Inflammation-, thrombosis- and autoimmune-feedback loops may lead to
persistent neutrophil self-stimulation in long COVID
Abstract
Understanding the pathophysiology of long COVID is one of the most
intriguing challenges confronting contemporary medicine.. Despite
observations recently made in the relevant molecular, cellular and
physiological domains, it is still difficult to say whether the
post-acute sequelae of COVID-19 correspond to the causes or the
consequences of SARS-CoV-2 infection. This work hypothesizes that
neutrophils and neutrophil extracellular traps (NETS) production are at
the interconnection of three positive feedback loops which are initiated
in the acute phase of SARS-CoV-2 infection, and which involve
inflammation, immunothrombosis and autoimmunity. This phenomenon could
be favored by the fact that SARS-CoV-2 may directly bind and penetrate
neutrophils. The ensuing strong neutrophil stimulation leads to a
progressive amplification of an exacerbated and uncontrolled NETs
production, potentially persisting for months beyond the acute phase of
infection. This continuous self-stimulation of neutrophils leads in turn
to systemic inflammation, micro-thromboses, and the production of
autoantibodies, whose significant consequences include the persistence
of endothelial and multi-organ damage, and vascular complications.