As the name implies, neutropenia is a decrease in the absolute value of neutrophils in the peripheral blood.
Neutrophils are the main component of white blood cells and normally make up 50% to 70% of the total peripheral blood leukocytes. A reduced white blood cell count is often a reduction in neutrophils, which can be involved in the regulation of inflammation and immune responses, and once they are reduced or even deficient, the body is extremely susceptible to infection.