Prognostic significance of immunological tests in lung cancer.

We performed a battery of tests on peripheral blood samples from 94 patients with lung cancer to determine the extent to which immunological depression was due to abnormal lymphocyte function, as compared to changes in the number of lymphoid cells in the peripheral blood or in the efficiency of purification of cells in Ficoll-Hypaque gradients in preparation for testing. The percentage of lymphocytes in the gradient-derived cell suspension (%LG) was the most informative test. It decreased significantly with advancing stage of cancer and could predict survival of patients with uniform stage. The %LG correlated with survival better than any other test when multivariate analyses of all test combinations were performed. Low values of %LG reflected both the depressed lymphocyte counts and the altered buoyant density of the leucocytes of many patients with advanced cancer. A large proportion of the depression in other immune function tests was statistically attributed to changes in %LG. We concluded that this simple measurement provides valuable information about patients with lung cancer.