Objectives: In order to evaluate the immunological milieu in renal cell carcinoma (RCC), we investigated infiltration by mature dendritic cells (CD83 positive cells), cytotoxic-T cells (CD8 positive cells) and helper-T cells (CD4 positive cells) in RCCs, as well as in surrounding normal tissues and correlations between the cell types.
Materials and methods: Specimens from 33 surgically resected RCCs were embedded in paraffin and then stained for CD4, CD8, CD83. Each section contained three areas, tumor tissue, tumor margin and normal renal parenchyma. Cells positive for CD4, CD8 and CD83 were counted each area.
Result: Cells positive for CD4, CD8 and CD83 were observed predominantly in the tumor margins, rather than tumor tissue and normal renal parenchyma. The differences were significant in the number of immune positive cells between tumor margin and tumor tissue, and between tumor margin and normal renal parenchyma. A significant correlations was found between CD4 and CD83 positive cells (r = 0.805, p < 0.0001), and also between CD8 and CD83 positive cells (r = 0.505, p < 0.0001).
Conclusion: It has been reported that mature dendritic cells induces cytotoxic-T cell and helper-T cell responses. Infiltrating mature dendritic cells, cytotoxic-T cells and helper-T cells were present only in the tumor margin. This may reflect significant immune reaction around the tumor margin.