Design
Double-blind, randomized, placebocontrolled trial.

Setting
University Hospital, Newark, NJ, a level I trauma center.

Patients
Persons older than 16 years with an Injury Severity Score greater than 20 and documented bacterial contamination at the time of injury (N=98).

Interventions
Recombinant human interferon gamma (n=46; 0.1 mg subcutaneously) or placebo (n=52) was given for 10 days following injury.

Outcomes
Incidence of major infection, monocyte and lymphocyte cell surface antigen expression, and interferon gamma production at multiple time points following injury.

Results
Peripheral monocyte HLA-DR was measured as percent of cells staining positive and as mean channel fluorescence. Both values were significantly increased in the interferon gamma group compared with the placebo group on days 3, 5, 8, and 11. The incidence of major infection was unaffected by interferon gamma administration. Infection decreased percent of HLA-DR—positive monocytes and mean channel fluorescence as compared with noninfected patients on postinjury days 8 and 11 in the placebo group but not in the interferon gamma group. Interferon gamma production improved from 3±3 U/mL on day 1 to 15 ±10 U/mL by day 30 but was always significantly lower than normal (25±3 [mean±SD] U/mL). Interferon gamma production was unaffected by either infection or interferon gamma administration.

Conclusions
Interferon gamma administration after injury stimulated monocyte HLA-DR antigen expression and density but failed to improve interferon gamma production, a T-cell—mediated function. The incidence of infection was not decreased by the administration of interferon gamma for 10 days. Improvement in monocyte HLA-DR antigen expression did not correlate with a global restoration of immune function, and other interventions will be necessary to decrease infection after injury.

(Arch Surg. 1994;129:172-178)