the pretreatment with the STAT1 inhibitor fludarabine decreased the apoptotic rate of human melanocytes following IFN-γ induction. In conclusion, the findings of the present study suggested that IFN-γ may induce the apoptosis of human melanocytes by activating the JAK1/STAT1 signaling pathway, alongside increasing the expression levels of Bax, Bak and cleaved caspase-3, and decreasing the expression levels of Bcl-2.

Lymphoid Stress Surveillance Response Contributes to Vitiligo Pathogenesis

Vitiligo is a chronic multifactorial depigmentation disorder characterized by the destruction and functional loss of melanocytes. Although a direct cytotoxic T cell attack is thought to be responsible for melanocyte damage, the events leading to the loss of self-tolerance toward melanocytic antigens are not understood. This research aimed to identify novel cellular and molecular factors that participate in vitiligo pathogenesis through the application of gene expression and immunofluorescence analysis of skin biopsy samples along with immunophenotyping of circulating cells. Our study provides insights into the mechanisms involved in melanocyte destruction. The upregulation of stress-ligand MICA/MICB, recognized by activating receptors on innate and innate-like T cells, imply involvement of lymphoid stress surveillance responses in vitiligo lesions. A simultaneous increase in the expression of transcription factor EOMES that is characteristic for innate-like virtual memory T cells, suggest a similar scenario. Local lymphoid stress surveillance has been previously associated with the amplification of systemic humoral responses that were mirrored in our study by increased T follicular helper cells and switched memory B cell proportions in patients with active vitiligo. In addition, microtubule-associated protein light chain 3 staining was compatible with the activation of autophagy in keratinocytes and in the remaining melanocytes of vitiligo lesional skin.

Concise review of recent studies in vitiligo

Vitiligo is an acquired pigmentry disorder of the skin and mucous membranes which manifests as white macules and patches due to selective loss of melanocytes. Etiological hypotheses of vitiligo include genetic, immunological, neurohormonal, cytotoxic, biochemical, oxidative stress and newer theories of melanocytorrhagy and decreased melanocytes survival. There are several types of vitiligo which are usually diagnosed clinically and by using a Wood's lamp; also vitiligo may be associated with autoimmune diseases, audiological and ophthalmological findings or it can be a part of polyendocrinopathy syndromes. Several interventions are available for the treatment for vitiligo to stop disease progression and/or to attain repigmentation or even depigmentation. In this article, we will present an overall view of current standing of vitiligo research work especially in the etiological factors most notably the genetic components, also, types and associations and various and newer treatment modalities.

Vitiligo in a Patient Treated with Interferon Alpha-2a for Behçet's Disease

Behçet's disease (BD) and vitiligo are diseases of unknown etiology. Interferon (IFN) alpha therapy is commonly used in Behçet uveitis. Interferon treatment in various diseases have also been observed causing certain autoimmune diseases such as vitiligo because of its immunomodulatory activity. The association between IFN therapy and vitiligo has been reported in the literature. We report a 21-year-old man with BD in whom vitiligo occurred during IFN treatment. To the best of our knowledge, this is the first reported case of such an association.