Immunoprotective effects of cyclooxygenase inhibition in patients with major surgical trauma

Dysfunctional monocytes (M phi), exerting their inhibitory functions via prostaglandin E2 (PGE2), have been implicated in the depression of immune responses following major surgical, accidental, and burn trauma. A randomized prospective study of the PG-synthetase inhibitor indomethacin (Indo) was performed in 43 patients undergoing major surgical procedures, to evaluate its efficacy in correcting postoperative abnormalities of the cell-mediated immune system (CMI) and preventing infectious morbidity and mortality. Patients, following gastrectomy (GX) or reconstruction of the abdominal aorta (AG), in the treated group (PIndo), received 100 mg IV of Indo 6 hours postoperatively and 3 x 50 mg IV Indo over 24 hours on postoperative days (D) 1,2,3,4. The rate of infectious complications was recorded. Parameters of CMI evaluated preoperatively (D0) and on D1,D3,D5,D7 were: Delayed type hypersensitivity (DTH) response to recall antigens, mitogen-induced lymphocyte proliferation (LP), interleukin 2 (IL-2) synthesis, and phenotyping of mononuclear blood leukocytes (PBMC's) with the monoclonal antibodies for CD3+, CD4+, IL-2 receptor (IL-2R)+ and LeuM3+ receptor sites. In contrast to the group of untreated patients (Pc), PIndo did not show a depression of their preoperative DTH responses, and they also showed a lower rate of early opportunistic infections. The in vitro test of CMI revealed that there was a higher LP capacity in PBMC's of PIndo (p less than 0.05); the postoperative profile of IL-2 synthesis was not statistically different between the groups. Indomethacin administration resulted in a considerable alleviation of postoperative monocytosis (p less than 0.05) and in a protective effect on lymphocyte receptor expression of CD3+, CD4+, and IL-2R+ cells. From these data it is concluded that in vivo cyclooxygenase inhibition may be useful to prevent impairment of CMI, a crucial predisposing factor of the high susceptibility to postoperative infection.