Abrogation of surgery-induced decline in circulating dendritic cells by subcutaneous preoperative administration of IL-2 in operable cancer patients.

Surgery-induced immunosuppression is characterized by a decline in lymphocyte count, particularly T lymphocyte number. In addition, preliminary studies have shown that the postoperative period is also characterized by a decline in the number of circulating dendritic cells (DC), whose fundamental anticancer role has been recently demonstrated. Previous studies had already shown that the preoperative injection of IL-2 may completely abrogate surgery-induced lymphocytopenia, whereas its eventual influence on DC system during the perioperative period is still unknown. The present study was performed to evaluate the influence of IL-2 preoperative immunotherapy on the perioperative changes in circulating DC number in patients affected by colorectal cancer. The study included 14 consecutive patients, who were randomized to be treated with or without IL-2 presurgical immunotherapy (12 million IU/day for 3 days subcutaneously). Circulating immature and mature cells were evaluated before surgery and at days 3 and 7 of the postoperative period. The detection was made by FACS using monoclonal antibodies against CD123 and CD11c to recognize immature and mature DC, respectively. Surgery induced a significant decline in the mean number of both immature and mature DC. The pre-surgical administration of IL-2 completely abrogated surgery-induced decline in immature DC cell amount. Moreover, mature DC mean number was diminished only at day 3 of the postoperative period, since the value observed at day 7 was not significantly lower than that found before surgery. This preliminary study shows that surgery-induced immunosuppression is characterized also by a significant decline in the mean number of both immature and mature DC. Moreover, this study would suggest that the preoperative immunotherapy with IL-2 may counteract surgery-induced failure of DC system. Because of the fundamental antitumor role of DC, this evidence could have a prognostic impact on the clinical course of the neoplastic disease.