Inhibition of leukocyte adherence by 3-M potassium chloride extracts of human colorectal tumors.

Leukocyte adherence inhibition (LAI) assays were performed to test whether peripheral blood leukocytes (PBL) from patients with colorectal cancer could be inhibited from attachment to a glass surface when tumor-associated antigens (TAA) of human colorectal tumors were present. The assays were performed with PBL from 41 patients with adenocarcinoma of the colon or rectum with 3-M KCl extracts of colorectal tumors. The results demonstrated the presence of colorectal TAA in the 3-M KCl extract of colorectal tumor materials. The reactivity of leukocytes from patients with a favorable prognosis showed an increasing LAI trend; the reactivity of leukocytes from patients with an unfavorable prognosis had a decreasing LAI trend. In individual patients, alterations in the sequential LAI results paralleled changes in the clinical status, which thus strongly indicated that the LAI assay could be of value in the assessment of antitumor immunity.