T- and B-cell responses in patients with malignant pleural effusions.

Lymphocytes of lymphocyte-rich pleural effusions and venous blood from 16 cancer patients, 7 patients with benign pleural effusions and blood from 23 normal blood donors, were examined for cytological features, rosette-forming capacity, immunofluorescent staining, and PHA-stimulated DNA synthesis. Total protein and immunoglobulin levels were also determined. Metastatic effusions revealed approximately 40% higher content of immunoglobulins G, A and M (P less than 0.002) as well as of total protein (P less than 0.005) than non-metastatic pleural effusions. However, the serum of the non-cancer patients contained approximately 50% higher level of Ig than in cancer patients (P less than 0.001). Whilst there was no significant difference in the relative T- or B-cell contents of pleural effusions between cancer and non-cancer patients (P greater than 0.05) spontaneous proliferation of lymphocytes was significantly increased (P greater than 0.01), which led to a lower PHA-stimulated transformation index in pleural effusions from cancer patients than in all other lymphocyte sources examined (P less than 0.001).