31 May–1 June 2021, online meeting

Neutrophil 2021 showcased some of the latest developments in neutrophil biology. In keeping with the time at which it was held, the role of neutrophils in COVID-19 was a major discussion point. However, the major advance showcased by this meeting was neutrophil plasticity. Only recently has it become apparent that despite their extremely short lifespan, neutrophils comprise a range of subtypes, just like other immune cells. How neutrophils respond to their environment and the mechanisms underpinning this were demonstrated in a range of situations ranging from angiogenesis to stress. Moreover, the power of sophisticated cell surface marker analysis together with bulk- and single-cell RNAseq made it possible to deliver a step change in our understanding of neutrophil diversity and plasticity. Having attended this meeting we are left in no doubt: neutrophils are not just indiscriminate killers that are indispensable for host immunity but can, if dysregulated, cause important host damage. In addition, neutrophils are highly plastic cells that not only cross-talk with other (immune) cells, but can even take on some of their characteristics.