Footnotes

• GP and OSK contributed equally.

• Contributors KIG, OSK, and GP conceived of the presented idea. OSK and GP wrote the manuscript. EK and DP performed the bronchoscopy. MI and KIG supervised the writing of the draft. All authors provided critical feedback and approved the final draft.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.