Observations in immunotherapy of lymphoma and melanoma patients.

Maintenance of remission solely by repeated BCG vaccinations in seven patients with non-Hodgkin's lymphoma who had achieved a complete clinical remission with initial standard therapy has provided sufficient encouragement to begin a randomized clinical trial. In vitro lymphocyte responses to mitogens and PPD used as parameters of cell-mediated immunity have not proved to be of value in predicting early or late recurrence in six pre-trial and trial patients. Eight out of twenty-one patients with malignant melanoma have shown a satisfactory clinical response (10-34 months) to immunotherapy. Those who respond must show immunological reactivity to the stimulating agent, however the best clinical responses were not associated with the highest degrees of in vivo and in vitro sensitization. The skin reactivity and the in vitro lymphocyte response to PPD as well as a 2-3-fold increase in the appearance of colony-forming units in the peripheral blood following the intratumour injection of BCG or PPD are helpful in prognosis and management of these patients. All patients with malignant melanoma who presented with a PHA response less than 40% of normal made a poor response to immunotherapy. Autopsies performed on seven patients dying with extensive melanocarcinomatous disease failed to show any serious adverse toxic reactions or infections from oral and intratumour injections of BCG.