[Clinical effect of human fibroblast interferon on malignant cancer. (2) Immunological study of the patients under treatment].

Several immunological studies were performed in patients with various malignant diseases under treatment of human fibroblast interferon (HFIF). Lymphocyte natural killer (NK) activity against culture cell lines was measured before and at various time after HFIF treatment. The majority of patients reached the highest level of NK activity at 18-24 hours, mostly at 24 hours after initiating HFIF. In one group of patients, thereafter, NK activity remained the highest level during HFIF treatment, and in another group of patients, NK activity declined even with daily infusion of HFIF but usually remained above pre-treatment level. There seemed to be no correlation between NK activity and clinical activity. In contrast to NK activity against culture cell lines, an increase in lymphocyte cytotoxic activity against autologous tumor cells was not observed following HFIF treatment. Mixed lymphocyte tumor cell reaction performed in 6 patients showed that a slight increase of 3H-thymidine uptake was seen in one patient, but the rest of them had no change. In vitro sensitization to assess the in vitro generation of cytotoxic cells were negative in all 6 patients. Lymphocyte blastogenic responses to non-specific mitogens showed no significant change. Delayed type hypersensitivity reaction to recall antigens was increased in about half of the patients after HFIF treatment.