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Cytokines derived from alveolar macrophages induce fever after bronchoscopy and bronchoalveolar lavage
1Department of Medicine III, Charité University Hospital, Humboldt University, Berlin, Germany.
Abstract:
As much as one-third of patients develop fever and flu-like symptoms after fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) for yet unknown reasons. The aim of the present study was to investigate factors mediating these side effects. Fifty consecutive patients with various pulmonary diseases who underwent FOB without further interventions (n = 30) or combined with BAL (n = 20) were enrolled. Serum levels of the proinflammatory cytokines IL-1beta, IL-6, and TNF-alpha were determined directly prior to (t0), directly after (t1), and 6 h after (t2) the procedures by ELISA. In parallel, blood cultures were drawn at t2. At to and t1, generally only low cytokine concentrations could be detected. At t2, however, significant increases of cytokine levels were found. IL-6 and TNF-alpha were significantly higher in patients after BAL than in patients after FOB. Comparing patients who developed fever (n = 12) with those who did not (n = 38), irrespective of the endoscopic procedures performed, dramatic increases of all three cytokines were detected in febrile patients that were significantly higher than in patients without fever. In the FOB group only patients who received local anesthesia by prilocaine bolus injection into the airways via the working channel of the bronchoscope developed fever and increases of IL-6 and IL-beta, whereas patients anaesthetized by inhalation of a prilocaine aerosol remained afebrile and had slight IL-6 increases only. There was a highly significant correlation between IL-6 values at t2 and the number of BAL alveolar macrophages (r = 0.98). All blood cultures remained sterile. These results indicate that fever after FOB and BAL is induced by proinflammatory cytokines derived from alveolar macrophages activated by instillation of fluid into the airways.
Insights
Fever after fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) is linked to increased proinflammatory cytokines. These cytokines, particularly IL-6, originate from activated alveolar macrophages, especially after BAL and with specific anesthetic methods.
Area of Science:
- Pulmonology
- Immunology
- Medical Procedures
Background:
- Fever and flu-like symptoms affect up to one-third of patients post-fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL).
- The underlying mechanisms for these post-procedural side effects remain unclear.
Purpose of the Study:
- To investigate the factors mediating fever and flu-like symptoms following FOB and BAL.
- To identify specific cytokines and cellular responses associated with these adverse events.
Main Methods:
- Fifty patients undergoing FOB (n=30) or FOB with BAL (n=20) were enrolled.
- Serum levels of IL-1beta, IL-6, and TNF-alpha were measured pre-procedure, immediately after, and 6 hours post-procedure using ELISA.
- Blood cultures were obtained 6 hours post-procedure.
Main Results:
- Significant increases in IL-1beta, IL-6, and TNF-alpha were observed 6 hours post-procedure.
- Higher IL-6 and TNF-alpha levels were noted in patients after BAL compared to FOB alone.
- Febrile patients exhibited dramatically higher levels of all three cytokines compared to afebrile patients.
- Local anesthesia via prilocaine bolus injection correlated with fever and cytokine increases, unlike aerosolized anesthesia.
- IL-6 levels at 6 hours strongly correlated with the number of BAL alveolar macrophages.
Conclusions:
- Fever following FOB and BAL is induced by proinflammatory cytokines.
- Activated alveolar macrophages, stimulated by airway fluid instillation during BAL, are a likely source of these cytokines.
- The method of local anesthesia may influence the occurrence of fever and cytokine release.