Abstract
PURPOSE: High-dose chemotherapy with peripheral blood stem cell transplantation (PBSCT) has become an important treatment for solid tumors including lung cancer. METHODS: We measured IL-12 levels in patients with lung cancer undergoing autologous PBSCT in order to elucidate the role of IL-12 in immune response recovery following stem cell transplantation. RESULTS: Compared to IL-12 levels at 1 week after PBSCT for lung cancer patients, those at 3 weeks were significantly increased ( P<0.01). In contrast, serum IL-12 levels in malignant lymphoma patients did not change significantly. There were no significant differences in levels of other cytokines between 1 week and 3 weeks after transplantation in patients with lung cancer. The frequency of helper/inducer T cells was increased in peripheral blood 1 week after transplantation in both lung cancer and malignant lymphoma patients. There was a significant increase in activated T cell numbers following PBSCT. Furthermore, high levels of other activated T cells persisted in the post-PBSCT period in patients with lung cancer and the number of cytotoxic T cells significantly increased. Natural killer (NK) cell numbers also tended to increase, although that of malignant lymphoma was not significant. A strong correlation was observed between serum IL-12 levels and NK cell numbers and interferon-gamma levels in lung cancer not but in malignant lymphoma patients. The analysis of transfused PBSC showed that the numbers of granulocyte/macrophage colony-forming units were similar in lung cancer and malignant lymphoma patients. However, the number of CD34+ cells was significantly higher in lung cancer than in malignant lymphoma patients. All of the CD34+ subpopulations were lower in percentage in patients with lung cancer than in patients with malignant lymphoma. In particular, the CD34+ CD33- subpopulation was significantly lower in percentage in lung cancer patients. CONCLUSION: Our findings suggest that PBSC in lung cancer are potent mediators of anticancer activity and that they might play an immunotherapeutic role against autologous malignant cells.