Immune status in lung cancer: effects of BCG immunotherapy.

Immunotherapy with bacille Calmette-Guérin (BCG) was administered according to a standard regimen to 23 patients with primary lung cancer who had completed conventional treatment, including surgery and/or radiation therapy. Five additional patients did not receive BCG. Skin tests and in vitro lymphocyte studies were performed serially at intervals for 12 months or until death. The aggregate of skin responses to nonmycobacterial antigens and lymphocyte responses to phytohemagglutinin and recall antigens increased only in the group of 7 patients with no clinically evident disease 12 months after the start of BCG administration. The group of 5 patients who did not receive BCG, but who remained clinically disease free, did not experience immunoenhancement, nor did BCG-treated patients with residual or recurrent malignancy. Patients who had received radiation therapy before BCG also did not experience immunoenhancement, but these patients also had recurrent or persistent disease. Enhancement of certain aspects of the immune response to within 1 SD of the response of a group of subjects with nonmalignant pulmonary disease was prognostic of a favorable clinical outcome at 12 months.