Leukocyte adherence inhibition in patients with nonmalignant disorders of the colon and colorectal cancer.

The tube leukocyte adherence inhibition (LAI) technique was used to investigate the antitumor immunity in two groups of patients generally considered to be at "high risk" of developing colorectal cancer. The first group comprised 21 patients with colorectal polyps and the second 12 patients with various forms of colitis. Also 29 patients with histologically confirmed colorectal cancer were tested. The tube LAI assay was performed using peripheral blood leukocytes from individual patients and crude extracts of colorectal and breast cancers. Positive LAI reactions were observed in 18 out of 29 (62%) patients with colorectal cancer, in 1 out of 21 (5%) patients with colorectal polyps and in 1 out of 12 (8%) patients with colitis. The results indicate that in confirmed cases of malignancies, sensitization to colon tumor-associated antigens could be detected in the tube LAI test, whereas, premalignant sensitization to these antigens in "high risk" groups of patients could not be demonstrated.