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Pathogenesis and Etiological Breakdown: Autoimmunity, Oxidative Stress, and Genetic Factors

The pathogenesis of vitiligo is intricate and complex. The medical community generally attributes it to the combined effects of genetic susceptibility, autoimmune abnormalities, cellular oxidative stress, and neurohumoral factors1。Understanding these underlying mechanisms is essential for grasping the therapeutic principles of modern targeted therapies.

Cytotoxic T-Cell-Mediated Autoimmune Destruction
The autoimmune response mediated by cytotoxic CD8+ T lymphocytes (CD8+ T cells) serves as the core driver of melanocyte death1。When immune tolerance is compromised:


Antigen Recognition & IFN-γ Release: Activated CD8+ T cells specifically recognize melanocyte surface antigens and secrete interferon-gamma (IFN-γ).

JAK-STAT Pathway Activation: IFN-γ binds to its cell-surface receptor, activating the intracellular Janus kinase (JAK1/JAK2) and Signal Transducer and Activator of Transcription (STAT) pathways.

Chemokine Recruitment Loop: This signaling cascade induces epidermal keratinocytes to secrete the chemokines CXCL9 and CXCL10, which continuously recruit additional T cells to the lesion.

This creates a self-sustaining autoimmune inflammatory feedback loop, ultimately leading to widespread melanocyte apoptosis4.

Vitiligo 白蝕 治療 香港 醫生 診所

Oxidative Stress and Melanocyte Vulnerability
The autoimmune response mediated by cytotoxic CD8+ T lymphocytes (CD8+ T cells) serves as the core driver of melanocyte death1.
ROS Accumulation: Melanogenesis inherently generates substantial amounts of reactive oxygen species (ROS).

Endoplasmic Reticulum Stress: If the melanocyte's intrinsic antioxidant enzyme defense is inherently deficient, excessive ROS accumulation disrupts endoplasmic reticulum function and induces cellular stress.

Immune Triggering: Stressed melanocytes release damage-associated molecular patterns (DAMPs), which alert and trigger a localized attack by the innate and adaptive immune systems1.

 

Genetics, Comorbidities, and Physical Triggers
Genetic Susceptibility: Genetic studies indicate that approximately one-third of vitiligo patients have a positive family history2.

Autoimmune Comorbidities: Vitiligo patients face a significantly higher risk of developing concurrent autoimmune conditions compared to the general population. Around one-third concurrently present with thyroid dysfunction (hyperthyroidism or hypothyroidism, such as Hashimoto's thyroiditis)2.

Koebner Phenomenon: Clinically, physical trauma such as scratches, sunburns, mechanical friction, or surgical incisions can induce new vitiligo lesions at the site of injury. This demonstrates that localized physical damage can directly provoke an inflammatory and autoimmune response.

Reference

  1. British Association of Dermatologists guidelines for the management of people with vitiligo 2021 | Request PDF - ResearchGate, https://www.researchgate.net/publication/352686774_British_Association_of_Dermatologists_guidelines_for_the_management_of_people_with_vitiligo_2021

  2. Vitiligo - Primary Care Dermatology Society, https://www.pcds.org.uk/clinical-guidance/vitiligo

  3. British Association of Dermatologists guidelines for the management of people with vitiligo 2021*, https://bpg.org.uk/wp-content/uploads/2024/01/Br-J-Dermatol-2021-Eleftheriadou-British-Association-of-Dermatologists-guidelines-for-the-management-of-people-with-vitiligo.pdf

  4. China Medical System: New Drug Application of Ruxolitinib Phosphate Cream for Vitiligo Approved in Hong Kong – CMS, https://web.cms.net.cn/en/2024/11/china-medical-system-new-drug-application-of-ruxolitinib-phosphate-cream-for-vitiligo-approved-in-hong-kong/

  5. Vitiligo: Unmet Need, Management and Treatment Guidelines - PMC, https://pmc.ncbi.nlm.nih.gov/articles/PMC10824320/

  6. Treatment for Nonsegmental Vitiligo | OPZELURA® (ruxolitinib), https://www.opzelura.com/vitiligo/

  7. Vitiligo: Diagnosis and treatment - American Academy of Dermatology, https://www.aad.org/public/diseases/a-z/vitiligo-treatment

  8. Professional Vitiligo Treatment in London | The Thomas Clinic, https://thomasclinic.com/conditions-treatments/vitiligo-treatment/