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 lymphocy te count, particularly T lymphocyte number. In addition, preliminary studie s have shown that the postoperative period is also characterized by a decli ne in the number of circulating dendritic cells (DC), whose fundamental ant icancer role has been recently demonstrated. Previous studies had already s hown that the preoperative injection of IL-2 may completely abrogate surger y-induced lymphocytopenia, whereas its eventual influence on DC system duri ng the perioperative period is still unknown. The present study was perform ed to evaluate the influence of IL-2 preoperative immunotherapy on the peri operative changes in circulating DC number in patients affected by colorect al 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 an d CD11c to recognize immature and mature DC, respectively. Surgery induced a significant decline in the mean number of both immature and mature DC. Th e pre-surgical administration of IL-2 completely abrogated surgery-induced decline in immature DC cell amount. Moreover, mature DC mean number was dim inished 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 character ized also by a significant decline in the mean number of both immature and mature DC. Moreover, this study would suggest that the preoperative immunot herapy with IL-2 may counteract surgery-induced failure of DC system. Becau se of the fundamental antitumor role of DC, this evidence could have a prog nostic impact on the clinical course of the neoplastic disease.