White blood cells, also called leukocytes, move throughout the bloodstream and perform many critical functions. Most of those functions relate to immunity. When the immune system detects a virus or bacterium, it releases chemicals that attract white blood cells. The leukocytes destroy the invaders. Too few white blood cells cause many health problems. Most healthy people produce millions of new white blood cells every day. However, many conditions may cause a low white blood cell count.
1. Bone Marrow Disorders
The bone marrow is in the center of the body’s long bones, such as the femur. It creates the immature cells that eventually mature into all of the types of blood cells, including leukocytes. A low white blood cell count may develop when there’s a problem with the bone marrow. Infections may interfere with the marrow’s ability to produce new cells. Cancers of the bone marrow may interfere with the maturation of blood cells, so the immature cells never mature into white blood cells. The marrow becomes filled with the cancerous cells, so it can’t do its job. Some cancer treatments, such as radiation, damage the bone marrow and interrupt its production of new white blood cells.