Increased expression of activation markers in renal cell carcinoma infiltrating lymphocytes

As manifested by the presence of immune competent cells, failure to control the progression of renal cell carcinoma by a local immune response attests to impaired local cell mediated immunity. To test this hypothesis we compared the expression of T-cell activation markers in renal cell carcinoma infiltrating lymphocytes with the expression of activation markers of peripheral blood lymphocytes in the same patients.

Tumor infiltrating lymphocytes were harvested from a patient with renal cell carcinoma undergoing radical nephrectomy. Peripheral blood was obtained before surgery. Tumor infiltrating and peripheral blood lymphocytes were incubated with monoclonal antibodies defining specific differentiation and activation markers on the cell surface, and analyzed by flow cytometry. Cell subsets are expressed as a fraction of the total number of mononuclear cells.

The T-cell subset level was significantly higher in peripheral blood than in renal cell carcinoma tissue of the same patient. However, the level of activated T-cell subset expressing HLA-DR was significantly higher in renal cell carcinoma tissue than in peripheral blood. The levels of interleukin-2 receptor and transferrin receptors expressing T-cell subsets were also significantly higher in carcinoma tissue than in peripheral blood. Natural killer cells were found in significantly higher proportions in renal cell carcinoma than in peripheral blood.

These results point to significant activation of T, B and natural killer tumor infiltrating lymphocytes. The inability of tumor infiltrating lymphocytes to mount an effective immune response to renal cell carcinoma may be secondary to the presence of suppressive factors in the tumor that prevent tumor infiltrating lymphocytes from transforming into effector cells. These factors may be particularly valuable for the further study of renal cell carcinoma-host interactivity.