Cathelicidin (LL-37) levels were significantly elevated in both lesional and non-lesional skin of vitiligo patients compared to controls, suggesting this antimicrobial peptide may contribute to vitiligo pathogenesis and disease activity.
p < 0.001Cathelicidin LL-37 expression was significantly higher in both lesional and non-lesional vitiligo skin compared to healthy controls.
What the researchers found
Cathelicidin (LL-37) immunohistochemical expression was significantly elevated in vitiligo patients compared to controls (p < 0.001). Lesional skin showed a mean expression score of 2.85 ± 0.67, while non-lesional skin scored 2.05 ± 0.51 — both significantly higher than control skin.
Cathelicidin levels in both lesional and non-lesional skin correlated significantly with the VIDA (Vitiligo Disease Activity) score (p < 0.001 and p = 0.016, respectively), linking higher LL-37 expression to more active disease.
Notably, the elevated cathelicidin in apparently normal-looking skin of vitiligo patients suggests LL-37 may be involved before visible depigmentation occurs, potentially serving as a predictive biomarker for future lesion development.
Why it matters
Vitiligo affects about 1% of the global population, and its exact mechanisms remain incompletely understood. Identifying cathelicidin as a potential contributor to vitiligo pathogenesis could open new therapeutic avenues, particularly since LL-37 is already being studied in other autoimmune skin conditions. The finding that LL-37 is elevated even in normal-appearing skin is especially intriguing for early disease detection.
How the study worked
This was a case-control study comparing 20 vitiligo patients with 20 age- and sex-matched healthy controls. Researchers took 3 mm punch biopsies from both lesional (depigmented) and non-lesional (normal-appearing) skin of each patient, plus control skin. Samples were stained with H&E and analyzed for cathelicidin expression using immunohistochemistry. Disease activity was assessed using the VIDA score.
What this study cannot tell us
The sample size was small (20 patients, 20 controls), limiting statistical power and generalizability. The study was cross-sectional, so it cannot establish whether elevated LL-37 causes vitiligo progression or is a consequence of it. The authors acknowledge that longitudinal studies are needed to confirm whether non-lesional LL-37 elevation truly predicts future lesion development.
How to read the evidence
This is a small case-control study with 20 patients and 20 controls. While it uses appropriate immunohistochemical methods and statistical analysis, the small sample size and cross-sectional design limit the strength of causal conclusions.
When this study was published
Published in 2025, this is a very recent study contributing to the growing understanding of innate immune peptides in autoimmune skin diseases.
The bigger picture
Cathelicidin LL-37 has been implicated in several autoimmune and inflammatory skin conditions including psoriasis and rosacea. This study extends that connection to vitiligo, reinforcing the idea that innate immune peptides may play broader roles in autoimmune skin diseases beyond their antimicrobial functions. Understanding LL-37's role in melanocyte destruction could inform targeted therapies.
Questions still open
- Does LL-37 directly contribute to melanocyte destruction in vitiligo, or is it a secondary marker of immune activation?
- Could targeting cathelicidin pathways offer a new therapeutic approach for vitiligo treatment?
- Can non-lesional LL-37 levels reliably predict where new vitiligo patches will appear?
Common questions
What is cathelicidin LL-37?
Could LL-37 help predict new vitiligo patches?
Read the original research
Study of cathelicidin (LL-37) immunoexpression in the skin of vitiligo patients.
Archives of dermatological research, 317(1), 316
Citation
Elgarhy, Lamia Hamouda; Ramadan, Basma Ramadan Refaey; Sallam, Fersan Abd Allah; Iskandarani, Dalya Ayman; Hewedy, El-Sayed Shaaban. (2025). Study of cathelicidin (LL-37) immunoexpression in the skin of vitiligo patients.. Archives of dermatological research, 317(1), 316. https://doi.org/10.1007/s00403-025-03801-2