Triggering receptors expressed on myeloid cells in pulmonary aspiration syndromes

Objective: To investigate the potential role of serum and alveolar soluble triggering receptor expressed on myeloid cells (sTREM-1) as a biological marker of pulmonary aspiration syndromes. Design: Prospective cohort study. Setting: University-affiliated intensive care unit. Patients: Seventy-five patients with pulmonary aspiration and 13 controls receiving mechanical ventilation. Interventions: Blood and bronchoalveolar lavage (BAL) fluid samples were collected on enrollment. Soluble TREM-1 levels were measured by an enzyme-linked immunosorbent assay. Measurements and results: Thirty-eight of 75 participants had documented BAL culture-positive pulmonary aspiration. While circulating levels of sTREM-1 were comparable between those with aspiration syndromes (19.81 ± 12.09 pg/ml) and controls (15.96 ± 11.16 pg/ml) (p = 0.27), the alveolar levels of sTREM-1 were higher in patients with culture-positive pulmonary aspiration (344.41 ± 152.82 pg/ml) compared with those culture-negative pulmonary aspiration (142.76 ± 89.88 pg/ml; p <0.001). A cut-off value of 250 pg/ml for alveolar sTREM-1 achieved a sensitivity of 65.8% (95% CI 48.6-80.4) and a specificity of 91.9% (95% CI 78.1-98.2) with an area under the curve of 0.87 (95% CI 0.78-0.94). Conclusions: Alveolar sTREM-1 levels can be a potential biomarker for distinguishing BAL culture-positive from BAL culture-negative pulmonary aspiration.