Increased FOXP3 expression in tumour-associated tissues of horses affected with equine sarcoid disease.
Authors: Mählmann K, Hamza E, Marti E, Dolf G, Klukowska J, Gerber V, Koch C
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: FOXP3 Expression in Equine Sarcoid Disease Equine sarcoid remains one of the most common skin tumours in horses, with bovine papillomavirus (BPV) established as the primary causative agent, yet the mechanisms permitting tumour persistence and progression are incompletely understood. Mählmann and colleagues measured mRNA expression of regulatory T cell (Treg) markers—specifically FOXP3—alongside immunomodulatory cytokines (IL-10, IL-4, IFN-γ) in lesional and distant skin samples from 11 sarcoid-affected horses compared to 12 healthy controls, using quantitative reverse transcription-PCR alongside quantification of BPV-1 E5 viral load. Within sarcoid lesions, FOXP3, IL-10 and IFN-γ expression were significantly elevated relative to non-lesional skin from the same horses, and BPV-1 copy numbers correlated positively with both IL-10 expression and clinical severity scores. Critically, non-lesional skin from sarcoid-affected horses showed no significant differences in Treg marker expression compared to healthy controls, suggesting a localised rather than systemic immune suppression. These findings implicate Treg-mediated immunosuppression within the tumour microenvironment as a mechanism facilitating BPV persistence, potentially explaining the chronicity and treatment resistance characteristic of equine sarcoid and suggesting that future therapeutic strategies might benefit from targeting local Treg populations to restore anti-viral immunity within affected tissues.
Read the full abstract on PubMed
Practical Takeaways
- •Equine sarcoids involve local immune suppression mediated by regulatory T cells, which may explain variable treatment responses and recurrence rates in clinical cases
- •Viral load appears associated with disease severity and immune dysregulation, suggesting viral management strategies may need to consider systemic as well as local immunological factors
- •Understanding that sarcoids create an immunosuppressive microenvironment could inform treatment selection and counselling regarding prognosis and recurrence risk
Key Findings
- •FOXP3, IL10 and IFNG mRNA expression levels were significantly increased in lesional tissue compared to tumour-distant tissue in ES-affected horses
- •BPV-1 E5 DNA copy numbers were significantly elevated in lesional compared to tumour-distant samples
- •Viral load in tumour-distant samples was positively correlated with IL10 expression and disease severity score
- •Increased Treg marker expression in tumour-associated tissues indicates local, Treg-induced immune suppression in equine sarcoid disease