Abstract
The subsets of tumor infiltrating lymphocytes (TILs) in 17 patients with renal cell carcinoma were studied by two-color flow cytometry and immunohistochemistry. In grade 1 tumors, CD4-positive cells were significantly increased compared to grade 2 and 3 tumors (35±7% vs 25±10%) (p<0.05). In 10 of 14 patients, CD8-positive cells were predominant over CD4-positive cells, resulting in less than one in CD4/CD8-ratio. Regarding CD4 cells in all 17 cases, the helper T-cells (CD4-positive and CD45RA-negative) were statistically predominant over the inducer T-cells (CD4-positive and CD45RA-positive) (p<0.01). When CD8 cells were investigated in 16 out of the 17 cases, the cytotoxic T-cells (CD8-positive and CD11b-negative) were found also significantly predominant over the suppressor T-cells (CD8-positive and CD11b-positive) (p<0.01).
Immunohistochemically, the infiltrating pattern of TILs in the 17 patients was classified into cluster (N=4), separate (N=6), and mixed types (N=7). The tumor in the cluster and mixed type had a tendency to be dominant in low grade tumors, and had the prominent CD8-positive cells (more than 90% were cytotoxic T-cells) over CD4-positive cells. However, no statistical significance was noted in this finding. The advanced tumor tended to show the single type of TIL infiltration. These results suggest that cytotoxic T-cells consisted of most of TILs in cluster and mixed types play an immunoreactive role against renal cell carcinoma.
