Disappearance after chemotherapy of blocking serum factors as measured in vitro with lymphocytes cytotoxic to tumor cells

Abstract

An in vitro assay capable of detecting lymphocytes cytotoxic to tumor cells is presented. Two patients with fibrosarcoma circulated lymphocytes that were cytotoxic to fibrosarcoma cells but not to squamous carcinoma cells. Although the patients had metastatic disease, no blocking serum factors could be demonstrated. A patient with liposarcoma metastatic to the lung yielded lymphocytes cytotoxic to sarcoma cells but not to carcinoma cells; the serum acted synergistically with the cytotoxic lymphocytes. A patient with Paget's osteitis deformans circulated both lymphocytes cytotoxic to osteosarcoma cells and serum factors blocking the cytotoxic effect of lymphocytes. Three patients with disseminated sarcomas circulated serum factors that specifically antagonized the cytotoxic effect of lymphocytes on sarcoma cells. After chemotherapy (the main agent was cytosine arabinoside), the blocking factors became undetectable. In one patient, temporary tumor regression coincided with the absence of blocking factors. In the two other patients, tumor growth continued while no blocking factors were present in the serum. Copyright © 1972 American Cancer Society