Leukaemia is a cancer of the blood cells. Leukaemia starts when normal healthy blood cells change and grow uncontrollably.
About blood cells
Blood cells are formed in the bone marrow, the red, spongy tissue inside the long bones in the body. Changes in the bone marrow cells can result in too few or too many specific blood cells. There are different types of blood cells –
- White blood cells that fight infection
- Red blood cells that carry oxygen throughout the body
- Platelets that help the blood to clot
Eosinophils are a type of white blood cell or leukocyte. They’re usually involved in responding to infections, especially those involving parasites, and also play a role in allergic reactions. Eosinophils typically make up less than 5 percent of all white blood cells.
Eosinophilic leukaemia is a cancer of the blood characterized by a high number of eosinophils in the blood, bone marrow, and other tissues. When levels of eosinophils are higher than usual, it’s called eosinophilia.
An average level of eosinophils is measured in a complete blood count of 350 to 500 cells per cubic millimetre (mm3). A person has eosinophilia when a complete blood count finds that eosinophil levels are above 500 mm3.
In addition to the usual effects of leukaemia, having high levels of eosinophils can also damage health. This is because eosinophils can secrete chemicals that harm various tissues and organs.
Chronic eosinophilic leukaemia usually progresses slowly and may stay the same for many years. It may change quickly into acute myelogenous leukaemia (AML) in some people.