Hyperactivity of the immune system is a
In a normal immune response, upon the intrusion of a foreign entity into the blood stream, first responders – macrophages and dendritic cells – are rushed in. Upon arrival, they release alert signals – cytokines – that in turn call in specialized immune cells aimed at destroying the invader. This attack by specialized immune cells results in a large population of dying cells, which are devoured by macrophages through a series of special cell-to-cell signalling. This devouring serves two purposes: a) it clears the blood stream of dying cells, and b) it serves as a relaxation signal for the first responders, who then set off a series of signals that send the immune system back into its normal, balanced state.
Hyperactivity of the immune system, referred to as a cytokine storm or Cytokine Release Syndrome (CRS), is a systemic inflammatory response in which cytokine release spirals out of control, leading to severe immune attacks on multiple healthy organs, which may result in organ damage, multiple organ failure, and mortality
A cytokine storm can be triggered by factors such as viral, bacterial and fungal infections, i.e. sepsis – as well as by complications following bone-marrow transplantations, i.e., GvHD.