Table 1. Established biomarkers for NA

Biomarkers, reference	Year	Patient recruitment	Clinical results	Key mechanisms
Spu IL-8 [15]	2001	EA (Spu Eos≥2.5%)Non-EA (Spu Neu<2.5%)	Non-EA>EACorrelation of NETs: +Spu Neu	None
Neutrophil autophagy and eDNA [18]	2016	SA1)Non-SA1)	SA>non-SACorrelation of NETs: +Autophagy –FEV1/FVC	NETs induced: ↑ Cell death and detachment ↓ Tight-junction proteins in AECs ↑ The release of IL-8 from AECs ↑ The release of ECP and EDN from eosinophils
Spu eDNA [13]	2016	NA (Spu Neu>61%)Non-NA (Spu Neu≤61%)	NA>non-NAAssociationCorrelation:+ACQ+Spu CXCL8 and IL-1β+NLRP3 gene expression–FEV1–FEV1/FVC	None
Spu eDNA [14]	2019	SA	Association:–ACT+Chronic bronchitis+Use of oral corticosteroids+NE-DNA and CitH3-DNA+Spu IL-1β and caspase-1 activityCorrelation:+Spu Neu+Spu MPO	NETs induced: The release of IL-6, IL-8, and G6PD from AECs
Spu TNFR1 and TNFR2 [80]	2021	NA (Spu Neu≥61%,Spu Eos<3%),EA (SPu Neu<61%,Spu Eos≥3%),MGA (Spu Neu≥61%,Spu Eos≥3%),PGA (Spu Neu<61%,Spu Eos<3%)	NA>EA, NA>PGAAssociation:+Asthma severity+Asthma exacerbation rates	None

NA, neutrophilic asthma; IL, interleukin; EA, eosinophilic asthma; SA, severe asthma; AEC, airway epithelial cells; TNFR, tumor necrosis factor receptor; MGA, mixed-granulocytic asthma; NET, neutrophil extracellular traps.