Elevated production of neutrophil leukotriene B4 precedes pulmonary failure in critically ill surgical patients.

Leukotriene B4, a potent neutrophil chemotactic factor, is also made by the neutrophil. Neutrophil function was studied in 12 patients at risk for the development of adult respiratory distress syndrome (ARDS) after admission to the surgical intensive care unit (ICU) to test the hypothesis that increased generation by the neutrophil generation of this mediator precedes the development of pulmonary failure. Peripheral blood neutrophils were tested for chemotaxis to f-met-leu-phe (fMLP) and leukotriene B4 (LTB4) and the generation of LTB4. Plasma was collected simultaneously for assay of C3a desArg levels. Five patients had ARDS a mean of 2.2 +/- 0.25 days after admission to the ICU. Neutrophil generation of LTB4 was significantly enhanced on ICU day 1 in these patients as compared with patients at risk for ARDS but not developing the syndrome (119.4 +/- 6.1 versus 101.0 +/- 5.1, per cent control, p less than 0.05). Chemotaxis to fMLP and LTB4 was significantly reduced in both groups of patients. However, neutrophil chemotaxis improved in patients who did not have pulmonary failure during the time in the ICU, whereas neutrophil chemotactic responsiveness worsened in patients who did have pulmonary failure. Plasma C3a desArg levels were significantly elevated over normal laboratory values on ICU day 1 in the ARDS patients (317.2 +/- 74.0 versus 132.0 +/- 16.0 milligrams per milliliter, p less than 0.01). These data indicate that LTB4 production by the neutrophil occurs concomitantly with complement activation, is a predictor of subsequent ARDS and may play a significant role in the development of pulmonary failure in critically ill surgical patients.