This study evaluates whether exosomes derived from human umbilical cord mesenchymal stem cells (hUMSCs-Exo) are safe and effective for treating vitiligo in adults.

Vitiligo is a skin condition that causes white patches due to loss of pigment-producing cells. Current treatments have limitations, especially for patients with active disease who require oral steroids with significant side effects.

This study is a single-center, randomized, controlled trial enrolling 96 adults aged 18 to 65 years with non-segmental vitiligo. Participants are divided into two groups based on disease activity: progressive vitiligo (new patches appearing or existing patches expanding in the past 3 months) and stable vitiligo (no changes in the past year).

For progressive vitiligo, participants are randomly assigned to either:

Experimental group: hUMSCs-Exo given by intravenous infusion every 2 weeks for 5 sessions, plus tacrolimus ointment and narrowband UVB light therapy, or Control group: oral prednisone (a standard steroid treatment) plus tacrolimus ointment and narrowband UVB light therapy

For stable vitiligo, participants are randomly assigned to either:

Experimental group: hUMSCs-Exo given by local injection into the white patches every 2 weeks for 5 sessions, plus tacrolimus ointment and narrowband UVB light therapy, or Control group: tacrolimus ointment plus narrowband UVB light therapy alone The treatment period lasts 12 weeks, with follow-up visits continuing to 24 weeks. The main outcome measures include improvement in skin repigmentation measured by the Vitiligo Area Scoring Index (VASI), changes in quality of life, and safety monitoring throughout the study.

This study aims to establish a standardized approach for using hUMSCs-Exo in vitiligo treatment and to explore how exosomes may work by reducing oxidative stress and regulating immune responses.

Inclusion Criteria:

• Clinically diagnosed non-segmental vitiligo
• Progressive vitiligo: new lesions or enlargement of existing lesions within the past 3 months (VIDA score ≥ 3); Stable vitiligo: no new lesions or enlargement of existing lesions within the past 1 year (VIDA score = 0)
• Total body surface area (BSA) of vitiligo lesions between 1% and 30%
• Age 18 to 65 years, male or female
• Willing to participate and provide written informed consent

Exclusion Criteria:

• Pregnancy or breastfeeding
• Known allergy to mesenchymal stem cells or exosome components
• Severe cardiac, hepatic, or renal dysfunction, or severe immunocompromised status
• For progressive vitiligo: use of systemic immunosuppressants, corticosteroids, phototherapy, or photochemotherapy within the past 3 months
• For stable vitiligo: use of phototherapy, topical immunosuppressants, or corticosteroids within the past 1 month
• Concurrent autoimmune diseases (e.g., systemic lupus erythematosus, rheumatoid arthritis, psoriasis) or severe infectious diseases
• History of malignancy or hematologic disorders
• History of psychiatric disorders or inability to comply with study procedures
• Any other condition that, in the investigator's judgment, may increase the risk to the participant or interfere with the conduct of the trial

The study is an open-label trial due to the nature of the cellular exosome intervention, which makes blinding of participants, investigators, and outcome assessors infeasible