Intrapulmonary cytokine accumulation following BAL and the role of endotoxin contamination

Study objectives: BAL induces alveolar inflammation, but its effects on int rapulmonary cytokines and the mechanisms causing inflammation are uncertain . The objectives of this study were: (I) to characterize cytokine response in the lungs to BAL, and (2) to determine whether endotoxin is introduced i nto the lungs during BAL, which could promote BAL-induced inflammation, Design and methods: We pet-formed two BAL procedures in healthy volunteers separated by 4 (n = 6), 24 (n = 5), or 72 h (n = 3), The initial BAL was pe rformed in the right middle lobe (RML) and the second BAL was pet-formed in the same location and the lingula. Concentrations of interleukin-8 (IL-8), interleukin-1 beta (IL-1 beta), and transforming growth factor-beta were m easured by enzyme-linked immunosorbent assay and tumor necrosis factor-alph a (TNF-alpha) bioactivity was determined. Endotoxin contents of saline (10 and 20 mt) infused through bronchoscopes as well as BAL fluids recovered fr om sis subjects were assessed by limulus amebocyte assay, Results: At 4 h after the initial lavage, but not at later times, BAL fluid recovered from the RML contained increased concentrations of IL-8 and IL-1 beta, and increased TNF-alpha bioactivity, BAL fluid recovered from the li ngula contained increased concentrations of TNF-alpha only at 4 h, All BAL samples tested contained detectable endotoxin as did all saline aliquots in stilled through bronchoscopes. Conclusions: There is intrapulmonary accumulation of the cytokines TNF-alph a, IL-8, and IL-1 beta in the lavaged lung within 4 h after BAL; this accum ulation resolves by 24 h, Endotoxin contamination of the lungs during bronc hoscopy ma! contribute to BAL-induced lung inflammation.