Characterization of the inflammatory infiltrate and cytokine expression in the skin of horses with recurrent urticaria.

The research article focuses on understanding the role of specific cells and cytokines (proteins that mediate in immune responses) in the skin condition, recurrent urticaria (RU), commonly found in horses. The study involved analyzing skin biopsies from horses with and without RU, revealing a higher presence of certain types of immune cells and cytokines in RU-affected skin.

Methods

• The study involved comparing the skin biopsies of 8 horses with RU, including lesional (affected) and nonlesional skin, and 8 healthy horses.
• The inflammatory cell infiltrate, including T cells, B cells, macrophages, and mast cells, in the skin samples, was observed via routine histology and immunohistochemistry.
• The expression of T-helper 2 cytokines (interleukins IL-4, IL-5, and IL-13), a T-helper 1 cytokine (interferon-γ), IL-4 receptor α, and thymic stromal lymphopoietin was measured using quantitative RT-PCR (a laboratory technique).

Results

• The lesional skin of horses with RU showed a significant increase in eosinophils, CD79-positive B cells, MAC387-positive macrophages, and tryptase-positive mast cells compared to healthy horses.
• A higher count of eosinophils and tryptase-positive mast cells were found in the lesional skin than the nonlesional skin of horses with RU.
• The nonlesional skin of RU-affected horses had a similar count of inflammatory cells as the skin from healthy horses.
• Significantly higher expressions of cytokines IL-4, IL-13, thymic stromal lymphopoietin, and IL-4 receptor α were observed in the lesional skin of horses with RU as compared to controls.

Conclusion

• The findings suggest that T-helper 2 cytokines, eosinophils, mast cells, and presumptive macrophages might have notable roles in the pathogenesis of equine RU, helping develop a deeper understanding of how this common skin disease in horses develops.