Immune responses in lung cancer patients measured by a modified leukocyte adherence inhibition test using serum

A modified leukocyte adherence inhibition (H-LAI) assay was used to study immunological factors in serum from lung cancer patients. In this test, 0.25% serum was added to the assay system, together with tumor antigen and trypsinized leukocytes from control persons. Extracts from a human lung cancer cell line (Calu-1) and a human breast cancer cell line (MCF-7) were used as antigens. The results obtained were compared with data found with the original hemocytometer (C-LAI) assay. Of 21 lung cancer patients studied, 20 (95%) gave a positive response in both the H-LAI and the C-LAI assay systems against Calu-1 antigen. Only 1 of the patients gave a positive response in the H-LAI system against MCF-7 antigen, while 3 patients (14%) responded in the C-LAI assay. None of the 14 control persons tested gave a positive response. While the C-LAI assay was limited to the use of fresh blood, the H-LAI system was performed on small amounts of serum. The serum could be stored in the frozen state for a long time period. The results indicate that the H-LAI assay possesses at least the same sensitivity and specificity as the original C-LAI test.