The injury: macrophages are recruited and differentiated in response to an injury. An injury is not just a physical or traumatic damage, but also infectious, toxic, ischemic, autoimmune and other types of insults. This wound evolves depending on many factors, and macrophages have an essential role in eliminating the damage and repairing the tissue. However, a delicate balance of all the factors involved dictates if an injury is effectively controlled or if it escalates and evolves into a chronic or fatal event. To complicate the picture even further, there are several types of macrophages, which can be linked to specific functions. Although several macrophage subpopulations will be involved at any given time in the resolution of an injury, it seems that a predominant type can be associated with a particular stage of the injury.
Progression or severity of the condition