Immunoreactive Interleukin-1 in Bronchoalveolar Lavage Fluid of High-Risk Patients and Patients with the Adult Respiratory Distress Syndrome

The adult respiratory distress syndrome (ARDS) is characterized by increased neutrophils and macrophages in bronchoalveolar lavage (BAL) fluid. Interleukin-1 (IL-1), an inflammatory mediator produced by macrophages, has been shown to be chemo-tactic for neutrophils and to stimulate lymphocyte activation and proliferation of fibro-blasts. BAL was performed in patients with ARDS, patients at high risk to develop ARDS, and in normal nonsmokers. After removal of cells and surfactant-complexed lipids by centrifugation, the remaining supernatant was concentrated by ukrafiltration utilizing membranes retaining substances greater than 5000 daltons. The concentrate was assayed for immunoreactive IL-1β by a radioimmunoassay method. Patients with ARDS (n = 9) had an IL-1 level of 184 ± 67 pg/ml, high-risk patients (n = 9) had 172 ± 62 pg/ml, and normals (n = 10) had 4 ± 1 pg/ml. There was a significant (p ≤ .05) increase in IL-1 in the ARDS and risk groups compared to normals. IL-1 was detected in serum from patient...