Demonstration of tube leukocyte adherence inhibition assay with coded samples of blood.

Heparinized samples of blood from three different patients were coded by impartial observers. The buffy coat leukocytes from the coded samples of blood were isolated and incubated separately with extracts of colon and pancreatic cancer in the tube leukocyte adherence inhibition assay. At the completion of the assay, the leukocytes from Patient 1 were equally nonadherent to both cancer extracts with a nonadherence index value of 8. By contrast, leukocytes from Patient 2 exhibited increased nonadherence to the extract of colon cancer (p = 0.02) with a nonadherence index value to colon cancer antigen of 89. Leukocytes from Patient 3 displayed increased nonadherence to the extract of pancreatic cancer (p less than 0.05) with a nonadherence index value to pancreatic cancer antigen of 39. When the code was broken, patients 1, 2, and 3 had diagnoses of malignant melanoma, colon cancer, and pancreatic cancer, respectively. Hence, this was a classical criss-cross experiment; the patient with malignant melanoma reacted to neither of the antigens, whereas the patients with colon and pancreatic cancer reacted to the sensitizing cancers which had unique organ-type specific neoantigens.