BAL induces an increase in peripheral blood neutrophils and cytokine levels in healthy volunteers and patients with pneumonia

STUDY OBJECTIVES: To examine the peripheral effects of BAL on the neutrophil counts and cytokine levels in the circulation. DESIGN AND METHODS: WBC counts and plasma cytokines were measured before and 4 h after fiberoptic bronchoscopy (FOB) without further interventions (n = 6), or combined with BAL in normal volunteer subjects (n = 6), and in patients with bacterial pneumonia (n = 4). The bronchus of the right middle lobe was wedged, and three 50-mL aliquots of sterile saline solution was instilled. There was no endotoxin contamination in the saline solution or the fluid obtained through the working channel of bronchoscope. RESULTS: In volunteers, peripheral WBC counts and the number of nonsegmented and segmented neutrophils increased after the BAL procedure (p < 0.05) associated with the increase in plasma concentration (mean +/- SEM) of interleukin (IL)-6 (0.99 +/- 0.32 pg/mL before BAL and 20.38 +/- 13.42 pg/mL after BAL; p < 0.05) and granulocyte colony-stimulating factor (G-CSF; 14.1 +/- 1.7 pg/mL before BAL and 38.5 +/- 9.7 pg/mL after BAL; p < 0.05). The increase in WBC counts and neutrophil counts was positively correlated to the increase in IL-6 (p < 0.05) and the increase in G-CSF (p < 0.05). In patients with pneumonia, IL-6 and G-CSF levels were higher after BAL than in normal volunteer subjects (p < 0.05). There was no increase in plasma concentration of IL-1beta, tumor necrosis factor-alpha, or IL-8 after BAL in normal volunteer subjects or in patients with pneumonia. FOB without BAL did not increase the WBC count, neutrophil count, or plasma cytokine levels. CONCLUSION: The BAL procedure increases the number of WBCs, and segmented and nonsegmented neutrophils in the peripheral circulation as well as circulating IL-6 and G-CSF levels.