SEARCH RESULTS FOR: Vitiligo-Pathogenesis-and-Clinical-Findings

Vitiligo Pathogenesis and Clinical Findings

Vitiligo: Pathogenesis and clinical findings Authors: Wisoo Shin Reviewers: Lauren Lee Stephen Williams Ben Campbell Laurie Parsons* Yan Yu* * MD at time of publication Genetic predisposition Variants in over 30 susceptibility loci Environmental exposure UV light, monobenzone, phenol, catechol Production of IgG auto- antibodies to melanocyte-specific proteins Auto-antibodies bind to melanocytes and trigger antibody-dependent cellular cytotoxicity: marking melanocytes for destruction by Fc- receptor bearing immune cells such as neutrophils Impaired mitochondrial function in melanocytes ↑ Susceptibility of melanocytes to oxidative stress ↓ E-cadherin or ↑ anti- adhesion molecule expression in melanocytes ↓ Adhesion of melanocytes to keratinocytes ↑ Clearance of melanocytes from epidermis ↑ Reactive oxygen species production within melanocytes Activation of apoptosis and senescence signaling pathways Pressure or friction Melanocytes excrete exosomes (melanocyte- specific antigens, microRNA, heat shock proteins) that, through complex mechanisms, stimulate the immune system’s CD8+ T-cells to destroy melanocytes Melanocytes enter apoptotic or senescent state ↓ Functional melanocytes ↓ Melanin production Overall loss of functional melanocytes Vitiligo Normal Skin Pigmented Epidermis Dermal- Epidermal Junction Dermis Autoimmune destruction of melanocytes Depigmented Epidermis Melanocytes Immune-mediated destruction of melanocytes (by both neutrophils and CD8+ T cells) A depigmenting skin disorder characterized by selective loss of melanocytes Depigmentation in areas of ↑ pressure, friction and/or trauma Nonsegmental vitiligo Smooth unpigmented macules or patches in bilateral, often symmetric pattern Somatic mosaicism (mutation limited to a subset of cells) in zygote during development Segmental vitiligo Smooth unpigmented macules or patches in unilateral pattern not crossing midline Vitiligo Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published February 15, 2022 on www.thecalgaryguide.com