Erythropoietin stimulates the production of red blood cells. Cytokines called interleukins also influence the production of blood cells. These can be broken down into deficiencies due to inadequate blood cell production and those due to excessive blood cell destruction or loss. These causes will be discussed below in relation to specific deficiencies. For example, leukopenia is a lack of white blood cells and neutropenia is a low level of neutrophils.
Pancytopenia refers to low levels of all types of blood cells.
Blood cell deficiencies may be the result of an autoimmune response in which a person's immune system attacks the blood-producing cells in the bone marrow. These agents damage the blood-producing cells, a condition known as bone marrow suppression or aplasia. Stem cells are particularly vulnerable to toxic drugs because they reproduce so rapidly. Damage to the bone marrow can lead to deficiencies of all types of blood cells. This list shows some of the drugs that commonly cause bone marrow suppression and blood cell deficiencies.