IL-10 and GM-CSF Expression and the Presence of Antigen-presenting Cells in Chronic Venous Ulcers

Background: White cell trapping and activation occurs in the legs of patients having chronic venous insufficiency (CVI), and it is thought that this process may be important in the development of CVI ulcers. This study has compared the tissue distribution of proinflammatory (GM-CSF) and anti-inflammatory cytokines (IL-10) and inflammatory cell markers (CD68, HLA-DR) between CVI ulcers, other chronic and acute wounds, and autologous nonwounded skin to determine whether cell-mediated immunity (CMI) is impaired in CVI ulcers.

Methods: Wound and donor site tissue was obtained from 10 patients with CVI ulcers and 10 patients with other chronic and acute wounds. Serial Formalin-fixed sections were processed by standard hematoxylin and eosin staining or by indirect immunoperoxidase histochemical staining.

Results: HLA-DR-positive antigen-presenting cells (APC), including CD68-positive macrophages and dermal dendritic cells, were found with greater frequency in CVI ulcers than in other chronic or acute wounds (P = 0.0015) or in the autologous CVI donor site tissue (P = 0.006). CVI ulcers also demonstrated increased IL-10 staining of the entire epidermis compared to non-CVI wounds (P = 0.0019) or autologous donor site tissue (P = 0.004), whereas there was no significant change in the presence of the counteracting cytokine, GM-CSF.

Conclusions: These findings suggest that although the cellular components of CMI are present in CVI ulcers, their function may be impaired by the increased level of IL-10. Future studies will examine whether IL-10-mediated suppression of CMI and/or inhibition of GM-CSF-stimulated keratinocyte proliferation may contribute to the chronic nature of CVI ulcers.