Abstract:Background. In Japan since the 1960s, patients with gastric cancer have routinely had splenectomy combined with gastrectomy to ensure that lymph node dissection is complete. However, the influence of splenectomy on long-term immunity is unclear. Methods. Forty-nine gastric cancer patients who underwent total gastrectomy for cure with (n ؍ 25) and without (n ؍ 24) splenectomy were assessed for immunologic function, including the proportion of lymphocyte subsets, purified protein derivative from tuberculin (PPD) response, natural killer (NK) activity, and phytohemagglutinin (PHA) response. Results. Peripheral T-cell mediated functions, e.g., PPD and PHA response, were significantly suppressed in patients who underwent gastrectomy with splenectomy compared with those who had gastrectomy alone. Decreased T-cell subsets (CD 3؉, 4؉, 8؉) and increased NK cell subsets (CD 16؉, 57؉) were observed in patients who underwent splenectomy. Patients who did not undergo splenectomy had immunologic responses within the normal range. Conclusions. Splenectomy decreased T-cell mediated responses over the long term. As a potential means to correct this T-cell dysfunction in patients with splenectomy, splenic autotransplantation should be considered in future research.