Table 3.
Circulating and tissue neutrophil extracellular traps (NETs) during SARS-CoV-2 infection
| Author | Patients N | Control | RoB | |
| Middleton et al36 | 33 COVID-19 (n=28 hospitalised, n=5 convalescent) | 17 HD | ↑ circulating NETs (MPO-DNA complexes) in patients vs HD and convalescent. NET levels in tracheal aspirate fluid>in plasma samples Plasma NETs levels=in HD and recovered patients ↑ baseline NETs levels in PMNs isolated from COVID-19 patients ↓ in PMN granularity vs HD ↑ circulating platelet-neutrophil aggregates |
High |
| Veras et al37 | 32 COVID-19 (17 critical and 15 severe) | 19 HD | ↑ circulating nets ↑ NETs in the tracheal aspirate from COVID-19 patients NET levels in tracheal aspirate fluid>in plasma samples ↑ baseline NET levels in PMNs isolated from COVID-19 patients ↑ branch lengths of the released NETs |
Unclear |
| Zuo et al39 | 51 COVID-19 (27 severe, 24 mild) |
30 HD | ↑ cell-free DNA, MPO-DNA complexes, citrullinated histone H3 COVID-19 sera trigger control neutrophils to release NETs |
High |
| Leppkes et al38 | 71 COVID-19 | None | ↑ PMNs with low buoyant density, activation pattern (low L-selectin, CD62L) and partial degranulation (increased CEACAM-8, CD66b) resembling low-density granulocytes. ↑ circulating platelet-neutrophil aggregates Exhausted phenotype with ↓ spontaneous oxidative burst ↑ MPO-DNA complexes and NE-DNA complexes ↑ NE activity in the blood more than 30-fold and 60-fold |
High |
DNA, desoxyribonucleic acid; HD, healthy donor; MPO, myeloperoxidase; NE, neutrophil elastase; NETs, neutrophil extracellular traps; PMNs, polymorphonuclear neutrophils.