Immune Response: Effects of Operative Stress in a Pediatric Model

Abstract Purpose: The purpose of this study is to delineate the effect of different operative procedures on the cell-mediated immune response in a pediatric animal model using the delayed type hypersensitivity (DTH) skin test. Methods: Sprague Dawley rats (1 week old) were sensitized against keyhole limpet hemocyanin (KLH). Animals were challenged 2 weeks later by an intradermal injection of KLH (0.3 mg) in sterile saline. Rats with positive DTH skin reactions at 24 and 48 hours after challenge (baseline) were divided randomly into five groups (n = 10 each): group I, unmanipulated control; group II, anesthesia; group III, anesthesia and midline extraperitoneal incision; Group IV, anesthesia and laparoscopy (pneumoperitoneum with carbon dioxide); Group V, anesthesia and midline laparotomy. Before each procedure (day 0) and on postoperative days 3 and 6, animals were again challenged intradermally with KLH (0.3 mg). DTH skin reaction was evaluated 24 and 48 hours later. Results: A statistically significant difference ( P Conclusions: These results suggest that in a pediatric animal model, abdominal surgical procedures accompanied by extensive tissue dissection produce a cellular immunosuppression, lasting up to 7 days, which is not observed in less invasive procedures. Observations concerning lesser immunosuppressive effects of laparoscopy when compared with laparotomy in adult models, as previously described by our laboratory, were also found in this pediatric model.