Journal of Allergy and Clinical Immunology: Global (Feb 2025)

Effect of prednisone on woodsmoke-induced sputum inflammation in healthy volunteers: A randomized, placebo-controlled pilot study

  • Terry L. Noah, MD,
  • Neil E. Alexis, PhD,
  • William D. Bennett, PhD,
  • Michelle L. Hernandez, MD,
  • Allison J. Burbank, MD,
  • Haolin Li, PhD,
  • Haibo Zhou, PhD,
  • Ilona Jaspers, PhD,
  • David B. Peden, MD, MS

Journal volume & issue
Vol. 4, no. 1
p. 100347

Abstract

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Background: Inhalation of biomass smoke is associated with adverse respiratory effects in those with chronic pulmonary conditions. There are few published data regarding the effects of anti-inflammatory interventions on these outcomes. Objective: Our aim was to assess the effects of postexposure prednisone on woodsmoke (WS)-induced sputum neutrophilia. Methods: We carried out a randomized, placebo-controlled, crossover pilot study assessing the effect of a postexposure dose of 60 mg prednisone on induced sputum inflammation after controlled exposure to WS (500 μg/m3 for 2 hours) in healthy adults who had been identified in a separate screening protocol as being “PMN responsive” to WS. Secondary end points were sputum cytokine level and mucociliary clearance as measured by γ-scintigraphy. Results: A total of 11 subjects yielded complete data for the primary analysis. At 24 hours after WS exposure, there was a significant increase in sputum percentage of PMNs (%PMN) versus at baseline after placebo (median = 42% [IQR = 31%-53%]) (P = .02) but not after prednisone (median = 32% [IQR = 18%-40%]) (P = .09). Prednisone reduced Δ%PMN at 24 hours, but this difference did not reach statistical significance. However, for the 8 of 11 subjects who were PMN responsive after placebo, prednisone reduced Δ%PMN significantly (P = .05). Prednisone had no significant effects on sputum levels of IL-1β, IL-6, IL-8, or TNF-α. WS exposure tended to reduce mucociliary clearance in the placebo arm but not in the prednisone arm. Conclusions: Prednisone taken immediately after exposure to WS mitigated short-term increase in sputum %PMN among healthy volunteers selected for their underlying inflammatory responsiveness to WS. Our data support future studies assessing anti-inflammatory interventions and the role of mucus clearance in WS-induced respiratory health effects.

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