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Background and Aims: Innate immunity cells play a crucial role in host anticancer defense: cancer patients with high levels of natural killer (NK) cells and eosinophils have a better prognosis. Recombinant interleukin-2 (rIL-2) immunotherapy stimulates innate immunity cells. This study aims to evaluate the toxicity of pre- and postoperative rIL-2 treatment and the effects on innate immunity both in peripheral blood and in cancer tissue of patients with resectable pancreatic adenocarcinoma., Materials and Methods: Seventeen patients received high dose rIL-2 preoperative subcutaneous administration and two low dose postoperative cycles. We evaluated NK cell and eosinophil count in blood and in pancreatic surgical specimens., Results: Toxicity was moderate. In the early postoperative period, blood NK cells and eosinophils significantly increased compared to basal values (p < 0.02). Histopathological analysis did not find significant intratumoral infiltration of NK cells nor of eosinophils., Conclusions: Preoperative high dose rIL-2 administration is able to counteract surgery-induced deficiency of NK cells and eosinophils in peripheral blood in the early postoperative period, although it cannot overcome local mechanisms of immune tumor escape in cancer tissue. The amplification of innate immunity, induced by immunotherapy, may improve the control of metastatic cells spreading in the perioperative period.

Several studies have shown that there is a paucity of immune cells within the stroma of pancreatic adenocarcinoma, a very aggressive cancer with a median survival of about 18 months. A 65-year-old man presented with jaundice. Abdominal ultrasound revealed intra- and extrahepatic bile duct dilatation and a 45-mm diameter hypoechoic solid mass within the pancreatic head; a computed tomography scan excluded vascular infiltration and metastatic lesions. The patient received immunotherapy consisting of 6,000,000 IU human recombinant interleukin-2 administered subcutaneously twice a day for 3 consecutive days. Thirty-six hours after the last dose, he underwent a pylorus-preserving pancreatoduodenectomy. Because of the presence of high-grade dysplasia detected by intraoperative histological examination of a distal section, a spleen preserving total pancreatectomy was performed. The postoperative course was uneventful. The patient died 32 months after surgery because of local recurrence. Histopathology showed G3 pancreatic ductal adenocarcinoma infiltrating the anterior and posterior peripancreatic tissue, duodenal wall and intrapancreatic common bile duct, with sarcoma-like foci and a component of intraductal tumor involving the common bile duct. In the distal pancreas, widespread foci of pancreatic intraepithelial neoplasia (PanI2-3) were found. The Ki-67 proliferation index was 16%. TNM staging was pT3 pN1 R1. Sections were immunostained for the T-lymphocyte marker CD3 and for the dendritic cell marker CD1a. Intratumoral infiltration was high for CD1a+ cells and mild for CD3+ cells. Preoperative immunotherapy with interleukin-2 may contribute to massive stromal infiltration of immune cells in pancreatic adenocarcinoma. This may prolong the survival even in the presence of negative prognostic factors (age >65 years, tumor diameter >20 mm, R1, tumor grade G3).