Is the composition of exhaled breath condensate a key to explain the course of COVID-19 in children?

Alicja Krejner-Bienias; Katarzyna Grzela; Rafal Krenke; Katarzyna Gorska; Patrycja Nejman-Gryz; Dorota Stadnik; Ewa Kobylska; Tomasz Grzela

doi:10.5114/ada.2020.97395

Is the composition of exhaled breath condensate a key to explain the course of COVID-19 in children?

Postepy Dermatol Alergol. 2021 Dec;38(6):1001-1005. doi: 10.5114/ada.2020.97395. Epub 2020 Nov 12.

Authors

Alicja Krejner-Bienias¹, Katarzyna Grzela², Rafal Krenke³, Katarzyna Gorska³, Patrycja Nejman-Gryz³, Dorota Stadnik⁴, Ewa Kobylska⁴, Tomasz Grzela¹

Affiliations

¹ Department of Histology and Embryology, Medical University of Warsaw, Warsaw, Poland.
² Department of Paediatric Pulmonology and Allergy, Medical University of Warsaw, Warsaw, Poland.
³ Department of Internal Medicine, Pulmonary Diseases and Allergy, Medical University of Warsaw, Warsaw, Poland.
⁴ Lukasiewicz Research Network - Institute of Biotechnology and Antibiotics, Warsaw, Poland.

Abstract

Introduction: The relative resistance of children to severe course of the novel coronavirus infection remains unclear. We hypothesized that there might be a link between this phenomenon and observation from our previous studies concerning an inhibitory or cytotoxic effect of exhaled breath condensate (EBC) on endothelial cell cultures in children.

Aim: Since we could not find any data on the similar effect caused by EBC in adults, the aim of our study was to evaluate and compare the biological activity of EBC in adults and children in an experimental in vitro model. Furthermore, in order to identify a putative agent responsible for these properties of EBC in children, we attempted to analyse the composition of selected EBC samples.

Material and methods: The influence of EBC samples on metabolic activity of endothelial cell line C-166 was assessed using colorimetric tetrazolium salt reduction assay (MTT assay). Selected EBC samples were fractionated using size exclusion chromatography and subjected to mass spectrometry analysis.

Results: Exhaled breath condensates in healthy children, but not in adults, revealed a cytotoxic effect on in vitro cell cultures. This effect was most significant in condensate fraction, which contained a prominent 4.8 kDa peak in the mass spectra.

Conclusions: Breath condensates of healthy children contain the factor which reveals the inhibitory/cytotoxic effect on endothelial cell cultures. Although the physiological role of this agent remains unclear, its identification may potentially be useful in ongoing research on SARS-CoV-2/COVID-19.

Keywords: Kawasaki-like syndrome; SARS-CoV-2/COVID-19; exhaled breath condensate.