Recombinant interleukin-2 (rIL-2) with flavone acetic acid (FAA) in advanced malignant melanoma: immunological studies.

Natural killer (NK) cell activity and lymphokine activated killer (LAK) cell cytotoxicity were measured in patients receiving recombinant interleukin 2 (rIL-2) and flavone acetic acid (FAA) for treatment of progressing metastatic melanoma. NK activity was increased in 23 of 26 patients and LAK activity induced in 13 of 26 patients. However, levels of cytotoxicity in the present study were not significantly greater than a previous study using rIL-2 alone. LAK cell precursors demonstrated by in vitro incubation of pretreatment lymphocytes with IL-2 and subsequent cytotoxicity were no different in the patients compared to normal controls. Analysis of cell surface phenotypes failed to reveal any significant changes in the cell populations examined, including IL-2R and Leu 19. Although five patients had tumour response, one being complete, there was no correlation with the immunological parameters examined.