Imaging pattern of previously in vitro sensitized and interleukin-2 expanded autologous lymphocytes in human cancer.
In vivo patterns of lymphocytes sensitized against autologous tumor (in vitro) were studied in seven patients with metastatic cancer as a potential candidate for an alternative method of radioimmunodetection and adoptive immunocytotherapy. Peripheral blood lymphocytes (PBL) were either activated in Interleukin-2 (IL-2) [lymphokine activated killer (LAK) cells] or sensitized against autologous tumor cells by in vitro co-culture (IVC) and expanded in IL-2 (educated cells); both were then labelled with 111In. Labelled autologous cells (1 x 10(7)-5 x 10(8)) were administered to patients and biodistribution studied by imaging under a gamma camera at various time intervals. In 4/7 cases, imaging with the educated cells showed concentrations of radioactivity at sites that correlated positively with clinically detectable metastatic tumor. By contrast, only one instance of positive uptake was seen with the LAK cells. Other than slight fever in three cases, infusions of labelled PBL were well tolerated. Educated lymphocytes were cytotoxic against autologous tumor cells and the cytotoxic reactivities of the educated cells were maintained in continuous culture in IL-2 for 4-6 weeks. Evidence of accumulation of radiolabelled educated autologous cells at a significantly higher frequency than that of the LAK cells suggests that in vitro expanded educated PBL might be better candidates for radioimmunodetection of human cancer, and continuous cultures of such educated autologous PBL might be sources for repeated administration of these effector cells.