Comparative Analysis of Human Epidermal and Peripheral Blood γ δ T Cell Cytokine Profiles

Background: Human epidermal gamma delta T cells are known to play crucial roles in the defense and homeostasis of the skin. However, their precise mechanism of action in skin inflammation remains less clear. Objective: In this study, we analyzed the cytokine expression profile of human epidermal gamma delta T cells and compared it to that of peripheral blood 76 T cells to investigate the specific activity of epidermal 7 a T cells in modulating skin inflammation. Methods: We isolated gamma delta T cells from epidermal tissue or peripheral blood obtained from healthy volunteers. Isolated 7 T cells were stimulated using immobilized anti-CD3 antibody and interleukin-2 plus phytohaemagglutinin, and were then analyzed using a cytokine array kit. Results: Both epidermal and peripheral blood gamma delta T cells produced comparable levels of granulocyte-macrophage colony-stimulating factor, 1-309, interferon- 7, macrophage migration inhibitory factor, macrophage inflammatory protein-1 a, and chemokine (C-C) ligand 5. The epidermal y delta T cells produced significantly higher levels of interleukin-4, -8, -13, and macrophage inflammatory protein-1 /3 than the peripheral blood gamma delta T cells did. Notably, the epidermal gamma delta T cells produced several hundred-fold higher levels of inter- leukin-13 than interleukin-4. Conclusion: These results suggest that the epidermal gamma delta T cells have a stronger potential to participate in the Th2-type response than the peripheral blood gamma delta T cells do. Furthermore, epidermal gamma delta T cells might play an important role in the pathogenesis of Th2-dominant skin diseases because of their active production of interleukin-13.