Twenty levamisole-treated and 14 placebotreated lung eancer patients were studied sequentially in assays of lymphocyte proliferation. Prior to treatment, the patients as a group had significantly depressed proliferative responses to mitogens and allogeneic cells (MLC), and this immunosuppression was especially noticeable in patients with clinically detectable tumor burdens. Following treatment, responses in both levamisole and placebo groups tended to increase slightly, although the increases were more consistent and persistent in the levamisole group. Increases within the levamisole group were similar for patients with and without detectable tumor burdens. Proportions of E and EAC rosette-forming cells were stable throughout treatment for all groups. No consistent response pattern was observed in patients crossed-over from placebo to levamisole treatments. Although these results do not contradict the concept that levamisole can reverse malignancy-induced immunosuppression, levamisole treatment clearly did not result in normalization of lymphocyte-proliferative capacity in these lung cancer patients. The usefulness of a placebo-treated group was apparent, as some increased responsiveness was commonly found with placebo treatment.
with other solid neoplasms [7]. This makes lung cancer an interesting disease for experimental immunotherapy, especially immunotherapy designed to restore proper immunologic function.
Considerable attention has been focused on the use of the agent levamisole for the treatment of malignant disease. Since the side effects of this agent are minimal and it can be taken orally, it is an attractive potential immunotherapeutic agent. Levamisole has been reported to result in a prolongation of the disease-free interval in patients with resected lung cancer [1], and has also been shown to potentiate immunological responses in a variety of systems reviewed [15]. The potentiating effect of levamisole appears to be most readily demonstrated in situations where the immune response is functioning suboptimally [10,14,16], and thus it probably should be considered a restorative agent for the immune systems. In view of this apparent beneficial effect of levamisole on the clinical status of patients with resected lung cancer, and of the apparent ability of this agent to augment cell-mediated immunity in certain situations, we designed the present study to evaluate the effects of levamisole on sequentially tested in vitro assays of cellular immunocompetence in lung cancer patients.