IN-111 LABELED LEUKOCYTES IN EVALUATION OF ACTIVE SPECIFIC IMMUNOTHERAPY RESPONSES

Active immunization of patients utilizing viral oncolysates (VO) has b een studied in clinical trials. VO are extracts of cultured tumor cell s that have been infected with certain types of viruses, particularly surface budding varieties. The objectives of the current studies were to examine the trafficking patterns of Indium (In)-111-labeled leukocy tes or lymphocytes in two groups of patients with gynecologic malignan cies to determine whether these cells migrate to sites of active immun ization after VO. Eight patients with ovarian cancer received VO intra peritoneally followed by In-111-labeled leukocytes or lymphocytes (500 mu Ci) intravenously. In a separate trial, three patients with cervic al cancer received In-111-labeled lymphocytes after they had been trea ted with VO administered by the intralymphatic route. Gamma camera ima ging was performed to evaluate the distribution patterns of the labele d cells at several time intervals after injection. Results indicate th at metastatic tumor sites exposed to VO therapy show significant uptak e of In-ill cells. These sites of malignancies were confirmed by compu terized tomography and ultrasound scans. In patients with ovarian canc er no uptake of the radiolabeled cells was observed in metastatic tumo rs of the liver and lymph nodes. In patients with cervical cancer, lym ph node metastases exposed to intralymphatic VO therapy were visualize d very well. Other known tumor sites not exposed to VO therapy showed no uptake of radioactivity. These findings confirm that VO induces imm une responses. This diagnostic nuclear medicine technique may prove to be a useful method for following-up responses to immunotherapy.