Immunomodulation in a treatment program including pre- and post-operative interleukin-2 and chemotherapy for childhood osteosarcoma

Aims and background: The treatment applied in our Institution to children with localized osteosarcoma between 1991 and 1999 consisted of four interleukin 2 (IL-2) courses (9 × 10⁶ IU/mL/daily × 4), alternated with pre- and post-operative polichemotherapy. The aims of the present study were to quantify the modifications of some immunological parameters induced by IL-2 and to verify whether polychemotherapy could reduce them. An additional aim was to assess whether any correlation between the immune modifications and the clinical outcome could be found. Patients and methods: We evaluated in 18 consecutive patients the following changes, induced in blood by each IL-2 course: number of lymphocyte subpopulations and natural killer (NK) cells, lymphokine activated killer (LAK) and NK activities. Results: Chemotherapy did not influence the modifications of the number of NK and CD4+ cells and of the LAK and NK activities, induced by each of the four courses of IL-2. The magnitudo of the NK activity and the peak of the NK absolute counts significantly correlated with the clinical outcome. Conclusions: The results show that the use of IL-2 permitted a repeated immune activation despite the intensive chemotherapy. Furthermore, although the limited number of cases precludes any definitive conclusion, the results suggest a possible role of the NK cells in the control of osteosarcoma.