Leukemia may cause leukopenia, but leukopenia is not necessarily caused by leukemia, it can be caused by other diseases. It is possible for a person with leukemia to have a decrease in white blood cells, but not every person with leukemia will have this condition. Red blood cells as well as platelets are reduced in leukemia patients, but white blood cells are not necessarily reduced. In the case of proliferative leukemia, the patient’s white blood cells will be elevated, and in hypoproliferative leukemia, they will be reduced. In addition, leukopenia can be caused by viral infections, autoimmune diseases, hematologic disorders, or thyroid disorders, which require prompt medical examination and treatment according to the cause.