* LEUKOPENIA IS low WBC count*
Low white cell counts are associated with chemotherapy, radiation therapy, leukemia (as malignant cells overwhelm the bone marrow), myelofibrosis and aplastic anemia (failure of white and red cell creation, along with poor platelet production). In addition, many common medications can cause leukopenia (eg. minocyclen, a commonly prescribed antibiotic).
Other causes of low white blood cell count include: Influenza, systemic lupus erythematosus, Hodgkin's lymphoma, some types of cancer, typhoid, malaria, tuberculosis, dengue, Rickettsial infections, enlargement of the spleen, folate deficiencies, psittacosis and sepsis. Many other causes exist, such as a deficiency in certain minerals such as copper and zinc.
Pseudoleukopenia can develop upon the onset of infection. The leukocytes (predominately Neutrophils, responding to injury first) are marginalized in the blood vessels so that they can scan for the site of infection. This means that even though there is increased WBC production, it will appear as though it is low from a blood sample, since the blood sample is of core blood and does not include the marginalized leukocytes.
There are also reports of Leukopenia caused by Depakote (Divalproex Sodium or Valproic Acid), a drug used for epilepsy (seizures), mania (with bipolar disorder) and migraine.
^^ Straight from Wikipedia