Concanavalin A-induced suppressor cell activity in patients with renal cell carcinoma

Concanavalin A (Con A)-induced suppressor cell activity against the proliferative response of autologous lymphocytes to phytohemagglutinin was examined in peripheral blood lymphocytes derived from 12 normal control subjects and 25 patients with renal cell carcinoma (RCC). The Con A-induced suppressor cell activity in patients with RCC (23.4 +/- 21.4%) was significantly higher than that in control subjects (9.7 +/- 10.7%, P less than 0.05). No significant difference between the degree of suppressor cell activity and stage of disease, grade of malignancy, or cell type was found, although the suppressor activity in patients with tumor microscopically infiltrated by lymphocytes was significantly higher than in patients without lymphocyte-infiltration into the tumor (P less than 0.05). Furthermore, compared with control subjects, Con A-induced suppressor activity in patients with high stage and in those with lymphocyte infiltration into the tumor was significantly higher (P less than 0.05 and P less than 0.01, respectively). In conclusion, because patients with RCC have high suppressor cell activity, abrogation of this activity may be necessary to treat the RCC.