A neutrophil is a type of white blood cell (WBC) and a part of the body’s immune system. Neutrophils are designed to kill and remove micro-organisms such as bacteria and fungus from the body. Most neutrophils are found in the blood where they circulate along with other types of blood cells such as red blood cells (RBCs) and lymphocytes. Neutrophils leave the blood and enter the tissue during an infection or after an injury.
The presence of neutrophils inside tissue is a feature of acute inflammation. A group of neutrophils inside tissue is called an abscess. A large collection of dead neutrophils and bacteria is called pus.
and Neutropenia means that the number of neutrophils in the blood is below normal and people with neutropenia are at risk for developing serious infections. Neutrophilia means that the number of neutrophils in the blood is higher than normal. The most common cause of neutrophilia is an infection although it can also be caused by tissue injury.