Leukocyte adherence inhibition microtest for the detection of cell-mediated immunity to tumor in gastric cancer patients.

The reactivities of leukocytes from gastric cancer and noncancer patients to gastric tumor and normal tissue extracts were tested by the leukocyte adherence inhibition (LAI) microtest, assessing cell-mediated immunoreactivity to adenocarcinoma of the stomach. The reactivities were expressed with the LAI index. All leukocyte preparations showed low reactivities, a LAI index of less than 20%, to normal tissue extracts and only the preparations of leukocytes from cancer patients displayed high reactivities, a LAI index of more than 20%, to tumor extracts. Assuming that a patient is sensitized to gastric tumor antigen if his leukocytes respond to at least one tumor extract with a LAI index of more than 20%, approximately half of the cancer tumor antigen. Thus, the LAI microtest appears to be a simple, rapid and specific method for demonstrating cell-mediated immunity to tumor.