[Analysis of suppressor cell activities in spleen cells from gastric cancer patients and the effect of splenectomy on prognosis of gastric cancer].

In gastric cancer patients, activities of Concanavalin-A induced suppressor cells ( ConAS ) and spontaneous suppressor cells (SpS) in spleen cells (SC), peripheral blood lymphocytes (PBL) and splenic vein lymphocytes (SVL) were comparatively investigated. Suppressions by ConAS in PBL were significantly increased in patients of Stages III and IV, while suppressions by SpS were increased in patients with recurrent tumors. Elevated activities of ConAS and SpS were observed in SCs and SVLs , respectively. ConAS activities were mostly indicated in the medium sized lymphocyte fractions which were fractionated on the basis of cell size, while SpS activities in the larger sized fraction. Cell numbers in the large sized lymphocyte fraction which contained higher proportion of Tg cells and OKT8 reactive T cells, tended to increase with advances of the disease. These results suggest that spleen contained much higher proportion of suppressor precursors which might be activated to become suppressor cells with advances of the disease. Furthermore, the effect of splenectomy on the prognosis of gastric cancer was investigated in randomized controlled trial. The patients who underwent total gastrectomy and had main location of the tumor on lesser curvature region were divided into two groups at random; splenectomy (+) and splenectomy (-) groups. A suggestive prolongation of survival time was observed in splenectomy (+) group. Thus, spleen seems to contribute to the immunosuppression in gastric cancer patients and splenectomy may lead to better prognosis.