Immunohistochemical study of dendritic cells, macrophages and lymphocytes in gastric cancer.

Infiltration of dendritic cells, macrophages and lymphcytes into tumor tissues was immunohistochemically investigated using new monoclonal antibodies ID-1 for dendritic cells and CD68 for macrophages in 68 patients with gastric cancer. A serial section technique and double staining method were used for the phenotypic analysis. In the normal musosa, ID-1+ cells were located under the surface epithelium, while CD68+ cells were widely distributed in the lamina propria. Most of ID-1+ cells and CD68+ cells in the normal mucosa were negative for ICAM-1 and activated markers of CD25 and HLA-DR antigens. In cases of mucosal cancer, the numbers of ID-1+ cells and CD 68+ cells in the cancer tissue were similar to the normal mucosa. When cancer cells invaded the submucosa, ID-1+ cells and CD68+ cells were significantly increased in the cancer tissue except for the cases of signet ring cell carcinoma. The increased ID-1+ cells were positive for ICAM-1, HLA-DR, CD25 and CD11c, while most of CD68+ cells were negative for ICAM-1 and CD25 antigans. Further, ID-1+ cells were predominantly distributed adjacent to the tumor tissues with a marked infiltration of CD3+ cells. Conversely, CD68+ cells were distributed in the cancer stroma and necrotic tissues without CD3+ cell infiltration. These findings suggested that ID-1+ dendritic cells play a crucial role in the immune response agaist the cancer tissue.