The Pathology Dictionary Team
March 21, 2023
Neutrophils are a type of white blood cell (WBC) and a part of the body’s innate immune system. They protect the body from infection and injury. Neutrophils are the most common type of WBC accounting for between 50% and 80% of all the WBCs in the body.
Neutrophils are designed to kill and remove microorganisms such as bacteria and fungi from the body. For this reason, they are the body’s first line of defence against infection. They also help the body recover from 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.
After being formed in the bone marrow, neutrophils travel through the blood to sites of infection and injury.
Neutropenia means that the number of neutrophils in the blood is below normal. People with neutropenia are at risk for developing serious infections. Neutropenia is commonly seen in people being treated for cancer. Other conditions associated with neutropenia include autoimmune diseases and long-standing or multiple 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. Neutrophilia helps the body fight off infections and recover from injury. The number of neutrophils in the blood returns to normal once the infection or injury has gone away.