Effects of laparotomy on systemic macrophage function

Surgical trauma induces immunosuppression that may adversely influence survival. This study examined the effect of laparotomy on two different macrophage populations, peritoneal macrophages (PM∅) and Kupffer cells. Female, 6- to 8-week old, CFW/C3H-HeN mice (n = 160) were randomly allocated to one of three study groups: control, ether anesthetic only, or ether anesthetic and laparotomy. On postoperative days 1 and 3, PM∅s and Kupffer cells were harvested and assayed for superoxide anion production (O_2-), percent macrophage phagocytosis of Candida albicans (CAP), percent C. albicans killed by macrophages (CAK), percent major histocompatibility complex (MHC)-class II antigen expression, and antigen presentation. Macrophages isolated on postoperative day 1 were also cocultured with 100 units/10⁶ cells/ml interferon-γ (IFN-γ). Laparotomy significantly impaired microbicidal activity (O_2-, percent CAP, and percent CAK) and antigen presentation on postoperative day 1. On postoperative day 3, O_2- and antigen presentation were increased significantly (p < 0.05) over control values, indicating a rebound phenomenon. Kupffer cell microbicidal function was unchanged on postoperative days 1 and 3. The initial immune impairment (PM∅s: O_2-, CAP, and CAK) was abrogated by IFN-γ treatment. In immunosuppressed hosts after injury, administration of macrophage-activating factors such as IFN-γ could be of therapeutic benefit.