White blood cells, also known as leukocytes, are divided into neutrophils, eosinophils, monocytes, basophils, lymphocytes, etc. The decrease of these cells is mostly due to pathologic factors, which are more serious. 1. Neutrophils: the normal range is (4~10)×10^9/L, and its decrease can be seen in chickenpox, rubella, cytomegalovirus infection, aplastic anemia, phagocytosis syndrome, severe iron-deficiency anemia, paroxysmal sleep hemoglobinuria, bone marrow metastatic carcinoma, portal vein cirrhosis, part of lymphoma, phagocytosis syndrome, Gaucher’s disease, Niemann-Pick disease, systemic erythematous plaque, and so on. Pick’s disease, systemic lupus erythematosus and other conditions. 2. Eosinophils: the normal range is (0.05~0.5)×10^9/L, and its decrease is seen in the early stage of typhoid fever, paratyphoid fever, or the stress state such as major surgery and burns. 3. Monocytes: the normal range is (0.12~0.8)×10^9/L, and its decrease is seen in hairy cell leukemia and other conditions. In general, it has no clinical significance. 4. Basophils: the normal range is (0~0.1)×10^9/L, and its decrease has no clinical significance. 5. Lymphocytes: the normal range is (0.8~4)×10^9/L, and its decrease can be seen in the application of adrenocorticotropic hormone, radiation injury, T-lymphocyte immunodeficiency disease, and gammaglobulin deficiency. If you have a decreased white blood cell count, you should go to the hospital in time and receive diagnosis and treatment under the guidance of your physician to avoid delaying your condition.