Chronic refractory cough (CRC) is characterised by cough hypersensitivity. Interferon-γ (IFN-γ) has been reported to induce calcium influx, action potentials of vagal neurons in vitro and cough response in guinea pigs. While the effect of IFN-γ in CRC patients remains unknown. Here, via flow-cytometry and inhalation cough challenge, we found CRC patients had significantly increased levels of sputum IFN-γ+CD4+ T cells, IFN-γ+CD8+ T cells as well as supernatant of IFN-γ. The average number of coughs in CRC patients increased as the concentration of inhaled IFN-γ went up in IFN-γ cough challenge. Two or more coughs and five or more coughs elicited by inhaled IFN-γ in CRC patients occurred in 7 of 10 and 2 of 10, respectively. Preinhaled IFN-γ (100 µg/mL) increased the capsaicin cough sensitivity in CRC patients but not healthy volunteers. Targeting IFN-γ may be a potential effective anti-tussive strategy in CRC patients.
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JS, CZ and ZD are joint first authors.
JS, CZ and ZD contributed equally.
Contributors JS contributed to data collection, data analysis, draft and interpretation, revising of the submitted manuscript. CZ and ZD contributed to data analysis, draft and interpretation, revising of the submitted manuscript. WL and QC contributed to sputum induction and differential cell count. MJ contributed to data analysis and interpretation. KL and NZ contributed to study concept, design, manuscript preparation and critical review. All authors provided review of the manuscript and approved its submission.
Funding This study was supported by the National Natural Science Foundation ofChina (Award number: 81270151, 81100028, 81970013).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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